binutils-gdb/gdb/amd64-obsd-tdep.c
Joel Brobecker 61baf725ec update copyright year range in GDB files
This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.

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        Update copyright year range in all GDB files.
2017-01-01 10:52:34 +04:00

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/* 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);
}