From 2ade2920dcefdf5595c6380ebed131c964190855 Mon Sep 17 00:00:00 2001 From: Chuck Ebbert <76306.1226@compuserve.com> Date: Tue, 26 Sep 2006 10:52:33 +0200 Subject: [PATCH] [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 --- arch/i386/kernel/ptrace.c | 10 +++++----- arch/x86_64/kernel/ptrace.c | 12 +++++------- 2 files changed, 10 insertions(+), 12 deletions(-) diff --git a/arch/i386/kernel/ptrace.c b/arch/i386/kernel/ptrace.c index d3db03f4085d..775f50e9395b 100644 --- a/arch/i386/kernel/ptrace.c +++ b/arch/i386/kernel/ptrace.c @@ -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; diff --git a/arch/x86_64/kernel/ptrace.c b/arch/x86_64/kernel/ptrace.c index 412c6a8bf906..addc14af0c56 100644 --- a/arch/x86_64/kernel/ptrace.c +++ b/arch/x86_64/kernel/ptrace.c @@ -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; -- 2.30.2