462 lines
13 KiB
C
462 lines
13 KiB
C
/* Target-dependent code for OpenBSD/amd64.
|
||
|
||
Copyright (C) 2003-2017 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 "frame.h"
|
||
#include "frame-unwind.h"
|
||
#include "gdbcore.h"
|
||
#include "symtab.h"
|
||
#include "objfiles.h"
|
||
#include "osabi.h"
|
||
#include "regcache.h"
|
||
#include "regset.h"
|
||
#include "target.h"
|
||
#include "trad-frame.h"
|
||
|
||
#include "obsd-tdep.h"
|
||
#include "amd64-tdep.h"
|
||
#include "i387-tdep.h"
|
||
#include "solib-svr4.h"
|
||
#include "bsd-uthread.h"
|
||
|
||
/* Support for signal handlers. */
|
||
|
||
/* Default page size. */
|
||
static const int amd64obsd_page_size = 4096;
|
||
|
||
/* Return whether THIS_FRAME corresponds to an OpenBSD sigtramp
|
||
routine. */
|
||
|
||
static int
|
||
amd64obsd_sigtramp_p (struct frame_info *this_frame)
|
||
{
|
||
CORE_ADDR pc = get_frame_pc (this_frame);
|
||
CORE_ADDR start_pc = (pc & ~(amd64obsd_page_size - 1));
|
||
const gdb_byte osigreturn[] =
|
||
{
|
||
0x48, 0xc7, 0xc0,
|
||
0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */
|
||
0xcd, 0x80 /* int $0x80 */
|
||
};
|
||
const gdb_byte sigreturn[] =
|
||
{
|
||
0x48, 0xc7, 0xc0,
|
||
0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */
|
||
0x0f, 0x05 /* syscall */
|
||
};
|
||
size_t buflen = (sizeof sigreturn) + 1;
|
||
gdb_byte *buf;
|
||
const 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;
|
||
|
||
/* If we can't read the instructions at START_PC, return zero. */
|
||
buf = (gdb_byte *) alloca ((sizeof sigreturn) + 1);
|
||
if (!safe_frame_unwind_memory (this_frame, start_pc + 6, buf, buflen))
|
||
return 0;
|
||
|
||
/* Check for sigreturn(2). Depending on how the assembler encoded
|
||
the `movq %rsp, %rdi' instruction, the code starts at offset 6 or
|
||
7. OpenBSD 5.0 and later use the `syscall' instruction. Older
|
||
versions use `int $0x80'. Check for both. */
|
||
if (memcmp (buf, sigreturn, sizeof sigreturn)
|
||
&& memcmp (buf + 1, sigreturn, sizeof sigreturn)
|
||
&& memcmp (buf, osigreturn, sizeof osigreturn)
|
||
&& memcmp (buf + 1, osigreturn, sizeof osigreturn))
|
||
return 0;
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Assuming THIS_FRAME is for a BSD sigtramp routine, return the
|
||
address of the associated sigcontext structure. */
|
||
|
||
static CORE_ADDR
|
||
amd64obsd_sigcontext_addr (struct frame_info *this_frame)
|
||
{
|
||
CORE_ADDR pc = get_frame_pc (this_frame);
|
||
ULONGEST offset = (pc & (amd64obsd_page_size - 1));
|
||
|
||
/* The %rsp register points at `struct sigcontext' upon entry of a
|
||
signal trampoline. The relevant part of the trampoline is
|
||
|
||
call *%rax
|
||
movq %rsp, %rdi
|
||
pushq %rdi
|
||
movq $SYS_sigreturn,%rax
|
||
int $0x80
|
||
|
||
(see /usr/src/sys/arch/amd64/amd64/locore.S). The `pushq'
|
||
instruction clobbers %rsp, but its value is saved in `%rdi'. */
