[PATCH V3 2/3] sim: eBPF simulator

Jose E. Marchesi jose.marchesi@oracle.com
Fri Jul 3 12:46:49 GMT 2020


This patch introduces the basics of an instruction-simulator for eBPF.
The simulator is based on CGEN.

sim/ChangeLog:

2020-07-03  Jose E. Marchesi  <jose.marchesi@oracle.com>
	    David Faust <david.faust@oracle.com>

	* configure.tgt (sim_arch): Add entry for bpf-*-*.
	* configure: Regenerate.
	* MAINTAINERS: Add maintainer for the BPF simulator.
	* bpf/Makefile.in: New file.
	* bpf/bpf-helpers.c: Likewise.
	* bpf/bpf-helpers.def: Likewise.
	* bpf/bpf-helpers.h: Likewise.
	* bpf/bpf-sim.h: Likewise.
	* bpf/bpf.c: Likewise.
	* bpf/config.in: Likewise.
	* bpf/configure.ac: Likewise.
	* bpf/decode.h: Likewise.
	* bpf/eng.h: Likewise.
	* bpf/mloop.in: Likewise.
	* bpf/sim-if.c: Likewise.
	* bpf/sim-main.h: Likewise.
	* bpf/traps.c: Likewise.

sim/testsuite/ChangeLog:

2020-07-03  David Faust  <david.faust@oracle.com>
	    Jose E. Marchesi  <jose.marchesi@oracle.com>

	* configure: Regenerate.
	* sim/bpf/allinsn.exp: New file.
	* sim/bpf/alu.s: Likewise.
	* sim/bpf/alu32.s: Likewise.
	* sim/bpf/endbe.s: Likewise.
	* sim/bpf/endle.s: Likewise.
	* sim/bpf/jmp.s: Likewise.
	* sim/bpf/jmp32.s: Likewise.
	* sim/bpf/ldabs.s: Likewise.
	* sim/bpf/mem.s: Likewise.
	* sim/bpf/mov.s: Likewise.
	* sim/bpf/testutils.inc: Likewise.
	* sim/bpf/xadd.s: Likewise.
---
 sim/ChangeLog                       |  21 ++
 sim/MAINTAINERS                     |   1 +
 sim/bpf/Makefile.in                 | 205 +++++++++++++++++
 sim/bpf/bpf-helpers.c               | 175 +++++++++++++++
 sim/bpf/bpf-helpers.def             | 194 +++++++++++++++++
 sim/bpf/bpf-helpers.h               |  31 +++
 sim/bpf/bpf-sim.h                   |  31 +++
 sim/bpf/bpf.c                       | 327 ++++++++++++++++++++++++++++
 sim/bpf/config.in                   | 248 +++++++++++++++++++++
 sim/bpf/configure.ac                |  13 ++
 sim/bpf/decode.h                    |  37 ++++
 sim/bpf/eng.h                       |  24 ++
 sim/bpf/mloop.in                    | 165 ++++++++++++++
 sim/bpf/sim-if.c                    | 216 ++++++++++++++++++
 sim/bpf/sim-main.h                  |  51 +++++
 sim/bpf/traps.c                     |  33 +++
 sim/configure                       |  22 +-
 sim/configure.tgt                   |   3 +
 sim/testsuite/ChangeLog             |  17 ++
 sim/testsuite/configure             |  23 +-
 sim/testsuite/sim/bpf/allinsn.exp   |  26 +++
 sim/testsuite/sim/bpf/alu.s         | 109 ++++++++++
 sim/testsuite/sim/bpf/alu32.s       |  99 +++++++++
 sim/testsuite/sim/bpf/endbe.s       |  46 ++++
 sim/testsuite/sim/bpf/endle.s       |  43 ++++
 sim/testsuite/sim/bpf/jmp.s         | 120 ++++++++++
 sim/testsuite/sim/bpf/jmp32.s       | 120 ++++++++++
 sim/testsuite/sim/bpf/ldabs.s       |  87 ++++++++
 sim/testsuite/sim/bpf/mem.s         |  56 +++++
 sim/testsuite/sim/bpf/mov.s         |  54 +++++
 sim/testsuite/sim/bpf/testutils.inc |  38 ++++
 sim/testsuite/sim/bpf/xadd.s        |  44 ++++
 32 files changed, 2674 insertions(+), 5 deletions(-)
 create mode 100644 sim/bpf/Makefile.in
 create mode 100644 sim/bpf/bpf-helpers.c
 create mode 100644 sim/bpf/bpf-helpers.def
 create mode 100644 sim/bpf/bpf-helpers.h
 create mode 100644 sim/bpf/bpf-sim.h
 create mode 100644 sim/bpf/bpf.c
 create mode 100644 sim/bpf/config.in
 create mode 100644 sim/bpf/configure.ac
 create mode 100644 sim/bpf/decode.h
 create mode 100644 sim/bpf/eng.h
 create mode 100644 sim/bpf/mloop.in
 create mode 100644 sim/bpf/sim-if.c
 create mode 100644 sim/bpf/sim-main.h
 create mode 100644 sim/bpf/traps.c
 create mode 100644 sim/testsuite/sim/bpf/allinsn.exp
 create mode 100644 sim/testsuite/sim/bpf/alu.s
 create mode 100644 sim/testsuite/sim/bpf/alu32.s
 create mode 100644 sim/testsuite/sim/bpf/endbe.s
 create mode 100644 sim/testsuite/sim/bpf/endle.s
 create mode 100644 sim/testsuite/sim/bpf/jmp.s
 create mode 100644 sim/testsuite/sim/bpf/jmp32.s
 create mode 100644 sim/testsuite/sim/bpf/ldabs.s
 create mode 100644 sim/testsuite/sim/bpf/mem.s
 create mode 100644 sim/testsuite/sim/bpf/mov.s
 create mode 100644 sim/testsuite/sim/bpf/testutils.inc
 create mode 100644 sim/testsuite/sim/bpf/xadd.s

diff --git a/sim/MAINTAINERS b/sim/MAINTAINERS
index 4ca67cfd1d..7dcd88422c 100644
--- a/sim/MAINTAINERS
+++ b/sim/MAINTAINERS
@@ -17,6 +17,7 @@ aarch64	        Nick Clifton <nickc@redhat.com>
 aarch64	        Jim Wilson <wilson@tuliptree.org>
 arm	        Nick Clifton <nickc@redhat.com>
 bfin		Mike Frysinger <vapier@gentoo.org>
+bpf		Jose E. Marchesi <jose.marchesi@oracle.com>
 cr16	        M R Swami Reddy <MR.Swami.Reddy@nsc.com>
 frv		Dave Brolley <brolley@redhat.com>
 ft32		James Bowman <james.bowman@ftdichip.com>
diff --git a/sim/bpf/Makefile.in b/sim/bpf/Makefile.in
new file mode 100644
index 0000000000..b12bb6a7d5
--- /dev/null
+++ b/sim/bpf/Makefile.in
@@ -0,0 +1,205 @@
+# Makefile template for configure for the eBPF simulator
+# Copyright (C) 2019 Free Software Foundation, Inc.
+#
+# This file is part of GDB, the GNU debugger.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+## COMMON_PRE_CONFIG_FRAG
+
+CGEN_STD_OBJS = cgen-run.o cgen-scache.o cgen-trace.o cgen-utils.o
+BPF_GEN_OBJS = arch.o cpu.o \
+               decode-le.o decode-be.o \
+               sem-le.o sem-be.o \
+               mloop-le.o mloop-be.o
+BPF_HAND_OBJS = bpf.o sim-if.o traps.o bpf-helpers.o
+
+SIM_OBJS = \
+	$(SIM_NEW_COMMON_OBJS) \
+	$(CGEN_STD_OBJS) \
+	$(BPF_GEN_OBJS) \
+	$(BPF_HAND_OBJS)
+
+SIM_EXTRA_DEPS = \
+	$(CGEN_INCLUDE_DEPS) \
+	arch.h \
+	bpf-sim.h \
+	$(srcdir)/../../opcodes/bpf-desc.h \
+	$(srcdir)/../../opcodes/bpf-opc.h
+
+SIM_EXTRA_CLEAN = bpf-clean
+
+## COMMON_POST_CONFIG_FRAG
+
+# cgen support, enable with --enable-cgen-maint
+CGEN_MAIN = ; @true
+# The following line is commented in or out depending upon --enable-cgen-maint.
+@CGEN_MAINT@CGEN_MAINT = 
+
+# BPF headers
+
+BPF_INCLUDE_DEPS = \
+	$(CGEN_MAIN_CPU_DEPS) \
+	$(SIM_EXTRA_DEPS) \
+	cpu.h cpuall.h \
+        decode-le.h decode-be.h \
+        defs-le.h defs-be.h \
+        eng-le.h eng-be.h \
+        config.h
+
+# Dependencies for binaries from CGEN generated source
+
+arch.o: arch.c $(SIM_MAIN_DEPS)
+cpu.o: cpu.c $(BPF_INCLUDE_DEPS)
+decode-le.o: decode-le.c $(BPF_INCLUDE_DEPS)
+decode-be.o: decode-be.c $(BPF_INCLUDE_DEPS)
+# XXX sem-switch.o: sem-switch.c $(BPF_INCLUDE_DEPS)
+# XXX model.o: model.c $(BPF_INCLUDE_DEPS)
+
+sim-if.o: sim-if.c $(SIM_MAIN_DEPS) $(srcdir)/../common/sim-core.h eng.h
+	$(COMPILE) $<
+	$(POSTCOMPILE)
+
+traps.o: traps.c $(SIM_MAIN_DEPS) eng.h
+	$(COMPILE) $<
+	$(POSTCOMPILE)
+
+mloop-le.o: mloop-le.c $(BPF_INCLUDE_DEPS)
+	$(CC) -c mloop-le.c $(ALL_CFLAGS) -DWANT_ISA_EBPFLE
+mloop-be.o: mloop-be.c $(BPF_INCLUDE_DEPS)
+	$(CC) -c mloop-be.c $(ALL_CFLAGS) -DWANT_ISA_EBPFBE
+
+decode-le.o: decode-le.c $(BPF_INCLUDE_DEPS)
+	$(CC) -c $(srcdir)/decode-le.c $(ALL_CFLAGS) -DWANT_ISA_EBPFLE
+decode-be.o: decode-be.c $(BPF_INCLUDE_DEPS)
+	$(CC) -c $(srcdir)/decode-be.c $(ALL_CFLAGS) -DWANT_ISA_EBPFBE
+
+sem-le.o: sem-le.c $(BPF_INCLUDE_DEPS)
+	$(CC) -c $(srcdir)/sem-le.c $(ALL_CFLAGS) -DWANT_ISA_EBPFLE
+sem-be.o: sem-be.c $(BPF_INCLUDE_DEPS)
+	$(CC) -c $(srcdir)/sem-be.c $(ALL_CFLAGS) -DWANT_ISA_EBPFBE
+
+arch = bpf
+
+CGEN_COMMON_DEPS = \
+	$(CGEN_READ_SCM) \
+	$(srcdir)/../../cpu/bpf.cpu \
+	$(srcdir)/../../cpu/bpf.opc \
+	Makefile
+
+stamp-arch: $(CGEN_COMMON_DEPS) $(CGEN_ARCH_SCM)
+	$(MAKE) cgen-arch $(CGEN_FLAGS_TO_PASS) \
+		mach=bpf cpu=bpfbf \
+		archfile=$(srcdir)/../../cpu/bpf.cpu \
+		FLAGS="with-scache"
+	touch $@
+$(srcdir)/arch.h $(srcdir)/arch.c $(srcdir)/cpuall.h: $(CGEN_MAINT) stamp-arch
+	@true
+
+stamp-cpu: $(CGEN_COMMON_DEPS) $(CGEN_CPU_SCM)
+	$(MAKE) cgen-cpu  $(CGEN_FLAGS_TO_PASS) \
+		isa=ebpfle,ebpfbe cpu=bpfbf mach=bpf \
+		archfile=$(srcdir)/../../cpu/bpf.cpu \
+		FLAGS="with-multiple-isa with-scache"
+	rm -f $(srcdir)/model.c
+	touch $@
+$(srcdir)/cpu.h $(srcdir)/cpu.c $(srcdir)/model.c: $(CGEN_MAINT) stamp-cpu
+	@true
+
+# We need to generate a group of files per ISA.
+# For eBPF little-endian:
+#    defs-le.h
+#    sem-le.c, decode-le.c, decode-le.h
+#    $(objdir)/mloop-le.c $(objdir)/eng-le.h
+# For eBPF big-endian:
+#    defs-be.h
+#    sem-be.c, decode-be.c, decode-be.h
+#    $(objdir)/mloop-be.c $(objdir)/eng-le.h
+#
+# The rules below take care of that.
+
+stamp-defs-le: $(CGEN_COMMON_DEPS) $(CGEN_CPU_SCM)
+	$(MAKE) cgen-defs $(CGEN_FLAGS_TO_PASS) \
+		isa=ebpfle cpu=bpfbf mach=bpf \
+		archfile=$(srcdir)/../../cpu/bpf.cpu \
+		FLAGS="with-scache" \
+                SUFFIX="-le"
+	touch $@
+$(srcdir)/defs-le.h: $(CGEN_MAINT) stamp-defs-le
+	@true
+
+
+stamp-defs-be: $(CGEN_COMMON_DEPS) $(CGEN_CPU_SCM)
+	$(MAKE) cgen-defs $(CGEN_FLAGS_TO_PASS) \
+		isa=ebpfbe cpu=bpfbf mach=bpf \
+		archfile=$(srcdir)/../../cpu/bpf.cpu \
+		FLAGS="with-scache" \
+                SUFFIX="-be"
+	touch $@
+$(srcdir)/defs-be.h: $(CGEN_MAINT) stamp-defs-be
+	@true
+
+stamp-decode-le: $(CGEN_COMMON_DEPS) $(CGEN_CPU_SCM) $(GEN_DECODE_SCM)
+	$(MAKE) cgen-decode $(CGEN_FLAGS_TO_PASS) \
+		isa=ebpfle cpu=bpfbf mach=bpf \
+		archfile=$(srcdir)/../../cpu/bpf.cpu \
+		FLAGS="with-scache" \
+                SUFFIX="-le" \
+		EXTRAFILES="$(CGEN_CPU_SEM)"
+	touch $@
+$(srcdir)/sem-le.c $(srcdir)/decode-le.c $(srcdir)/decode-le.h: \
+              $(CGEN_MAINT) stamp-decode-le
+	@true
+
+
+stamp-decode-be: $(CGEN_COMMON_DEPS) $(CGEN_CPU_SCM) $(GEN_DECODE_SCM)
+	$(MAKE) cgen-decode $(CGEN_FLAGS_TO_PASS) \
+		isa=ebpfbe cpu=bpfbf mach=bpf \
+		archfile=$(srcdir)/../../cpu/bpf.cpu \
+		FLAGS="with-scache" \
+                SUFFIX="-be" \
+		EXTRAFILES="$(CGEN_CPU_SEM)"
+	touch $@
+$(srcdir)/sem-be.c $(srcdir)/decode-be.c $(srcdir)/decode-be.h: \
+              $(CGEN_MAINT) stamp-decode-be
+	@true
+
+# Note the following files are generated in objdir, not srcdir.
