[RFC/RFA] Trampoline skipping for OpenBSD/hppa
Mark Kettenis
mark.kettenis@xs4all.nl
Fri Jan 20 23:39:00 GMT 2006
> Date: Sat, 14 Jan 2006 22:45:54 +0100 (CET)
> From: Mark Kettenis <mark.kettenis@xs4all.nl>
>
> Hi Randolph,
>
> The trampoline skipping code in hppa-linux-tdep.c is useful on systems
> too. Basically every ELF system that uses the GNU toolchain will
> needs it. The attached patch moves the code into hppa-tdep.c. I
> couldn't resist cleaning up the code a bit. Unfortunately, I don't
> have a PA-RISC Linux system around, so I can't test whether this
> breaks Linux support. Could you (or anyone else) give this a spin on
> Linux? Comments are welcome too of course.
>
> Mark
After private convesation with Randolph, I've committed the attached.
Mark
Index: ChangeLog
===================================================================
RCS file: /cvs/src/src/gdb/ChangeLog,v
retrieving revision 1.7553
diff -u -p -r1.7553 ChangeLog
--- ChangeLog 20 Jan 2006 22:31:07 -0000 1.7553
+++ ChangeLog 20 Jan 2006 23:36:17 -0000
@@ -1,3 +1,27 @@
+2006-01-20 Mark Kettenis <kettenis@gnu.org>
+
+ * hppa-tdep.h (hppa_in_solib_call_trampoline)
+ (hppa_skip_trampoline_code): New prototypes.
+ * hppa-tdep.c (struct insn_pattern): New.
+ (hppa_long_branch_stub, hppa_long_branch_pic_stub)
+ (hppa_import_stub, hppa_import_pic_stub, hppa_plt_stub): Moved
+ here from hppa-linux-tdep.c
+ (HPPA_MAX_INSN_PATTERN_LEN): New define.
+ (hppa_match_insns, hppa_match_insns_relaxed, hppa_in_dyncall)
+ (hppa_in_solib_call_trampoline, hppa_skip_trampoline_code): New
+ functions based on functions removed from hppa-linux-tdep.c.
+ * hppa-linux-tdep.c (hppa_long_branch_stub)
+ (hppa_long_branch_pic_stub, hppa_import_stub)
+ (hppa_import_pic_stub, hppa_plt_stub): Moved to hppa-tdep.c.
+ (insns_match_pattern_relaxed, hppa_linux_in_dyncall)
+ (hppa_linux_in_solib_call_trampoline)
+ (hppa_linux_skip_trampoline_code): Removed.
+ (hppa_linux_init_abi): Set TDEP->in_solib_call_tranpoline to
+ hppa_in_solib_call_trampoline and skip_trampoline_code to
+ hppa_skip_trampoline_code.
+ * hppabsd-tdep.c (hppabsd_init_abi): Set
+ TDEP->in_solib_call_trampoline and skip_trampoline_code.
+
2006-01-20 Jim Blandy <jimb@redhat.com>
* MAINTAINERS: Change my E-mail address.
Index: hppa-linux-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/hppa-linux-tdep.c,v
retrieving revision 1.16
diff -u -p -r1.16 hppa-linux-tdep.c
--- hppa-linux-tdep.c 14 Jan 2006 18:45:12 -0000 1.16
+++ hppa-linux-tdep.c 20 Jan 2006 23:36:17 -0000
@@ -1,6 +1,6 @@
/* Target-dependent code for GNU/Linux running on PA-RISC, for GDB.
- Copyright (C) 2004 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2006 Free Software Foundation, Inc.
This file is part of GDB.
