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[binutils-gdb] RISC-V: Linux signal frame support.
- From: Jim Wilson <wilson at sourceware dot org>
- To: gdb-cvs at sourceware dot org
- Date: 26 Oct 2018 17:33:30 -0000
- Subject: [binutils-gdb] RISC-V: Linux signal frame support.
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=77c6f5fcdae65da0428ff75fa81059f1b5271cf0
commit 77c6f5fcdae65da0428ff75fa81059f1b5271cf0
Author: Jim Wilson <jimw@sifive.com>
Date: Fri Oct 26 10:32:58 2018 -0700
RISC-V: Linux signal frame support.
Add support for recognizing signal trampolines, parsing the signal frame,
and reading register values from it.
gdb/
* riscv-linux-tdep.c: Include tramp-frame.h and trad-frame.h.
(riscv_linux_sigframe_init): Declare.
(RISCV_INST_LI_A7_SIGRETURN, RISCV_INT_ECALL): New.
(riscv_linux_sigframe): New.
(SIGFRAME_SIGINFO_SIZE, UCONTEXT_MCONTEXT_OFFSET): New.
(riscv_linux_sigframe_init): Define.
(riscv_linux_init_abi): Call tramp_frame_prepend_unwinder.
Diff:
---
gdb/ChangeLog | 8 +++++
gdb/riscv-linux-tdep.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 88 insertions(+)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 4d068ee..f457212 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,13 @@
2018-10-26 Jim Wilson <jimw@sifive.com>
+ * riscv-linux-tdep.c: Include tramp-frame.h and trad-frame.h.
+ (riscv_linux_sigframe_init): Declare.
+ (RISCV_INST_LI_A7_SIGRETURN, RISCV_INT_ECALL): New.
+ (riscv_linux_sigframe): New.
+ (SIGFRAME_SIGINFO_SIZE, UCONTEXT_MCONTEXT_OFFSET): New.
+ (riscv_linux_sigframe_init): Define.
+ (riscv_linux_init_abi): Call tramp_frame_prepend_unwinder.
+
* riscv-tdep.c (riscv_isa_xlen): Refer to riscv-tdep.h comment.
(riscv_isa_flen): Likewise. Drop static.
* riscv-tdep.h (riscv_isa_xlen): Move riscv-tdep.c comment to here.
diff --git a/gdb/riscv-linux-tdep.c b/gdb/riscv-linux-tdep.c
index d072c0b..ece75db 100644
--- a/gdb/riscv-linux-tdep.c
+++ b/gdb/riscv-linux-tdep.c
@@ -23,6 +23,8 @@
#include "linux-tdep.h"
#include "solib-svr4.h"
#include "regset.h"
+#include "tramp-frame.h"
+#include "trad-frame.h"
/* Define the general register mapping. The kernel puts the PC at offset 0,
gdb puts it at offset 32. Register x0 is always 0 and can be ignored.
@@ -56,6 +58,82 @@ riscv_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
/* TODO: Add FP register support. */
}
+/* Signal trampoline support. */
+
+static void riscv_linux_sigframe_init (const struct tramp_frame *self,
+ struct frame_info *this_frame,
+ struct trad_frame_cache *this_cache,
+ CORE_ADDR func);
+
+#define RISCV_INST_LI_A7_SIGRETURN 0x08b00893
+#define RISCV_INST_ECALL 0x00000073
+
+static const struct tramp_frame riscv_linux_sigframe = {
+ SIGTRAMP_FRAME,
+ 4,
+ {
+ { RISCV_INST_LI_A7_SIGRETURN, ULONGEST_MAX },
+ { RISCV_INST_ECALL, ULONGEST_MAX },
+ { TRAMP_SENTINEL_INSN }
+ },
+ riscv_linux_sigframe_init,
+ NULL
+};
+
+/* Runtime signal frames look like this:
+ struct rt_sigframe {
+ struct siginfo info;
+ struct ucontext uc;
+ };
+
+ struct ucontext {
+ unsigned long __uc_flags;
+ struct ucontext *uclink;
+ stack_t uc_stack;
+ sigset_t uc_sigmask;
+ char __glibc_reserved[1024 / 8 - sizeof (sigset_t)];
+ mcontext_t uc_mcontext;
+ }; */
+
+#define SIGFRAME_SIGINFO_SIZE 128
+#define UCONTEXT_MCONTEXT_OFFSET 176
+
+static void
+riscv_linux_sigframe_init (const struct tramp_frame *self,
+ struct frame_info *this_frame,
+ struct trad_frame_cache *this_cache,
+ CORE_ADDR func)
+{
+ struct gdbarch *gdbarch = get_frame_arch (this_frame);
+ int xlen = riscv_isa_xlen (gdbarch);
+ int flen = riscv_isa_flen (gdbarch);
+ CORE_ADDR frame_sp = get_frame_sp (this_frame);
+ CORE_ADDR mcontext_base;
+ CORE_ADDR regs_base;
+
+ mcontext_base = frame_sp + SIGFRAME_SIGINFO_SIZE + UCONTEXT_MCONTEXT_OFFSET;
+
+ /* Handle the integer registers. The first one is PC, followed by x1
+ through x31. */
+ regs_base = mcontext_base;
+ trad_frame_set_reg_addr (this_cache, RISCV_PC_REGNUM, regs_base);
+ for (int i = 1; i < 32; i++)
+ trad_frame_set_reg_addr (this_cache, RISCV_ZERO_REGNUM + i,
+ regs_base + (i * xlen));
+
+ /* Handle the FP registers. First comes the 32 FP registers, followed by
+ fcsr. */
+ regs_base += 32 * xlen;
+ for (int i = 0; i < 32; i++)
+ trad_frame_set_reg_addr (this_cache, RISCV_FIRST_FP_REGNUM + i,
+ regs_base + (i * flen));
+ regs_base += 32 * flen;
+ trad_frame_set_reg_addr (this_cache, RISCV_CSR_FCSR_REGNUM, regs_base);
+
+ /* Choice of the bottom of the sigframe is somewhat arbitrary. */
+ trad_frame_set_id (this_cache, frame_id_build (frame_sp, func));
+}
+
/* Initialize RISC-V Linux ABI info. */
static void
@@ -82,6 +160,8 @@ riscv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
set_gdbarch_iterate_over_regset_sections
(gdbarch, riscv_linux_iterate_over_regset_sections);
+
+ tramp_frame_prepend_unwinder (gdbarch, &riscv_linux_sigframe);
}
/* Initialize RISC-V Linux target support. */