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Commit 611b1597 authored by Pekka Paalanen's avatar Pekka Paalanen Committed by Ingo Molnar
Browse files

x86: fix mmiotrace 8-bit register decoding 



When SIL, DIL, BPL or SPL registers were used in MMIO, the datum
was extracted from AH, BH, CH, or DH, which are incorrect.

Signed-off-by: default avatarPekka Paalanen <pq@iki.fi>
Cc: "Vegard Nossum" <vegard.nossum@gmail.com>
Cc: "Steven Rostedt" <srostedt@redhat.com>
Cc: proski@gnu.org
Cc: "Pekka Enberg"
	<penberg@cs.helsinki.fi>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 5f87f112

arch/x86/mm/pf_in.c

+84 −37
Original line number Diff line number Diff line
@@ -79,25 +79,34 @@ static unsigned int mw32[] = { 0xC7 }; 
static unsigned int mw64[] = { 0x89, 0x8B };

#endif /* not __i386__ */



static int skip_prefix(unsigned char *addr, int *shorted, int *enlarged,

								int *rexr)

struct prefix_bits {

	unsigned shorted:1;

	unsigned enlarged:1;

	unsigned rexr:1;

	unsigned rex:1;

};



static int skip_prefix(unsigned char *addr, struct prefix_bits *prf)

{

	int i;

	unsigned char *p = addr;

	*shorted = 0;

	*enlarged = 0;

	*rexr = 0;

	prf->shorted = 0;

	prf->enlarged = 0;

	prf->rexr = 0;

	prf->rex = 0;



restart:

	for (i = 0; i < ARRAY_SIZE(prefix_codes); i++) {

		if (*p == prefix_codes[i]) {

			if (*p == 0x66)

				*shorted = 1;

				prf->shorted = 1;

#ifdef __amd64__

			if ((*p & 0xf8) == 0x48)

				*enlarged = 1;

				prf->enlarged = 1;

			if ((*p & 0xf4) == 0x44)

				*rexr = 1;

				prf->rexr = 1;

			if ((*p & 0xf0) == 0x40)

				prf->rex = 1;

#endif

			p++;

			goto restart;
@@ -135,12 +144,12 @@ enum reason_type get_ins_type(unsigned long ins_addr) 
{

	unsigned int opcode;

	unsigned char *p;

	int shorted, enlarged, rexr;

	struct prefix_bits prf;

	int i;

	enum reason_type rv = OTHERS;



	p = (unsigned char *)ins_addr;

	p += skip_prefix(p, &shorted, &enlarged, &rexr);

	p += skip_prefix(p, &prf);

	p += get_opcode(p, &opcode);



	CHECK_OP_TYPE(opcode, reg_rop, REG_READ);
@@ -156,10 +165,11 @@ static unsigned int get_ins_reg_width(unsigned long ins_addr) 
{

	unsigned int opcode;

	unsigned char *p;

	int i, shorted, enlarged, rexr;

	struct prefix_bits prf;

	int i;



	p = (unsigned char *)ins_addr;

	p += skip_prefix(p, &shorted, &enlarged, &rexr);

	p += skip_prefix(p, &prf);

	p += get_opcode(p, &opcode);



	for (i = 0; i < ARRAY_SIZE(rw8); i++)
@@ -168,7 +178,7 @@ static unsigned int get_ins_reg_width(unsigned long ins_addr) 


	for (i = 0; i < ARRAY_SIZE(rw32); i++)

		if (rw32[i] == opcode)

			return (shorted ? 2 : (enlarged ? 8 : 4));

			return prf.shorted ? 2 : (prf.enlarged ? 8 : 4);



	printk(KERN_ERR "mmiotrace: Unknown opcode 0x%02x\n", opcode);

	return 0;
@@ -178,10 +188,11 @@ unsigned int get_ins_mem_width(unsigned long ins_addr) 
{

	unsigned int opcode;

	unsigned char *p;

	int i, shorted, enlarged, rexr;

	struct prefix_bits prf;

	int i;



	p = (unsigned char *)ins_addr;

	p += skip_prefix(p, &shorted, &enlarged, &rexr);

	p += skip_prefix(p, &prf);

	p += get_opcode(p, &opcode);



	for (i = 0; i < ARRAY_SIZE(mw8); i++)
@@ -194,11 +205,11 @@ unsigned int get_ins_mem_width(unsigned long ins_addr) 


	for (i = 0; i < ARRAY_SIZE(mw32); i++)

		if (mw32[i] == opcode)

			return shorted ? 2 : 4;

			return prf.shorted ? 2 : 4;



	for (i = 0; i < ARRAY_SIZE(mw64); i++)

		if (mw64[i] == opcode)

			return shorted ? 2 : (enlarged ? 8 : 4);

			return prf.shorted ? 2 : (prf.enlarged ? 8 : 4);



	printk(KERN_ERR "mmiotrace: Unknown opcode 0x%02x\n", opcode);

	return 0;
@@ -238,7 +249,7 @@ enum { 
#endif

};



static unsigned char *get_reg_w8(int no, struct pt_regs *regs)

static unsigned char *get_reg_w8(int no, int rex, struct pt_regs *regs)

