diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/uprobes.h | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/uprobes.c | 33 |
2 files changed, 35 insertions, 0 deletions
diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index f3971bb..cee5862 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -46,6 +46,8 @@ struct arch_uprobe_task { #ifdef CONFIG_X86_64 unsigned long saved_scratch_register; #endif +#define UPROBE_CLEAR_TF (1 << 0) + unsigned int restore_flags; }; extern int arch_uprobe_analyze_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long addr); diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 36fd420..309a0e0 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -41,6 +41,9 @@ /* Adjust the return address of a call insn */ #define UPROBE_FIX_CALL 0x2 +/* Instruction will modify TF, don't change it */ +#define UPROBE_FIX_SETF 0x4 + #define UPROBE_FIX_RIP_AX 0x8000 #define UPROBE_FIX_RIP_CX 0x4000 @@ -239,6 +242,10 @@ static void prepare_fixups(struct arch_uprobe *auprobe, struct insn *insn) insn_get_opcode(insn); /* should be a nop */ switch (OPCODE1(insn)) { + case 0x9d: + /* popf */ + auprobe->fixups |= UPROBE_FIX_SETF; + break; case 0xc3: /* ret/lret */ case 0xcb: case 0xc2: @@ -673,3 +680,29 @@ bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs) } return false; } + +void arch_uprobe_enable_step(struct arch_uprobe *auprobe) +{ + struct uprobe_task *utask = current->utask; + struct arch_uprobe_task *autask = &utask->autask; + + autask->restore_flags = 0; + if (!test_tsk_thread_flag(current, TIF_SINGLESTEP) && + !(auprobe->fixups & UPROBE_FIX_SETF)) + autask->restore_flags |= UPROBE_CLEAR_TF; + /* + * The state of TIF_BLOCKSTEP is not saved. With the TF flag set we + * would to examine the opcode and the flags to make it right. Without + * TF block stepping makes no sense. + */ + user_enable_single_step(current); +} + +void arch_uprobe_disable_step(struct arch_uprobe *auprobe) +{ + struct uprobe_task *utask = current->utask; + struct arch_uprobe_task *autask = &utask->autask; + + if (autask->restore_flags & UPROBE_CLEAR_TF) + user_disable_single_step(current); +} |
