527 lines
15 KiB
C
527 lines
15 KiB
C
/* Target-dependent code for OpenBSD/i386.
|
||
|
||
Copyright (C) 1988, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002, 2003,
|
||
2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
|
||
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 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 "defs.h"
|
||
#include "arch-utils.h"
|
||
#include "frame.h"
|
||
#include "frame-unwind.h"
|
||
#include "gdbcore.h"
|
||
#include "regcache.h"
|
||
#include "regset.h"
|
||
#include "symtab.h"
|
||
#include "objfiles.h"
|
||
#include "osabi.h"
|
||
#include "target.h"
|
||
#include "trad-frame.h"
|
||
|
||
#include "gdb_assert.h"
|
||
#include "gdb_string.h"
|
||
|
||
#include "i386-tdep.h"
|
||
#include "i387-tdep.h"
|
||
#include "solib-svr4.h"
|
||
#include "bsd-uthread.h"
|
||
|
||
/* Support for signal handlers. */
|
||
|
||
/* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
|
||
in virtual memory. The randomness makes it somewhat tricky to
|
||
detect it, but fortunately we can rely on the fact that the start
|
||
of the sigtramp routine is page-aligned. We recognize the
|
||
trampoline by looking for the code that invokes the sigreturn
|
||
system call. The offset where we can find that code varies from
|
||
release to release.
|
||
|
||
By the way, the mapping mentioned above is read-only, so you cannot
|
||
place a breakpoint in the signal trampoline. */
|
||
|
||
/* Default page size. */
|
||
static const int i386obsd_page_size = 4096;
|
||
|
||
/* Offset for sigreturn(2). */
|
||
static const int i386obsd_sigreturn_offset[] = {
|
||
0x0a, /* OpenBSD 3.2 */
|
||
0x14, /* OpenBSD 3.6 */
|
||
0x3a, /* OpenBSD 3.8 */
|
||
-1
|
||
};
|
||
|
||
/* Return whether THIS_FRAME corresponds to an OpenBSD sigtramp
|
||
routine. */
|
||
|
||
static int
|
||
i386obsd_sigtramp_p (struct frame_info *this_frame)
|
||
{
|
||
CORE_ADDR pc = get_frame_pc (this_frame);
|
||
CORE_ADDR start_pc = (pc & ~(i386obsd_page_size - 1));
|
||
/* The call sequence invoking sigreturn(2). */
|
||
const gdb_byte sigreturn[] =
|
||
{
|
||
0xb8,
|
||
0x67, 0x00, 0x00, 0x00, /* movl $SYS_sigreturn, %eax */
|
||
0xcd, 0x80 /* int $0x80 */
|
||
};
|
||
size_t buflen = sizeof sigreturn;
|
||
const int *offset;
|
||
gdb_byte *buf;
|
||
char *name;
|
||
|
||
/* If the function has a valid symbol name, it isn't a
|
||
trampoline. */
|
||
find_pc_partial_function (pc, &name, NULL, NULL);
|
||
if (name != NULL)
|
||
return 0;
|
||
|
||
/* If the function lives in a valid section (even without a starting
|
||
point) it isn't a trampoline. */
|
||
if (find_pc_section (pc) != NULL)
|
||
return 0;
|
||
|
||
/* Allocate buffer. */
|
||
buf = alloca (buflen);
|
||
|
||
/* Loop over all offsets. */
|
||
for (offset = i386obsd_sigreturn_offset; *offset != -1; offset++)
|
||
{
|
||
/* If we can't read the instructions, return zero. */
|
||
if (!safe_frame_unwind_memory (this_frame, start_pc + *offset,
|
||
buf, buflen))
|
||
return 0;
|
||
|
||
/* Check for sigreturn(2). */
|
||
if (memcmp (buf, sigreturn, buflen) == 0)
|
||
return 1;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Mapping between the general-purpose registers in `struct reg'
