-/* 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 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
This file is part of GDB.
#include "value.h"
#include "regcache.h"
#include "inferior.h"
+#include "osabi.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 "gdb_string.h"
#include "i386-tdep.h"
#include "i386-linux-tdep.h"
+#include "glibc-tdep.h"
+#include "solib-svr4.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_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)
{
+ CORE_ADDR pc = frame_pc_unwind (next_frame);
unsigned char buf[LINUX_SIGTRAMP_LEN];
/* We only recognize a signal trampoline if PC is at the start of
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_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)
{
+ CORE_ADDR pc = frame_pc_unwind (next_frame);
unsigned char buf[LINUX_RT_SIGTRAMP_LEN];
/* We only recognize a signal trampoline if PC is at the start of
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);
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;
}
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. */
+/* The register sets used in GNU/Linux ELF core-dumps are identical to
+ the register sets in `struct user' that are used for a.out
+ core-dumps. These are also used by ptrace(2). The corresponding
+ types are `elf_gregset_t' for the general-purpose registers (with
+ `elf_greg_t' the type of a single GP register) and `elf_fpregset_t'
+ for the floating-point registers.
-static struct minimal_symbol *
-find_minsym_and_objfile (char *name, struct objfile **objfilep)
-{
- struct objfile *objfile;
-
- ALL_OBJFILES (objfile)
- {
- struct minimal_symbol *msym;
+ Those types used to be available under the names `gregset_t' and
+ `fpregset_t' too, and GDB used those names in the past. But those
+ names are now used for the register sets used in the `mcontext_t'
+ type, which have a different size and layout. */
- ALL_OBJFILE_MSYMBOLS (objfile, msym)
- {
- if (SYMBOL_LINKAGE_NAME (msym)
- && strcmp (SYMBOL_LINKAGE_NAME (msym), name) == 0)
- {
- *objfilep = objfile;
- return msym;
- }
- }
- }
+/* Mapping between the general-purpose registers in `struct user'
+ format and GDB's register cache layout. */
- return 0;
-}
-
-static CORE_ADDR
-skip_gnu_resolver (CORE_ADDR pc)
+/* From <sys/reg.h>. */
+static int i386_linux_gregset_reg_offset[] =
{
- /* 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;
- }
+ 6 * 4, /* %eax */
+ 1 * 4, /* %ecx */
+ 2 * 4, /* %edx */
+ 0 * 4, /* %ebx */
+ 15 * 4, /* %esp */
+ 5 * 4, /* %ebp */
+ 3 * 4, /* %esi */
+ 4 * 4, /* %edi */
+ 12 * 4, /* %eip */
+ 14 * 4, /* %eflags */
+ 13 * 4, /* %cs */
+ 16 * 4, /* %ss */
+ 7 * 4, /* %ds */
+ 8 * 4, /* %es */
+ 9 * 4, /* %fs */
+ 10 * 4, /* %gs */
+ -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1,
+ -1,
+ 11 * 4 /* "orig_eax" */
+};
- return lmp;
-}
-\f
+/* Mapping between the general-purpose registers in `struct
+ sigcontext' format and GDB's register cache layout. */
/* From <asm/sigcontext.h>. */
static int i386_linux_sc_reg_offset[] =
set_gdbarch_register_name (gdbarch, i386_linux_register_name);
set_gdbarch_register_reggroup_p (gdbarch, i386_linux_register_reggroup_p);
+ tdep->gregset_reg_offset = i386_linux_gregset_reg_offset;
+ tdep->gregset_num_regs = ARRAY_SIZE (i386_linux_gregset_reg_offset);
+ tdep->sizeof_gregset = 17 * 4;
+
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);
+ /* GNU/Linux uses SVR4-style shared libraries. */
+ set_solib_svr4_fetch_link_map_offsets
+ (gdbarch, svr4_ilp32_fetch_link_map_offsets);
- set_solib_svr4_fetch_link_map_offsets (gdbarch,
- i386_linux_svr4_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);
}
/* Provide a prototype to silence -Wmissing-prototypes. */
projects / deliverable / binutils-gdb.git / blobdiff