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Diffstat (limited to 'arch/x86/kernel/uprobes.c')
-rw-r--r--arch/x86/kernel/uprobes.c52
1 files changed, 51 insertions, 1 deletions
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 36fd42091fa..9538f00827a 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:
@@ -646,7 +653,7 @@ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
* Skip these instructions as per the currently known x86 ISA.
* 0x66* { 0x90 | 0x0f 0x1f | 0x0f 0x19 | 0x87 0xc0 }
*/
-bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
+static bool __skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
int i;
@@ -673,3 +680,46 @@ bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
}
return false;
}
+
+bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ bool ret = __skip_sstep(auprobe, regs);
+ if (ret && (regs->flags & X86_EFLAGS_TF))
+ send_sig(SIGTRAP, current, 0);
+ return ret;
+}
+
+void arch_uprobe_enable_step(struct arch_uprobe *auprobe)
+{
+ struct task_struct *task = current;
+ struct arch_uprobe_task *autask = &task->utask->autask;
+ struct pt_regs *regs = task_pt_regs(task);
+
+ autask->saved_tf = !!(regs->flags & X86_EFLAGS_TF);
+
+ regs->flags |= X86_EFLAGS_TF;
+ if (test_tsk_thread_flag(task, TIF_BLOCKSTEP))
+ set_task_blockstep(task, false);
+}
+
+void arch_uprobe_disable_step(struct arch_uprobe *auprobe)
+{
+ struct task_struct *task = current;
+ struct arch_uprobe_task *autask = &task->utask->autask;
+ bool trapped = (task->utask->state == UTASK_SSTEP_TRAPPED);
+ struct pt_regs *regs = task_pt_regs(task);
+ /*
+ * The state of TIF_BLOCKSTEP was not saved so we can get an extra
+ * SIGTRAP if we do not clear TF. We need to examine the opcode to
+ * make it right.
+ */
+ if (unlikely(trapped)) {
+ if (!autask->saved_tf)
+ regs->flags &= ~X86_EFLAGS_TF;
+ } else {
+ if (autask->saved_tf)
+ send_sig(SIGTRAP, task, 0);
+ else if (!(auprobe->fixups & UPROBE_FIX_SETF))
+ regs->flags &= ~X86_EFLAGS_TF;
+ }
+}