|
||
|
||
if (offset > 5)
|
||
return get_frame_register_unsigned (this_frame, AMD64_RDI_REGNUM);
|
||
else
|
||
return get_frame_register_unsigned (this_frame, AMD64_RSP_REGNUM);
|
||
}
|
||
|
||
/* OpenBSD 3.5 or later. */
|
||
|
||
/* Mapping between the general-purpose registers in `struct reg'
|
||
format and GDB's register cache layout. */
|
||
|
||
/* From <machine/reg.h>. */
|
||
int amd64obsd_r_reg_offset[] =
|
||
{
|
||
14 * 8, /* %rax */
|
||
13 * 8, /* %rbx */
|
||
3 * 8, /* %rcx */
|
||
2 * 8, /* %rdx */
|
||
1 * 8, /* %rsi */
|
||
0 * 8, /* %rdi */
|
||
12 * 8, /* %rbp */
|
||
15 * 8, /* %rsp */
|
||
4 * 8, /* %r8 .. */
|
||
5 * 8,
|
||
6 * 8,
|
||
7 * 8,
|
||
8 * 8,
|
||
9 * 8,
|
||
10 * 8,
|
||
11 * 8, /* ... %r15 */
|
||
16 * 8, /* %rip */
|
||
17 * 8, /* %eflags */
|
||
18 * 8, /* %cs */
|
||
19 * 8, /* %ss */
|
||
20 * 8, /* %ds */
|
||
21 * 8, /* %es */
|
||
22 * 8, /* %fs */
|
||
23 * 8 /* %gs */
|
||
};
|
||
|
||
/* From <machine/signal.h>. */
|
||
static int amd64obsd_sc_reg_offset[] =
|
||
{
|
||
14 * 8, /* %rax */
|
||
13 * 8, /* %rbx */
|
||
3 * 8, /* %rcx */
|
||
2 * 8, /* %rdx */
|
||
1 * 8, /* %rsi */
|
||
0 * 8, /* %rdi */
|
||
12 * 8, /* %rbp */
|
||
24 * 8, /* %rsp */
|
||
4 * 8, /* %r8 ... */
|
||
5 * 8,
|
||
6 * 8,
|
||
7 * 8,
|
||
8 * 8,
|
||
9 * 8,
|
||
10 * 8,
|
||
11 * 8, /* ... %r15 */
|
||
21 * 8, /* %rip */
|
||
23 * 8, /* %eflags */
|
||
22 * 8, /* %cs */
|
||
25 * 8, /* %ss */
|
||
18 * 8, /* %ds */
|
||
17 * 8, /* %es */
|
||
16 * 8, /* %fs */
|
||
15 * 8 /* %gs */
|
||
};
|
||
|
||
/* From /usr/src/lib/libpthread/arch/amd64/uthread_machdep.c. */
|
||
static int amd64obsd_uthread_reg_offset[] =
|
||
{
|
||
19 * 8, /* %rax */
|
||
16 * 8, /* %rbx */
|
||
18 * 8, /* %rcx */
|
||
17 * 8, /* %rdx */
|
||
14 * 8, /* %rsi */
|
||
13 * 8, /* %rdi */
|
||
15 * 8, /* %rbp */
|
||
-1, /* %rsp */
|
||
12 * 8, /* %r8 ... */
|
||
11 * 8,
|
||
10 * 8,
|
||
9 * 8,
|
||
8 * 8,
|
||
7 * 8,
|
||
6 * 8,
|
||
5 * 8, /* ... %r15 */
|
||
20 * 8, /* %rip */
|
||
4 * 8, /* %eflags */
|
||
21 * 8, /* %cs */
|
||
-1, /* %ss */
|
||
3 * 8, /* %ds */
|
||
2 * 8, /* %es */
|
||
1 * 8, /* %fs */
|
||
0 * 8 /* %gs */
|
||
};
|
||
|
||
/* Offset within the thread structure where we can find the saved
|
||
stack pointer (%esp). */
|
||
#define AMD64OBSD_UTHREAD_RSP_OFFSET 400
|
||
|
||
static void
|
||
amd64obsd_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 + AMD64OBSD_UTHREAD_RSP_OFFSET;
|
||
CORE_ADDR sp = 0;
|
||
gdb_byte buf[8];
|
||
int i;
|
||
|
||
gdb_assert (regnum >= -1);
|
||
|
||
if (regnum == -1 || regnum == AMD64_RSP_REGNUM)
|
||
{
|
||
int offset;
|
||
|
||
/* Fetch stack pointer from thread structure. */
|
||
sp = read_memory_unsigned_integer (sp_addr, 8, byte_order);
|
||
|
||
/* Adjust the stack pointer such that it looks as if we just
|
||
returned from _thread_machdep_switch. */
|
