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Commit a7b0133e authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Ingo Molnar
Browse files

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: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: default avatarJiri 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: default avatarIngo Molnar <mingo@kernel.org>
parent c7e85c42

arch/x86/kernel/kprobes/common.h

+0 −5
Original line number Diff line number Diff line
@@ -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;

arch/x86/kernel/kprobes/core.c

+1 −1
Original line number Diff line number Diff line
@@ -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)

arch/x86/kernel/kprobes/opt.c

+22 −78
Original line number Diff line number Diff line
@@ -371,19 +371,21 @@ 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)

/*

 * 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;

	u8 insn_buf[RELATIVEJUMP_SIZE];



	list_for_each_entry_safe(op, tmp, oplist, list) {

		s32 rel = (s32)((long)op->optinsn.insn -

			((long)op->kp.addr + RELATIVEJUMP_SIZE));



		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);
@@ -391,44 +393,23 @@ static void __kprobes setup_optimize_kprobe(struct text_poke_param *tprm, 
		insn_buf[0] = RELATIVEJUMP_OPCODE;

		*(s32 *)(&insn_buf[1]) = rel;



	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);



/*

 * 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_batch(jump_poke_params, c);

}



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;

}