-/* Target-dependent code for GNU/Linux running on i386's, for GDB.
+/* Target-dependent code for GNU/Linux i386.
- Copyright 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
+ Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007
+ Free Software Foundation, Inc.
This file is part of GDB.
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 2 of the License, or
+ 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,
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, write to the Free Software
- Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "gdbcore.h"
#include "value.h"
#include "regcache.h"
#include "inferior.h"
-#include "reggroups.h"
-
-/* For i386_linux_skip_solib_resolver. */
-#include "symtab.h"
-#include "symfile.h"
-#include "objfiles.h"
-
-#include "solib-svr4.h" /* For struct link_map_offsets. */
-
#include "osabi.h"
+#include "reggroups.h"
+#include "dwarf2-frame.h"
+#include "gdb_string.h"
#include "i386-tdep.h"
#include "i386-linux-tdep.h"
+#include "glibc-tdep.h"
+#include "solib-svr4.h"
+#include "symtab.h"
/* Return the name of register REG. */
Checking for the code sequence should be somewhat reliable, because
the effect is to call the system call sigreturn. This is unlikely
- to occur anywhere other than a signal trampoline.
+ to occur anywhere other than in a signal trampoline.
It kind of sucks that we have to read memory from the process in
order to identify a signal trampoline, but there doesn't seem to be
- any other way. The PC_IN_SIGTRAMP macro in tm-linux.h arranges to
- only call us if no function name could be identified, which should
- be the case since the code is on the stack.
+ any other way. Therefore we only do the memory reads if no
+ function name could be identified, which should be the case since
+ the code is on the stack.
Detection of signal trampolines for handlers that set the
SA_RESTORER flag is in general not possible. Unfortunately this is
#define LINUX_SIGTRAMP_INSN2 0xcd /* int */
#define LINUX_SIGTRAMP_OFFSET2 6
-static const unsigned char linux_sigtramp_code[] =
+static const gdb_byte linux_sigtramp_code[] =
{
LINUX_SIGTRAMP_INSN0, /* pop %eax */
LINUX_SIGTRAMP_INSN1, 0x77, 0x00, 0x00, 0x00, /* mov $0x77, %eax */
#define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code)
-/* If PC is in a sigtramp routine, return the address of the start of
- the routine. Otherwise, return 0. */
+/* If NEXT_FRAME unwinds into a sigtramp routine, return the address
+ of the start of the routine. Otherwise, return 0. */
static CORE_ADDR
-i386_linux_sigtramp_start (CORE_ADDR pc)
+i386_linux_sigtramp_start (struct frame_info *next_frame)
{
- unsigned char buf[LINUX_SIGTRAMP_LEN];
+ CORE_ADDR pc = frame_pc_unwind (next_frame);
+ gdb_byte buf[LINUX_SIGTRAMP_LEN];
/* We only recognize a signal trampoline if PC is at the start of
one of the three instructions. We optimize for finding the PC at
PC is not at the start of the instruction sequence, there will be
a few trailing readable bytes on the stack. */
- if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0)
+ if (!safe_frame_unwind_memory (next_frame, pc, buf, LINUX_SIGTRAMP_LEN))
return 0;
if (buf[0] != LINUX_SIGTRAMP_INSN0)
pc -= adjust;
- if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0)
+ if (!safe_frame_unwind_memory (next_frame, pc, buf, LINUX_SIGTRAMP_LEN))
return 0;
}
#define LINUX_RT_SIGTRAMP_INSN1 0xcd /* int */
