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Commit 2ade2920 authored by Chuck Ebbert's avatar Chuck Ebbert Committed by Andi Kleen
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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: default avatarChuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
parent 91cd444e

arch/i386/kernel/ptrace.c

+5 −5
Original line number Diff line number Diff line
@@ -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;

arch/x86_64/kernel/ptrace.c

+5 −7
Original line number Diff line number Diff line
@@ -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;