+
+stamp-mloop: stamp-mloop-le stamp-mloop-be
+
+stamp-mloop-le: $(srcdir)/../common/genmloop.sh mloop.in Makefile
+	$(SHELL) $(srccom)/genmloop.sh -shell $(SHELL) \
+		-mono -scache -prefix bpfbf_ebpfle -cpu bpfbf \
+                -infile $(srcdir)/mloop.in
+	$(SHELL) $(srcroot)/move-if-change eng.hin eng-le.h
+	$(SHELL) $(srcroot)/move-if-change mloop.cin mloop-le.c
+	touch $@
+mloop-le.c eng-le.h: stamp-mloop-le
+	@true
+
+stamp-mloop-be: $(srcdir)/../common/genmloop.sh mloop.in Makefile
+	$(SHELL) $(srccom)/genmloop.sh -shell $(SHELL) \
+		-mono -scache -prefix bpfbf_ebpfbe -cpu bpfbf \
+                -infile $(srcdir)/mloop.in
+	$(SHELL) $(srcroot)/move-if-change eng.hin eng-be.h
+	$(SHELL) $(srcroot)/move-if-change mloop.cin mloop-be.c
+	touch $@
+mloop-be.c eng-be.h: stamp-mloop-be
+	@true
+
+.PHONY = bpf-clean
+
+bpf-clean:
+	rm -f stamp-arch stamp-cpu stamp-decode stamp-defs stamp-mloop
diff --git a/sim/bpf/bpf-helpers.c b/sim/bpf/bpf-helpers.c
new file mode 100644
index 0000000000..8d979e0fe0
--- /dev/null
+++ b/sim/bpf/bpf-helpers.c
@@ -0,0 +1,175 @@
+/* Emulation of eBPF helpers.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   This file is part of GDB, the GNU debugger.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* BPF programs rely on the existence of several helper functions,
+   which are provided by the kernel.  This simulator provides an
+   implementation of the helpers, which can be customized by the
+   user.  */
+
+#define WANT_CPU_BPFBF
+#define WANT_CPU bpfbf
+
+#include "sim-main.h"
+#include "cgen-mem.h"
+#include "cgen-ops.h"
+#include "cpu.h"
+
+/* bpf_trace_printk is a printk-like facility for debugging.
+
+   In the kernel, it appends a line to the Linux's tracing debugging
+   interface.
+
+   In this simulator, it uses the simulator's tracing interface
+   instead.
+
+   The format tags recognized by this helper are:
+   %d, %i, %u, %x, %ld, %li, %lu, %lx, %lld, %lli, %llu, %llx,
+   %p, %s
+   
+   A maximum of three tags are supported.
+
+   This helper returns the number of bytes written, or a negative
+   value in case of failure.  */
+
+int
+bpf_trace_printk (SIM_CPU *current_cpu)
+{ 
+  va_list ap;
+  SIM_DESC sd = CPU_STATE (current_cpu);
+
+  DI fmt_address;
+  uint32_t size, tags_processed;
+  size_t i, bytes_written = 0;
+
+  /* The first argument is the format string, which is passed as a
+     pointer in %r1.  */
+  fmt_address = GET_H_GPR (1);
+  
+  /* The second argument is the length of the format string, as an
+     unsigned 32-bit number in %r2.  */
+  size = GET_H_GPR (2);
+
+  /* Read the format string from the memory pointed by %r2, printing
+     out the stuff as we go.  There is a maximum of three format tags
+     supported, which are read from %r3, %r4 and %r5 respectively.  */
+  for (i = 0, tags_processed = 0; i < size;)
+    {
+      QI c = GETMEMUQI (current_cpu, CPU_PC_GET (current_cpu),
+                        fmt_address + i);
+
+      switch (c)
+        {
+        case '%':
+          /* Check we are not exceeding the limit of three format
+             tags.  */
+          if (tags_processed > 2)
+            return -1; /* XXX look for kernel error code.  */
+          
+          /* Depending on the kind of tag, extract the value from the
+             proper argument.  */
+          if (i++ >= size)
+            return -1; /* XXX look for kernel error code.  */
+
+          UDI value = GET_H_GPR (3 + tags_processed);
+
+          switch ((GETMEMUQI (current_cpu, CPU_PC_GET (current_cpu),
+                             fmt_address + i)))
+            {
+            case 'd':
+              trace_printf (sd, current_cpu, "%d", value);
+              break;
+            case 'i':
+              trace_printf (sd, current_cpu, "%i", value);
+              break;
+            case 'u':
+              trace_printf (sd, current_cpu, "%u", value);
+              break;
+            case 'x':
+              trace_printf (sd, current_cpu, "%x", value);
+              break;
+            case 'l':
+              {
+                if (i++ >= size)
+                  return -1;
+                switch (GETMEMUQI (current_cpu, CPU_PC_GET (current_cpu),
+                             fmt_address + i))
+                  {
+                  case 'd':
+                    trace_printf (sd, current_cpu, "%ld", value);
+                    break;
+                  case 'i':
+                    trace_printf (sd, current_cpu, "%li", value);
+                    break;
+                  case 'u':
+                    trace_printf (sd, current_cpu, "%lu", value);
+                    break;
+                  case 'x':
+                    trace_printf (sd, current_cpu, "%lx", value);
+                    break;
+                  case 'l':
+                    {
+                      if (i++ >= size)
+                        return -1;
+                      switch (GETMEMUQI (current_cpu, CPU_PC_GET (current_cpu),
+                                fmt_address + i)) {
+                        case 'd':
+                          trace_printf (sd, current_cpu, "%lld", value);
+                          break;
+                        case 'i':
+                          trace_printf (sd, current_cpu, "%lli", value);
+                          break;
+                        case 'u':
+                          trace_printf (sd, current_cpu, "%llu", value);
+                          break;
+                        case 'x':
+                          trace_printf (sd, current_cpu, "%llx", value);
+                          break;
+                        default:
+                          assert (0);
+                          break;
+                      }
+                      break;
+                    }
+                  default:
+                    assert (0);
+                    break;
+                }
+                break;
+              }
+            default:
+              /* XXX completeme */
+              assert (0);
+              break;
+            }
+
+          tags_processed++;
+          i++;
+          break;
+        case '\0':
+          i = size;
+          break;
+        default:
+          trace_printf (sd, current_cpu, "%c", c);
+          bytes_written++;
+          i++;
+          break;
+        }
+    }
+  
+  return bytes_written;
+}
diff --git a/sim/bpf/bpf-helpers.def b/sim/bpf/bpf-helpers.def
new file mode 100644
index 0000000000..6106ac794a
--- /dev/null
+++ b/sim/bpf/bpf-helpers.def
@@ -0,0 +1,194 @@
+/* BPF helpers database.
+   Copyright (C) 2019-2020 Free Software Foundation, Inc.
+
+This file is part of the GNU simulator.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+/* This file contains the definition of the helpers that are available
+   to BPF programs.
+
+   The primary source for information on kernel helpers is the
+   linux/include/uapi/linux/bpf.h file in the Linux source tree.
+   Please keep this database in sync.
+
+   The first column is the first kernel version featuring the helper
+   function.  This should be an enumerate from bpf_kernel_version,
+   defined in bpf-opts.h.  Note that the backend assumes that helpers
+   never get deprecated in the kernel.  If that eventually happens,
+   then we will need to use a bitmask here instead of an enumerate.
+
+   The second column is the constant-name for the helper.
+   The third column is the program-name of the helper.
+
+   The fourth column is a list of names describing the types of the
+   values returned and accepted by the helper, in one of these forms:
+
+     TYPES (type1, type2, ..., 0)
+     VTYPES (type1, type2, ..., 0)
+
+   VTYPES should be used should the helper accept a variable number of
+   arguments, TYPES otherwise.  The valid type names are:
+
+     `vt' for void.
+     `it' for signed int.
+     `ut' for unsigned int.
+     `pt' for void*.
+     `cpt' for const void*.
+     `st' for short int.
+     `ust' for unsigned short int.
+     `cst' for const char *.
+     `ullt' for unsigned long long.
+     `llt' for long long.
+     `u32t' for uint32.
+     `u64t' for uint64.
+  
+   In types descriptions, the firt entry corresponds to the value
+   returned by the helper.  Subsequent names correspond to the helper
+   arguments.  Finally, a 0 should close the list.
+
+   VERY IMPORTANT: the helper entries should be listed in the same
+   order than in the definition of __BPF_FUNC_MAPPER in
+   linux/include/uapi/linux/bpf.h!  */
+
+DEF_HELPER (LINUX_V4_0, MAP_LOOKUP_ELEM, map_lookup_elem, TYPES (pt, pt, pt, 0))
+DEF_HELPER (LINUX_V4_0, MAP_UPDATE_ELEM, map_update_elem, TYPES (it, pt, pt, pt, ullt, 0))
+DEF_HELPER (LINUX_V4_0, MAP_DELETE_ELEM, map_delete_elem, TYPES (it, pt, pt, 0))
+DEF_HELPER (LINUX_V4_1, PROBE_READ, probe_read, TYPES (it, pt, ut, cpt, 0))
+DEF_HELPER (LINUX_V4_1, KTIME_GET_NS, ktime_get_ns, TYPES (ullt, 0))
+DEF_HELPER (LINUX_V4_1, TRACE_PRINTK, trace_printk, VTYPES (it, cst, it, 0))
+DEF_HELPER (LINUX_V4_1, GET_PRANDOM_U32, get_prandom_u32, TYPES (ullt, 0))
+DEF_HELPER (LINUX_V4_1, GET_SMP_PROCESSOR_ID, get_smp_processor_id, TYPES (ullt, 0))
+DEF_HELPER (LINUX_V4_1, SKB_STORE_BYTES, skb_store_bytes, TYPES (it, pt, it, pt, it, it, 0))
+DEF_HELPER (LINUX_V4_1, L3_CSUM_REPLACE, l3_csum_replace, TYPES (it, pt, it, it ,it ,it, 0))
+DEF_HELPER (LINUX_V4_1, L4_CSUM_REPLACE, l4_csum_replace, TYPES (it, pt, it, it, it, it, 0))
+DEF_HELPER (LINUX_V4_2, TAIL_CALL, tail_call, TYPES (vt, pt, pt, it, 0))
+DEF_HELPER (LINUX_V4_2, CLONE_REDIRECT, clone_redirect, TYPES (it, pt, it, it, 0))
+DEF_HELPER (LINUX_V4_2, GET_CURRENT_PID_TGID, get_current_pid_tgid, TYPES (ullt, 0))
+DEF_HELPER (LINUX_V4_2, GET_CURRENT_UID_GID, get_current_uid_gid, TYPES (ullt, 0))
+DEF_HELPER (LINUX_V4_2, GET_CURRENT_COMM, get_current_comm, TYPES (it, pt, it, 0))
+DEF_HELPER (LINUX_V4_3, GET_CGROUP_CLASSID, get_cgroup_classid, TYPES (it, pt, 0))
+DEF_HELPER (LINUX_V4_3, SKB_VLAN_PUSH, skb_vlan_push, TYPES (it, pt, st, ust, 0))
+DEF_HELPER (LINUX_V4_3, SKB_VLAN_POP, skb_vlan_pop, TYPES (it, pt, 0))
+DEF_HELPER (LINUX_V4_3, SKB_GET_TUNNEL_KEY, skb_get_tunnel_key, TYPES (it, pt, pt, it, it, 0))
+DEF_HELPER (LINUX_V4_3, SKB_SET_TUNNEL_KEY, skb_set_tunnel_key, TYPES (it, pt, pt, it, it, 0))
+DEF_HELPER (LINUX_V4_3, PERF_EVENT_READ, perf_event_read, TYPES (ullt, pt, ullt, 0))
+DEF_HELPER (LINUX_V4_4, REDIRECT, redirect, TYPES (it, it, it, 0))
+DEF_HELPER (LINUX_V4_4, GET_ROUTE_REALM, get_route_realm, TYPES (ut, pt, 0))
+DEF_HELPER (LINUX_V4_4, PERF_EVENT_OUTPUT, perf_event_output, \
+	    TYPES (it, pt, pt, ullt, pt, it, 0))
