1 files changed, 636 insertions, 360 deletions

diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 5c09f365c842..54651fc2d412 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -98,13 +98,8 @@ static unsigned long __kprobes dform_ea(unsigned int instr, struct pt_regs *regs
 
 	ra = (instr >> 16) & 0x1f;
 	ea = (signed short) instr;		/* sign-extend */
-	if (ra) {
+	if (ra)
 		ea += regs->gpr[ra];
-		if (instr & 0x04000000) {		/* update forms */
-			if ((instr>>26) != 47) 		/* stmw is not an update form */
-				regs->gpr[ra] = ea;
-		}
-	}
 
 	return truncate_if_32bit(regs->msr, ea);
 }
@@ -120,11 +115,8 @@ static unsigned long __kprobes dsform_ea(unsigned int instr, struct pt_regs *reg
 
 	ra = (instr >> 16) & 0x1f;
 	ea = (signed short) (instr & ~3);	/* sign-extend */
-	if (ra) {
+	if (ra)
 		ea += regs->gpr[ra];
-		if ((instr & 3) == 1)		/* update forms */
-			regs->gpr[ra] = ea;
-	}
 
 	return truncate_if_32bit(regs->msr, ea);
 }
@@ -133,8 +125,8 @@ static unsigned long __kprobes dsform_ea(unsigned int instr, struct pt_regs *reg
 /*
  * Calculate effective address for an X-form instruction
  */
-static unsigned long __kprobes xform_ea(unsigned int instr, struct pt_regs *regs,
-				     int do_update)
+static unsigned long __kprobes xform_ea(unsigned int instr,
+					struct pt_regs *regs)
 {
 	int ra, rb;
 	unsigned long ea;
@@ -142,11 +134,8 @@ static unsigned long __kprobes xform_ea(unsigned int instr, struct pt_regs *regs
 	ra = (instr >> 16) & 0x1f;
 	rb = (instr >> 11) & 0x1f;
 	ea = regs->gpr[rb];
-	if (ra) {
+	if (ra)
 		ea += regs->gpr[ra];
-		if (do_update)		/* update forms */
-			regs->gpr[ra] = ea;
-	}
 
 	return truncate_if_32bit(regs->msr, ea);
 }
@@ -611,6 +600,23 @@ static void __kprobes do_cmp_unsigned(struct pt_regs *regs, unsigned long v1,
 	regs->ccr = (regs->ccr & ~(0xf << shift)) | (crval << shift);
 }
 
+static int __kprobes trap_compare(long v1, long v2)
+{
+	int ret = 0;
+
+	if (v1 < v2)
+		ret |= 0x10;
+	else if (v1 > v2)
+		ret |= 0x08;
+	else
+		ret |= 0x04;
+	if ((unsigned long)v1 < (unsigned long)v2)
+		ret |= 0x02;
+	else if ((unsigned long)v1 > (unsigned long)v2)
+		ret |= 0x01;
+	return ret;
+}
+
 /*
  * Elements of 32-bit rotate and mask instructions.
  */
@@ -627,26 +633,27 @@ static void __kprobes do_cmp_unsigned(struct pt_regs *regs, unsigned long v1,
 #define ROTATE(x, n)	((n) ? (((x) << (n)) | ((x) >> (8 * sizeof(long) - (n)))) : (x))
 
 /*
- * Emulate instructions that cause a transfer of control,
- * loads and stores, and a few other instructions.
- * Returns 1 if the step was emulated, 0 if not,
- * or -1 if the instruction is one that should not be stepped,
- * such as an rfid, or a mtmsrd that would clear MSR_RI.
+ * Decode an instruction, and execute it if that can be done just by
+ * modifying *regs (i.e. integer arithmetic and logical instructions,
+ * branches, and barrier instructions).
+ * Returns 1 if the instruction has been executed, or 0 if not.
+ * Sets *op to indicate what the instruction does.
  */
-int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
+int __kprobes analyse_instr(struct instruction_op *op, struct pt_regs *regs,
+			    unsigned int instr)
 {
 	unsigned int opcode, ra, rb, rd, spr, u;
 	unsigned long int imm;
 	unsigned long int val, val2;
-	unsigned long int ea;
-	unsigned int cr, mb, me, sh;
-	int err;
-	unsigned long old_ra, val3;
+	unsigned int mb, me, sh;
 	long ival;
 
