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kprobes/x86: Use text_poke_bp() instead of text_poke_smp*() 

Use text_poke_bp() for optimizing kprobes instead of
text_poke_smp*(). Since the number of kprobes is usually not so
large (<100) and text_poke_bp() is much lighter than
text_poke_smp() [which uses stop_machine()], this just stops
using batch processing.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Borislav Petkov <bpetkov@suse.de>
Link: http://lkml.kernel.org/r/20130718114750.26675.9174.stgit@mhiramat-M0-7522
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Masami Hiramatsu 2013-07-18 20:47:50 +09:00 committed by Ingo Molnar
parent c7e85c42be
commit a7b0133ea9
3 changed files with 25 additions and 86 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
arch/x86/kernel/kprobes/common.h
View File

@ -82,14 +82,9 @@ extern void synthesize_reljump(void *from, void *to);
extern void synthesize_relcall(void *from, void *to);
#ifdef CONFIG_OPTPROBES
extern int arch_init_optprobes(void);
extern int setup_detour_execution(struct kprobe *p, struct pt_regs *regs, int reenter);
extern unsigned long __recover_optprobed_insn(kprobe_opcode_t *buf, unsigned long addr);
#else /* !CONFIG_OPTPROBES */
static inline int arch_init_optprobes(void)
{
return 0;
}
static inline int setup_detour_execution(struct kprobe *p, struct pt_regs *regs, int reenter)
{
return 0;

2
arch/x86/kernel/kprobes/core.c
View File

@ -1068,7 +1068,7 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
int __init arch_init_kprobes(void)
{
return arch_init_optprobes();
return 0;
}
int __kprobes arch_trampoline_kprobe(struct kprobe *p)

104
arch/x86/kernel/kprobes/opt.c
View File

@ -371,31 +371,6 @@ int __kprobes arch_prepare_optimized_kprobe(struct optimized_kprobe *op)
return 0;
}
#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)
{
s32 rel = (s32)((long)op->optinsn.insn -
((long)op->kp.addr + RELATIVEJUMP_SIZE));
/* Backup instructions which will be replaced by jump address */
memcpy(op->optinsn.copied_insn, op->kp.addr + INT3_SIZE,
RELATIVE_ADDR_SIZE);
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.
@ -403,32 +378,38 @@ static void __kprobes setup_optimize_kprobe(struct text_poke_param *tprm,
void __kprobes arch_optimize_kprobes(struct list_head *oplist)
{
struct optimized_kprobe *op, *tmp;
int c = 0;
u8 insn_buf[RELATIVEJUMP_SIZE];
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;
}
s32 rel = (s32)((long)op->optinsn.insn -
((long)op->kp.addr + RELATIVEJUMP_SIZE));
text_poke_smp_batch(jump_poke_params, c);
WARN_ON(kprobe_disabled(&op->kp));
/* Backup instructions which will be replaced by jump address */
memcpy(op->optinsn.copied_insn, op->kp.addr + INT3_SIZE,
RELATIVE_ADDR_SIZE);
insn_buf[0] = RELATIVEJUMP_OPCODE;
*(s32 *)(&insn_buf[1]) = rel;
text_poke_bp(op->kp.addr, insn_buf, RELATIVEJUMP_SIZE,
op->optinsn.insn);
list_del_init(&op->list);
}
}
static void __kprobes setup_unoptimize_kprobe(struct text_poke_param *tprm,
u8 *insn_buf,
struct optimized_kprobe *op)
/* Replace a relative jump with a breakpoint (int3). */
void __kprobes arch_unoptimize_kprobe(struct optimized_kprobe *op)
{
u8 insn_buf[RELATIVEJUMP_SIZE];
/* 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;
text_poke_bp(op->kp.addr, insn_buf, RELATIVEJUMP_SIZE,
op->optinsn.insn);
}
/*
@ -439,29 +420,11 @@ 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);
arch_unoptimize_kprobe(op);
list_move(&op->list, done_list);
if (++c >= MAX_OPTIMIZE_PROBES)
break;
}
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)
{
u8 buf[RELATIVEJUMP_SIZE];
/* Set int3 to first byte for kprobes */
buf[0] = BREAKPOINT_INSTRUCTION;
memcpy(buf + 1, op->optinsn.copied_insn, RELATIVE_ADDR_SIZE);
text_poke_smp(op->kp.addr, buf, RELATIVEJUMP_SIZE);
}
int __kprobes
@ -481,22 +444,3 @@ setup_detour_execution(struct kprobe *p, struct pt_regs *regs, int reenter)
}
return 0;
}
int __kprobes arch_init_optprobes(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;
}