@@ -68,57 +68,6 @@ struct insn_pattern
unsigned int mask; /* ... with this mask. */
};
-/* See bfd/elf32-hppa.c */
-static struct insn_pattern hppa_long_branch_stub[] = {
- /* ldil LR'xxx,%r1 */
- { 0x20200000, 0xffe00000 },
- /* be,n RR'xxx(%sr4,%r1) */
- { 0xe0202002, 0xffe02002 },
- { 0, 0 }
-};
-
-static struct insn_pattern hppa_long_branch_pic_stub[] = {
- /* b,l .+8, %r1 */
- { 0xe8200000, 0xffe00000 },
- /* addil LR'xxx - ($PIC_pcrel$0 - 4), %r1 */
- { 0x28200000, 0xffe00000 },
- /* be,n RR'xxxx - ($PIC_pcrel$0 - 8)(%sr4, %r1) */
- { 0xe0202002, 0xffe02002 },
- { 0, 0 }
-};
-
-static struct insn_pattern hppa_import_stub[] = {
- /* addil LR'xxx, %dp */
- { 0x2b600000, 0xffe00000 },
- /* ldw RR'xxx(%r1), %r21 */
- { 0x48350000, 0xffffb000 },
- /* bv %r0(%r21) */
- { 0xeaa0c000, 0xffffffff },
- /* ldw RR'xxx+4(%r1), %r19 */
- { 0x48330000, 0xffffb000 },
- { 0, 0 }
-};
-
-static struct insn_pattern hppa_import_pic_stub[] = {
- /* addil LR'xxx,%r19 */
- { 0x2a600000, 0xffe00000 },
- /* ldw RR'xxx(%r1),%r21 */
- { 0x48350000, 0xffffb000 },
- /* bv %r0(%r21) */
- { 0xeaa0c000, 0xffffffff },
- /* ldw RR'xxx+4(%r1),%r19 */
- { 0x48330000, 0xffffb000 },
- { 0, 0 },
-};
-
-static struct insn_pattern hppa_plt_stub[] = {
- /* b,l 1b, %r20 - 1b is 3 insns before here */
- { 0xea9f1fdd, 0xffffffff },
- /* depi 0,31,2,%r20 */
- { 0xd6801c1e, 0xffffffff },
- { 0, 0 }
-};
-
static struct insn_pattern hppa_sigtramp[] = {
/* ldi 0, %r25 or ldi 1, %r25 */
{ 0x34190000, 0xfffffffd },
@@ -162,133 +111,6 @@ insns_match_pattern (CORE_ADDR pc,
return 1;
}
-/* The relaxed version of the insn matcher allows us to match from somewhere
- inside the pattern, by looking backwards in the instruction scheme. */
-static int
-insns_match_pattern_relaxed (CORE_ADDR pc,
- struct insn_pattern *pattern,
- unsigned int *insn)
-{
- int pat_len = 0;
- int offset;
-
- while (pattern[pat_len].mask)
- pat_len++;
-
- for (offset = 0; offset < pat_len; offset++)
- {
- if (insns_match_pattern (pc - offset * 4,
- pattern, insn))
- return 1;
- }
-
- return 0;
-}
-
-static int
-hppa_linux_in_dyncall (CORE_ADDR pc)
-{
- struct unwind_table_entry *u;
- u = find_unwind_entry (hppa_symbol_address ("$$dyncall"));
-
- if (!u)
- return 0;
-
- return pc >= u->region_start && pc <= u->region_end;
-}
-
-/* There are several kinds of "trampolines" that we need to deal with:
- - long branch stubs: these are inserted by the linker when a branch
- target is too far away for a branch insn to reach
- - plt stubs: these should go into the .plt section, so are easy to find
- - import stubs: used to call from object to shared lib or shared lib to
- shared lib; these go in regular text sections. In fact the linker tries
- to put them throughout the code because branches have limited reachability.
- We use the same mechanism as ppc64 to recognize the stub insn patterns.
- - $$dyncall: similar to hpux, hppa-linux uses $$dyncall for indirect function
- calls. $$dyncall is exported by libgcc.a */
-static int
-hppa_linux_in_solib_call_trampoline (CORE_ADDR pc, char *name)
-{
- unsigned int insn[HPPA_MAX_INSN_PATTERN_LEN];
- int r;
- struct unwind_table_entry *u;
-
- /* on hppa-linux, linker stubs have no unwind information. Since the pattern
- matching for linker stubs can be quite slow, we try to avoid it if
- we can. */
- u = find_unwind_entry (pc);
-
- r = in_plt_section (pc, name)
