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* amd64-tdep.c (amd64_skip_prefixes): Renamed from skip_prefixes.

Browse Source 
All callers updated.
	(amd64_get_insn_details): Handle more 3-byte opcode insns.
	(amd64_breakpoint_p): Delete.
	(amd64_displaced_step_fixup): When fixing up after stepping an int3,
	don't back up pc to the start of the int3.
	* i386-tdep.c: #include opcode/i386.h.
	(i386_skip_prefixes): New function.
	(i386_absolute_jmp_p): Constify argument.
	(i386_absolute_call_p,i386_ret_p,i386_call_p,i386_syscall_p): Ditto.
	(i386_breakpoint_p): Delete.
	(i386_displaced_step_fixup): Handle unnecessary or redundant prefixes.
	When fixing up after stepping an int3, don't back up pc to the start
	of the int3.

	* gdb.arch/amd64-disp-step.S (test_int3): New test.
	* gdb.arch/amd64-disp-step.exp (test_int3): New test.
	* gdb.arch/i386-disp-step.S (test_prefixed_abs_jump): New test.
	(test_prefixed_syscall,test_int3): New tests.
	* gdb.arch/i386-disp-step.exp (test_prefixed_abs_jump): New test.
	(test_prefixed_syscall,test_int3): New tests.
This commit is contained in:
Doug Evans 2009-02-17 06:14:17 +00:00
parent ed38e4b974
commit 1903f0e64b
8 changed files with 271 additions and 58 deletions
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17
gdb/ChangeLog
View File

@ -1,3 +1,20 @@
2009-02-16 Doug Evans <dje@google.com>
* amd64-tdep.c (amd64_skip_prefixes): Renamed from skip_prefixes.
All callers updated.
(amd64_get_insn_details): Handle more 3-byte opcode insns.
(amd64_breakpoint_p): Delete.
(amd64_displaced_step_fixup): When fixing up after stepping an int3,
don't back up pc to the start of the int3.
* i386-tdep.c: #include opcode/i386.h.
(i386_skip_prefixes): New function.
(i386_absolute_jmp_p): Constify argument.
(i386_absolute_call_p,i386_ret_p,i386_call_p,i386_syscall_p): Ditto.
(i386_breakpoint_p): Delete.
(i386_displaced_step_fixup): Handle unnecessary or redundant prefixes.
When fixing up after stepping an int3, don't back up pc to the start
of the int3.
2009-02-16 Pedro Alves <pedro@codesourcery.com>
* corelow.c (core_close): Don't hardcode the core's pid.

43
gdb/amd64-tdep.c
View File

@ -805,7 +805,7 @@ rex_prefix_p (gdb_byte pfx)
about falling off the end of the buffer. */
static gdb_byte *
skip_prefixes (gdb_byte *insn)
amd64_skip_prefixes (gdb_byte *insn)
{
while (1)
{
@ -974,7 +974,7 @@ amd64_get_insn_details (gdb_byte *insn, struct amd64_insn *details)
details->modrm_offset = -1;
/* Skip legacy instruction prefixes. */
insn = skip_prefixes (insn);
insn = amd64_skip_prefixes (insn);
/* Skip REX instruction prefix. */
if (rex_prefix_p (*insn))
@ -992,13 +992,21 @@ amd64_get_insn_details (gdb_byte *insn, struct amd64_insn *details)
need_modrm = twobyte_has_modrm[*insn];
/* Check for three-byte opcode. */
if (*insn == 0x38 || *insn == 0x3a)
switch (*insn)
{
case 0x24:
case 0x25:
case 0x38:
case 0x3a:
case 0x7a:
case 0x7b:
++insn;
details->opcode_len = 3;
}
else
break;
default:
details->opcode_len = 2;
break;
}
}
else
{
@ -1217,14 +1225,6 @@ amd64_call_p (const struct amd64_insn *details)
return 0;
}
static int
amd64_breakpoint_p (const struct amd64_insn *details)
{
const gdb_byte *insn = &details->raw_insn[details->opcode_offset];
return insn[0] == 0xcc; /* int 3 */
}
/* Return non-zero if INSN is a system call, and set *LENGTHP to its
length in bytes. Otherwise, return zero. */
@ -1323,20 +1323,9 @@ amd64_displaced_step_fixup (struct gdbarch *gdbarch,
{
ULONGEST rip = orig_rip - insn_offset;
/* If we have stepped over a breakpoint, set %rip to
point at the breakpoint instruction itself.
(gdbarch_decr_pc_after_break was never something the core
of GDB should have been concerned with; arch-specific
code should be making PC values consistent before
presenting them to GDB.) */
if (amd64_breakpoint_p (insn_details))
{
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog,
"displaced: stepped breakpoint\n");
rip--;
}
/* If we just stepped over a breakpoint insn, we don't backup
the pc on purpose; this is to match behaviour without
stepping. */
regcache_cooked_write_unsigned (regs, AMD64_RIP_REGNUM, rip);

