/* 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, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002, 2003,
+ 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
This file is part of GDB.
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. */
+ Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ Boston, MA 02110-1301, USA. */
#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;
+/* 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 the frame preceding NEXT_FRAME corresponds to an
OpenBSD sigtramp routine. */
{
CORE_ADDR pc = frame_pc_unwind (next_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 */
};
size_t buflen = sizeof sigreturn;
- char *name, *buf;
+ const int *offset;
+ gdb_byte *buf;
+ char *name;
/* If the function has a valid symbol name, it isn't a
trampoline. */
/* Allocate buffer. */
buf = alloca (buflen);
- /* If we can't read the instructions at START_PC, return zero. */
- if (!safe_frame_unwind_memory (next_frame, start_pc + 0x0a, buf, buflen))
- return 0;
-
- /* Check for sigreturn(2). */
- if (memcmp (buf, sigreturn, buflen) == 0)
- return 1;
-
- /* If we can't read the instructions at START_PC, return zero. */
- if (!safe_frame_unwind_memory (next_frame, start_pc + 0x14, buf, buflen))
- return 0;
-
- /* Check for sigreturn(2) (again). */
- if (memcmp (buf, sigreturn, buflen) == 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 (next_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)
+{
+ 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);
+
+ /* 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, 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);
+
+ /* 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)
+{
+ 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) - offset;
+
+ /* Store the stack pointer. */
+ write_memory_unsigned_integer (sp_addr, 4, 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);
+
+ /* 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 *next_frame, void **this_cache)
+{
+ 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 (next_frame);
+ *this_cache = cache;
+
+ /* NORMAL_FRAME matches the type in i386obsd_trapframe_unwind, but
+ SIGTRAMP_FRAME might be more appropriate. */
+ func = frame_func_unwind (next_frame, NORMAL_FRAME);
+ sp = frame_unwind_register_unsigned (next_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);
+ if ((cs & I386_SEL_RPL) == I386_SEL_UPL)
+ {
+ /* Trap from user space; terminate backtrace. */
+ trad_frame_set_id (cache, null_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 *next_frame,
+ void **this_cache, struct frame_id *this_id)
+{
+ struct trad_frame_cache *cache =
+ i386obsd_trapframe_cache (next_frame, this_cache);
+
+ trad_frame_get_id (cache, this_id);
+}
+
+static void
+i386obsd_trapframe_prev_register (struct frame_info *next_frame,
+ void **this_cache, int regnum,
+ int *optimizedp, enum lval_type *lvalp,
+ CORE_ADDR *addrp, int *realnump,
+ gdb_byte *valuep)
+{
+ struct trad_frame_cache *cache =
+ i386obsd_trapframe_cache (next_frame, this_cache);
+
+ trad_frame_get_register (cache, next_frame, regnum,
+ optimizedp, lvalp, addrp, realnump, valuep);
+}
+
+static int
+i386obsd_trapframe_sniffer (const struct frame_unwind *self,
+ struct frame_info *next_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 = frame_unwind_register_unsigned (next_frame, I386_CS_REGNUM);
+ if ((cs & I386_SEL_RPL) == I386_SEL_UPL)
+ return 0;
+
+ find_pc_partial_function (frame_pc_unwind (next_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,
+ 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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