Commit cd7ebe22 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Ingo Molnar

kprobes: Use text_poke_smp_batch for optimizing

Use text_poke_smp_batch() in optimization path for reducing
the number of stop_machine() issues. If the number of optimizing
probes is more than MAX_OPTIMIZE_PROBES(=256), kprobes optimizes
first MAX_OPTIMIZE_PROBES probes and kicks optimizer for
remaining probes.

Changes in v5:
- Use kick_kprobe_optimizer() instead of directly calling
  schedule_delayed_work().
- Rescheduling optimizer outside of kprobe mutex lock.

Changes in v2:
- Allocate code buffer and parameters in arch_init_kprobes()
  instead of using static arraies.
- Merge previous max optimization limit patch into this patch.
  So, this patch introduces upper limit of optimization at
  once.
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@redhat.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: <20101203095428.2961.8994.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 7deb18dc
......@@ -1405,10 +1405,16 @@ int __kprobes arch_prepare_optimized_kprobe(struct optimized_kprobe *op)
return 0;
}
/* Replace a breakpoint (int3) with a relative jump. */
int __kprobes arch_optimize_kprobe(struct optimized_kprobe *op)
#define MAX_OPTIMIZE_PROBES 256
static struct text_poke_param *jump_poke_params;
static struct jump_poke_buffer {
u8 buf[RELATIVEJUMP_SIZE];
} *jump_poke_bufs;
static void __kprobes setup_optimize_kprobe(struct text_poke_param *tprm,
u8 *insn_buf,
struct optimized_kprobe *op)
{
unsigned char jmp_code[RELATIVEJUMP_SIZE];
s32 rel = (s32)((long)op->optinsn.insn -
((long)op->kp.addr + RELATIVEJUMP_SIZE));
......@@ -1416,16 +1422,39 @@ int __kprobes arch_optimize_kprobe(struct optimized_kprobe *op)
memcpy(op->optinsn.copied_insn, op->kp.addr + INT3_SIZE,
RELATIVE_ADDR_SIZE);
jmp_code[0] = RELATIVEJUMP_OPCODE;
*(s32 *)(&jmp_code[1]) = rel;
insn_buf[0] = RELATIVEJUMP_OPCODE;
*(s32 *)(&insn_buf[1]) = rel;
tprm->addr = op->kp.addr;
tprm->opcode = insn_buf;
tprm->len = RELATIVEJUMP_SIZE;
}
/*
* Replace breakpoints (int3) with relative jumps.
* Caller must call with locking kprobe_mutex and text_mutex.
*/
void __kprobes arch_optimize_kprobes(struct list_head *oplist)
{
struct optimized_kprobe *op, *tmp;
int c = 0;
list_for_each_entry_safe(op, tmp, oplist, list) {
WARN_ON(kprobe_disabled(&op->kp));
/* Setup param */
setup_optimize_kprobe(&jump_poke_params[c],
jump_poke_bufs[c].buf, op);
list_del_init(&op->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(op->kp.addr, jmp_code, RELATIVEJUMP_SIZE);
return 0;
text_poke_smp_batch(jump_poke_params, c);
}
/* Replace a relative jump with a breakpoint (int3). */
......@@ -1457,11 +1486,35 @@ static int __kprobes setup_detour_execution(struct kprobe *p,
}
return 0;
}
static int __kprobes init_poke_params(void)
{
/* Allocate code buffer and parameter array */
jump_poke_bufs = kmalloc(sizeof(struct jump_poke_buffer) *
MAX_OPTIMIZE_PROBES, GFP_KERNEL);
if (!jump_poke_bufs)
return -ENOMEM;
jump_poke_params = kmalloc(sizeof(struct text_poke_param) *
MAX_OPTIMIZE_PROBES, GFP_KERNEL);
if (!jump_poke_params) {
kfree(jump_poke_bufs);
jump_poke_bufs = NULL;
return -ENOMEM;
}
return 0;
}
#else /* !CONFIG_OPTPROBES */
static int __kprobes init_poke_params(void)
{
return 0;
}
#endif
int __init arch_init_kprobes(void)
{
return 0;
return init_poke_params();
}
int __kprobes arch_trampoline_kprobe(struct kprobe *p)
......
......@@ -275,7 +275,7 @@ extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op);
extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
extern int arch_optimize_kprobe(struct optimized_kprobe *op);
extern void arch_optimize_kprobes(struct list_head *oplist);
extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
extern kprobe_opcode_t *get_optinsn_slot(void);
extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty);
......
......@@ -480,8 +480,6 @@ static DECLARE_COMPLETION(optimizer_comp);
*/
static __kprobes void do_optimize_kprobes(void)
{
struct optimized_kprobe *op, *tmp;
/* Optimization never be done when disarmed */
if (kprobes_all_disarmed || !kprobes_allow_optimization ||
list_empty(&optimizing_list))
......@@ -499,12 +497,7 @@ static __kprobes void do_optimize_kprobes(void)
*/
get_online_cpus();
mutex_lock(&text_mutex);
list_for_each_entry_safe(op, tmp, &optimizing_list, list) {
WARN_ON(kprobe_disabled(&op->kp));
if (arch_optimize_kprobe(op) < 0)
op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
list_del_init(&op->list);
}
arch_optimize_kprobes(&optimizing_list);
mutex_unlock(&text_mutex);
put_online_cpus();
}
......@@ -598,8 +591,12 @@ static __kprobes void kprobe_optimizer(struct work_struct *work)
mutex_unlock(&kprobe_mutex);
mutex_unlock(&module_mutex);
/* Wake up all waiters */
complete_all(&optimizer_comp);
/* Step 5: Kick optimizer again if needed */
if (!list_empty(&optimizing_list))
kick_kprobe_optimizer();
else
/* Wake up all waiters */
complete_all(&optimizer_comp);
}
/* Wait for completing optimization and unoptimization */
......
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