#define LINUX_RT_SIGTRAMP_OFFSET1 5
-static const unsigned char linux_rt_sigtramp_code[] =
+static const gdb_byte linux_rt_sigtramp_code[] =
{
LINUX_RT_SIGTRAMP_INSN0, 0xad, 0x00, 0x00, 0x00, /* mov $0xad, %eax */
LINUX_RT_SIGTRAMP_INSN1, 0x80 /* int $0x80 */
#define LINUX_RT_SIGTRAMP_LEN (sizeof linux_rt_sigtramp_code)
-/* If PC is in a RT sigtramp routine, return the address of the start
- of the routine. Otherwise, return 0. */
+/* If NEXT_FRAME unwinds into an RT sigtramp routine, return the
+ address of the start of the routine. Otherwise, return 0. */
static CORE_ADDR
-i386_linux_rt_sigtramp_start (CORE_ADDR pc)
+i386_linux_rt_sigtramp_start (struct frame_info *next_frame)
{
- unsigned char buf[LINUX_RT_SIGTRAMP_LEN];
+ CORE_ADDR pc = frame_pc_unwind (next_frame);
+ gdb_byte buf[LINUX_RT_SIGTRAMP_LEN];
/* We only recognize a signal trampoline if PC is at the start of
one of the two instructions. We optimize for finding the PC at
PC is not at the start of the instruction sequence, there will be
a few trailing readable bytes on the stack. */
- if (read_memory_nobpt (pc, (char *) buf, LINUX_RT_SIGTRAMP_LEN) != 0)
+ if (!safe_frame_unwind_memory (next_frame, pc, buf, LINUX_RT_SIGTRAMP_LEN))
return 0;
if (buf[0] != LINUX_RT_SIGTRAMP_INSN0)
pc -= LINUX_RT_SIGTRAMP_OFFSET1;
- if (read_memory_nobpt (pc, (char *) buf, LINUX_RT_SIGTRAMP_LEN) != 0)
+ if (!safe_frame_unwind_memory (next_frame, pc, buf,
+ LINUX_RT_SIGTRAMP_LEN))
return 0;
}
return pc;
}
-/* Return whether PC is in a GNU/Linux sigtramp routine. */
+/* Return whether the frame preceding NEXT_FRAME corresponds to a
+ GNU/Linux sigtramp routine. */
static int
-i386_linux_pc_in_sigtramp (CORE_ADDR pc, char *name)
+i386_linux_sigtramp_p (struct frame_info *next_frame)
{
+ CORE_ADDR pc = frame_pc_unwind (next_frame);
+ char *name;
+
+ find_pc_partial_function (pc, &name, NULL, NULL);
+
/* If we have NAME, we can optimize the search. The trampolines are
named __restore and __restore_rt. However, they aren't dynamically
exported from the shared C library, so the trampoline may appear to
be part of the preceding function. This should always be sigaction,
__sigaction, or __libc_sigaction (all aliases to the same function). */
if (name == NULL || strstr (name, "sigaction") != NULL)
- return (i386_linux_sigtramp_start (pc) != 0
- || i386_linux_rt_sigtramp_start (pc) != 0);
+ return (i386_linux_sigtramp_start (next_frame) != 0
+ || i386_linux_rt_sigtramp_start (next_frame) != 0);
return (strcmp ("__restore", name) == 0
|| strcmp ("__restore_rt", name) == 0);
}
+/* Return one if the unwound PC from NEXT_FRAME is in a signal trampoline
+ which may have DWARF-2 CFI. */
+
+static int
+i386_linux_dwarf_signal_frame_p (struct gdbarch *gdbarch,
+ struct frame_info *next_frame)
+{
+ CORE_ADDR pc = frame_pc_unwind (next_frame);
+ char *name;
+
+ find_pc_partial_function (pc, &name, NULL, NULL);
+
+ /* If a vsyscall DSO is in use, the signal trampolines may have these
+ names. */
+ if (name && (strcmp (name, "__kernel_sigreturn") == 0
+ || strcmp (name, "__kernel_rt_sigreturn") == 0))
+ return 1;
+
+ return 0;
+}
+
/* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */
#define I386_LINUX_UCONTEXT_SIGCONTEXT_OFFSET 20
{
CORE_ADDR pc;
CORE_ADDR sp;
- char buf[4];
+ gdb_byte buf[4];
frame_unwind_register (next_frame, I386_ESP_REGNUM, buf);
sp = extract_unsigned_integer (buf, 4);
- pc = i386_linux_sigtramp_start (frame_pc_unwind (next_frame));
