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| author |   Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> | 2010-12-03 18:54:34 +0900 |
|---|---|---|
| committer |   Ingo Molnar <mingo@elte.hu> | 2010-12-06 17:59:32 +0100 |
| commit | f984ba4eb575e4a27ed28a76d4126d2aa9233c32 (patch) | |
| tree | 0df5f1510537edac10ae9cc1e5572d70dcf0a8c7 /arch/x86/kernel/kprobes.c | |
| parent | kprobes: Use text_poke_smp_batch for optimizing (diff) | |
| download | linux-dev-f984ba4eb575e4a27ed28a76d4126d2aa9233c32.tar.xz linux-dev-f984ba4eb575e4a27ed28a76d4126d2aa9233c32.zip | |
kprobes: Use text_poke_smp_batch for unoptimizing
Use text_poke_smp_batch() on unoptimization path for reducing
the number of stop_machine() issues. If the number of
unoptimizing probes is more than MAX_OPTIMIZE_PROBES(=256),
kprobes unoptimizes first MAX_OPTIMIZE_PROBES probes and kicks
optimizer for remaining probes.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20101203095434.2961.22657.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/kprobes.c')
| -rw-r--r-- | arch/x86/kernel/kprobes.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index 25a8af76feb5..5940282bd2f9 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -1457,6 +1457,46 @@ void __kprobes arch_optimize_kprobes(struct list_head *oplist) text_poke_smp_batch(jump_poke_params, c); } +static void __kprobes setup_unoptimize_kprobe(struct text_poke_param *tprm, + u8 *insn_buf, + struct optimized_kprobe *op) +{ + /* Set int3 to first byte for kprobes */ + insn_buf[0] = BREAKPOINT_INSTRUCTION; + memcpy(insn_buf + 1, op->optinsn.copied_insn, RELATIVE_ADDR_SIZE); + + tprm->addr = op->kp.addr; + tprm->opcode = insn_buf; + tprm->len = RELATIVEJUMP_SIZE; +} + +/* + * Recover original instructions and breakpoints from relative jumps. + * Caller must call with locking kprobe_mutex. + */ +extern void arch_unoptimize_kprobes(struct list_head *oplist, + struct list_head *done_list) +{ + struct optimized_kprobe *op, *tmp; + int c = 0; + + list_for_each_entry_safe(op, tmp, oplist, list) { + /* Setup param */ + setup_unoptimize_kprobe(&jump_poke_params[c], + jump_poke_bufs[c].buf, op); + list_move(&op->list, done_list); + if (++c >= MAX_OPTIMIZE_PROBES) + break; + } + + /* + * text_poke_smp doesn't support NMI/MCE code modifying. + * However, since kprobes itself also doesn't support NMI/MCE + * code probing, it's not a problem. + */ + text_poke_smp_batch(jump_poke_params, c); +} + /* Replace a relative jump with a breakpoint (int3). */ void __kprobes arch_unoptimize_kprobe(struct optimized_kprobe *op) { |