+DEF_HELPER (LINUX_V4_5, SKB_LOAD_BYTES, skb_load_bytes, TYPES (it, pt, it, pt, it, 0))
+DEF_HELPER (LINUX_V4_6, GET_STACKID, get_stackid, TYPES (it, pt, pt, it, 0))
+DEF_HELPER (LINUX_V4_6, CSUM_DIFF, csum_diff, TYPES (it, pt, it, pt, it, it, 0))
+DEF_HELPER (LINUX_V4_6, SKB_GET_TUNNEL_OPT, skb_get_tunnel_opt, TYPES (it, pt, pt, it, 0))
+DEF_HELPER (LINUX_V4_6, SKB_SET_TUNNEL_OPT, skb_set_tunnel_opt, TYPES (it, pt, pt, it, 0))
+DEF_HELPER (LINUX_V4_8, SKB_CHANGE_PROTO, skb_change_proto, TYPES (it, pt, st, u64t, 0))
+DEF_HELPER (LINUX_V4_8, SKB_CHANGE_TYPE, skb_change_type, TYPES (it, pt, u32t, 0))
+DEF_HELPER (LINUX_V4_8, SKB_UNDER_CGROUP, skb_under_cgroup, TYPES (it, pt, pt, it, 0))
+DEF_HELPER (LINUX_V4_8, GET_HASH_RECALC, get_hash_recalc, TYPES (ut, pt, 0))
+DEF_HELPER (LINUX_V4_8, GET_CURRENT_TASK, get_current_task, TYPES (ullt, 0))
+DEF_HELPER (LINUX_V4_8, PROBE_WRITE_USER, probe_write_user, TYPES (it, pt, cpt, ut, 0))
+DEF_HELPER (LINUX_V4_9, CURRENT_TASK_UNDER_CGROUP, current_task_under_cgroup, \
+	    TYPES (it, pt, it, 0))
+DEF_HELPER (LINUX_V4_9, SKB_CHANGE_TAIL, skb_change_tail, TYPES (it, pt, ut, u64t, 0))
+DEF_HELPER (LINUX_V4_9, SKB_PULL_DATA, skb_pull_data, TYPES (it, pt, it, 0))
+DEF_HELPER (LINUX_V4_9, CSUM_UPDATE, csum_update, TYPES (llt, pt, u32t, 0))
+DEF_HELPER (LINUX_V4_9, SET_HASH_INVALID, set_hash_invalid, TYPES (vt, pt, 0))
+DEF_HELPER (LINUX_V4_10, GET_NUMA_NODE_ID, get_numa_node_id, TYPES (it, 0))
+DEF_HELPER (LINUX_V4_10, SKB_CHANGE_HEAD, skb_change_head, TYPES (it, pt, it, it, 0))
+DEF_HELPER (LINUX_V4_10, XDP_ADJUST_HEAD, xdp_adjust_head, TYPES (it, pt, it, 0))
+DEF_HELPER (LINUX_V4_11, PROBE_READ_STR, probe_read_str, TYPES (it, pt, u32t, cpt, 0))
+DEF_HELPER (LINUX_V4_12, GET_SOCKET_COOKIE, get_socket_cookie, TYPES (it, pt, 0))
+DEF_HELPER (LINUX_V4_12, GET_SOCKET_UID, get_socket_uid, TYPES (ut, pt, 0))
+DEF_HELPER (LINUX_V4_13, SET_HASH, set_hash, TYPES (ut, pt, u32t, 0))
+DEF_HELPER (LINUX_V4_13, SETSOCKOPT, setsockopt, TYPES (it, pt, it, it, pt, it, 0))
+DEF_HELPER (LINUX_V4_13, SKB_ADJUST_ROOM, skb_adjust_room, TYPES (it, pt, st, u32t, ullt, 0))
+DEF_HELPER (LINUX_V4_14, REDIRECT_MAP, redirect_map, TYPES (it, pt, it, it, 0))
+DEF_HELPER (LINUX_V4_14, SK_REDIRECT_MAP, sk_redirect_map, TYPES (it, pt, pt, it, it, 0))
+DEF_HELPER (LINUX_V4_14, SOCK_MAP_UPDATE, sock_map_update, TYPES (it, pt, pt, pt, ullt, 0))
+DEF_HELPER (LINUX_V4_15, XDP_ADJUST_META, xdp_adjust_meta, TYPES (it, pt, it, 0))
+DEF_HELPER (LINUX_V4_15, PERF_EVENT_READ_VALUE, perf_event_read_value,
+	    TYPES (it, pt, ullt, pt, ut, 0))
+DEF_HELPER (LINUX_V4_15, PERF_PROG_READ_VALUE, perf_prog_read_value,
+	    TYPES (it, pt, pt, ut, 0))
+DEF_HELPER (LINUX_V4_15, GETSOCKOPT, getsockopt, TYPES (it, pt, it, it, pt, it, 0))
+
+DEF_HELPER (LINUX_V4_16, OVERRIDE_RETURN, override_return, TYPES (it, pt, ult, 0))
+DEF_HELPER (LINUX_V4_16, SOCK_OPS_CB_FLAGS_SET, sock_ops_cb_flags_set, TYPES (it, pt, it, 0))
+DEF_HELPER (LINUX_V4_17, MSG_REDIRECT_MAP, msg_redirect_map, TYPES (it, pt, pt, it, it, 0))
+DEF_HELPER (LINUX_V4_17, MSG_APPLY_BYTES, msg_apply_bytes, TYPES (it, pt, it, 0))
+DEF_HELPER (LINUX_V4_17, MSG_CORK_BYTES, msg_cork_bytes, TYPES (it, pt, it, 0))
+DEF_HELPER (LINUX_V4_17, MSG_PULL_DATA, msg_pull_data, TYPES (it, pt, it, it, it, 0))
+DEF_HELPER (LINUX_V4_17, BIND, bind, TYPES (it, pt, pt, it, 0))
+DEF_HELPER (LINUX_V4_18, XDP_ADJUST_TAIL, xdp_adjust_tail, TYPES (it, pt, it, 0))
+DEF_HELPER (LINUX_V4_18, SKB_GET_XFRM_STATE,
+	    skb_get_xfrm_state, TYPES (it, pt, it, pt, it, it, 0))
+DEF_HELPER (LINUX_V4_18, GET_STACK, get_stack, TYPES (it, pt, pt, it, it, 0))
+DEF_HELPER (LINUX_V4_18, SKB_LOAD_BYTES_RELATIVE, skb_load_bytes_relative,
+	    TYPES (it, pt, it, pt, it, ut, 0))
+DEF_HELPER (LINUX_V4_18, FIB_LOOKUP, fib_lookup, TYPES (it, pt, pt, it, ut, 0))
+DEF_HELPER (LINUX_V4_18, SOCK_HASH_UPDATE, sock_hash_update, TYPES (it, pt, pt, pt, ullt, 0))
+DEF_HELPER (LINUX_V4_18, MSG_REDIRECT_HASH, msg_redirect_hash, TYPES (it, pt, pt, pt, it, 0))
+DEF_HELPER (LINUX_V4_18, SK_REDIRECT_HASH, sk_redirect_hash, TYPES (it, pt, pt, pt, it, 0))
+DEF_HELPER (LINUX_V4_18, LWT_PUSH_ENCAP, lwt_push_encap, TYPES (it, pt, ut, pt, ut, 0))
+DEF_HELPER (LINUX_V4_18, LWT_SEG6_STORE_BYTES, lwt_seg6_store_bytes,
+	    TYPES (it, pt, ut, pt, ut, 0))
+DEF_HELPER (LINUX_V4_18, LWT_SEG6_ADJUST_SRH, lwt_seg6_adjust_srh, TYPES (it, pt, ut, ut, 0))
+DEF_HELPER (LINUX_V4_18, LWT_SEG6_ACTION, lwt_seg6_action, TYPES (it, pt, ut, pt, ut, 0))
+DEF_HELPER (LINUX_V4_18, RC_REPEAT, rc_repeat, TYPES (it, pt, 0))
+DEF_HELPER (LINUX_V4_18, RC_KEYDOWN, rc_keydown, TYPES (it, pt, ut, ullt, ut, 0))
+DEF_HELPER (LINUX_V4_18, SKB_CGROUP_ID, skb_cgroup_id, TYPES (ullt, pt, 0))
+DEF_HELPER (LINUX_V4_18, GET_CURRENT_CGROUP_ID, get_current_cgroup_id, TYPES (ullt, 0))
+DEF_HELPER (LINUX_V4_19, GET_LOCAL_STORAGE, get_local_storage, TYPES (pt, pt, ullt, 0))
+DEF_HELPER (LINUX_V4_19, SK_SELECT_REUSEPORT, sk_select_reuseport,
+	    TYPES (it, pt, pt, pt, ut, 0))
+DEF_HELPER (LINUX_V4_19, SKB_ANCESTOR_CGROUP_ID, skb_ancestor_cgroup_id,
+	    TYPES (ullt, pt, it, 0))
+DEF_HELPER (LINUX_V4_20, SK_LOOKUP_TCP, sk_lookup_tcp, TYPES (pt, pt, pt, it, ullt, ullt, 0))
+DEF_HELPER (LINUX_V4_20, SK_LOOKUP_UDP, sk_lookup_udp, TYPES (pt, pt, pt, it, ullt, ullt, 0))
+DEF_HELPER (LINUX_V4_20, SK_RELEASE, sk_release, TYPES (it, pt, 0))
+DEF_HELPER (LINUX_V4_20, MAP_PUSH_ELEM, map_push_elem, TYPES (it, pt, pt, ullt, 0))
+DEF_HELPER (LINUX_V4_20, MAP_POP_ELEM, map_pop_elem, TYPES (it, pt, pt, 0))
+DEF_HELPER (LINUX_V4_20, MAP_PEEK_ELEM, map_peek_elem, TYPES (it, pt, pt, 0))
+DEF_HELPER (LINUX_V4_20, MSG_PUSH_DATA, msg_push_data, TYPES (it, pt, it, it, it, 0))
+DEF_HELPER (LINUX_V5_0, MSG_POP_DATA, msg_pop_data, TYPES (it, pt, it, it, it, 0))
+DEF_HELPER (LINUX_V5_0, RC_POINTER_REL, rc_pointer_rel, TYPES (it, pt, it, it, 0))
+DEF_HELPER (LINUX_V5_1, SPIN_LOCK, spin_lock, TYPES (vt, pt, 0))
+DEF_HELPER (LINUX_V5_1, SPIN_UNLOCK, spin_unlock, TYPES (vt, pt, 0))
+DEF_HELPER (LINUX_V5_1, SK_FULLSOCK, sk_fullsock, TYPES (pt, pt, 0))
+DEF_HELPER (LINUX_V5_1, TCP_SOCK, tcp_sock, TYPES (pt, pt, 0))
+DEF_HELPER (LINUX_V5_1, SKB_ECN_SET_CE, skb_ecn_set_ce, TYPES (it, pt, 0))
+DEF_HELPER (LINUX_V5_1, GET_LISTENER_SOCK, get_listener_sock, TYPES (pt, pt, 0))
+DEF_HELPER (LINUX_V5_2, SKC_LOOKUP_TCP, skc_lookup_tcp,
+	    TYPES (pt, pt, pt, u32t, u64t, u64t, 0))
+DEF_HELPER (LINUX_V5_2, TCP_CHECK_SYNCOOKIE, tcp_check_syncookie,
+	    TYPES (it, pt, pt, u32t, pt, u32t, 0))
+DEF_HELPER (LINUX_V5_2, SYSCTL_GET_NAME, sysctl_get_name, TYPES (it, pt, pt, ullt, u64t, 0))
+DEF_HELPER (LINUX_V5_2, SYSCTL_GET_CURRENT_VALUE, sysctl_get_current_value,
+	    TYPES (it, pt, pt, ullt, 0))
+DEF_HELPER (LINUX_V5_2, SYSCTL_GET_NEW_VALUE, sysctl_get_new_value,
+	    TYPES (it, pt, pt, ullt, 0))
+DEF_HELPER (LINUX_V5_2, SYSCTL_SET_NEW_VALUE, sysctl_set_new_value,
+	    TYPES (it, pt, pt, ullt, 0))
+DEF_HELPER (LINUX_V5_2, STRTOL, strtol, TYPES (it, cst, ullt, u64t, pt, 0))
+DEF_HELPER (LINUX_V5_2, STRTOUL, strtoul, TYPES (it, pt, ullt, u64t, pt, 0))
+DEF_HELPER (LINUX_V5_2, SK_STORAGE_GET, sk_storage_get, TYPES (pt, pt, pt, pt, u64t, 0))
+DEF_HELPER (LINUX_V5_2, SK_STORAGE_DELETE, sk_storage_delete, TYPES (it, pt, pt, 0))
+
+/*
+Local variables:
+mode:c
+End:
+*/
diff --git a/sim/bpf/bpf-helpers.h b/sim/bpf/bpf-helpers.h
new file mode 100644
index 0000000000..fe9413f266
--- /dev/null
+++ b/sim/bpf/bpf-helpers.h
@@ -0,0 +1,31 @@
+/* Emulation of eBPF helpers.  Interface.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   This file is part of GDB, the GNU debugger.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef BPF_HELPERS_H
+#define BPF_HELPERS_H
+
+enum bpf_kernel_helper
+  {
+#define DEF_HELPER(kver, name, fn, types) name,
+#include "bpf-helpers.def"
+#undef DEF_HELPER
+  };
+
+/* void bpf_trace_printk (const char *fmt); */
+
+#endif /* ! BPF_HELPERS_H */
diff --git a/sim/bpf/bpf-sim.h b/sim/bpf/bpf-sim.h
new file mode 100644
index 0000000000..6b5c275cd5
--- /dev/null
+++ b/sim/bpf/bpf-sim.h
@@ -0,0 +1,31 @@
+/* eBPF simulator support code header
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   This file is part of GDB, the GNU debugger.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef BPF_SIM_H
+#define BPF_SIM_H
+
+void bpfbf_insn_before (sim_cpu* current_cpu, SEM_PC vpc, const IDESC *idesc);
+void bpfbf_insn_after (sim_cpu* current_cpu, SEM_PC vpc, const IDESC *idesc);
+
+DI bpfbf_endbe (SIM_CPU *, DI, UINT);
+DI bpfbf_endle (SIM_CPU *, DI, UINT);
+DI bpfbf_skb_data_offset (SIM_CPU *);
+VOID bpfbf_call (SIM_CPU *, INT, UINT);
+VOID bpfbf_exit (SIM_CPU *);
+
+#endif /* ! BPF_SIM_H */
diff --git a/sim/bpf/bpf.c b/sim/bpf/bpf.c
new file mode 100644
index 0000000000..766b7ddc1c
--- /dev/null
+++ b/sim/bpf/bpf.c
@@ -0,0 +1,327 @@
+/* eBPF simulator support code
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   This file is part of GDB, the GNU debugger.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#define WANT_CPU_BPFBF
+#define WANT_CPU bpfbf
+
+#include "sim-main.h"
+#include "sim-fpu.h"
+#include "cgen-mem.h"
+#include "cgen-ops.h"
+#include "cpuall.h"
+#include "decode.h"
+
+#include "defs-le.h"  /* For SCACHE */
+
+/* It is not possible to include both defs-le.h and defs-be.h due to
+   duplicated definitions, so we need a bunch of forward declarations
+   here.  */
+extern void bpfbf_ebpfle_init_idesc_table (SIM_CPU *);
+extern void bpfbf_ebpfbe_init_idesc_table (SIM_CPU *);
+
+uint64_t skb_data_offset;
+
+IDESC *bpf_idesc_le;
+IDESC *bpf_idesc_be;
+
+
+int
+bpfbf_fetch_register (SIM_CPU *current_cpu,
+                      int rn,
+                      unsigned char *buf,
+                      int len)
+{
+  if (rn == 11)
+    SETTDI (buf, CPU_PC_GET (current_cpu));
+  else if (0 <= rn && rn < 10)
+    SETTDI (buf, GET_H_GPR (rn));
+  else
+    return 0;
+
+  return len;
+}
+
+int
+bpfbf_store_register (SIM_CPU *current_cpu,
+                      int rn,
+                      unsigned char *buf,
+                      int len)
+{
+  if (rn == 11)
+    CPU_PC_SET (current_cpu, GETTDI (buf));
+  else if (0 <= rn && rn < 10)
+    SET_H_GPR (rn, GETTDI (buf));
+  else
+    return 0;
+
+  return len;
+}
+
+void
+bpfbf_model_insn_before (SIM_CPU *current_cpu, int first_p)
+{
+  /* XXX */
+}
+
+void
+bpfbf_model_insn_after (SIM_CPU *current_cpu, int first_p)
+{
+  /* XXX */
+}
+
+
+/***** Instruction helpers.  *****/
+
+/* The semantic routines for most instructions are expressed in RTL in
+   the cpu/bpf.cpu file, and automatically translated to C in the
+   sem-*.c files in this directory.
