/* Target-dependent code for OpenBSD/i386.
- Copyright 1988, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002,
- 2003, 2004
- Free Software Foundation, Inc.
+ Copyright (C) 1988-2013 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 "arch-utils.h"
#include "frame.h"
+#include "frame-unwind.h"
#include "gdbcore.h"
#include "regcache.h"
#include "regset.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. By the way, the mapping
- is read-only, so you cannot place a breakpoint in the signal
- trampoline. */
+ 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;
-/* Return whether the frame preceding NEXT_FRAME corresponds to an
- OpenBSD sigtramp routine. */
+/* 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 *next_frame)
+i386obsd_sigtramp_p (struct frame_info *this_frame)
{
- CORE_ADDR pc = frame_pc_unwind (next_frame);
+ CORE_ADDR pc = get_frame_pc (this_frame);
CORE_ADDR start_pc = (pc & ~(i386obsd_page_size - 1));
- const char sigreturn[] =
+ /* The call sequence invoking sigreturn(2). */
+ const gdb_byte sigreturn[] =
{
0xb8,
0x67, 0x00, 0x00, 0x00, /* movl $SYS_sigreturn, %eax */
0xcd, 0x80 /* int $0x80 */
};
- char *name, *buf;
+ size_t buflen = sizeof sigreturn;
+ const int *offset;
+ gdb_byte *buf;
+ const char *name;
/* If the function has a valid symbol name, it isn't a
trampoline. */
return 0;
/* Allocate buffer. */
- buf = alloca (sizeof sigreturn);
-
- /* If we can't read the instructions at START_PC, return zero. */
- if (target_read_memory (start_pc + 0x0a, buf, sizeof sigreturn))
- return 0;
-
- /* Check for sigreturn(2). */
- if (memcmp (buf, sigreturn, sizeof sigreturn) == 0)
- return 1;
+ buf = alloca (buflen);
- /* If we can't read the instructions at START_PC, return zero. */
- if (target_read_memory (start_pc + 0x14, buf, sizeof sigreturn))
- return 0;
-
- /* Check for sigreturn(2) (again). */
- if (memcmp (buf, sigreturn, sizeof sigreturn) == 0)
- return 1;
+ /* 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;
}
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, (char *) regs + tdep->sizeof_gregset);
+ i387_supply_fsave (regcache, regnum, gregs + tdep->sizeof_gregset);
}
static const struct regset *
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);
+ }
+ }
+}
+\f
+/* 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;
+ const 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;
+ 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, 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
+};
+\f
+
static void
i386obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
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. */
i386_elf_init_abi (info, gdbarch);
/* OpenBSD ELF uses SVR4-style shared libraries. */
- set_gdbarch_in_solib_call_trampoline
- (gdbarch, generic_in_solib_call_trampoline);
set_solib_svr4_fetch_link_map_offsets
(gdbarch, svr4_ilp32_fetch_link_map_offsets);
}
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