- || hppa_linux_in_dyncall (pc)
- || (u == NULL
- && (insns_match_pattern_relaxed (pc, hppa_import_stub, insn)
- || insns_match_pattern_relaxed (pc, hppa_import_pic_stub, insn)
- || insns_match_pattern_relaxed (pc, hppa_long_branch_stub, insn)
- || insns_match_pattern_relaxed (pc, hppa_long_branch_pic_stub, insn)));
-
- return r;
-}
-
-static CORE_ADDR
-hppa_linux_skip_trampoline_code (CORE_ADDR pc)
-{
- unsigned int insn[HPPA_MAX_INSN_PATTERN_LEN];
- int dp_rel, pic_rel;
-
- /* dyncall handles both PLABELs and direct addresses */
- if (hppa_linux_in_dyncall (pc))
- {
- pc = (CORE_ADDR) read_register (22);
-
- /* PLABELs have bit 30 set; if it's a PLABEL, then dereference it */
- if (pc & 0x2)
- pc = (CORE_ADDR) read_memory_integer (pc & ~0x3, TARGET_PTR_BIT / 8);
-
- return pc;
- }
-
- dp_rel = pic_rel = 0;
- if ((dp_rel = insns_match_pattern (pc, hppa_import_stub, insn))
- || (pic_rel = insns_match_pattern (pc, hppa_import_pic_stub, insn)))
- {
- /* Extract the target address from the addil/ldw sequence. */
- pc = hppa_extract_21 (insn[0]) + hppa_extract_14 (insn[1]);
-
- if (dp_rel)
- pc += (CORE_ADDR) read_register (27);
- else
- pc += (CORE_ADDR) read_register (19);
-
- /* fallthrough */
- }
-
- if (in_plt_section (pc, NULL))
- {
- pc = (CORE_ADDR) read_memory_integer (pc, TARGET_PTR_BIT / 8);
-
- /* if the plt slot has not yet been resolved, the target will
- be the plt stub */
- if (in_plt_section (pc, NULL))
- {
- /* Sanity check: are we pointing to the plt stub? */
- if (insns_match_pattern (pc, hppa_plt_stub, insn))
- {
- /* this should point to the fixup routine */
- pc = (CORE_ADDR) read_memory_integer (pc + 8, TARGET_PTR_BIT / 8);
- }
- else
- {
- error (_("Cannot resolve plt stub at 0x%s."),
- paddr_nz (pc));
- pc = 0;
- }
- }
- }
-
- return pc;
-}
-
/* Signal frames. */
/* (This is derived from MD_FALLBACK_FRAME_STATE_FOR in gcc.)
@@ -600,9 +422,8 @@ hppa_linux_init_abi (struct gdbarch_info
set_solib_svr4_fetch_link_map_offsets
(gdbarch, svr4_ilp32_fetch_link_map_offsets);
- tdep->in_solib_call_trampoline = hppa_linux_in_solib_call_trampoline;
- set_gdbarch_skip_trampoline_code
- (gdbarch, hppa_linux_skip_trampoline_code);
+ tdep->in_solib_call_trampoline = hppa_in_solib_call_trampoline;
+ set_gdbarch_skip_trampoline_code (gdbarch, hppa_skip_trampoline_code);
/* GNU/Linux uses the dynamic linker included in the GNU C Library. */
set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
Index: hppa-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/hppa-tdep.c,v
retrieving revision 1.217
diff -u -p -r1.217 hppa-tdep.c
--- hppa-tdep.c 17 Dec 2005 22:34:00 -0000 1.217
+++ hppa-tdep.c 20 Jan 2006 23:36:19 -0000
@@ -2737,6 +2737,223 @@ hppa_frame_prev_register_helper (struct
}
+/* An instruction to match. */
+struct insn_pattern
+{
+ unsigned int data; /* See if it matches this.... */
+ unsigned int mask; /* ... with this mask. */
+};
+
+/* See bfd/elf32-hppa.c */
+static struct insn_pattern hppa_long_branch_stub[] = {
+ /* ldil LR'xxx,%r1 */
+ { 0x20200000, 0xffe00000 },
+ /* be,n RR'xxx(%sr4,%r1) */
+ { 0xe0202002, 0xffe02002 },
+ { 0, 0 }
+};
+
+static struct insn_pattern hppa_long_branch_pic_stub[] = {
+ /* b,l .+8, %r1 */
+ { 0xe8200000, 0xffe00000 },
+ /* addil LR'xxx - ($PIC_pcrel$0 - 4), %r1 */
+ { 0x28200000, 0xffe00000 },
+ /* be,n RR'xxxx - ($PIC_pcrel$0 - 8)(%sr4, %r1) */