+
+   However, some of the semantic routines make use of helper C
+   functions.  This happens when the semantics of the instructions
+   can't be expressed in RTL alone in a satisfactory way, or not at
+   all.
+
+   The following functions implement these C helpers. */
+
+DI
+bpfbf_endle (SIM_CPU *current_cpu, DI value, UINT bitsize)
+{
+  switch (bitsize)
+    {
+      case 16: return endian_h2le_2(endian_t2h_2(value));
+      case 32: return endian_h2le_4(endian_t2h_4(value));
+      case 64: return endian_h2le_8(endian_t2h_8(value));
+      default: assert(0);
+    }
+  return value;
+}
+
+DI
+bpfbf_endbe (SIM_CPU *current_cpu, DI value, UINT bitsize)
+{
+  switch (bitsize)
+    {
+      case 16: return endian_h2be_2(endian_t2h_2(value));
+      case 32: return endian_h2be_4(endian_t2h_4(value));
+      case 64: return endian_h2be_8(endian_t2h_8(value));
+      default: assert(0);
+    }
+  return value;
+}
+
+DI
+bpfbf_skb_data_offset (SIM_CPU *current_cpu)
+{
+  /* Simply return the user-configured value.
+     This will be 0 if it has not been set. */
+  return skb_data_offset;
+}
+
+
+VOID
+bpfbf_call (SIM_CPU *current_cpu, INT disp32, UINT src)
+{
+  /* eBPF supports two kind of CALL instructions: the so called pseudo
+     calls ("bpf to bpf") and external calls ("bpf to helper").
+
+     Both kind of calls use the same instruction (CALL).  However,
+     external calls are constructed by passing a constant argument to
+     the instruction, that identifies the helper, whereas pseudo calls
+     result from expressions involving symbols.
+
+     We distinguish calls from pseudo-calls with the later having a 1
+     stored in the SRC field of the instruction.  */
+
+  if (src == 1)
+    {
+      /* This is a pseudo-call.  */
+
+      /* XXX allocate a new stack frame and transfer control.  For
+         that we need to analyze the target function, like the kernel
+         verifier does.  We better populate a cache
+         (function_start_address -> frame_size) so we avoid
+         calculating this more than once.  */
+      /* XXX note that disp32 is PC-relative in number of 64-bit
+         words, _minus one_.  */
+    }
+  else
+    {
+      /* This is a call to a helper. 
+
+         DISP32 contains the helper number.  Dispatch to the
+         corresponding helper emulator in bpf-helpers.c.  */
+
+      switch (disp32) {
+        /* case TRACE_PRINTK: */
+        case 7:
+          bpf_trace_printk (current_cpu);
+          break;
+        default:;
+      }
+    }
+}
+
+VOID
+bpfbf_exit (SIM_CPU *current_cpu)
+{
+  SIM_DESC sd = CPU_STATE (current_cpu);
+
+  /*  r0 holds "return code" */
+  DI r0 = GET_H_GPR (0);
+
+  printf ("exit %ld (0x%lx)\n", r0, r0);
+
+  sim_engine_halt (sd, current_cpu, NULL, CPU_PC_GET (current_cpu),
+                   sim_exited, 0 /* sigrc */);
+}
+
+VOID
+bpfbf_breakpoint (SIM_CPU *current_cpu)
+{
+  SIM_DESC sd = CPU_STATE (current_cpu);
+
+  sim_engine_halt (sd, current_cpu, NULL, CPU_PC_GET (current_cpu),
+                   sim_stopped, SIM_SIGTRAP);
+}
+
+/* We use the definitions below instead of the cgen-generated model.c,
+   because the later is not really able to work with cpus featuring
+   several ISAs.  This should be fixed in CGEN.  */
+
+static void
+bpf_def_model_init ()
+{
+  /* Do nothing.  */
+}
+
+static void
+bpfbf_prepare_run (SIM_CPU *cpu)
+{
+  /* Nothing.  */
+}
+
+void
+bpf_engine_run_full (SIM_CPU *cpu)
+{
+  if (current_target_byte_order == BFD_ENDIAN_LITTLE)
+    {
+      if (!bpf_idesc_le)
+        {
+          bpfbf_ebpfle_init_idesc_table (cpu);
+          bpf_idesc_le = CPU_IDESC (cpu);
+        }
+      else
+        CPU_IDESC (cpu) = bpf_idesc_le;
+
+      bpfbf_ebpfle_engine_run_full (cpu);
+    }
+  else
+    {
+      if (!bpf_idesc_be)
+        {
+          bpfbf_ebpfbe_init_idesc_table (cpu);
+          bpf_idesc_be = CPU_IDESC (cpu);
+        }
+      else
+        CPU_IDESC (cpu) = bpf_idesc_be;
+
+      bpfbf_ebpfbe_engine_run_full (cpu);
+    }
+}
+
+#if WITH_FAST
+
+void
+bpf_engine_run_fast (SIM_CPU *cpu)
+{
+  if (current_target_byte_order == BFD_ENDIAN_LITTLE)
+    {
+      if (!bpf_idesc_le)
+        {
+          bpfbf_ebpfle_init_idesc_table (cpu);
+          bpf_idesc_le = CPU_IDESC (cpu);
+        }
+      else
+        CPU_IDESC (cpu) = bpf_idesc_le;
+
+      bpfbf_ebpfle_engine_run_fast (cpu);
+    }
+  else
+    {
+      if (!bpf_idesc_be)
+        {
+          bpfbf_ebpfbe_init_idesc_table (cpu);
+          bpf_idesc_be = CPU_IDESC (cpu);
+        }
+      else
+        CPU_IDESC (cpu) = bpf_idesc_be;
+
+      bpfbf_ebpfbe_engine_run_fast (cpu);
+    }
+}
+
+#endif /* WITH_FAST */
+
+static const CGEN_INSN *
+bpfbf_get_idata (SIM_CPU *cpu, int inum)
+{
+  return CPU_IDESC (cpu) [inum].idata;
+}
+
+static void
+bpf_init_cpu (SIM_CPU *cpu)
+{
+  CPU_REG_FETCH (cpu) = bpfbf_fetch_register;
+  CPU_REG_STORE (cpu) = bpfbf_store_register;
+  CPU_PC_FETCH (cpu) = bpfbf_h_pc_get;
+  CPU_PC_STORE (cpu) = bpfbf_h_pc_set;
+  CPU_GET_IDATA (cpu) = bpfbf_get_idata;
+  /* Only used by profiling.  0 disables it. */
+  CPU_MAX_INSNS (cpu) = 0;
+  CPU_INSN_NAME (cpu) = cgen_insn_name;
+  CPU_FULL_ENGINE_FN (cpu) = bpf_engine_run_full;
+#if WITH_FAST
+  CPU_FAST_ENGINE_FN (cpu) = bpf_engine_run_fast;
+#else
+  CPU_FAST_ENGINE_FN (cpu) = bpf_engine_run_full;
+#endif
+}
+
+static const SIM_MODEL bpf_models[] =
+{
+ { "bpf-def", & bpf_mach, MODEL_BPF_DEF, NULL, bpf_def_model_init },
+ { 0 }
+};
+
+static const SIM_MACH_IMP_PROPERTIES bpfbf_imp_properties =
+{
+  sizeof (SIM_CPU),
+#if WITH_SCACHE
+  sizeof (SCACHE)
+#else
+  0
+#endif
+};
+
+const SIM_MACH bpf_mach =
+{
+  "bpf", "bpf", MACH_BPF,
+  32, 32, & bpf_models[0], & bpfbf_imp_properties,
+  bpf_init_cpu,
+  bpfbf_prepare_run
+};
diff --git a/sim/bpf/config.in b/sim/bpf/config.in
new file mode 100644
index 0000000000..7c667a1c0d
--- /dev/null
+++ b/sim/bpf/config.in
@@ -0,0 +1,248 @@
+/* config.in.  Generated from configure.ac by autoheader.  */
+
+/* Define if building universal (internal helper macro) */
+#undef AC_APPLE_UNIVERSAL_BUILD
+
+/* Sim debug setting */
+#undef DEBUG
+
+/* Define to 1 if translation of program messages to the user's native
+   language is requested. */
+#undef ENABLE_NLS
+
+/* Define to 1 if you have the <dlfcn.h> header file. */
+#undef HAVE_DLFCN_H
+
+/* Define to 1 if you have the <errno.h> header file. */
+#undef HAVE_ERRNO_H
+
+/* Define to 1 if you have the <fcntl.h> header file. */
+#undef HAVE_FCNTL_H
+
+/* Define to 1 if you have the <fpu_control.h> header file. */
+#undef HAVE_FPU_CONTROL_H
+
+/* Define to 1 if you have the `ftruncate' function. */
+#undef HAVE_FTRUNCATE
+
+/* Define to 1 if you have the `getrusage' function. */
+#undef HAVE_GETRUSAGE
+
+/* Define to 1 if you have the <inttypes.h> header file. */
+#undef HAVE_INTTYPES_H
+
+/* Define to 1 if you have the `nsl' library (-lnsl). */
+#undef HAVE_LIBNSL
+
+/* Define to 1 if you have the `socket' library (-lsocket). */
+#undef HAVE_LIBSOCKET
+
+/* Define to 1 if you have the `lstat' function. */
+#undef HAVE_LSTAT
+
+/* Define to 1 if you have the <memory.h> header file. */
+#undef HAVE_MEMORY_H
+
+/* Define to 1 if you have the `mmap' function. */
+#undef HAVE_MMAP
+
+/* Define to 1 if you have the `munmap' function. */
+#undef HAVE_MUNMAP
+
+/* Define to 1 if you have the `posix_fallocate' function. */
+#undef HAVE_POSIX_FALLOCATE
+
+/* Define to 1 if you have the `sigaction' function. */
+#undef HAVE_SIGACTION
+
+/* Define to 1 if the system has the type `socklen_t'. */
+#undef HAVE_SOCKLEN_T
+
+/* Define to 1 if you have the <stdint.h> header file. */
+#undef HAVE_STDINT_H
+
+/* Define to 1 if you have the <stdlib.h> header file. */
+#undef HAVE_STDLIB_H
+
+/* Define to 1 if you have the <strings.h> header file. */
+#undef HAVE_STRINGS_H
+
+/* Define to 1 if you have the <string.h> header file. */
+#undef HAVE_STRING_H
+
+/* Define to 1 if `st_atime' is a member of `struct stat'. */
+#undef HAVE_STRUCT_STAT_ST_ATIME
+
+/* Define to 1 if `st_blksize' is a member of `struct stat'. */
+#undef HAVE_STRUCT_STAT_ST_BLKSIZE
+
+/* Define to 1 if `st_blocks' is a member of `struct stat'. */
+#undef HAVE_STRUCT_STAT_ST_BLOCKS
+
+/* Define to 1 if `st_ctime' is a member of `struct stat'. */
+#undef HAVE_STRUCT_STAT_ST_CTIME
+
+/* Define to 1 if `st_dev' is a member of `struct stat'. */
+#undef HAVE_STRUCT_STAT_ST_DEV
+
+/* Define to 1 if `st_gid' is a member of `struct stat'. */
+#undef HAVE_STRUCT_STAT_ST_GID
+
+/* Define to 1 if `st_ino' is a member of `struct stat'. */
+#undef HAVE_STRUCT_STAT_ST_INO
+
+/* Define to 1 if `st_mode' is a member of `struct stat'. */
+#undef HAVE_STRUCT_STAT_ST_MODE
+
+/* Define to 1 if `st_mtime' is a member of `struct stat'. */
+#undef HAVE_STRUCT_STAT_ST_MTIME
+
+/* Define to 1 if `st_nlink' is a member of `struct stat'. */
+#undef HAVE_STRUCT_STAT_ST_NLINK
+
+/* Define to 1 if `st_rdev' is a member of `struct stat'. */
+#undef HAVE_STRUCT_STAT_ST_RDEV
+
+/* Define to 1 if `st_size' is a member of `struct stat'. */
+#undef HAVE_STRUCT_STAT_ST_SIZE
+
+/* Define to 1 if `st_uid' is a member of `struct stat'. */
+#undef HAVE_STRUCT_STAT_ST_UID
+
+/* Define to 1 if you have the <sys/mman.h> header file. */
+#undef HAVE_SYS_MMAN_H
+
+/* Define to 1 if you have the <sys/resource.h> header file. */
+#undef HAVE_SYS_RESOURCE_H
+
+/* Define to 1 if you have the <sys/stat.h> header file. */
+#undef HAVE_SYS_STAT_H
+
+/* Define to 1 if you have the <sys/times.h> header file. */
+#undef HAVE_SYS_TIMES_H
+
+/* Define to 1 if you have the <sys/time.h> header file. */
+#undef HAVE_SYS_TIME_H
+
+/* Define to 1 if you have the <sys/types.h> header file. */
+#undef HAVE_SYS_TYPES_H
+
+/* Define to 1 if you have the `time' function. */
+#undef HAVE_TIME
+
+/* Define to 1 if you have the <time.h> header file. */
+#undef HAVE_TIME_H
+
+/* Define to 1 if you have the `truncate' function. */
+#undef HAVE_TRUNCATE
+
+/* Define to 1 if you have the <unistd.h> header file. */
+#undef HAVE_UNISTD_H
+
+/* Define to 1 if you have the <windows.h> header file. */
+#undef HAVE_WINDOWS_H
+
+/* Define to 1 if you have the `__setfpucw' function. */
+#undef HAVE___SETFPUCW
+
+/* Define to the sub-directory in which libtool stores uninstalled libraries.
