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[PATCH] i386/x86-64: rename is_at_popf(), add iret to tests and fix 

is_at_popf() needs to test for the iret instruction as well as
popf.  So add that test and rename it to is_setting_trap_flag().

Also change max insn length from 16 to 15 to match reality.

LAHF / SAHF can't affect TF, so the comment in x86_64 is removed.

Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: Andi Kleen <ak@suse.de>
This commit is contained in:
Chuck Ebbert 2006-09-26 10:52:33 +02:00 committed by Andi Kleen
parent 91cd444e56
commit 2ade2920dc
2 changed files with 10 additions and 12 deletions
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10
arch/i386/kernel/ptrace.c
View File

@ -185,17 +185,17 @@ static unsigned long convert_eip_to_linear(struct task_struct *child, struct pt_
return addr;
}
static inline int is_at_popf(struct task_struct *child, struct pt_regs *regs)
static inline int is_setting_trap_flag(struct task_struct *child, struct pt_regs *regs)
{
int i, copied;
unsigned char opcode[16];
unsigned char opcode[15];
unsigned long addr = convert_eip_to_linear(child, regs);
copied = access_process_vm(child, addr, opcode, sizeof(opcode), 0);
for (i = 0; i < copied; i++) {
switch (opcode[i]) {
/* popf */
case 0x9d:
/* popf and iret */
case 0x9d: case 0xcf:
return 1;
/* opcode and address size prefixes */
case 0x66: case 0x67:
@ -247,7 +247,7 @@ static void set_singlestep(struct task_struct *child)
* don't mark it as being "us" that set it, so that we
* won't clear it by hand later.
*/
if (is_at_popf(child, regs))
if (is_setting_trap_flag(child, regs))
return;
child->ptrace |= PT_DTRACE;

12
arch/x86_64/kernel/ptrace.c
View File

@ -116,17 +116,17 @@ unsigned long convert_rip_to_linear(struct task_struct *child, struct pt_regs *r
return addr;
}
static int is_at_popf(struct task_struct *child, struct pt_regs *regs)
static int is_setting_trap_flag(struct task_struct *child, struct pt_regs *regs)
{
int i, copied;
unsigned char opcode[16];
unsigned char opcode[15];
unsigned long addr = convert_rip_to_linear(child, regs);
copied = access_process_vm(child, addr, opcode, sizeof(opcode), 0);
for (i = 0; i < copied; i++) {
switch (opcode[i]) {
/* popf */
case 0x9d:
/* popf and iret */
case 0x9d: case 0xcf:
return 1;
/* CHECKME: 64 65 */
@ -189,10 +189,8 @@ static void set_singlestep(struct task_struct *child)
* ..but if TF is changed by the instruction we will trace,
* don't mark it as being "us" that set it, so that we
* won't clear it by hand later.
*
* AK: this is not enough, LAHF and IRET can change TF in user space too.
*/
if (is_at_popf(child, regs))
if (is_setting_trap_flag(child, regs))
return;
child->ptrace |= PT_DTRACE;