+ pc = i386_linux_sigtramp_start (next_frame);
if (pc)
{
/* The sigcontext structure lives on the stack, right after
return sp;
}
- pc = i386_linux_rt_sigtramp_start (frame_pc_unwind (next_frame));
+ pc = i386_linux_rt_sigtramp_start (next_frame);
if (pc)
{
CORE_ADDR ucontext_addr;
pointer to the user context is passed as the third argument
to the signal handler. */
read_memory (sp + 8, buf, 4);
- ucontext_addr = extract_unsigned_integer (buf, 4) + 20;
+ ucontext_addr = extract_unsigned_integer (buf, 4);
return ucontext_addr + I386_LINUX_UCONTEXT_SIGCONTEXT_OFFSET;
}
- error ("Couldn't recognize signal trampoline.");
+ error (_("Couldn't recognize signal trampoline."));
return 0;
}
/* Set the program counter for process PTID to PC. */
static void
-i386_linux_write_pc (CORE_ADDR pc, ptid_t ptid)
+i386_linux_write_pc (struct regcache *regcache, CORE_ADDR pc)
{
- write_register_pid (I386_EIP_REGNUM, pc, ptid);
+ regcache_cooked_write_unsigned (regcache, I386_EIP_REGNUM, pc);
/* We must be careful with modifying the program counter. If we
just interrupted a system call, the kernel might try to restart
when we resume the inferior on return from a function call from
within GDB. In all other cases the system call will not be
restarted. */
- write_register_pid (I386_LINUX_ORIG_EAX_REGNUM, -1, ptid);
-}
-\f
-/* Calling functions in shared libraries. */
-
-/* Find the minimal symbol named NAME, and return both the minsym
- struct and its objfile. This probably ought to be in minsym.c, but
- everything there is trying to deal with things like C++ and
- SOFUN_ADDRESS_MAYBE_TURQUOISE, ... Since this is so simple, it may
- be considered too special-purpose for general consumption. */
-
-static struct minimal_symbol *
-find_minsym_and_objfile (char *name, struct objfile **objfilep)
-{
- struct objfile *objfile;
-
- ALL_OBJFILES (objfile)
- {
- struct minimal_symbol *msym;
-
- ALL_OBJFILE_MSYMBOLS (objfile, msym)
- {
- if (SYMBOL_LINKAGE_NAME (msym)
- && strcmp (SYMBOL_LINKAGE_NAME (msym), name) == 0)
- {
- *objfilep = objfile;
- return msym;
- }
- }
- }
-
- return 0;
-}
-
-static CORE_ADDR
-skip_gnu_resolver (CORE_ADDR pc)
-{
- /* The GNU dynamic linker is part of the GNU C library, so many
- GNU/Linux distributions use it. (All ELF versions, as far as I
- know.) An unresolved PLT entry points to "_dl_runtime_resolve",
- which calls "fixup" to patch the PLT, and then passes control to
- the function.
-
- We look for the symbol `_dl_runtime_resolve', and find `fixup' in
- the same objfile. If we are at the entry point of `fixup', then
- we set a breakpoint at the return address (at the top of the
- stack), and continue.
-
- It's kind of gross to do all these checks every time we're
- called, since they don't change once the executable has gotten
- started. But this is only a temporary hack --- upcoming versions
- of GNU/Linux will provide a portable, efficient interface for
- debugging programs that use shared libraries. */
-
- struct objfile *objfile;
- struct minimal_symbol *resolver
- = find_minsym_and_objfile ("_dl_runtime_resolve", &objfile);
-
- if (resolver)
- {
- struct minimal_symbol *fixup
- = lookup_minimal_symbol ("fixup", NULL, objfile);
-
- if (fixup && SYMBOL_VALUE_ADDRESS (fixup) == pc)
- return frame_pc_unwind (get_current_frame ());
- }
-
- return 0;
-}
-
-/* See the comments for SKIP_SOLIB_RESOLVER at the top of infrun.c.