+   */
+#undef LT_OBJDIR
+
+/* Name of this package. */
+#undef PACKAGE
+
+/* Define to the address where bug reports for this package should be sent. */
+#undef PACKAGE_BUGREPORT
+
+/* Define to the full name of this package. */
+#undef PACKAGE_NAME
+
+/* Define to the full name and version of this package. */
+#undef PACKAGE_STRING
+
+/* Define to the one symbol short name of this package. */
+#undef PACKAGE_TARNAME
+
+/* Define to the home page for this package. */
+#undef PACKAGE_URL
+
+/* Define to the version of this package. */
+#undef PACKAGE_VERSION
+
+/* Additional package description */
+#undef PKGVERSION
+
+/* Sim profile settings */
+#undef PROFILE
+
+/* Bug reporting address */
+#undef REPORT_BUGS_TO
+
+/* Define as the return type of signal handlers (`int' or `void'). */
+#undef RETSIGTYPE
+
+/* Define to 1 if you have the ANSI C header files. */
+#undef STDC_HEADERS
+
+/* Enable extensions on AIX 3, Interix.  */
+#ifndef _ALL_SOURCE
+# undef _ALL_SOURCE
+#endif
+/* Enable GNU extensions on systems that have them.  */
+#ifndef _GNU_SOURCE
+# undef _GNU_SOURCE
+#endif
+/* Enable threading extensions on Solaris.  */
+#ifndef _POSIX_PTHREAD_SEMANTICS
+# undef _POSIX_PTHREAD_SEMANTICS
+#endif
+/* Enable extensions on HP NonStop.  */
+#ifndef _TANDEM_SOURCE
+# undef _TANDEM_SOURCE
+#endif
+/* Enable general extensions on Solaris.  */
+#ifndef __EXTENSIONS__
+# undef __EXTENSIONS__
+#endif
+
+
+/* Sim assert settings */
+#undef WITH_ASSERT
+
+/* Sim debug setting */
+#undef WITH_DEBUG
+
+/* Sim default environment */
+#undef WITH_ENVIRONMENT
+
+/* Sim profile settings */
+#undef WITH_PROFILE
+
+/* How to route I/O */
+#undef WITH_STDIO
+
+/* Sim trace settings */
+#undef WITH_TRACE
+
+/* Define WORDS_BIGENDIAN to 1 if your processor stores words with the most
+   significant byte first (like Motorola and SPARC, unlike Intel). */
+#if defined AC_APPLE_UNIVERSAL_BUILD
+# if defined __BIG_ENDIAN__
+#  define WORDS_BIGENDIAN 1
+# endif
+#else
+# ifndef WORDS_BIGENDIAN
+#  undef WORDS_BIGENDIAN
+# endif
+#endif
+
+/* Define to 1 if on MINIX. */
+#undef _MINIX
+
+/* Define to 2 if the system does not provide POSIX.1 features except with
+   this defined. */
+#undef _POSIX_1_SOURCE
+
+/* Define to 1 if you need to in order for `stat' and other things to work. */
+#undef _POSIX_SOURCE
diff --git a/sim/bpf/configure.ac b/sim/bpf/configure.ac
new file mode 100644
index 0000000000..16ca54e86c
--- /dev/null
+++ b/sim/bpf/configure.ac
@@ -0,0 +1,13 @@
+dnl Process this file with autoconf to produce a configure script.
+AC_INIT(Makefile.in)
+sinclude(../common/acinclude.m4)
+
+SIM_AC_COMMON
+
+SIM_AC_OPTION_ENDIAN([], [LITTLE])
+SIM_AC_OPTION_ALIGNMENT(NONSTRICT_ALIGNMENT)
+SIM_AC_OPTION_SCACHE(16384)
+SIM_AC_OPTION_DEFAULT_MODEL([bpf-def])
+SIM_AC_OPTION_CGEN_MAINT
+
+SIM_AC_OUTPUT
diff --git a/sim/bpf/decode.h b/sim/bpf/decode.h
new file mode 100644
index 0000000000..74d31cbdfe
--- /dev/null
+++ b/sim/bpf/decode.h
@@ -0,0 +1,37 @@
+/* Decode declarations.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   Contributed by Oracle, Inc.
+
+This file is part of the GNU simulators.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Include declarations for eBPF LE and eBPF BE ISAs. */
+
+#ifndef DECODE_H
+#define DECODE_H
+
+#undef WITH_PROFILE_MODEL_P
+
+#ifdef WANT_ISA_EBPFLE
+#include "decode-le.h"
+#include "defs-le.h"
+#endif /* WANT_ISA_EBPFLE */
+
+#ifdef WANT_ISA_EBPFBE
+#include "decode-be.h"
+#include "defs-be.h"
+#endif /* WANT_ISA_EBPFBE */
+
+#endif /* DECODE_H */
diff --git a/sim/bpf/eng.h b/sim/bpf/eng.h
new file mode 100644
index 0000000000..08e29f99a8
--- /dev/null
+++ b/sim/bpf/eng.h
@@ -0,0 +1,24 @@
+/* Engine declarations.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   Contributed by Oracle, Inc.
+
+This file is part of the GNU simulators.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Include declarations for eBPF LE and eBPF BE ISAs. */
+
+#include "eng-le.h"
+#include "eng-be.h"
+
diff --git a/sim/bpf/mloop.in b/sim/bpf/mloop.in
new file mode 100644
index 0000000000..2661eed8a8
--- /dev/null
+++ b/sim/bpf/mloop.in
@@ -0,0 +1,165 @@
+# Simulator main loop for eBPF. -*- C -*-
+#
+# Copyright (C) 2020 Free Software Foundation, Inc.
+#
+# This file is part of the GNU Simulators.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Syntax:
+# /bin/sh mloop.in command
+#
+# Command is one of:
+#
+# init
+# support
+# extract-{simple,scache,pbb}
+# {full,fast}-exec-{simple,scache,pbb}
+#
+# A target need only provide a "full" version of one of simple,scache,pbb.
+# If the target wants it can also provide a fast version of same, or if
+# the slow (full featured) version is `simple', then the fast version can be
+# one of scache/pbb.
+# A target can't provide more than this.
+# However for illustration's sake this file provides examples of all.
+
+# ??? After a few more ports are done, revisit.
+# Will eventually need to machine generate a lot of this.
+
+case "x$1" in
+
+xsupport)
+
+cat <<EOF
+
+static INLINE const IDESC *
+extract (SIM_CPU *current_cpu, PCADDR pc, CGEN_INSN_WORD insn,
+         ARGBUF *abuf, int fast_p)
+{
+  const IDESC *id = @prefix@_decode (current_cpu, pc, insn, abuf);
+  @prefix@_fill_argbuf (current_cpu, abuf, id, pc, fast_p);
+  if (!fast_p)
+    {
+      int trace_p = PC_IN_TRACE_RANGE_P (current_cpu, pc);
+      int profile_p = PC_IN_PROFILE_RANGE_P (current_cpu, pc);
+      @prefix@_fill_argbuf_tp (current_cpu, abuf, trace_p, profile_p);
+    }
+  return id;
+}
+
+static INLINE SEM_PC
+execute (SIM_CPU *current_cpu, SCACHE *sc, int fast_p)
+{
+  SEM_PC vpc;
+  
+  if (fast_p)
+      vpc = (*sc->argbuf.semantic.sem_fast) (current_cpu, sc);
+  else
+    {
+      ARGBUF *abuf = &sc->argbuf;
+      const IDESC *idesc = abuf->idesc;
+      const CGEN_INSN *idata = idesc->idata;
+      int virtual_p = 0;
+
+      if (! virtual_p)
+        {
+          /* FIXME: call x-before */
+          if (ARGBUF_PROFILE_P (abuf))
+            PROFILE_COUNT_INSN (current_cpu, abuf->addr, idesc->num);
+          /* FIXME: Later make cover macros: PROFILE_INSN_{INIT,FINI}.  */
+          if (PROFILE_MODEL_P (current_cpu)
+              && ARGBUF_PROFILE_P (abuf))
+            @cpu@_model_insn_before (current_cpu, 1 /*first_p*/);
+          CGEN_TRACE_INSN_INIT (current_cpu, abuf, 1);
+          CGEN_TRACE_INSN (current_cpu, idata,
+                      (const struct argbuf *) abuf, abuf->addr);
+        }
+      vpc = (*sc->argbuf.semantic.sem_full) (current_cpu, sc);
+      if (! virtual_p)
+        {
+          /* FIXME: call x-after */
+          if (PROFILE_MODEL_P (current_cpu)
+              && ARGBUF_PROFILE_P (abuf))
+            {
+              int cycles;
+
+              cycles = (*idesc->timing->model_fn) (current_cpu, sc);
+              @cpu@_model_insn_after (current_cpu, 1 /*last_p*/, cycles);
+            }
+          CGEN_TRACE_INSN_FINI (current_cpu, abuf, 1);
+        }
+    }
+
+  return vpc;
+}
+
+EOF
+
+;;
+
+xinit)
+
+# Nothing needed.
+
+;;
+
+xextract-scache)
+
+cat <<EOF
+{
+
+  UDI insn = GETIMEMUDI (current_cpu, vpc);
+
+  if (current_target_byte_order == BFD_ENDIAN_BIG)
+    {
+      /* eBPF instructions are little-endian, but GETIMEMUDI reads according
+         to target byte order. Swap to little-endian. */
+      insn = SWAP_8 (insn);
+
+      /* But, the imm32 and offset16 fields within instructions follow target
+         byte order. Swap those fields back. */
+      UHI off16 = (UHI) ((insn & 0x00000000ffff0000) >> 16);
+      USI imm32 = (USI) ((insn & 0xffffffff00000000) >> 32);
+      off16 = SWAP_2 (off16);
+      imm32 = SWAP_4 (imm32);
+
+      insn = (((UDI) imm32) << 32) | (((UDI) off16) << 16) | (insn & 0xffff);
+    }
+
+  extract (current_cpu, vpc, insn, sc, FAST_P);
+
+  //XXX  SEM_SKIP_COMPILE (current_cpu, sc, 1);
+}
+EOF
+
+;;
+
+xfull-exec-* | xfast-exec-*)
+
+# Inputs: current_cpu, vpc, sc, FAST_P
+# Outputs: vpc
+# vpc is the virtual program counter.
+
+cat <<EOF
+   vpc = execute (current_cpu, sc, FAST_P);
+EOF
+
+;;
+
+*)
+  echo "Invalid argument to mainloop.in: $1" >&2
+  exit 1
+  ;;
+
+esac
diff --git a/sim/bpf/sim-if.c b/sim/bpf/sim-if.c
new file mode 100644
index 0000000000..964cc705eb
--- /dev/null
+++ b/sim/bpf/sim-if.c
@@ -0,0 +1,216 @@
+/* Main simulator entry points specific to the eBPF.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   This file is part of GDB, the GNU debugger.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "sim-main.h"
+#include "sim-options.h"
+#include "libiberty.h"
+#include "bfd.h"
+
+/* Globals.  */
+
+/* String with the name of the section containing the BPF program to
+   run.  */
+static char *bpf_program_section = NULL;
+
+extern uint64_t skb_data_offset;
+
+
+/* Handle BPF-specific options.  */
+
+static SIM_RC bpf_option_handler (SIM_DESC, sim_cpu *, int, char *, int);
+
+typedef enum
+{
+ OPTION_BPF_SET_PROGRAM = OPTION_START,
+ OPTION_BPF_LIST_PROGRAMS,
+ OPTION_BPF_VERIFY_PROGRAM,
+ OPTION_BPF_SKB_DATA_OFFSET,
+} BPF_OPTION;
+
+static const OPTION bpf_options[] =
+{
+ { {"bpf-set-program", required_argument, NULL, OPTION_BPF_SET_PROGRAM},
+   '\0', "SECTION_NAME", "Set the entry point",
+   bpf_option_handler },
+ { {"bpf-list-programs", no_argument, NULL, OPTION_BPF_LIST_PROGRAMS},
+   '\0', "", "List loaded bpf programs",
+   bpf_option_handler },
+ { {"bpf-verify-program", required_argument, NULL, OPTION_BPF_VERIFY_PROGRAM},
+   '\0', "PROGRAM", "Run the verifier on the given BPF program",
+   bpf_option_handler },
+ { {"skb-data-offset", required_argument, NULL, OPTION_BPF_SKB_DATA_OFFSET},
+   '\0', "OFFSET", "Configure offsetof(struct sk_buff, data)",
+   bpf_option_handler },
+
+ { {NULL, no_argument, NULL, 0}, '\0', NULL, NULL, NULL, NULL }
+};
+
+static SIM_RC
+bpf_option_handler (SIM_DESC sd, sim_cpu *cpu ATTRIBUTE_UNUSED, int opt,
+                    char *arg, int is_command ATTRIBUTE_UNUSED)
+{
+  switch ((BPF_OPTION) opt)
+    {
+    case OPTION_BPF_VERIFY_PROGRAM:
+      /* XXX call the verifier. */
+      sim_io_printf (sd, "Verifying BPF program %s...\n", arg);
+      break;
+
+    case OPTION_BPF_LIST_PROGRAMS:
+      /* XXX list programs.  */
+      sim_io_printf (sd, "BPF programs available:\n");
+      break;
+
+    case OPTION_BPF_SET_PROGRAM:
+      /* XXX: check that the section exists and tell the user about a
+         new start_address.  */
+      bpf_program_section = xstrdup (arg);
+      break;
+
+    case OPTION_BPF_SKB_DATA_OFFSET:
+      skb_data_offset = strtoul (arg, NULL, 0);
+      break;
+
+    default:
+      sim_io_eprintf (sd, "Unknown option `%s'\n", arg);
+      return SIM_RC_FAIL;
+    }
+
+  return SIM_RC_OK;
+}
+
+/* Like sim_state_free, but free the cpu buffers as well.  */
+
+static void
+bpf_free_state (SIM_DESC sd)
+{
+  if (STATE_MODULES (sd) != NULL)
+    sim_module_uninstall (sd);
+
+  sim_cpu_free_all (sd);
+  sim_state_free (sd);
+}
+
+/* Create an instance of the simulator.  */
+
+SIM_DESC
+sim_open (SIM_OPEN_KIND kind,
+          host_callback *callback,
+          struct bfd *abfd,
+	  char * const *argv)
+{
+  /* XXX Analyze the program, and collect per-function information
+     like the kernel verifier does.  The implementation of the CALL
+     instruction will need that information, to update %fp.  */
+
+  SIM_DESC sd = sim_state_alloc (kind, callback);
+
+  /* ... */
+
+  if (sim_cpu_alloc_all (sd, 1, cgen_cpu_max_extra_bytes ())
+      != SIM_RC_OK)
+    goto error;
+
+  if (sim_pre_argv_init (sd, argv[0]) != SIM_RC_OK)
+    goto error;
+
+  /* Add the BPF-specific option list to the simulator.  */
+  if (sim_add_option_table (sd, NULL, bpf_options) != SIM_RC_OK)
+    {
+      bpf_free_state (sd);
+      return 0;
+    }
+
+  if (sim_parse_args (sd, argv) != SIM_RC_OK)
+    goto error;
+
+  if (sim_analyze_program (sd,
+                           (STATE_PROG_ARGV (sd) != NULL
+                            ? *STATE_PROG_ARGV (sd)
+                            : NULL), abfd) != SIM_RC_OK)
+    goto error;
+
+  if (sim_config (sd) != SIM_RC_OK)
+    goto error;
+
+  if (sim_post_argv_init (sd) != SIM_RC_OK)
+    goto error;
+
+  /* ... */
+
+  /* Initialize the CPU descriptors and the disassemble in the cpu
+     descriptor table entries.  */
+  {
+    int i;
+    CGEN_CPU_DESC cd = bpf_cgen_cpu_open_1 (STATE_ARCHITECTURE (sd)->printable_name,
+                                            CGEN_ENDIAN_LITTLE);
+
+    /* We have one cpu per installed program! MAX_NR_PROCESSORS is an
+       arbitrary upper limit.  XXX where is it defined?  */
+    for (i = 0; i < MAX_NR_PROCESSORS; ++i)
+      {
+        SIM_CPU *cpu = STATE_CPU (sd, i);
+
+        CPU_CPU_DESC (cpu) = cd;
+        CPU_DISASSEMBLER (cpu) = sim_cgen_disassemble_insn;
+      }
+
+    bpf_cgen_init_dis (cd);
+  }
+
+  /* Initialize various cgen things not done by common framework.