89
gdb/i386-tdep.c
View File

@ -20,6 +20,7 @@
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "opcode/i386.h"
#include "arch-utils.h"
#include "command.h"
#include "dummy-frame.h"
@ -278,9 +279,44 @@ i386_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pc, int *len)
/* Displaced instruction handling. */
/* Skip the legacy instruction prefixes in INSN.
Not all prefixes are valid for any particular insn
but we needn't care, the insn will fault if it's invalid.
The result is a pointer to the first opcode byte,
or NULL if we run off the end of the buffer. */
static gdb_byte *
i386_skip_prefixes (gdb_byte *insn, size_t max_len)
{
gdb_byte *end = insn + max_len;
while (insn < end)
{
switch (*insn)
{
case DATA_PREFIX_OPCODE:
case ADDR_PREFIX_OPCODE:
case CS_PREFIX_OPCODE:
case DS_PREFIX_OPCODE:
case ES_PREFIX_OPCODE:
case FS_PREFIX_OPCODE:
case GS_PREFIX_OPCODE:
case SS_PREFIX_OPCODE:
case LOCK_PREFIX_OPCODE:
case REPE_PREFIX_OPCODE:
case REPNE_PREFIX_OPCODE:
++insn;
continue;
default:
return insn;
}
}
return NULL;
}
static int
i386_absolute_jmp_p (gdb_byte *insn)
i386_absolute_jmp_p (const gdb_byte *insn)
{
/* jmp far (absolute address in operand) */
if (insn[0] == 0xea)
@ -301,7 +337,7 @@ i386_absolute_jmp_p (gdb_byte *insn)
}
static int
i386_absolute_call_p (gdb_byte *insn)
i386_absolute_call_p (const gdb_byte *insn)
{
/* call far, absolute */
if (insn[0] == 0x9a)
@ -322,7 +358,7 @@ i386_absolute_call_p (gdb_byte *insn)
}
static int
i386_ret_p (gdb_byte *insn)
i386_ret_p (const gdb_byte *insn)
{
switch (insn[0])
{
@ -339,7 +375,7 @@ i386_ret_p (gdb_byte *insn)
}
static int
i386_call_p (gdb_byte *insn)
i386_call_p (const gdb_byte *insn)
{
if (i386_absolute_call_p (insn))
return 1;
@ -351,16 +387,11 @@ i386_call_p (gdb_byte *insn)
return 0;
}
static int
i386_breakpoint_p (gdb_byte *insn)
{
return insn[0] == 0xcc; /* int 3 */
}
/* Return non-zero if INSN is a system call, and set *LENGTHP to its
length in bytes. Otherwise, return zero. */
static int
i386_syscall_p (gdb_byte *insn, ULONGEST *lengthp)
i386_syscall_p (const gdb_byte *insn, ULONGEST *lengthp)
{
if (insn[0] == 0xcd)
{
@ -373,6 +404,7 @@ i386_syscall_p (gdb_byte *insn, ULONGEST *lengthp)
/* Fix up the state of registers and memory after having single-stepped
a displaced instruction. */
void
i386_displaced_step_fixup (struct gdbarch *gdbarch,
struct displaced_step_closure *closure,
@ -388,6 +420,8 @@ i386_displaced_step_fixup (struct gdbarch *gdbarch,
/* Since we use simple_displaced_step_copy_insn, our closure is a
copy of the instruction. */
gdb_byte *insn = (gdb_byte *) closure;
/* The start of the insn, needed in case we see some prefixes. */
gdb_byte *insn_start = insn;
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog,
@ -401,6 +435,18 @@ i386_displaced_step_fixup (struct gdbarch *gdbarch,
/* Relocate the %eip, if necessary. */
/* The instruction recognizers we use assume any leading prefixes
have been skipped. */
{
/* This is the size of the buffer in closure. */
size_t max_insn_len = gdbarch_max_insn_length (gdbarch);
gdb_byte *opcode = i386_skip_prefixes (insn, max_insn_len);
/* If there are too many prefixes, just ignore the insn.
It will fault when run. */
if (opcode != NULL)
insn = opcode;
}
/* Except in the case of absolute or indirect jump or call
instructions, or a return instruction, the new eip is relative to
the displaced instruction; make it relative. Well, signal
@ -430,7 +476,7 @@ i386_displaced_step_fixup (struct gdbarch *gdbarch,
it unrelocated. Goodness help us if there are PC-relative
system calls. */
if (i386_syscall_p (insn, &insn_len)
&& orig_eip != to + insn_len)
&& orig_eip != to + (insn - insn_start) + insn_len)
{
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog,
@ -441,20 +487,9 @@ i386_displaced_step_fixup (struct gdbarch *gdbarch,
{
ULONGEST eip = (orig_eip - insn_offset) & 0xffffffffUL;
/* If we have stepped over a breakpoint, set the %eip to
point at the breakpoint instruction itself.
(gdbarch_decr_pc_after_break was never something the core
of GDB should have been concerned with; arch-specific
code should be making PC values consistent before
presenting them to GDB.) */
if (i386_breakpoint_p (insn))
{
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog,
"displaced: stepped breakpoint\n");
eip--;
}
/* If we just stepped over a breakpoint insn, we don't backup
the pc on purpose; this is to match behaviour without
stepping. */
regcache_cooked_write_unsigned (regs, I386_EIP_REGNUM, eip);
@ -493,8 +528,6 @@ i386_displaced_step_fixup (struct gdbarch *gdbarch,
paddr_nz (retaddr));
}
}
#ifdef I386_REGNO_TO_SYMMETRY
#error "The Sequent Symmetry is no longer supported."