+ { 0xe0202002, 0xffe02002 },
+ { 0, 0 }
+};
+
+static struct insn_pattern hppa_import_stub[] = {
+ /* addil LR'xxx, %dp */
+ { 0x2b600000, 0xffe00000 },
+ /* ldw RR'xxx(%r1), %r21 */
+ { 0x48350000, 0xffffb000 },
+ /* bv %r0(%r21) */
+ { 0xeaa0c000, 0xffffffff },
+ /* ldw RR'xxx+4(%r1), %r19 */
+ { 0x48330000, 0xffffb000 },
+ { 0, 0 }
+};
+
+static struct insn_pattern hppa_import_pic_stub[] = {
+ /* addil LR'xxx,%r19 */
+ { 0x2a600000, 0xffe00000 },
+ /* ldw RR'xxx(%r1),%r21 */
+ { 0x48350000, 0xffffb000 },
+ /* bv %r0(%r21) */
+ { 0xeaa0c000, 0xffffffff },
+ /* ldw RR'xxx+4(%r1),%r19 */
+ { 0x48330000, 0xffffb000 },
+ { 0, 0 },
+};
+
+static struct insn_pattern hppa_plt_stub[] = {
+ /* b,l 1b, %r20 - 1b is 3 insns before here */
+ { 0xea9f1fdd, 0xffffffff },
+ /* depi 0,31,2,%r20 */
+ { 0xd6801c1e, 0xffffffff },
+ { 0, 0 }
+};
+
+static struct insn_pattern hppa_sigtramp[] = {
+ /* ldi 0, %r25 or ldi 1, %r25 */
+ { 0x34190000, 0xfffffffd },
+ /* ldi __NR_rt_sigreturn, %r20 */
+ { 0x3414015a, 0xffffffff },
+ /* be,l 0x100(%sr2, %r0), %sr0, %r31 */
+ { 0xe4008200, 0xffffffff },
+ /* nop */
+ { 0x08000240, 0xffffffff },
+ { 0, 0 }
+};
+
+/* Maximum number of instructions on the patterns above. */
+#define HPPA_MAX_INSN_PATTERN_LEN 4
+
+/* Return non-zero if the instructions at PC match the series
+ described in PATTERN, or zero otherwise. PATTERN is an array of
+ 'struct insn_pattern' objects, terminated by an entry whose mask is
+ zero.
+
+ When the match is successful, fill INSN[i] with what PATTERN[i]
+ matched. */
+
+static int
+hppa_match_insns (CORE_ADDR pc, struct insn_pattern *pattern,
+ unsigned int *insn)
+{
+ CORE_ADDR npc = pc;
+ int i;
+
+ for (i = 0; pattern[i].mask; i++)
+ {
+ gdb_byte buf[HPPA_INSN_SIZE];
+
+ deprecated_read_memory_nobpt (npc, buf, HPPA_INSN_SIZE);
+ insn[i] = extract_unsigned_integer (buf, HPPA_INSN_SIZE);
+ if ((insn[i] & pattern[i].mask) == pattern[i].data)
+ npc += 4;
+ else
+ return 0;
+ }
+
+ return 1;
+}
+
+/* This relaxed version of the insstruction matcher allows us to match
+ from somewhere inside the pattern, by looking backwards in the
+ instruction scheme. */
+
+static int
+hppa_match_insns_relaxed (CORE_ADDR pc, struct insn_pattern *pattern,
+ unsigned int *insn)
+{
+ int offset, len = 0;
+
+ while (pattern[len].mask)
+ len++;
+
+ for (offset = 0; offset < len; offset++)
+ if (hppa_match_insns (pc - offset * HPPA_INSN_SIZE, pattern, insn))
+ return 1;
+
+ return 0;
+}
+
+static int
+hppa_in_dyncall (CORE_ADDR pc)
+{
+ struct unwind_table_entry *u;
+
+ u = find_unwind_entry (hppa_symbol_address ("$$dyncall"));
+ if (!u)
+ return 0;
+
+ return (pc >= u->region_start && pc <= u->region_end);
+}
+
+int
+hppa_in_solib_call_trampoline (CORE_ADDR pc, char *name)
+{
+ unsigned int insn[HPPA_MAX_INSN_PATTERN_LEN];
+ struct unwind_table_entry *u;
+
+ if (in_plt_section (pc, name) || hppa_in_dyncall (pc))
+ return 1;
+
+ /* The GNU toolchain produces linker stubs without unwind
+ information. Since the pattern matching for linker stubs can be
+ quite slow, so bail out if we do have an unwind entry. */
+
+ u = find_unwind_entry (pc);
+ if (u == NULL)
+ return 0;
+
+ return (hppa_match_insns_relaxed (pc, hppa_import_stub, insn)
+ || hppa_match_insns_relaxed (pc, hppa_import_pic_stub, insn)
+ || hppa_match_insns_relaxed (pc, hppa_long_branch_stub, insn)
