diff options
| -rw-r--r-- | arch/x86/kernel/uprobes.c | 30 |
1 files changed, 14 insertions, 16 deletions
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 5df1bca7c2bc..2ebadb252093 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -326,22 +326,24 @@ static void riprel_analyze(struct arch_uprobe *auprobe, struct insn *insn) } } +static inline unsigned long * +scratch_reg(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + return (auprobe->def.fixups & UPROBE_FIX_RIP_AX) ? ®s->ax : ®s->cx; +} + /* * If we're emulating a rip-relative instruction, save the contents * of the scratch register and store the target address in that register. */ static void riprel_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) { - struct uprobe_task *utask = current->utask; + if (auprobe->def.fixups & (UPROBE_FIX_RIP_AX | UPROBE_FIX_RIP_CX)) { + struct uprobe_task *utask = current->utask; + unsigned long *sr = scratch_reg(auprobe, regs); - if (auprobe->def.fixups & UPROBE_FIX_RIP_AX) { - utask->autask.saved_scratch_register = regs->ax; - regs->ax = utask->vaddr; - regs->ax += auprobe->def.riprel_target; - } else if (auprobe->def.fixups & UPROBE_FIX_RIP_CX) { - utask->autask.saved_scratch_register = regs->cx; - regs->cx = utask->vaddr; - regs->cx += auprobe->def.riprel_target; + utask->autask.saved_scratch_register = *sr; + *sr = utask->vaddr + auprobe->def.riprel_target; } } @@ -349,14 +351,10 @@ static void riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, long *correction) { if (auprobe->def.fixups & (UPROBE_FIX_RIP_AX | UPROBE_FIX_RIP_CX)) { - struct arch_uprobe_task *autask; - - autask = ¤t->utask->autask; - if (auprobe->def.fixups & UPROBE_FIX_RIP_AX) - regs->ax = autask->saved_scratch_register; - else - regs->cx = autask->saved_scratch_register; + struct uprobe_task *utask = current->utask; + unsigned long *sr = scratch_reg(auprobe, regs); + *sr = utask->autask.saved_scratch_register; /* * The original instruction includes a displacement, and so * is 4 bytes longer than what we've just single-stepped. |