9
gdb/testsuite/ChangeLog
View File

@ -1,3 +1,12 @@
2009-02-16 Doug Evans <dje@google.com>
* gdb.arch/amd64-disp-step.S (test_int3): New test.
* gdb.arch/amd64-disp-step.exp (test_int3): New test.
* gdb.arch/i386-disp-step.S (test_prefixed_abs_jump): New test.
(test_prefixed_syscall,test_int3): New tests.
* gdb.arch/i386-disp-step.exp (test_prefixed_abs_jump): New test.
(test_prefixed_syscall,test_int3): New tests.
2009-02-14 Vladimir Prus <vladimir@codesourcery.com>
* lib/mi-support.exp (mi_expect_stop): Adjust the order of fields.

28
gdb/testsuite/gdb.arch/amd64-disp-step.S
View File

@ -23,6 +23,8 @@
main:
nop
/***********************************************/
/* test call/ret */
.global test_call
@ -33,6 +35,8 @@ test_call:
test_ret_end:
nop
/***********************************************/
/* test abs-jmp/rep-ret */
test_abs_jmp_setup:
@ -48,6 +52,8 @@ test_abs_jmp_return:
test_rep_ret_end:
nop
/***********************************************/
/* test syscall */
.global test_syscall
@ -58,6 +64,24 @@ test_syscall:
test_syscall_end:
nop
/***********************************************/
/* Test stepping over int3.
The prefixes are pointless, but it's possible, so we exercise it. */
nop
.global test_int3
test_int3:
repz
repz
int3
nop
.global test_int3_end
test_int3_end:
nop
/***********************************************/
/* test rip-relative
GDB picks a spare register to hold the rip-relative address.
Exercise all the possibilities (rax-rdi, sans rsp). */
@ -118,6 +142,8 @@ test_rip_rdi_end:
answer: .8byte 42
/***********************************************/
/* all done */
done:
@ -139,6 +165,8 @@ test_call_end:
test_ret:
ret
/***********************************************/
/* subroutine to help test abs-jmp/rep-ret */
test_abs_jmp_subr:

20
gdb/testsuite/gdb.arch/amd64-disp-step.exp
View File

@ -141,6 +141,26 @@ gdb_test "continue" \
##########################################
# int3 (with prefixes)
# These don't occur in normal code, but gdb should still DTRT.
gdb_test "break test_int3" \
"Breakpoint.*at.* file .*$srcfile, line.*" \
"break test_int3"
gdb_test "break test_int3_end" \
"Breakpoint.*at.* file .*$srcfile, line.*" \
"break test_int3_end"
gdb_test "continue" \
"Continuing.*Breakpoint.*, test_int3 ().*" \
"continue to test_int3"
gdb_test "continue" \
"Continuing.*Breakpoint.*, test_int3_end ().*" \
"continue to test_int3_end"
##########################################
# Test rip-relative.
# GDB picks a spare register to hold the rip-relative address.
# Exercise all the possibilities (rax-rdi, sans rsp).