|
||
format and GDB's register cache layout. */
|
||
|
||
/* From <machine/reg.h>. */
|
||
static int i386obsd_r_reg_offset[] =
|
||
{
|
||
0 * 4, /* %eax */
|
||
1 * 4, /* %ecx */
|
||
2 * 4, /* %edx */
|
||
3 * 4, /* %ebx */
|
||
4 * 4, /* %esp */
|
||
5 * 4, /* %ebp */
|
||
6 * 4, /* %esi */
|
||
7 * 4, /* %edi */
|
||
8 * 4, /* %eip */
|
||
9 * 4, /* %eflags */
|
||
10 * 4, /* %cs */
|
||
11 * 4, /* %ss */
|
||
12 * 4, /* %ds */
|
||
13 * 4, /* %es */
|
||
14 * 4, /* %fs */
|
||
15 * 4 /* %gs */
|
||
};
|
||
|
||
static void
|
||
i386obsd_aout_supply_regset (const struct regset *regset,
|
||
struct regcache *regcache, int regnum,
|
||
const void *regs, size_t len)
|
||
{
|
||
const struct gdbarch_tdep *tdep = gdbarch_tdep (regset->arch);
|
||
const gdb_byte *gregs = regs;
|
||
|
||
gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FSAVE);
|
||
|
||
i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset);
|
||
i387_supply_fsave (regcache, regnum, gregs + tdep->sizeof_gregset);
|
||
}
|
||
|
||
static const struct regset *
|
||
i386obsd_aout_regset_from_core_section (struct gdbarch *gdbarch,
|
||
const char *sect_name,
|
||
size_t sect_size)
|
||
{
|
||
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
|
||
|
||
/* OpenBSD a.out core dumps don't use seperate register sets for the
|
||
general-purpose and floating-point registers. */
|
||
|
||
if (strcmp (sect_name, ".reg") == 0
|
||
&& sect_size >= tdep->sizeof_gregset + I387_SIZEOF_FSAVE)
|
||
{
|
||
if (tdep->gregset == NULL)
|
||
tdep->gregset =
|
||
regset_alloc (gdbarch, i386obsd_aout_supply_regset, NULL);
|
||
return tdep->gregset;
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
|
||
/* Sigtramp routine location for OpenBSD 3.1 and earlier releases. */
|
||
CORE_ADDR i386obsd_sigtramp_start_addr = 0xbfbfdf20;
|
||
CORE_ADDR i386obsd_sigtramp_end_addr = 0xbfbfdff0;
|
||
|
||
/* From <machine/signal.h>. */
|
||
int i386obsd_sc_reg_offset[I386_NUM_GREGS] =
|
||
{
|
||
10 * 4, /* %eax */
|
||
9 * 4, /* %ecx */
|
||
8 * 4, /* %edx */
|
||
7 * 4, /* %ebx */
|
||
14 * 4, /* %esp */
|
||
6 * 4, /* %ebp */
|
||
5 * 4, /* %esi */
|
||
4 * 4, /* %edi */
|
||
11 * 4, /* %eip */
|
||
13 * 4, /* %eflags */
|
||
12 * 4, /* %cs */
|
||
15 * 4, /* %ss */
|
||
3 * 4, /* %ds */
|
||
2 * 4, /* %es */
|
||
1 * 4, /* %fs */
|
||
0 * 4 /* %gs */
|
||
};
|
||
|
||
/* From /usr/src/lib/libpthread/arch/i386/uthread_machdep.c. */
|
||
static int i386obsd_uthread_reg_offset[] =
|
||
{
|
||
11 * 4, /* %eax */
|
||
10 * 4, /* %ecx */
|
||
9 * 4, /* %edx */
|
||
8 * 4, /* %ebx */
|
||
-1, /* %esp */
|
||
6 * 4, /* %ebp */
|
||
5 * 4, /* %esi */
|
||
4 * 4, /* %edi */
|
||
12 * 4, /* %eip */
|
||
-1, /* %eflags */
|
||
13 * 4, /* %cs */
|
||
-1, /* %ss */
|
||
3 * 4, /* %ds */
|
||
2 * 4, /* %es */
|
||
1 * 4, /* %fs */
|
||
0 * 4 /* %gs */
|
||
};
|
||
|
||
/* Offset within the thread structure where we can find the saved
|
||
stack pointer (%esp). */
|
||
#define I386OBSD_UTHREAD_ESP_OFFSET 176
|
||
|
||
static void
|
||
i386obsd_supply_uthread (struct regcache *regcache,
|
||
int regnum, CORE_ADDR addr)
|
||
{
|
||
struct gdbarch *gdbarch = get_regcache_arch (regcache);