+     Must be done after bpf_cgen_cpu_open.  */
+  cgen_init (sd);
+
+  /* XXX do eBPF sim specific initializations.  */
+
+  return sd;
+
+ error:
+      bpf_free_state (sd);
+      return NULL;
+}
+
+
+SIM_RC
+sim_create_inferior (SIM_DESC sd, struct bfd *abfd,
+		     char *const *argv, char *const *envp)
+{
+  SIM_CPU *current_cpu = STATE_CPU (sd, 0);
+  SIM_ADDR addr;
+
+  /* Determine the start address.
+
+     XXX acknowledge bpf_program_section.  If it is NULL, emit a
+     warning explaining that we are using the ELF file start address,
+     which often is not what is actually wanted.  */
+  if (abfd != NULL)
+    addr = bfd_get_start_address (abfd);
+  else
+    addr = 0;
+
+  sim_pc_set (current_cpu, addr);
+
+  if (STATE_PROG_ARGV (sd) != argv)
+    {
+      freeargv (STATE_PROG_ARGV (sd));
+      STATE_PROG_ARGV (sd) = dupargv (argv);
+    }
+
+  return SIM_RC_OK;
+}
diff --git a/sim/bpf/sim-main.h b/sim/bpf/sim-main.h
new file mode 100644
index 0000000000..fc1e69f6f3
--- /dev/null
+++ b/sim/bpf/sim-main.h
@@ -0,0 +1,51 @@
+/* eBPF simulator main header
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   This file is part of GDB, the GNU debugger.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef SIM_MAIN_H
+#define SIM_MAIN_H
+
+#include "sim-basics.h"
+#include "cgen-types.h"
+#include "bpf-desc.h"
+#include "bpf-opc.h"
+#include "arch.h"
+#include "sim-base.h"
+#include "cgen-sim.h"
+#include "bpf-sim.h"
+
+
+struct _sim_cpu
+{
+  sim_cpu_base base;
+  CGEN_CPU cgen_cpu;
+
+#if defined (WANT_CPU_BPFBF)
+  BPFBF_CPU_DATA cpu_data;
+#endif
+};
+
+
+
+struct sim_state
+{
+  sim_cpu *cpu[MAX_NR_PROCESSORS];
+  CGEN_STATE cgen_state;
+  sim_state_base base;
+};
+
+#endif /* ! SIM_MAIN_H */
diff --git a/sim/bpf/traps.c b/sim/bpf/traps.c
new file mode 100644
index 0000000000..e7ac0c2838
--- /dev/null
+++ b/sim/bpf/traps.c
@@ -0,0 +1,33 @@
+/* Trap handlers for eBPF.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   This file is part of GDB, the GNU debugger.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#define WANT_CPU bpfbf
+#define WANT_CPU_BPFBF
+
+#include "sim-main.h"
+
+SEM_PC
+sim_engine_invalid_insn (SIM_CPU *current_cpu ATTRIBUTE_UNUSED,
+                         IADDR cia ATTRIBUTE_UNUSED,
+                         SEM_PC pc ATTRIBUTE_UNUSED)
+{
+  /* Can't just return 0 here: the return value is used to set vpc
+     (see decdde-{le,be}.c)
+     Returning 0 will cause an infinite loop! */
+  abort();
+}
diff --git a/sim/configure b/sim/configure
index 72f95cd5c7..107e635fef 100755
--- a/sim/configure
+++ b/sim/configure
@@ -633,6 +633,7 @@ infodir
 docdir
 oldincludedir
 includedir
+runstatedir
 localstatedir
 sharedstatedir
 sysconfdir
@@ -669,6 +670,7 @@ ac_subdirs_all='aarch64
 arm
 avr
 bfin
+bpf
 cr16
 cris
 d10v
@@ -734,6 +736,7 @@ datadir='${datarootdir}'
 sysconfdir='${prefix}/etc'
 sharedstatedir='${prefix}/com'
 localstatedir='${prefix}/var'
+runstatedir='${localstatedir}/run'
 includedir='${prefix}/include'
 oldincludedir='/usr/include'
 docdir='${datarootdir}/doc/${PACKAGE}'
@@ -986,6 +989,15 @@ do
   | -silent | --silent | --silen | --sile | --sil)
     silent=yes ;;
 
+  -runstatedir | --runstatedir | --runstatedi | --runstated \
+  | --runstate | --runstat | --runsta | --runst | --runs \
+  | --run | --ru | --r)
+    ac_prev=runstatedir ;;
+  -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
+  | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
+  | --run=* | --ru=* | --r=*)
+    runstatedir=$ac_optarg ;;
+
   -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
     ac_prev=sbindir ;;
   -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
@@ -1123,7 +1135,7 @@ fi
 for ac_var in	exec_prefix prefix bindir sbindir libexecdir datarootdir \
 		datadir sysconfdir sharedstatedir localstatedir includedir \
 		oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
-		libdir localedir mandir
+		libdir localedir mandir runstatedir
 do
   eval ac_val=\$$ac_var
   # Remove trailing slashes.
@@ -1276,6 +1288,7 @@ Fine tuning of the installation directories:
   --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
   --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
   --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
+  --runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]
   --libdir=DIR            object code libraries [EPREFIX/lib]
   --includedir=DIR        C header files [PREFIX/include]
   --oldincludedir=DIR     C header files for non-gcc [/usr/include]
@@ -3717,6 +3730,13 @@ subdirs="$subdirs aarch64"
   subdirs="$subdirs bfin"
 
 
+       ;;
+   bpf-*-*)
+
+  sim_arch=bpf
+  subdirs="$subdirs bpf"
+
+
        ;;
    cr16*-*-*)
 
diff --git a/sim/configure.tgt b/sim/configure.tgt
index 8a8e03d96f..c115c3c8dd 100644
--- a/sim/configure.tgt
+++ b/sim/configure.tgt
@@ -26,6 +26,9 @@ case "${target}" in
    bfin-*-*)
        SIM_ARCH(bfin)
        ;;
+   bpf-*-*)
+       SIM_ARCH(bpf)
+       ;;
    cr16*-*-*)
        SIM_ARCH(cr16)
        ;;
diff --git a/sim/testsuite/configure b/sim/testsuite/configure
index a3e7fa7131..64e0d9bc69 100755
--- a/sim/testsuite/configure
+++ b/sim/testsuite/configure
@@ -619,6 +619,7 @@ infodir
 docdir
 oldincludedir
 includedir
+runstatedir
 localstatedir
 sharedstatedir
 sysconfdir
@@ -686,6 +687,7 @@ datadir='${datarootdir}'
 sysconfdir='${prefix}/etc'
 sharedstatedir='${prefix}/com'
 localstatedir='${prefix}/var'
+runstatedir='${localstatedir}/run'
 includedir='${prefix}/include'
 oldincludedir='/usr/include'
 docdir='${datarootdir}/doc/${PACKAGE}'
@@ -938,6 +940,15 @@ do
   | -silent | --silent | --silen | --sile | --sil)
     silent=yes ;;
 
+  -runstatedir | --runstatedir | --runstatedi | --runstated \
+  | --runstate | --runstat | --runsta | --runst | --runs \
+  | --run | --ru | --r)
+    ac_prev=runstatedir ;;
+  -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
+  | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
+  | --run=* | --ru=* | --r=*)
+    runstatedir=$ac_optarg ;;
+
   -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
     ac_prev=sbindir ;;
   -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
@@ -1075,7 +1086,7 @@ fi
 for ac_var in	exec_prefix prefix bindir sbindir libexecdir datarootdir \
 		datadir sysconfdir sharedstatedir localstatedir includedir \
 		oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
-		libdir localedir mandir
+		libdir localedir mandir runstatedir
 do
   eval ac_val=\$$ac_var
   # Remove trailing slashes.
@@ -1228,6 +1239,7 @@ Fine tuning of the installation directories:
   --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
   --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
   --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
+  --runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]
   --libdir=DIR            object code libraries [EPREFIX/lib]
   --includedir=DIR        C header files [PREFIX/include]
   --oldincludedir=DIR     C header files for non-gcc [/usr/include]
@@ -1875,6 +1887,9 @@ case "${target}" in
    bfin-*-*)
        sim_arch=bfin
        ;;
+   bpf-*-*)
+       sim_arch=bpf
+       ;;
    cr16*-*-*)
        sim_arch=cr16
        ;;
@@ -1928,6 +1943,9 @@ case "${target}" in
    or1k-*-* | or1knd-*-*)
        sim_arch=or1k
        ;;
+   pru*-*-*)
+       sim_arch=pru
+       ;;
    rl78-*-*)
        sim_arch=rl78
        ;;
@@ -1946,9 +1964,6 @@ case "${target}" in
    powerpc*-*-*)
        sim_arch=ppc
        ;;
-   pru*-*-*)
-       sim_arch=pru
-       ;;
    ft32-*-*)
        sim_arch=ft32
        ;;
diff --git a/sim/testsuite/sim/bpf/allinsn.exp b/sim/testsuite/sim/bpf/allinsn.exp
new file mode 100644
index 0000000000..2cca77021a
--- /dev/null
+++ b/sim/testsuite/sim/bpf/allinsn.exp
@@ -0,0 +1,26 @@
+# eBPF simulator testsuite
+
+if [istarget bpf-unknown-none] {
+    # all machines
+    set all_machs "bpf"
+
+    global global_sim_options
+    if ![info exists global_sim_options] {
+	set global_sim_options "--memory-size=4Mb"
+    }
+
+    global global_ld_options
+    if ![info exists global_ld_options] {
+        set global_ld_options "-Ttext=0x0"
+    }
+
+    foreach src [lsort [glob -nocomplain $srcdir/$subdir/*.s]] {
+	# If we're only testing specific files and this isn't one of them,
+	# skip it.
+	if ![runtest_file_p $runtests $src] {
+	    continue
+	}
+
+	run_sim_test $src $all_machs
+    }
+}
diff --git a/sim/testsuite/sim/bpf/alu.s b/sim/testsuite/sim/bpf/alu.s
new file mode 100644
index 0000000000..6013ac7eb9
--- /dev/null
+++ b/sim/testsuite/sim/bpf/alu.s
@@ -0,0 +1,109 @@
+# mach: bpf
+# output: pass\nexit 0 (0x0)\n
+;;; alu.s
+;;; Tests for ALU64 BPF instructions in simulator
+
+    .include "testutils.inc"
+
+    .text
+    .global main
+    .type main, @function
+main:
+    mov         %r1, 0
+    mov         %r2, -1
+
+    ;; add
+    add         %r1, 1
+    add         %r2, -1
+    add         %r1, %r2
+    fail_ne     %r1, -1
+
+    ;; sub
+    sub         %r1, %r1
+    fail_ne     %r1, 0
+    sub         %r1, 10
+    sub         %r2, %r1
+    fail_ne     %r2, 8
+
+    ;; mul
+    mul         %r2, %r2        ; r2 = 64
+    mul         %r2, 3          ; r2 = 192
+    mov         %r1, -3
+    mul         %r1, %r2        ; r1 = -576
+    mul         %r2, 0
+    fail_ne     %r1, -576
+    fail_ne     %r2, 0
+    mul         %r1, %r1
+    mul         %r1, %r1
+    fail_ne     %r1, 110075314176
+
+    ;; div
+    div         %r2, %r1
+    fail_ne     %r2, 0
+    div         %r1, -10000
+    fail_ne     %r1, -11007531
+    div         %r1, %r1
+    fail_ne     %r1, 1
+
+    ;; and
+    lddw        %r1, 0xaaaaaaaa55555555
+    and         %r1, 0x55aaaaaa         ; we still only have 32-bit imm.
+    fail_ne     %r1, 0x0000000055000000
+    lddw        %r2, 0x5555555a5aaaaaaa
+    and         %r2, %r1
+    fail_ne     %r2, 0x0000000050000000
+
+    ;; or
+    or          %r2, 0xdeadbeef
+    fail_ne     %r2, 0xffffffffdeadbeef ; 0xdeadbeef gets sign extended
+    lddw        %r1, 0xdead00000000beef
+    lddw        %r2, 0x0000123456780000
+    or          %r1, %r2
+    fail_ne     %r1, 0xdead12345678beef
+
+    ;; lsh
+    mov         %r1, 0xdeadbeef
+    lsh         %r1, 11
+    fail_ne     %r1, 0xfffffef56df77800 ; because deadbeef gets sign ext.