+ || hppa_match_insns_relaxed (pc, hppa_long_branch_pic_stub, insn));
+}
+
+/* This code skips several kind of "trampolines" used on PA-RISC
+ systems: $$dyncall, import stubs and PLT stubs. */
+
+CORE_ADDR
+hppa_skip_trampoline_code (CORE_ADDR pc)
+{
+ unsigned int insn[HPPA_MAX_INSN_PATTERN_LEN];
+ int dp_rel;
+
+ /* $$dyncall handles both PLABELs and direct addresses. */
+ if (hppa_in_dyncall (pc))
+ {
+ pc = read_register (HPPA_R0_REGNUM + 22);
+
+ /* PLABELs have bit 30 set; if it's a PLABEL, then dereference it. */
+ if (pc & 0x2)
+ pc = read_memory_typed_address (pc & ~0x3, builtin_type_void_func_ptr);
+
+ return pc;
+ }
+
+ dp_rel = hppa_match_insns (pc, hppa_import_stub, insn);
+ if (dp_rel || hppa_match_insns (pc, hppa_import_pic_stub, insn))
+ {
+ /* Extract the target address from the addil/ldw sequence. */
+ pc = hppa_extract_21 (insn[0]) + hppa_extract_14 (insn[1]);
+
+ if (dp_rel)
+ pc += read_register (HPPA_DP_REGNUM);
+ else
+ pc += read_register (HPPA_R0_REGNUM + 19);
+
+ /* fallthrough */
+ }
+
+ if (in_plt_section (pc, NULL))
+ {
+ pc = read_memory_typed_address (pc, builtin_type_void_func_ptr);
+
+ /* If the PLT slot has not yet been resolved, the target will be
+ the PLT stub. */
+ if (in_plt_section (pc, NULL))
+ {
+ /* Sanity check: are we pointing to the PLT stub? */
+ if (!hppa_match_insns (pc, hppa_plt_stub, insn))
+ {
+ warning (_("Cannot resolve PLT stub at 0x%s."), paddr_nz (pc));
+ return 0;
+ }
+
+ /* This should point to the fixup routine. */
+ pc = read_memory_typed_address (pc + 8, builtin_type_void_func_ptr);
+ }
+ }
+
+ return pc;
+}
+
+
/* Here is a table of C type sizes on hppa with various compiles
and options. I measured this on PA 9000/800 with HP-UX 11.11
and these compilers:
Index: hppa-tdep.h
===================================================================
RCS file: /cvs/src/src/gdb/hppa-tdep.h,v
retrieving revision 1.24
diff -u -p -r1.24 hppa-tdep.h
--- hppa-tdep.h 14 Jan 2006 12:24:36 -0000 1.24
+++ hppa-tdep.h 20 Jan 2006 23:36:19 -0000
@@ -1,6 +1,6 @@
/* Target-dependent code for the HP PA-RISC architecture.
- Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
+ Copyright (C) 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
This file is part of GDB.
@@ -250,4 +250,7 @@ extern struct minimal_symbol *
extern struct hppa_objfile_private *
hppa_init_objfile_priv_data (struct objfile *objfile);
-#endif /* HPPA_TDEP_H */
+extern int hppa_in_solib_call_trampoline (CORE_ADDR pc, char *name);
+extern CORE_ADDR hppa_skip_trampoline_code (CORE_ADDR pc);
+
+#endif /* hppa-tdep.h */
Index: hppabsd-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/hppabsd-tdep.c,v
retrieving revision 1.5
diff -u -p -r1.5 hppabsd-tdep.c
--- hppabsd-tdep.c 13 Jan 2006 23:09:08 -0000 1.5
+++ hppabsd-tdep.c 20 Jan 2006 23:36:20 -0000
@@ -178,8 +178,10 @@ hppabsd_init_abi (struct gdbarch_info in
(gdbarch, hppabsd_regset_from_core_section);
/* OpenBSD and NetBSD use ELF. */
- tdep->find_global_pointer = hppabsd_find_global_pointer;
tdep->is_elf = 1;
+ tdep->find_global_pointer = hppabsd_find_global_pointer;
+ tdep->in_solib_call_trampoline = hppa_in_solib_call_trampoline;
+ set_gdbarch_skip_trampoline_code (gdbarch, hppa_skip_trampoline_code);
/* OpenBSD and NetBSD use SVR4-style shared libraries. */
set_solib_svr4_fetch_link_map_offsets
More information about the Gdb-patches
mailing list