|
||
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
|
||
CORE_ADDR sp_addr = addr + I386OBSD_UTHREAD_ESP_OFFSET;
|
||
CORE_ADDR sp = 0;
|
||
gdb_byte buf[4];
|
||
int i;
|
||
|
||
gdb_assert (regnum >= -1);
|
||
|
||
if (regnum == -1 || regnum == I386_ESP_REGNUM)
|
||
{
|
||
int offset;
|
||
|
||
/* Fetch stack pointer from thread structure. */
|
||
sp = read_memory_unsigned_integer (sp_addr, 4, byte_order);
|
||
|
||
/* Adjust the stack pointer such that it looks as if we just
|
||
returned from _thread_machdep_switch. */
|
||
offset = i386obsd_uthread_reg_offset[I386_EIP_REGNUM] + 4;
|
||
store_unsigned_integer (buf, 4, byte_order, sp + offset);
|
||
regcache_raw_supply (regcache, I386_ESP_REGNUM, buf);
|
||
}
|
||
|
||
for (i = 0; i < ARRAY_SIZE (i386obsd_uthread_reg_offset); i++)
|
||
{
|
||
if (i386obsd_uthread_reg_offset[i] != -1
|
||
&& (regnum == -1 || regnum == i))
|
||
{
|
||
/* Fetch stack pointer from thread structure (if we didn't
|
||
do so already). */
|
||
if (sp == 0)
|
||
sp = read_memory_unsigned_integer (sp_addr, 4, byte_order);
|
||
|
||
/* Read the saved register from the stack frame. */
|
||
read_memory (sp + i386obsd_uthread_reg_offset[i], buf, 4);
|
||
regcache_raw_supply (regcache, i, buf);
|
||
}
|
||
}
|
||
}
|
||
|
||
static void
|
||
i386obsd_collect_uthread (const struct regcache *regcache,
|
||
int regnum, CORE_ADDR addr)
|
||
{
|
||
struct gdbarch *gdbarch = get_regcache_arch (regcache);
|
||
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
|
||
CORE_ADDR sp_addr = addr + I386OBSD_UTHREAD_ESP_OFFSET;
|
||
CORE_ADDR sp = 0;
|
||
gdb_byte buf[4];
|
||
int i;
|
||
|
||
gdb_assert (regnum >= -1);
|
||
|
||
if (regnum == -1 || regnum == I386_ESP_REGNUM)
|
||
{
|
||
int offset;
|
||
|
||
/* Calculate the stack pointer (frame pointer) that will be
|
||
stored into the thread structure. */
|
||
offset = i386obsd_uthread_reg_offset[I386_EIP_REGNUM] + 4;
|
||
regcache_raw_collect (regcache, I386_ESP_REGNUM, buf);
|
||
sp = extract_unsigned_integer (buf, 4, byte_order) - offset;
|
||
|
||
/* Store the stack pointer. */
|
||
write_memory_unsigned_integer (sp_addr, 4, byte_order, sp);
|
||
|
||
/* The stack pointer was (potentially) modified. Make sure we
|
||
build a proper stack frame. */
|
||
regnum = -1;
|
||
}
|
||
|
||
for (i = 0; i < ARRAY_SIZE (i386obsd_uthread_reg_offset); i++)
|
||
{
|
||
if (i386obsd_uthread_reg_offset[i] != -1
|
||
&& (regnum == -1 || regnum == i))
|
||
{
|
||
/* Fetch stack pointer from thread structure (if we didn't
|
||
calculate it already). */
|
||
if (sp == 0)
|
||
sp = read_memory_unsigned_integer (sp_addr, 4, byte_order);
|
||
|
||
/* Write the register into the stack frame. */
|
||
regcache_raw_collect (regcache, i, buf);
|
||
write_memory (sp + i386obsd_uthread_reg_offset[i], buf, 4);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Kernel debugging support. */
|
||
|
||
/* From <machine/frame.h>. Note that %esp and %ess are only saved in
|
||
a trap frame when entering the kernel from user space. */
|
||
static int i386obsd_tf_reg_offset[] =
|
||
{
|
||
10 * 4, /* %eax */
|
||
9 * 4, /* %ecx */
|
||
8 * 4, /* %edx */
|
||
7 * 4, /* %ebx */
