diff options
Diffstat (limited to 'arch/x86/kernel/kprobes/opt.c')
| -rw-r--r-- | arch/x86/kernel/kprobes/opt.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c index 3f45b5c43a71..ea13f6888284 100644 --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -71,6 +71,21 @@ found: return (unsigned long)buf; } +static void synthesize_clac(kprobe_opcode_t *addr) +{ + /* + * Can't be static_cpu_has() due to how objtool treats this feature bit. + * This isn't a fast path anyway. + */ + if (!boot_cpu_has(X86_FEATURE_SMAP)) + return; + + /* Replace the NOP3 with CLAC */ + addr[0] = 0x0f; + addr[1] = 0x01; + addr[2] = 0xca; +} + /* Insert a move instruction which sets a pointer to eax/rdi (1st arg). */ static void synthesize_set_arg1(kprobe_opcode_t *addr, unsigned long val) { @@ -92,6 +107,9 @@ asm ( /* We don't bother saving the ss register */ " pushq %rsp\n" " pushfq\n" + ".global optprobe_template_clac\n" + "optprobe_template_clac:\n" + ASM_NOP3 SAVE_REGS_STRING " movq %rsp, %rsi\n" ".global optprobe_template_val\n" @@ -111,6 +129,9 @@ asm ( #else /* CONFIG_X86_32 */ " pushl %esp\n" " pushfl\n" + ".global optprobe_template_clac\n" + "optprobe_template_clac:\n" + ASM_NOP3 SAVE_REGS_STRING " movl %esp, %edx\n" ".global optprobe_template_val\n" @@ -134,6 +155,8 @@ asm ( void optprobe_template_func(void); STACK_FRAME_NON_STANDARD(optprobe_template_func); +#define TMPL_CLAC_IDX \ + ((long)optprobe_template_clac - (long)optprobe_template_entry) #define TMPL_MOVE_IDX \ ((long)optprobe_template_val - (long)optprobe_template_entry) #define TMPL_CALL_IDX \ @@ -389,6 +412,8 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, op->optinsn.size = ret; len = TMPL_END_IDX + op->optinsn.size; + synthesize_clac(buf + TMPL_CLAC_IDX); + /* Set probe information */ synthesize_set_arg1(buf + TMPL_MOVE_IDX, (unsigned long)op); |