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Commit 89ae465b authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Frederic Weisbecker
Browse files

kprobes: Cleanup fix_riprel() using insn decoder on x86 



Cleanup fix_riprel() in arch/x86/kernel/kprobes.c by using the new x86
instruction decoder instead of using comparisons with raw ad hoc numeric
opcodes.

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it>
Cc: Roland McGrath <roland@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
LKML-Reference: <20090813203436.31965.34374.stgit@localhost.localdomain>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent b46b3d70

arch/x86/kernel/kprobes.c

+23 −105
Original line number Original line Diff line number Diff line
@@ -108,50 +108,6 @@ static const u32 twobyte_is_boostable[256 / 32] = { 
	/*      -----------------------------------------------         */

	/*      -----------------------------------------------         */

	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */

	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */

};

};

static const u32 onebyte_has_modrm[256 / 32] = {

	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */

	/*      -----------------------------------------------         */

	W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 00 */

	W(0x10, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 10 */

	W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 20 */

	W(0x30, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 30 */

	W(0x40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 40 */

	W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */

	W(0x60, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0) | /* 60 */

	W(0x70, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 70 */

	W(0x80, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */

	W(0x90, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 90 */

	W(0xa0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* a0 */

	W(0xb0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* b0 */

	W(0xc0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* c0 */

	W(0xd0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */

	W(0xe0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* e0 */

	W(0xf0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1)   /* f0 */

	/*      -----------------------------------------------         */

	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */

};

static const u32 twobyte_has_modrm[256 / 32] = {

	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */

	/*      -----------------------------------------------         */

	W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1) | /* 0f */

	W(0x10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0) , /* 1f */

	W(0x20, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* 2f */

	W(0x30, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 3f */

	W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 4f */

	W(0x50, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 5f */

	W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 6f */

	W(0x70, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1) , /* 7f */

	W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 8f */

	W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 9f */

	W(0xa0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) | /* af */

	W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1) , /* bf */

	W(0xc0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* cf */

	W(0xd0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* df */

	W(0xe0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* ef */

	W(0xf0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0)   /* ff */

	/*      -----------------------------------------------         */

	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */

};

#undef W

#undef W





struct kretprobe_blackpoint kretprobe_blacklist[] = {

struct kretprobe_blackpoint kretprobe_blacklist[] = {
@@ -348,68 +304,30 @@ static int __kprobes is_IF_modifier(kprobe_opcode_t *insn) 
static void __kprobes fix_riprel(struct kprobe *p)

static void __kprobes fix_riprel(struct kprobe *p)

{

{

#ifdef CONFIG_X86_64

#ifdef CONFIG_X86_64

	u8 *insn = p->ainsn.insn;

	struct insn insn;

	s64 disp;

	kernel_insn_init(&insn, p->ainsn.insn);

	int need_modrm;



	/* Skip legacy instruction prefixes.  */

	while (1) {

		switch (*insn) {

		case 0x66:

		case 0x67:

		case 0x2e:

		case 0x3e:

		case 0x26:

		case 0x64:

		case 0x65:

		case 0x36:

		case 0xf0:

		case 0xf3:

		case 0xf2:

			++insn;

			continue;

		}

		break;

	}





	/* Skip REX instruction prefix.  */

	if (insn_rip_relative(&insn)) {

	if (is_REX_prefix(insn))

		s64 newdisp;

		++insn;

		u8 *disp;



		insn_get_displacement(&insn);

	if (*insn == 0x0f) {

		/* Two-byte opcode.  */

		++insn;

		need_modrm = test_bit(*insn,

				      (unsigned long *)twobyte_has_modrm);

	} else

		/* One-byte opcode.  */

		need_modrm = test_bit(*insn,

				      (unsigned long *)onebyte_has_modrm);



	if (need_modrm) {

		u8 modrm = *++insn;

		if ((modrm & 0xc7) == 0x05) {

			/* %rip+disp32 addressing mode */

			/* Displacement follows ModRM byte.  */

			++insn;

		/*

		/*

			 * The copied instruction uses the %rip-relative

		 * The copied instruction uses the %rip-relative addressing

			 * addressing mode.  Adjust the displacement for the

		 * mode.  Adjust the displacement for the difference between

			 * difference between the original location of this

		 * the original location of this instruction and the location

			 * instruction and the location of the copy that will

		 * of the copy that will actually be run.  The tricky bit here

			 * actually be run.  The tricky bit here is making sure

		 * is making sure that the sign extension happens correctly in

			 * that the sign extension happens correctly in this

		 * this calculation, since we need a signed 32-bit result to

			 * calculation, since we need a signed 32-bit result to

		 * be sign-extended to 64 bits when it's added to the %rip

			 * be sign-extended to 64 bits when it's added to the

		 * value and yield the same 64-bit result that the sign-

			 * %rip value and yield the same 64-bit result that the

		 * extension of the original signed 32-bit displacement would

			 * sign-extension of the original signed 32-bit

		 * have given.

			 * displacement would have given.

		 */

		 */

			disp = (u8 *) p->addr + *((s32 *) insn) -

		newdisp = (u8 *) p->addr + (s64) insn.displacement.value -

			  (u8 *) p->ainsn.insn;

			  (u8 *) p->ainsn.insn;

			BUG_ON((s64) (s32) disp != disp); /* Sanity check.  */

		BUG_ON((s64) (s32) newdisp != newdisp); /* Sanity check.  */

			*(s32 *)insn = (s32) disp;

		disp = (u8 *) p->ainsn.insn + insn_offset_displacement(&insn);

		}

		*(s32 *) disp = (s32) newdisp;

	}

	}

#endif

#endif

}

}