|
||
-1, /* %esp */
|
||
6 * 4, /* %ebp */
|
||
5 * 4, /* %esi */
|
||
4 * 4, /* %edi */
|
||
13 * 4, /* %eip */
|
||
15 * 4, /* %eflags */
|
||
14 * 4, /* %cs */
|
||
-1, /* %ss */
|
||
3 * 4, /* %ds */
|
||
2 * 4, /* %es */
|
||
0 * 4, /* %fs */
|
||
1 * 4 /* %gs */
|
||
};
|
||
|
||
static struct trad_frame_cache *
|
||
i386obsd_trapframe_cache (struct frame_info *this_frame, void **this_cache)
|
||
{
|
||
struct gdbarch *gdbarch = get_frame_arch (this_frame);
|
||
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
|
||
struct trad_frame_cache *cache;
|
||
CORE_ADDR func, sp, addr;
|
||
ULONGEST cs;
|
||
char *name;
|
||
int i;
|
||
|
||
if (*this_cache)
|
||
return *this_cache;
|
||
|
||
cache = trad_frame_cache_zalloc (this_frame);
|
||
*this_cache = cache;
|
||
|
||
func = get_frame_func (this_frame);
|
||
sp = get_frame_register_unsigned (this_frame, I386_ESP_REGNUM);
|
||
|
||
find_pc_partial_function (func, &name, NULL, NULL);
|
||
if (name && strncmp (name, "Xintr", 5) == 0)
|
||
addr = sp + 8; /* It's an interrupt frame. */
|
||
else
|
||
addr = sp;
|
||
|
||
for (i = 0; i < ARRAY_SIZE (i386obsd_tf_reg_offset); i++)
|
||
if (i386obsd_tf_reg_offset[i] != -1)
|
||
trad_frame_set_reg_addr (cache, i, addr + i386obsd_tf_reg_offset[i]);
|
||
|
||
/* Read %cs from trap frame. */
|
||
addr += i386obsd_tf_reg_offset[I386_CS_REGNUM];
|
||
cs = read_memory_unsigned_integer (addr, 4, byte_order);
|
||
if ((cs & I386_SEL_RPL) == I386_SEL_UPL)
|
||
{
|
||
/* Trap from user space; terminate backtrace. */
|
||
trad_frame_set_id (cache, outer_frame_id);
|
||
}
|
||
else
|
||
{
|
||
/* Construct the frame ID using the function start. */
|
||
trad_frame_set_id (cache, frame_id_build (sp + 8, func));
|
||
}
|
||
|
||
return cache;
|
||
}
|
||
|
||
static void
|
||
i386obsd_trapframe_this_id (struct frame_info *this_frame,
|
||
void **this_cache, struct frame_id *this_id)
|
||
{
|
||
struct trad_frame_cache *cache =
|
||
i386obsd_trapframe_cache (this_frame, this_cache);
|
||
|
||
trad_frame_get_id (cache, this_id);
|
||
}
|
||
|
||
static struct value *
|
||
i386obsd_trapframe_prev_register (struct frame_info *this_frame,
|
||
void **this_cache, int regnum)
|
||
{
|
||
struct trad_frame_cache *cache =
|
||
i386obsd_trapframe_cache (this_frame, this_cache);
|
||
|
||
return trad_frame_get_register (cache, this_frame, regnum);
|
||
}
|
||
|
||
static int
|
||
i386obsd_trapframe_sniffer (const struct frame_unwind *self,
|
||
struct frame_info *this_frame,
|
||
void **this_prologue_cache)
|
||
{
|
||
ULONGEST cs;
|
||
char *name;
|
||
|
||
/* Check Current Privilege Level and bail out if we're not executing
|
||
in kernel space. */
|
||
cs = get_frame_register_unsigned (this_frame, I386_CS_REGNUM);
|
||
if ((cs & I386_SEL_RPL) == I386_SEL_UPL)
|
||
return 0;
|
||
|
||
find_pc_partial_function (get_frame_pc (this_frame), &name, NULL, NULL);
|
||
return (name && (strcmp (name, "calltrap") == 0
|
||
|| strcmp (name, "syscall1") == 0
|
||
|| strncmp (name, "Xintr", 5) == 0
|
||
|| strncmp (name, "Xsoft", 5) == 0));
|
||
}
|
||
|
||
static const struct frame_unwind i386obsd_trapframe_unwind = {
|
||