||
offset = amd64obsd_uthread_reg_offset[AMD64_RIP_REGNUM] + 8;
|
||
store_unsigned_integer (buf, 8, byte_order, sp + offset);
|
||
regcache_raw_supply (regcache, AMD64_RSP_REGNUM, buf);
|
||
}
|
||
|
||
for (i = 0; i < ARRAY_SIZE (amd64obsd_uthread_reg_offset); i++)
|
||
{
|
||
if (amd64obsd_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, 8, byte_order);
|
||
|
||
/* Read the saved register from the stack frame. */
|
||
read_memory (sp + amd64obsd_uthread_reg_offset[i], buf, 8);
|
||
regcache_raw_supply (regcache, i, buf);
|
||
}
|
||
}
|
||
}
|
||
|
||
static void
|
||
amd64obsd_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 + AMD64OBSD_UTHREAD_RSP_OFFSET;
|
||
CORE_ADDR sp = 0;
|
||
gdb_byte buf[8];
|
||
int i;
|
||
|
||
gdb_assert (regnum >= -1);
|
||
|
||
if (regnum == -1 || regnum == AMD64_RSP_REGNUM)
|
||
{
|
||
int offset;
|
||
|
||
/* Calculate the stack pointer (frame pointer) that will be
|
||
stored into the thread structure. */
|
||
offset = amd64obsd_uthread_reg_offset[AMD64_RIP_REGNUM] + 8;
|
||
regcache_raw_collect (regcache, AMD64_RSP_REGNUM, buf);
|
||
sp = extract_unsigned_integer (buf, 8, byte_order) - offset;
|
||
|
||
/* Store the stack pointer. */
|
||
write_memory_unsigned_integer (sp_addr, 8, 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 (amd64obsd_uthread_reg_offset); i++)
|
||
{
|
||
if (amd64obsd_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, 8, byte_order);
|
||
|
||
/* Write the register into the stack frame. */
|
||
regcache_raw_collect (regcache, i, buf);
|
||
write_memory (sp + amd64obsd_uthread_reg_offset[i], buf, 8);
|
||
}
|
||
}
|
||
}
|
||
/* Kernel debugging support. */
|
||
|
||
/* From <machine/frame.h>. Easy since `struct trapframe' matches
|
||
`struct sigcontext'. */
|
||
#define amd64obsd_tf_reg_offset amd64obsd_sc_reg_offset
|
||
|
||
static struct trad_frame_cache *
|
||
amd64obsd_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;
|
||
const char *name;
|
||
int i;
|
||
|
||
if (*this_cache)
|
||
return (struct trad_frame_cache *) *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, AMD64_RSP_REGNUM);
|
||
|
||
find_pc_partial_function (func, &name, NULL, NULL);
|
||
if (name && startswith (name, "Xintr"))
|
||
addr = sp + 8; /* It's an interrupt frame. */
|
||
else
|
||
addr = sp;
|
||
|
||
for (i = 0; i < ARRAY_SIZE (amd64obsd_tf_reg_offset); i++)
|
||
if (amd64obsd_tf_reg_offset[i] != -1)
|
||
trad_frame_set_reg_addr (cache, i, addr + amd64obsd_tf_reg_offset[i]);
|
||
|
||
/* Read %cs from trap frame. */
|
||
addr += amd64obsd_tf_reg_offset[AMD64_CS_REGNUM];
|
||
cs = read_memory_unsigned_integer (addr, 8, 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 + 16, func));
|
||
}
|
||
|
||
return cache;
|
||
}
|
||
|
||
static void
|
||
amd64obsd_trapframe_this_id (struct frame_info *this_frame,
|
||
void **this_cache, struct frame_id *this_id)
|
||
{
|
||