- This function:
- 1) decides whether a PLT has sent us into the linker to resolve
- a function reference, and
- 2) if so, tells us where to set a temporary breakpoint that will
- trigger when the dynamic linker is done. */
-
-CORE_ADDR
-i386_linux_skip_solib_resolver (CORE_ADDR pc)
-{
- CORE_ADDR result;
-
- /* Plug in functions for other kinds of resolvers here. */
- result = skip_gnu_resolver (pc);
- if (result)
- return result;
-
- return 0;
-}
-
-/* Fetch (and possibly build) an appropriate link_map_offsets
- structure for native GNU/Linux x86 targets using the struct offsets
- defined in link.h (but without actual reference to that file).
-
- This makes it possible to access GNU/Linux x86 shared libraries
- from a GDB that was not built on an GNU/Linux x86 host (for cross
- debugging). */
-
-static struct link_map_offsets *
-i386_linux_svr4_fetch_link_map_offsets (void)
-{
- static struct link_map_offsets lmo;
- static struct link_map_offsets *lmp = NULL;
-
- if (lmp == NULL)
- {
- lmp = &lmo;
-
- lmo.r_debug_size = 8; /* The actual size is 20 bytes, but
- this is all we need. */
- lmo.r_map_offset = 4;
- lmo.r_map_size = 4;
-
- lmo.link_map_size = 20; /* The actual size is 552 bytes, but
- this is all we need. */
- lmo.l_addr_offset = 0;
- lmo.l_addr_size = 4;
-
- lmo.l_name_offset = 4;
- lmo.l_name_size = 4;
-
- lmo.l_next_offset = 12;
- lmo.l_next_size = 4;
-
- lmo.l_prev_offset = 16;
- lmo.l_prev_size = 4;
- }
-
- return lmp;
+ regcache_cooked_write_unsigned (regcache, I386_LINUX_ORIG_EAX_REGNUM, -1);
}
\f
tdep->jb_pc_offset = 20; /* From <bits/setjmp.h>. */
+ tdep->sigtramp_p = i386_linux_sigtramp_p;
tdep->sigcontext_addr = i386_linux_sigcontext_addr;
tdep->sc_reg_offset = i386_linux_sc_reg_offset;
tdep->sc_num_regs = ARRAY_SIZE (i386_linux_sc_reg_offset);
- /* When the i386 Linux kernel calls a signal handler, the return
- address points to a bit of code on the stack. This function is
- used to identify this bit of code as a signal trampoline in order
- to support backtracing through calls to signal handlers. */
- set_gdbarch_pc_in_sigtramp (gdbarch, i386_linux_pc_in_sigtramp);
+ /* N_FUN symbols in shared libaries have 0 for their values and need
+ to be relocated. */
+ set_gdbarch_sofun_address_maybe_missing (gdbarch, 1);
+
+ /* GNU/Linux uses SVR4-style shared libraries. */
+ set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
+ set_solib_svr4_fetch_link_map_offsets
+ (gdbarch, svr4_ilp32_fetch_link_map_offsets);
+
+ /* GNU/Linux uses the dynamic linker included in the GNU C Library. */
+ set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
+
+ dwarf2_frame_set_signal_frame_p (gdbarch, i386_linux_dwarf_signal_frame_p);
- set_solib_svr4_fetch_link_map_offsets (gdbarch,
- i386_linux_svr4_fetch_link_map_offsets);
+ /* Enable TLS support. */
+ set_gdbarch_fetch_tls_load_module_address (gdbarch,
+ svr4_fetch_objfile_link_map);
}
/* Provide a prototype to silence -Wmissing-prototypes. */
projects / deliverable / binutils-gdb.git / blobdiff