{

	unsigned char *rv = NULL;
@@ -255,18 +266,6 @@ static unsigned char *get_reg_w8(int no, struct pt_regs *regs) 
	case arg_DL:

		rv = (unsigned char *)&regs->dx;

		break;

	case arg_AH:

		rv = 1 + (unsigned char *)&regs->ax;

		break;

	case arg_BH:

		rv = 1 + (unsigned char *)&regs->bx;

		break;

	case arg_CH:

		rv = 1 + (unsigned char *)&regs->cx;

		break;

	case arg_DH:

		rv = 1 + (unsigned char *)&regs->dx;

		break;

#ifdef __amd64__

	case arg_R8:

		rv = (unsigned char *)&regs->r8;
@@ -294,9 +293,55 @@ static unsigned char *get_reg_w8(int no, struct pt_regs *regs) 
		break;

#endif

	default:

		printk(KERN_ERR "mmiotrace: Error reg no# %d\n", no);

		break;

	}



	if (rv)

		return rv;



	if (rex) {

		/*

		 * If REX prefix exists, access low bytes of SI etc.

		 * instead of AH etc.

		 */

		switch (no) {

		case arg_SI:

			rv = (unsigned char *)&regs->si;

			break;

		case arg_DI:

			rv = (unsigned char *)&regs->di;

			break;

		case arg_BP:

			rv = (unsigned char *)&regs->bp;

			break;

		case arg_SP:

			rv = (unsigned char *)&regs->sp;

			break;

		default:

			break;

		}

	} else {

		switch (no) {

		case arg_AH:

			rv = 1 + (unsigned char *)&regs->ax;

			break;

		case arg_BH:

			rv = 1 + (unsigned char *)&regs->bx;

			break;

		case arg_CH:

			rv = 1 + (unsigned char *)&regs->cx;

			break;

		case arg_DH:

			rv = 1 + (unsigned char *)&regs->dx;

			break;

		default:

			break;

		}

	}



	if (!rv)

		printk(KERN_ERR "mmiotrace: Error reg no# %d\n", no);



	return rv;

}
@@ -368,11 +413,12 @@ unsigned long get_ins_reg_val(unsigned long ins_addr, struct pt_regs *regs) 
	unsigned char mod_rm;

	int reg;

	unsigned char *p;

	int i, shorted, enlarged, rexr;

	struct prefix_bits prf;

	int i;

	unsigned long rv;



	p = (unsigned char *)ins_addr;

	p += skip_prefix(p, &shorted, &enlarged, &rexr);

	p += skip_prefix(p, &prf);

	p += get_opcode(p, &opcode);

	for (i = 0; i < ARRAY_SIZE(reg_rop); i++)

		if (reg_rop[i] == opcode) {
@@ -392,10 +438,10 @@ unsigned long get_ins_reg_val(unsigned long ins_addr, struct pt_regs *regs) 


do_work:

	mod_rm = *p;

	reg = ((mod_rm >> 3) & 0x7) | (rexr << 3);

	reg = ((mod_rm >> 3) & 0x7) | (prf.rexr << 3);

	switch (get_ins_reg_width(ins_addr)) {

	case 1:

		return *get_reg_w8(reg, regs);

		return *get_reg_w8(reg, prf.rex, regs);



	case 2:

		return *(unsigned short *)get_reg_w32(reg, regs);
@@ -422,11 +468,12 @@ unsigned long get_ins_imm_val(unsigned long ins_addr) 
	unsigned char mod_rm;

	unsigned char mod;

	unsigned char *p;

	int i, shorted, enlarged, rexr;

	struct prefix_bits prf;

	int i;

	unsigned long rv;



	p = (unsigned char *)ins_addr;

	p += skip_prefix(p, &shorted, &enlarged, &rexr);

	p += skip_prefix(p, &prf);

	p += get_opcode(p, &opcode);

	for (i = 0; i < ARRAY_SIZE(imm_wop); i++)

		if (imm_wop[i] == opcode) {