+    mov         %r2, 21
+    lsh         %r1, %r2
+    fail_ne     %r1, 0xdeadbeef00000000
+
+    ;; rsh
+    rsh         %r1, 11
+    fail_ne     %r1, 0x001bd5b7dde00000 ; 0xdeadbeef 00000000 >> 0xb
+    rsh         %r1, %r2
+    fail_ne     %r1, 0x00000000deadbeef
+
+    ;; arsh
+    arsh        %r1, 8
+    fail_ne     %r1, 0x0000000000deadbe
+    lsh         %r1, 40                 ; r1 = 0xdead be00 0000 0000
+    arsh        %r1, %r2                ; r1 arsh (r2 == 21)
+    fail_ne     %r1, 0xfffffef56df00000
+
+    ;; mod
+    mov         %r1, 1025
+    mod         %r1, -16
+    fail_ne     %r1, 1
+    mov         %r1, -25
+    mov         %r2, 5
+    mod         %r1, %r2
+    fail_ne     %r1, 0
+
+    ;; xor
+    xor         %r1, %r2
+    fail_ne     %r1, 5
+    xor         %r1, 0x7eadbeef
+    fail_ne     %r1, 0x7eadbeea
+    xor         %r1, %r1
+    fail_ne     %r1, 0
+
+    ;; neg
+    neg         %r2
+    fail_ne     %r2, -5
+    mov         %r1, -1025
+    neg         %r1
+    fail_ne     %r1, 1025
+
+    pass
diff --git a/sim/testsuite/sim/bpf/alu32.s b/sim/testsuite/sim/bpf/alu32.s
new file mode 100644
index 0000000000..a611abd6f6
--- /dev/null
+++ b/sim/testsuite/sim/bpf/alu32.s
@@ -0,0 +1,99 @@
+# mach: bpf
+# output: pass\nexit 0 (0x0)\n
+;; alu32.s
+;; Tests for ALU(32) BPF instructions in simulator
+
+    .include "testutils.inc"
+
+    .text
+    .global main
+    .type main, @function
+main:
+    mov32       %r1, 10         ; r1 = 10
+    mov32       %r2, -5         ; r2 = -5
+   
+    ;; add
+    add32       %r1, 1          ; r1 += 1  (r1 = 11)
+    add32       %r2, -1         ; r2 += -1 (r2 = -6)
+    add32       %r1, %r2        ; r1 += r2 (r1 = 11 + -6 = 5)
+    fail_ne32   %r1, 5
+
+    ;; sub
+    sub32       %r1, 5          ; r1 -= 5 (r1 = 0)
+    sub32       %r1, -5         ; r1 -= -5 (r1 = 5)
+    sub32       %r1, %r2        ; r1 -= r2 (r1 = 5 - -6 = 11)
+    fail_ne32   %r1, 11
+
+    ;; mul
+    mul32       %r1, 2          ; r1 *= 2  (r1 = 22)
+    mul32       %r1, -2         ; r1 *= -2 (r1 = -44)
+    mul32       %r1, %r2        ; r1 *= r2 (r1 = -44 * -6 = 264)
+    fail_ne32   %r1, 264
+
+    ;; div
+    div32       %r1, %r2        ; r1 /= r2 (r1 = 264 / -6 = -44)
+    div32       %r1, -2         ; r1 /= -2 (r1 = 22)
+    div32       %r1, 2          ; r1 /= 2  (r1 = 11)
+    fail_ne32   %r1, 11
+
+    ;; and (bitwise)
+    mov32       %r1, 0xb        ; r1  = (0xb = 0b1011)
+    mov32       %r2, 0x5        ; r2  = (0x5 = 0b0101)
+    and32       %r1, 0xa        ; r1 &= (0xa = 0b1010) = (0b1010 = 0xa)
+    fail_ne32   %r1, 0xa
+    and32       %r1, %r2        ; r1 &= r2 = 0x0
+    fail_ne32   %r1, 0x0
+
+    ;; or (bitwise)
+    or32        %r1, 0xb
+    or32        %r1, %r2
+    fail_ne32   %r1, 0xf
+
+    ;; lsh (left shift)
+    lsh32       %r1, 4          ; r1 <<= 4 (r1 = 0xf0)
+    mov32       %r2, 24         ; r2 = 24
+    lsh32       %r1, %r2
+    fail_ne32   %r1, 0xf0000000
+
+    ;; rsh (right logical shift)
+    rsh32       %r1, 2
+    rsh32       %r1, %r2
+    fail_ne32   %r1, 0x3c       ; (0xf000 0000 >> 26)
+
+    ;; arsh (right arithmetic shift)
+    arsh32      %r1, 1
+    or32        %r1, 0x80000000
+    mov32       %r2, 3
+    arsh32      %r1, %r2
+    fail_ne     %r1, 0x00000000F0000003
+                                ; Note: make sure r1 is NOT sign-extended
+                                ; i.e. upper-32 bits should be untouched
+
+    ;; mod
+    mov32       %r1, -25
+    mov32       %r2, 4
+    mod32       %r1, %r2
+    fail_ne32   %r1, -1
+    mov32       %r1, 25
+    mod32       %r1, 5
+    fail_ne32   %r1, 0
+
+    ;; xor
+    xor32       %r1, %r2
+    fail_ne32   %r1, 4
+    xor32       %r1, 0xF000000F
+    fail_ne     %r1, 0xF000000B ; Note: check for (bad) sign-extend
+    xor32       %r1, %r1
+    fail_ne     %r1, 0
+
+    ;; neg
+    mov32       %r1, -1
+    mov32       %r2, 0x7fffffff
+    neg32       %r1
+    neg32       %r2
+    fail_ne32   %r1, 1
+    fail_ne     %r2, 0x80000001 ; Note: check for (bad) sign-extend
+    neg32       %r2
+    fail_ne32   %r2, 0x7fffffff
+
+    pass
diff --git a/sim/testsuite/sim/bpf/endbe.s b/sim/testsuite/sim/bpf/endbe.s
new file mode 100644
index 0000000000..2f662aec02
--- /dev/null
+++ b/sim/testsuite/sim/bpf/endbe.s
@@ -0,0 +1,46 @@
+# mach: bpf
+# as: --EB
+# ld: --EB
+# sim: -E big
+# output: pass\nexit 0 (0x0)\n
+;;; endbe.s
+;;; Tests for BPF endianness-conversion instructions in simulator
+;;; running in BIG ENDIAN
+;;;
+;;; Both 'be' and 'le' ISAs have both endbe and endle instructions.
+
+    .include "testutils.inc"
+
+    .text
+    .global main
+    .type main, @function
+main:
+    lddw        %r1, 0x12345678deadbeef
+    endle       %r1, 64
+    fail_ne     %r1, 0xefbeadde78563412
+    endle       %r1, 64
+    fail_ne     %r1, 0x12345678deadbeef
+
+    ;; `bitsize` < 64 will truncate
+    endle       %r1, 32
+    fail_ne     %r1, 0xefbeadde
+    endle       %r1, 32
+    fail_ne     %r1, 0xdeadbeef
+
+    endle       %r1, 16
+    fail_ne     %r1, 0xefbe
+    endle       %r1, 16
+    fail_ne     %r1, 0xbeef
+
+    ;; endbe on be should be noop (except truncate)
+    lddw        %r1, 0x12345678deadbeef
+    endbe       %r1, 64
+    fail_ne     %r1, 0x12345678deadbeef
+
+    endbe       %r1, 32
+    fail_ne     %r1, 0xdeadbeef
+
+    endbe       %r1, 16
+    fail_ne     %r1, 0xbeef
+
+    pass
diff --git a/sim/testsuite/sim/bpf/endle.s b/sim/testsuite/sim/bpf/endle.s
new file mode 100644
index 0000000000..d8f5ceb977
--- /dev/null
+++ b/sim/testsuite/sim/bpf/endle.s
@@ -0,0 +1,43 @@
+# mach: bpf
+# output: pass\nexit 0 (0x0)\n
+;;; endle.s
+;;; Tests for BPF endianness-conversion instructions in simulator
+;;; running in LITTLE ENDIAN
+;;;
+;;; Both 'be' and 'le' ISAs have both endbe and endle instructions.
+
+    .include "testutils.inc"
+
+    .text
+    .global main
+    .type main, @function
+main:
+    lddw        %r1, 0x12345678deadbeef
+    endbe       %r1, 64
+    fail_ne     %r1, 0xefbeadde78563412
+    endbe       %r1, 64
+    fail_ne     %r1, 0x12345678deadbeef
+
+    ;; `bitsize` < 64 will truncate
+    endbe       %r1, 32
+    fail_ne     %r1, 0xefbeadde
+    endbe       %r1, 32
+    fail_ne     %r1, 0xdeadbeef
+
+    endbe       %r1, 16
+    fail_ne     %r1, 0xefbe
+    endbe       %r1, 16
+    fail_ne     %r1, 0xbeef
+
+    ;; endle on le should be noop (except truncate)
+    lddw        %r1, 0x12345678deadbeef
+    endle       %r1, 64
+    fail_ne     %r1, 0x12345678deadbeef
+
+    endle       %r1, 32
+    fail_ne     %r1, 0xdeadbeef
+
+    endle       %r1, 16
+    fail_ne     %r1, 0xbeef
+
+    pass
diff --git a/sim/testsuite/sim/bpf/jmp.s b/sim/testsuite/sim/bpf/jmp.s
new file mode 100644
index 0000000000..a9fe88be4a
--- /dev/null
+++ b/sim/testsuite/sim/bpf/jmp.s
@@ -0,0 +1,120 @@
+# mach: bpf
+# output: pass\nexit 0 (0x0)\n
+;;; jmp.s
+;;; Tests for eBPF JMP instructions in simulator
+
+    .include "testutils.inc"
+
+    .text
+    .global main
+    .type main, @function
+main:
+    mov         %r1, 5
+    mov         %r2, 2
+    mov         %r3, 7
+    mov         %r4, -1
+
+    ;; ja - jump absolute (unconditional)
+    ja          2f
+1:  fail
+
+2:  ;; jeq - jump eq
+    jeq         %r1, 4, 1b      ; no
+    jeq         %r1, %r2, 1b    ; no
+    jeq         %r1, 5, 2f      ; yes
+    fail
+2:  jeq         %r1, %r1, 2f    ; yes
+    fail
+
+2:  ;; jgt - jump (unsigned) greater-than
+    jgt         %r1, 6, 1b      ; no
+    jgt         %r1, -5, 1b     ; no - unsigned
+    jgt         %r1, %r4, 1b    ; no - unsigned
+    jgt         %r1, 4, 2f      ; yes
+    fail
+2:  jgt         %r1, %r2, 2f    ; yes
+    fail
+
+2:  ;; jge - jump (unsigned) greater-than-or-equal-to
+    jge         %r1, 6, 1b      ; no
+    jge         %r1, 5, 2f      ; yes
+    fail
+2:  jge         %r1, %r3, 1b    ; no
+    jge         %r1, -5, 1b     ; no - unsigned
+    jge         %r1, %r2, 2f    ; yes
+    fail
+
+2:  ;; jlt - jump (unsigned) less-than
+    jlt         %r1, 5, 1b      ; no
+    jlt         %r1, %r2, 1b    ; no
+    jlt         %r4, %r1, 1b    ; no - unsigned
+    jlt         %r1, 6, 2f      ; yes
+    fail
+2:
+    jlt         %r1, %r3, 2f    ; yes
+    fail
+
+2:  ;; jle - jump (unsigned) less-than-or-equal-to
+    jle         %r1, 4, 1b      ; no
+    jle         %r1, %r2, 1b    ; no
+    jle         %r4, %r1, 1b    ; no
+    jle         %r1, 5, 2f      ; yes
+    fail
+2:  jle         %r1, %r1, 2f    ; yes
+    fail
+   
+2:  ;; jset - jump "test" (AND)
+    jset        %r1, 2, 1b      ; no (5 & 2 = 0)
+    jset        %r1, %r2, 1b    ; no (same)
+    jset        %r1, 4, 2f      ; yes (5 & 4 != 0)
+    fail
+
+2:  ;; jne  - jump not-equal-to
+    jne         %r1, 5, 1b      ; no
+    jne         %r1, %r1, 1b    ; no
+    jne         %r1, 6, 2f      ; yes
+    fail
+2:  jne         %r1, %r4, 2f    ; yes
+    fail
+
+2:  ;; jsgt - jump (signed) greater-than
+    jsgt        %r1, %r3, 1b    ; no
+    jsgt        %r1, %r1, 1b    ; no
+    jsgt        %r1, 5, 1b      ; no
+    jsgt        %r1, -4, 2f     ; yes
+    fail
+2:  jsgt        %r1, %r4, 2f    ; yes
+    fail
+
+2:  ;; jsge - jump (signed) greater-than-or-equal-to
+    jsge        %r1, %r3, 1b    ; no
+    jsge        %r1, %r1, 2f    ; yes
+    fail
+2:  jsge        %r1, 7, 1b      ; no
+    jsge        %r1, -4, 2f     ; yes
+    fail
+2:  jsge        %r1, %r4, 2f    ; yes
+    fail
+
+2:  ;; jslt - jump (signed) less-than
+    jslt        %r1, 5, 1b      ; no
+    jslt        %r1, %r2, 1b    ; no
+    jslt        %r4, %r1, 2f    ; yes
+    fail
+2:  jslt        %r1, 6, 2f      ; yes
+    fail
+2:  jslt        %r1, %r3, 2f    ; yes
+    fail
+
+2:  ;; jsle - jump (signed) less-than-or-equal-to
+    jsle         %r1, 4, 1b      ; no
+    jsle         %r1, %r2, 1b    ; no
+    jsle         %r4, %r1, 2f    ; yes
+    fail
+2:  jsle         %r1, 5, 2f      ; yes
+    fail
+2:  jsle         %r1, %r3, 2f    ; yes
+    fail
+
+2: 
+    pass
diff --git a/sim/testsuite/sim/bpf/jmp32.s b/sim/testsuite/sim/bpf/jmp32.s
new file mode 100644
index 0000000000..3621295129
--- /dev/null
+++ b/sim/testsuite/sim/bpf/jmp32.s
@@ -0,0 +1,120 @@
+# mach: bpf
+# output: pass\nexit 0 (0x0)\n
+;;; jmp32.s
+;;; Tests for eBPF JMP32 instructions in simulator
+
+    .include "testutils.inc"
+
+    .text
+    .global main
+    .type main, @function
+main:
+    mov32       %r1, 5
+    mov32       %r2, 2
+    mov32       %r3, 7
+    mov32       %r4, -1
+
+    ;; ja - jump absolute (unconditional)
+    ja          2f
+1:  fail
+
+2:  ;; jeq - jump eq
+    jeq32       %r1, 4, 1b      ; no
+    jeq32       %r1, %r2, 1b    ; no
+    jeq32       %r1, 5, 2f      ; yes
+    fail
+2:  jeq32       %r1, %r1, 2f    ; yes
+    fail
+
+2:  ;; jgt - jump (unsigned) greater-than
+    jgt32       %r1, 6, 1b      ; no
+    jgt32       %r1, -5, 1b     ; no - unsigned
+    jgt32       %r1, %r4, 1b    ; no - unsigned
+    jgt32       %r1, 4, 2f      ; yes
+    fail
+2:  jgt32       %r1, %r2, 2f    ; yes
+    fail
+
+2:  ;; jge - jump (unsigned) greater-than-or-equal-to
+    jge32       %r1, 6, 1b      ; no
+    jge32       %r1, 5, 2f      ; yes
+    fail
+2:  jge32       %r1, %r3, 1b    ; no
+    jge32       %r1, -5, 1b     ; no - unsigned
+    jge32       %r1, %r2, 2f    ; yes
+    fail
+
+2:  ;; jlt - jump (unsigned) less-than
+    jlt32       %r1, 5, 1b      ; no
+    jlt32       %r1, %r2, 1b    ; no
+    jlt32       %r4, %r1, 1b    ; no - unsigned
+    jlt32       %r1, 6, 2f      ; yes
+    fail
+2:
+    jlt32       %r1, %r3, 2f    ; yes
+    fail
+
+2:  ;; jle - jump (unsigned) less-than-or-equal-to
+    jle32       %r1, 4, 1b      ; no
+    jle32       %r1, %r2, 1b    ; no
+    jle32       %r4, %r1, 1b    ; no
+    jle32       %r1, 5, 2f      ; yes
+    fail
+2:  jle32       %r1, %r1, 2f    ; yes
+    fail
+   
+2:  ;; jset - jump "test" (AND)
+    jset32      %r1, 2, 1b      ; no (5 & 2 = 0)
+    jset32      %r1, %r2, 1b    ; no (same)
+    jset32      %r1, 4, 2f      ; yes (5 & 4 != 0)
+    fail
+
+2:  ;; jne  - jump not-equal-to
+    jne32       %r1, 5, 1b      ; no
+    jne32       %r1, %r1, 1b    ; no
+    jne32       %r1, 6, 2f      ; yes
+    fail
+2:  jne32       %r1, %r4, 2f    ; yes
+    fail
+
+2:  ;; jsgt - jump (signed) greater-than
+    jsgt32      %r1, %r3, 1b    ; no
+    jsgt32      %r1, %r1, 1b    ; no
+    jsgt32      %r1, 5, 1b      ; no
+    jsgt32      %r1, -4, 2f     ; yes
+    fail
+2:  jsgt32      %r1, %r4, 2f    ; yes
+    fail
+
+2:  ;; jsge - jump (signed) greater-than-or-equal-to
+    jsge32      %r1, %r3, 1b    ; no
+    jsge32      %r1, %r1, 2f    ; yes
+    fail
+2:  jsge32      %r1, 7, 1b      ; no
+    jsge32      %r1, -4, 2f     ; yes
+    fail
+2:  jsge32      %r1, %r4, 2f    ; yes
+    fail
+
+2:  ;; jslt - jump (signed) less-than
+    jslt32      %r1, 5, 1b      ; no
+    jslt32      %r1, %r2, 1b    ; no
+    jslt32      %r4, %r1, 2f    ; yes
+    fail
+2:  jslt32      %r1, 6, 2f      ; yes
+    fail
+2:  jslt32      %r1, %r3, 2f    ; yes
+    fail
+
+2:  ;; jsle - jump (signed) less-than-or-equal-to
+    jsle32       %r1, 4, 1b      ; no
+    jsle32       %r1, %r2, 1b    ; no
+    jsle32       %r4, %r1, 2f    ; yes
+    fail
+2:  jsle32       %r1, 5, 2f      ; yes
+    fail
+2:  jsle32       %r1, %r3, 2f    ; yes
+    fail
+
+2: 
+    pass
diff --git a/sim/testsuite/sim/bpf/ldabs.s b/sim/testsuite/sim/bpf/ldabs.s
new file mode 100644
index 0000000000..ae777f1cf5
--- /dev/null
+++ b/sim/testsuite/sim/bpf/ldabs.s
@@ -0,0 +1,87 @@
+# mach: bpf
+# sim: --skb-data-offset=0x20
+# output: pass\nexit 0 (0x0)\n
+;;; ldabs.s
+;;; Tests for non-generic BPF load instructions in simulator.