struct trad_frame_cache *cache =
|
||
amd64obsd_trapframe_cache (this_frame, this_cache);
|
||
|
||
trad_frame_get_id (cache, this_id);
|
||
}
|
||
|
||
static struct value *
|
||
amd64obsd_trapframe_prev_register (struct frame_info *this_frame,
|
||
void **this_cache, int regnum)
|
||
{
|
||
struct trad_frame_cache *cache =
|
||
amd64obsd_trapframe_cache (this_frame, this_cache);
|
||
|
||
return trad_frame_get_register (cache, this_frame, regnum);
|
||
}
|
||
|
||
static int
|
||
amd64obsd_trapframe_sniffer (const struct frame_unwind *self,
|
||
struct frame_info *this_frame,
|
||
void **this_prologue_cache)
|
||
{
|
||
ULONGEST cs;
|
||
const char *name;
|
||
|
||
/* Check Current Privilege Level and bail out if we're not executing
|
||
in kernel space. */
|
||
cs = get_frame_register_unsigned (this_frame, AMD64_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, "osyscall1") == 0)
|
||
|| (strcmp (name, "Xsyscall") == 0)
|
||
|| (startswith (name, "Xintr"))));
|
||
}
|
||
|
||
static const struct frame_unwind amd64obsd_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,
|
||
amd64obsd_trapframe_this_id,
|
||
amd64obsd_trapframe_prev_register,
|
||
NULL,
|
||
amd64obsd_trapframe_sniffer
|
||
};
|
||
|
||
|
||
static void
|
||
amd64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
|
||
{
|
||
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
|
||
|
||
amd64_init_abi (info, gdbarch);
|
||
obsd_init_abi (info, gdbarch);
|
||
|
||
/* Initialize general-purpose register set details. */
|
||
tdep->gregset_reg_offset = amd64obsd_r_reg_offset;
|
||
tdep->gregset_num_regs = ARRAY_SIZE (amd64obsd_r_reg_offset);
|
||
tdep->sizeof_gregset = 24 * 8;
|
||
|
||
tdep->jb_pc_offset = 7 * 8;
|
||
|
||
tdep->sigtramp_p = amd64obsd_sigtramp_p;
|
||
tdep->sigcontext_addr = amd64obsd_sigcontext_addr;
|
||
tdep->sc_reg_offset = amd64obsd_sc_reg_offset;
|
||
tdep->sc_num_regs = ARRAY_SIZE (amd64obsd_sc_reg_offset);
|
||
|
||
/* OpenBSD provides a user-level threads implementation. */
|
||
bsd_uthread_set_supply_uthread (gdbarch, amd64obsd_supply_uthread);
|
||
bsd_uthread_set_collect_uthread (gdbarch, amd64obsd_collect_uthread);
|
||
|
||
/* OpenBSD uses SVR4-style shared libraries. */
|
||
set_solib_svr4_fetch_link_map_offsets
|
||
(gdbarch, svr4_lp64_fetch_link_map_offsets);
|
||
|
||
/* Unwind kernel trap frames correctly. */
|
||
frame_unwind_prepend_unwinder (gdbarch, &amd64obsd_trapframe_unwind);
|
||
}
|
||
|
||
|
||
/* Provide a prototype to silence -Wmissing-prototypes. */
|
||
void _initialize_amd64obsd_tdep (void);
|
||
|
||
void
|
||
_initialize_amd64obsd_tdep (void)
|
||
{
|
||
/* The OpenBSD/amd64 native dependent code makes this assumption. */
|
||
gdb_assert (ARRAY_SIZE (amd64obsd_r_reg_offset) == AMD64_NUM_GREGS);
|
||
|
||
gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
|
||
GDB_OSABI_OPENBSD, amd64obsd_init_abi);
|
||
}
|