[PATCH RFCv3 10/23] uprobes/x86: Add support to emulate nop5 instruction
From: Jiri Olsa <jolsa@kernel.org>
Date: 2025-03-20 11:43:58
Also in:
bpf, lkml
Subsystem:
the rest, uprobes, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Masami Hiramatsu, Oleg Nesterov, Peter Zijlstra, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Adding support to emulate nop5 as the original uprobe instruction. Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- arch/x86/kernel/uprobes.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 5ee2cce4c63e..1661e0ab2a3d 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c@@ -308,6 +308,11 @@ static int uprobe_init_insn(struct arch_uprobe *auprobe, struct insn *insn, bool return -ENOTSUPP; } +static int is_nop5_insn(uprobe_opcode_t *insn) +{ + return !memcmp(insn, x86_nops[5], 5); +} + #ifdef CONFIG_X86_64 asm (
@@ -865,6 +870,11 @@ void arch_uprobe_clear_state(struct mm_struct *mm) hlist_for_each_entry_safe(tramp, n, &state->head_tramps, node) destroy_uprobe_trampoline(tramp); } + +static bool emulate_nop5_insn(struct arch_uprobe *auprobe) +{ + return is_nop5_insn((uprobe_opcode_t *) &auprobe->insn); +} #else /* 32-bit: */ /* * No RIP-relative addressing on 32-bit
@@ -878,6 +888,10 @@ static void riprel_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) static void riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) { } +static bool emulate_nop5_insn(struct arch_uprobe *auprobe) +{ + return false; +} #endif /* CONFIG_X86_64 */ struct uprobe_xol_ops {
@@ -1109,6 +1123,8 @@ static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn) break; case 0x0f: + if (emulate_nop5_insn(auprobe)) + goto setup; if (insn->opcode.nbytes != 2) return -ENOSYS; /*
--
2.49.0