diff options
| author | Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> | 2012-06-05 19:28:38 +0900 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2012-07-31 10:29:59 -0400 |
| commit | e52538965119319447c0800c534da73142c27be2 (patch) | |
| tree | c7d380720da19d6c5ba996947ddda360e538cc9c | |
| parent | ae6aa16fdc163afe6b04b6c073ad4ddd4663c03b (diff) | |
kprobes/x86: ftrace based optimization for x86
Add function tracer based kprobe optimization support
handlers on x86. This allows kprobes to use function
tracer for probing on mcount call.
Link: http://lkml.kernel.org/r/20120605102838.27845.26317.stgit@localhost.localdomain
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
[ Updated to new port of ftrace save regs functions ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| -rw-r--r-- | arch/x86/include/asm/kprobes.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/kprobes.c | 48 | ||||
| -rw-r--r-- | include/linux/kprobes.h | 2 | ||||
| -rw-r--r-- | kernel/kprobes.c | 2 |
4 files changed, 51 insertions, 2 deletions
diff --git a/arch/x86/include/asm/kprobes.h b/arch/x86/include/asm/kprobes.h index 547882539157..d3ddd17405d0 100644 --- a/arch/x86/include/asm/kprobes.h +++ b/arch/x86/include/asm/kprobes.h @@ -27,6 +27,7 @@ #include <asm/insn.h> #define __ARCH_WANT_KPROBES_INSN_SLOT +#define ARCH_SUPPORTS_KPROBES_ON_FTRACE struct pt_regs; struct kprobe; diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index e2f751efb7b1..47ae1023a93c 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -1052,6 +1052,54 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) return 0; } +#ifdef KPROBES_CAN_USE_FTRACE +/* Ftrace callback handler for kprobes */ +void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *ops, struct pt_regs *regs) +{ + struct kprobe *p; + struct kprobe_ctlblk *kcb; + unsigned long flags; + + /* Disable irq for emulating a breakpoint and avoiding preempt */ + local_irq_save(flags); + + p = get_kprobe((kprobe_opcode_t *)ip); + if (unlikely(!p) || kprobe_disabled(p)) + goto end; + + kcb = get_kprobe_ctlblk(); + if (kprobe_running()) { + kprobes_inc_nmissed_count(p); + } else { + regs->ip += sizeof(kprobe_opcode_t); + + __this_cpu_write(current_kprobe, p); + kcb->kprobe_status = KPROBE_HIT_ACTIVE; + if (p->pre_handler) + p->pre_handler(p, regs); + + if (unlikely(p->post_handler)) { + /* Emulate singlestep as if there is a 5byte nop */ + regs->ip = ip + MCOUNT_INSN_SIZE; + kcb->kprobe_status = KPROBE_HIT_SSDONE; + p->post_handler(p, regs, 0); + } + __this_cpu_write(current_kprobe, NULL); + regs->ip = ip; /* Recover for next callback */ + } +end: + local_irq_restore(flags); +} + +int __kprobes arch_prepare_kprobe_ftrace(struct kprobe *p) +{ + p->ainsn.insn = NULL; + p->ainsn.boostable = -1; + return 0; +} +#endif + int __init arch_init_kprobes(void) { return arch_init_optprobes(); diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index aa0d05e852e3..23755ba42abc 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -318,7 +318,7 @@ extern int proc_kprobes_optimization_handler(struct ctl_table *table, #endif /* CONFIG_OPTPROBES */ #ifdef KPROBES_CAN_USE_FTRACE extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, - struct pt_regs *regs); + struct ftrace_ops *ops, struct pt_regs *regs); extern int arch_prepare_kprobe_ftrace(struct kprobe *p); #endif diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 69c16efc315b..35b4315d84f5 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -921,7 +921,7 @@ static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p) #ifdef KPROBES_CAN_USE_FTRACE static struct ftrace_ops kprobe_ftrace_ops __read_mostly = { - .regs_func = kprobe_ftrace_handler, + .func = kprobe_ftrace_handler, .flags = FTRACE_OPS_FL_SAVE_REGS, }; static int kprobe_ftrace_enabled; |