65
gdb/testsuite/gdb.arch/i386-disp-step.S
View File

@ -23,8 +23,11 @@
main:
nop
/* test call/ret */
/***********************************************/
/* Test call/ret. */
nop
.global test_call
test_call:
call test_call_subr
@ -33,16 +36,72 @@ test_call:
test_ret_end:
nop
/* test syscall */
/***********************************************/
/* Absolute jump with leading prefixes.
These don't occur in normal code, but gdb should still DTRT. */
nop
.global test_prefixed_abs_jump
test_prefixed_abs_jump:
ds
jmp *test_prefixed_abs_jump_addr
.data
test_prefixed_abs_jump_addr:
.4byte test_prefixed_abs_jump_target
.text
test_prefixed_abs_jump_target:
nop
.global test_prefixed_abs_jump_end
test_prefixed_abs_jump_end:
nop
/***********************************************/
/* Test syscall. */
.global test_syscall
mov $0x14,%eax /* getpid */
.global test_syscall
test_syscall:
int $0x80
nop
.global test_syscall_end
test_syscall_end:
nop
/***********************************************/
/* Test syscall again, this time with a prefix.
These don't occur in normal code, but gdb should still DTRT. */
mov $0x14,%eax /* getpid */
.global test_prefixed_syscall
test_prefixed_syscall:
repnz
int $0x80
nop
.global test_prefixed_syscall_end
test_prefixed_syscall_end:
nop
/***********************************************/
/* Test stepping over int3.
The prefixes are pointless, but it's possible, so we exercise it. */
nop
.global test_int3
test_int3:
repz
repz
int3
nop
.global test_int3_end
test_int3_end:
nop
/***********************************************/
/* all done */
pushl $0

58
gdb/testsuite/gdb.arch/i386-disp-step.exp
View File

@ -89,6 +89,25 @@ gdb_test "continue" \
##########################################
# Absolute jump with leading prefixes.
# These don't occur in normal code, but gdb should still DTRT.
gdb_test "break test_prefixed_abs_jump" \
"Breakpoint.*at.* file .*$srcfile, line.*" \
"break test_prefixed_abs_jump"
gdb_test "break test_prefixed_abs_jump_end" \
"Breakpoint.*at.* file .*$srcfile, line.*" \
"break test_prefixed_abs_jump_end"
gdb_test "continue" \
"Continuing.*Breakpoint.*, test_prefixed_abs_jump ().*" \
"continue to test_prefixed_abs_jump"
gdb_test "continue" \
"Continuing.*Breakpoint.*, test_prefixed_abs_jump_end ().*" \
"continue to test_prefixed_abs_jump_end"
##########################################
# Test syscall.
gdb_test "break test_syscall" \
@ -107,6 +126,45 @@ gdb_test "continue" \
##########################################
# Test prefixed syscall.
# These don't occur in normal code, but gdb should still DTRT.
gdb_test "break test_prefixed_syscall" \
"Breakpoint.*at.* file .*$srcfile, line.*" \
"break test_prefixed_syscall"
gdb_test "break test_prefixed_syscall_end" \
"Breakpoint.*at.* file .*$srcfile, line.*" \
"break test_prefixed_syscall_end"
gdb_test "continue" \
"Continuing.*Breakpoint.*, test_prefixed_syscall ().*" \
"continue to test_prefixed_syscall"
gdb_test "continue" \
"Continuing.*Breakpoint.*, test_prefixed_syscall_end ().*" \
"continue to test_prefixed_syscall_end"
##########################################
# int3 (with prefixes)
# These don't occur in normal code, but gdb should still DTRT.
gdb_test "break test_int3" \
"Breakpoint.*at.* file .*$srcfile, line.*" \
"break test_int3"
gdb_test "break test_int3_end" \
"Breakpoint.*at.* file .*$srcfile, line.*" \
"break test_int3_end"
gdb_test "continue" \
"Continuing.*Breakpoint.*, test_int3 ().*" \
"continue to test_int3"
gdb_test "continue" \
"Continuing.*Breakpoint.*, test_int3_end ().*" \
"continue to test_int3_end"
##########################################
# Done, run program to exit.
gdb_continue_to_end "i386-disp-step"