/* FIXME: kettenis/20051219: This really is more like an interrupt
|
||
frame, but SIGTRAMP_FRAME would print <signal handler called>,
|
||
which really is not what we want here. */
|
||
NORMAL_FRAME,
|
||
default_frame_unwind_stop_reason,
|
||
i386obsd_trapframe_this_id,
|
||
i386obsd_trapframe_prev_register,
|
||
NULL,
|
||
i386obsd_trapframe_sniffer
|
||
};
|
||
|
||
|
||
static void
|
||
i386obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
|
||
{
|
||
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
|
||
|
||
/* Obviously OpenBSD is BSD-based. */
|
||
i386bsd_init_abi (info, gdbarch);
|
||
|
||
/* OpenBSD has a different `struct reg'. */
|
||
tdep->gregset_reg_offset = i386obsd_r_reg_offset;
|
||
tdep->gregset_num_regs = ARRAY_SIZE (i386obsd_r_reg_offset);
|
||
tdep->sizeof_gregset = 16 * 4;
|
||
|
||
/* OpenBSD uses -freg-struct-return by default. */
|
||
tdep->struct_return = reg_struct_return;
|
||
|
||
/* OpenBSD uses a different memory layout. */
|
||
tdep->sigtramp_start = i386obsd_sigtramp_start_addr;
|
||
tdep->sigtramp_end = i386obsd_sigtramp_end_addr;
|
||
tdep->sigtramp_p = i386obsd_sigtramp_p;
|
||
|
||
/* OpenBSD has a `struct sigcontext' that's different from the
|
||
original 4.3 BSD. */
|
||
tdep->sc_reg_offset = i386obsd_sc_reg_offset;
|
||
tdep->sc_num_regs = ARRAY_SIZE (i386obsd_sc_reg_offset);
|
||
|
||
/* OpenBSD provides a user-level threads implementation. */
|
||
bsd_uthread_set_supply_uthread (gdbarch, i386obsd_supply_uthread);
|
||
bsd_uthread_set_collect_uthread (gdbarch, i386obsd_collect_uthread);
|
||
|
||
/* Unwind kernel trap frames correctly. */
|
||
frame_unwind_prepend_unwinder (gdbarch, &i386obsd_trapframe_unwind);
|
||
}
|
||
|
||
/* OpenBSD a.out. */
|
||
|
||
static void
|
||
i386obsd_aout_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
|
||
{
|
||
i386obsd_init_abi (info, gdbarch);
|
||
|
||
/* OpenBSD a.out has a single register set. */
|
||
set_gdbarch_regset_from_core_section
|
||
(gdbarch, i386obsd_aout_regset_from_core_section);
|
||
}
|
||
|
||
/* OpenBSD ELF. */
|
||
|
||
static void
|
||
i386obsd_elf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
|
||
{
|
||
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
|
||
|
||
/* It's still OpenBSD. */
|
||
i386obsd_init_abi (info, gdbarch);
|
||
|
||
/* But ELF-based. */
|
||
i386_elf_init_abi (info, gdbarch);
|
||
|
||
/* OpenBSD ELF uses SVR4-style shared libraries. */
|
||
set_solib_svr4_fetch_link_map_offsets
|
||
(gdbarch, svr4_ilp32_fetch_link_map_offsets);
|
||
}
|
||
|
||
|
||
/* Provide a prototype to silence -Wmissing-prototypes. */
|
||
void _initialize_i386obsd_tdep (void);
|
||
|
||
void
|
||
_initialize_i386obsd_tdep (void)
|
||
{
|
||
/* FIXME: kettenis/20021020: Since OpenBSD/i386 binaries are
|
||
indistingushable from NetBSD/i386 a.out binaries, building a GDB
|
||
that should support both these targets will probably not work as
|
||
expected. */
|
||
#define GDB_OSABI_OPENBSD_AOUT GDB_OSABI_NETBSD_AOUT
|
||
|
||
gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_OPENBSD_AOUT,
|
||
i386obsd_aout_init_abi);
|
||
gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_OPENBSD_ELF,
|
||
i386obsd_elf_init_abi);
|
||
}
|