+;;; These instructions (ld{abs,ind}{b,h,w,dw}) are used to access
+;;; kernel socket data from BPF programs for high performance filters.
+;;;
+;;; Register r6 is an implicit input holding a pointer to a struct sk_buff.
+;;; Register r0 is an implicit output, holding the fetched data.
+;;;
+;;; e.g.
+;;; ldabsw means:
+;;; r0 = ntohl (*(u32 *) (((struct sk_buff *)r6)->data + imm32))
+;;;
+;;; ldindw means
+;;; r0 = ntohl (*(u32 *) (((struct sk_buff *)r6)->data + src_reg + imm32))
+
+    .include "testutils.inc"
+
+    .text
+    .global main
+    .type main, @function
+main:
+    ;; R6 holds a pointer to a struct sk_buff, which we pretend
+    ;; exists at 0x1000
+    mov         %r6, 0x1000
+
+    ;; We configure skb-data-offset=0x20
+    ;; This specifies offsetof(struct sk_buff, data), where the field 'data'
+    ;; is a pointer a data buffer, in this case at 0x2000
+    stw         [%r6+0x20], 0x2000
+
+    ;; Write the value 0x7eadbeef into memory at 0x2004
+    ;; i.e. offset 4 within the data buffer pointed to by
+    ;; ((struct sk_buff *)r6)->data
+    stw         [%r6+0x1004], 0xdeadbeef
+
+    ;; Now load data[4] into r0 using the ldabsw instruction
+    ldabsw      0x4
+
+    ;; ...and compare to what we expect
+    fail_ne32   %r0, 0xdeadbeef
+
+    ;; Repeat for a half-word (2-bytes)
+    sth         [%r6+0x1008], 0x1234
+    ldabsh      0x8
+    fail_ne32   %r0, 0x1234
+
+    ;; Repeat for a single byte
+    stb         [%r6+0x1010], 0x5a
+    ldabsb      0x10
+    fail_ne32   %r0, 0x5a
+
+    ;; Repeat for a double-word (8-byte)
+    ;; (note: fail_ne macro uses r0, so copy to another r1 to compare)
+    lddw        %r2, 0x1234deadbeef5678
+    stxdw       [%r6+0x1018], %r2
+    ldabsdw     0x18
+    mov         %r1, %r0
+    fail_ne     %r1, 0x1234deadbeef5678
+
+    ;; Now, we do the same for the indirect loads
+    mov         %r7, 0x100
+    stw         [%r6+0x1100], 0xfeedbeef
+
+    ldindw      %r7, 0x0
+    fail_ne32   %r0, 0xfeedbeef
+
+    ;; half-word
+    sth         [%r6+0x1104], 0x6789
+    ldindh      %r7, 0x4
+    fail_ne32   %r0, 0x6789
+
+    ;; byte
+    stb         [%r6+0x1108], 0x5f
+    ldindb      %r7, 0x8
+    fail_ne32   %r0, 0x5f
+
+    ;; double-word
+    lddw        %r2, 0xcafe12345678d00d
+    stxdw       [%r6+0x1110], %r2
+    ldinddw     %r7, 0x10
+    mov         %r1, %r0
+    fail_ne     %r1, 0xcafe12345678d00d
+
+    pass
diff --git a/sim/testsuite/sim/bpf/mem.s b/sim/testsuite/sim/bpf/mem.s
new file mode 100644
index 0000000000..2dea57d227
--- /dev/null
+++ b/sim/testsuite/sim/bpf/mem.s
@@ -0,0 +1,56 @@
+# mach: bpf
+# output: pass\nexit 0 (0x0)\n
+;;; mem.s
+;;; Tests for BPF memory (ldx, stx, ..) instructions in simulator
+
+    .include "testutils.inc"
+
+    .text
+    .global main
+    .type main, @function
+main:  
+    lddw        %r1, 0x1234deadbeef5678
+    mov         %r2, 0x1000
+
+    ;; basic store/load check
+    stxb        [%r2+0], %r1
+    stxh        [%r2+2], %r1
+    stxw        [%r2+4], %r1
+    stxdw       [%r2+8], %r1
+
+    stb         [%r2+16], 0x5a
+    sth         [%r2+18], 0xcafe
+    stw         [%r2+20], 0xbeefface
+    stdw        [%r2+24], 0x7eadbeef
+
+    ldxb        %r1, [%r2+16]
+    fail_ne     %r1, 0x5a
+    ldxh        %r1, [%r2+18]
+    fail_ne     %r1, 0xffffffffffffcafe
+    ldxw        %r1, [%r2+20]
+    fail_ne     %r1, 0xffffffffbeefface
+    ldxdw       %r1, [%r2+24]
+    fail_ne     %r1, 0x7eadbeef
+
+    ldxb        %r3, [%r2+0]
+    fail_ne     %r3, 0x78
+    ldxh        %r3, [%r2+2]
+    fail_ne     %r3, 0x5678
+    ldxw        %r3, [%r2+4]
+    fail_ne     %r3, 0xffffffffbeef5678
+    ldxdw       %r3, [%r2+8]
+    fail_ne     %r3, 0x1234deadbeef5678
+
+    ldxw        %r4, [%r2+10]
+    fail_ne     %r4, 0xffffffffdeadbeef
+
+    ;; negative offsets
+    add         %r2, 16
+    ldxh        %r5, [%r2+-14]
+    fail_ne     %r5, 0x5678
+    ldxw        %r5, [%r2+-12]
+    fail_ne     %r5, 0xffffffffbeef5678
+    ldxdw       %r5, [%r2+-8]
+    fail_ne     %r5, 0x1234deadbeef5678
+
+    pass
diff --git a/sim/testsuite/sim/bpf/mov.s b/sim/testsuite/sim/bpf/mov.s
new file mode 100644
index 0000000000..6665450468
--- /dev/null
+++ b/sim/testsuite/sim/bpf/mov.s
@@ -0,0 +1,54 @@
+# mach: bpf
+# output: pass\nexit 0 (0x0)\n
+;; mov.s
+;; Tests for mov and mov32 instructions
+
+    .include "testutils.inc"
+
+    .text
+    .global main
+    .type main, @function
+main:
+    ;; some basic sanity checks
+    mov32       %r1, 5
+    fail_ne     %r1, 5
+
+    mov32       %r2, %r1
+    fail_ne     %r2, 5
+
+    mov         %r2, %r1
+    fail_ne     %r2, 5
+
+    mov         %r1, -666
+    fail_ne     %r1, -666
+
+    ;; should NOT sign extend
+    mov32       %r1, -1
+    fail_ne     %r1, 0x00000000ffffffff
+
+    ;; should sign extend
+    mov         %r2, -1
+    fail_ne     %r2, 0xffffffffffffffff
+
+    mov         %r3, 0x80000000
+
+    ;; should NOT sign extend
+    mov32       %r4, %r3
+    fail_ne     %r4, 0x0000000080000000
+
+    ;; should sign extend
+    mov         %r5, %r3
+    fail_ne     %r5, 0xffffffff80000000
+
+    mov32       %r1, -2147483648
+    mov32       %r1, %r1
+    fail_ne32   %r1, -2147483648
+
+    ;; casting shenanigans
+    mov         %r1, %r1
+    fail_ne     %r1, +2147483648
+    mov32       %r2, -1
+    mov         %r2, %r2
+    fail_ne     %r2, +4294967295
+
+    pass
diff --git a/sim/testsuite/sim/bpf/testutils.inc b/sim/testsuite/sim/bpf/testutils.inc
new file mode 100644
index 0000000000..d3d6b17b5b
--- /dev/null
+++ b/sim/testsuite/sim/bpf/testutils.inc
@@ -0,0 +1,38 @@
+
+    ;; Print "pass\n" and 'exit 0'
+    .macro      pass
+    .data
+mpass:
+    .string "pass\n"
+    .text
+_pass:
+    mov         %r1, mpass      ; point to "pass\n" string
+    mov         %r2, 5          ; strlen mpass
+    call        7               ; printk
+    mov         %r0, 0          ;
+    exit                        ; exit 0
+    .endm
+
+;;; MACRO fail
+;;; Exit with status 1
+    .macro fail
+    mov %r0, 1
+    exit
+    .endm
+
+;;; MACRO fail_ne32
+;;; Exit with status 1 if \reg32 != \val
+    .macro      fail_ne32 reg val
+    jeq32       \reg, \val, 2
+    mov         %r0, 1
+    exit
+    .endm
+
+;;; MACRO fail_ne
+;;; Exit with status1 if \reg ne \val
+    .macro      fail_ne reg val
+    lddw        %r0, \val
+    jeq         \reg, %r0, 2
+    mov         %r0, 1
+    exit
+    .endm
diff --git a/sim/testsuite/sim/bpf/xadd.s b/sim/testsuite/sim/bpf/xadd.s
new file mode 100644
index 0000000000..1ca7577145
--- /dev/null
+++ b/sim/testsuite/sim/bpf/xadd.s
@@ -0,0 +1,44 @@
+# mach: bpf
+# output: pass\nexit 0 (0x0)\n
+;;; xadd.s
+;;; Tests for BPF atomic exchange-and-add instructions in simulator
+;;;
+;;; The xadd instructions (XADDW, XADDDW) operate on a memory location
+;;; specified in $dst + offset16, atomically adding the value in $src.
+;;;
+;;; In the simulator, there isn't anything else happening. The atomic
+;;; instructions are identical to a non-atomic load/add/store.
+
+    .include "testutils.inc"
+   
+    .text
+    .global main
+    .type main, @function
+main:
+    mov         %r1, 0x1000
+    mov         %r2, 5
+
+    ;; basic xadd w
+    stw         [%r1+0], 10
+    xaddw       [%r1+0], %r2
+    ldxw        %r3, [%r1+0]
+    fail_ne     %r3, 15
+
+    ;; basic xadd dw
+    stdw        [%r1+8], 42
+    xadddw      [%r1+8], %r2
+    ldxdw       %r3, [%r1+8]
+    fail_ne     %r3, 47
+
+    ;; xadd w negative value
+    mov         %r4, -1
+    xaddw       [%r1+0], %r4
+    ldxw        %r3, [%r1+0]
+    fail_ne     %r3, 14
+
+    ;; xadd dw negative val
+    xadddw      [%r1+8], %r4
+    ldxdw       %r3, [%r1+8]
+    fail_ne     %r3, 46
+
+    pass
-- 
2.25.0.2.g232378479e



More information about the Gdb-patches mailing list