+	op->type = COMPUTE;
+
 	opcode = instr >> 26;
 	switch (opcode) {
 	case 16:	/* bc */
+		op->type = BRANCH;
 		imm = (signed short)(instr & 0xfffc);
 		if ((instr & 2) == 0)
 			imm += regs->nip;
@@ -659,26 +666,14 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
 		return 1;
 #ifdef CONFIG_PPC64
 	case 17:	/* sc */
-		/*
-		 * N.B. this uses knowledge about how the syscall
-		 * entry code works.  If that is changed, this will
-		 * need to be changed also.
-		 */
-		if (regs->gpr[0] == 0x1ebe &&
-		    cpu_has_feature(CPU_FTR_REAL_LE)) {
-			regs->msr ^= MSR_LE;
-			goto instr_done;
-		}
-		regs->gpr[9] = regs->gpr[13];
-		regs->gpr[10] = MSR_KERNEL;
-		regs->gpr[11] = regs->nip + 4;
-		regs->gpr[12] = regs->msr & MSR_MASK;
-		regs->gpr[13] = (unsigned long) get_paca();
-		regs->nip = (unsigned long) &system_call_common;
-		regs->msr = MSR_KERNEL;
-		return 1;
+		if ((instr & 0xfe2) == 2)
+			op->type = SYSCALL;
+		else
+			op->type = UNKNOWN;
+		return 0;
 #endif
 	case 18:	/* b */
+		op->type = BRANCH;
 		imm = instr & 0x03fffffc;
 		if (imm & 0x02000000)
 			imm -= 0x04000000;
@@ -691,8 +686,16 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
 		return 1;
 	case 19:
 		switch ((instr >> 1) & 0x3ff) {
+		case 0:		/* mcrf */
+			rd = (instr >> 21) & 0x1c;
+			ra = (instr >> 16) & 0x1c;
+			val = (regs->ccr >> ra) & 0xf;
+			regs->ccr = (regs->ccr & ~(0xfUL << rd)) | (val << rd);
+			goto instr_done;
+
 		case 16:	/* bclr */
 		case 528:	/* bcctr */
+			op->type = BRANCH;
 			imm = (instr & 0x400)? regs->ctr: regs->link;
 			regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
 			imm = truncate_if_32bit(regs->msr, imm);
@@ -703,9 +706,13 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
 			return 1;
 
 		case 18:	/* rfid, scary */
-			return -1;
+			if (regs->msr & MSR_PR)
+				goto priv;
+			op->type = RFI;
+			return 0;
 
 		case 150:	/* isync */
+			op->type = BARRIER;
 			isync();
 			goto instr_done;
 
@@ -731,6 +738,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
 	case 31:
 		switch ((instr >> 1) & 0x3ff) {
 		case 598:	/* sync */
+			op->type = BARRIER;
 #ifdef __powerpc64__
 			switch ((instr >> 21) & 3) {
 			case 1:		/* lwsync */
@@ -745,6 +753,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
 			goto instr_done;
 
 		case 854:	/* eieio */
+			op->type = BARRIER;
 			eieio();
 			goto instr_done;
 		}
@@ -760,6 +769,17 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
 	rb = (instr >> 11) & 0x1f;
 
 	switch (opcode) {
+#ifdef __powerpc64__
+	case 2:		/* tdi */
+		if (rd & trap_compare(regs->gpr[ra], (short) instr))
+			goto trap;
+		goto instr_done;
+#endif
+	case 3:		/* twi */
+		if (rd & trap_compare((int)regs->gpr[ra], (short) instr))
+			goto trap;
+		goto instr_done;
+
 	case 7:		/* mulli */
 		regs->gpr[rd] = regs->gpr[ra] * (short) instr;
 		goto instr_done;
@@ -908,35 +928,44 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
 
 	case 31:
 		switch ((instr >> 1) & 0x3ff) {
+		case 4:		/* tw */
+			if (rd == 0x1f ||
+			    (rd & trap_compare((int)regs->gpr[ra],
+					       (int)regs->gpr[rb])))
+				goto trap;
+			goto instr_done;
+#ifdef __powerpc64__
+		case 68:	/* td */
+			if (rd & trap_compare(regs->gpr[ra], regs->gpr[rb]))
+				goto trap;
+			goto instr_done;
+#endif
 		case 83:	/* mfmsr */
 			if (regs->msr & MSR_PR)
-				break;
-			regs->gpr[rd] = regs->msr & MSR_MASK;
-			goto instr_done;
+				goto priv;
+			op->type = MFMSR;
+			op->reg = rd;
+			return 0;
 		case 146:	/* mtmsr */
 			if (regs->msr & MSR_PR)
-				break;
-			imm = regs->gpr[rd];
-			if ((imm & MSR_RI) == 0)
-				/* can't step mtmsr that would clear MSR_RI */
-				return -1;
-			regs->msr = imm;
-			goto instr_done;
+				goto priv;
+			op->type = MTMSR;
+			op->reg = rd;
+			op->val = 0xffffffff & ~(MSR_ME | MSR_LE);
+			return 0;
 #ifdef CONFIG_PPC64
 		case 178:	/* mtmsrd */
-			/* only MSR_EE and MSR_RI get changed if bit 15 set */
-			/* mtmsrd doesn't change MSR_HV and MSR_ME */
 			if (regs->msr & MSR_PR)
-				break;
-			imm = (instr & 0x10000)? 0x8002: 0xefffffffffffefffUL;
-			imm = (regs->msr & MSR_MASK & ~imm)
-				| (regs->gpr[rd] & imm);
-			if ((imm & MSR_RI) == 0)
-				/* can't step mtmsrd that would clear MSR_RI */
-				return -1;
-			regs->msr = imm;
-			goto instr_done;
+				goto priv;
+			op->type = MTMSR;
+			op->reg = rd;
+			/* only MSR_EE and MSR_RI get changed if bit 15 set */
+			/* mtmsrd doesn't change MSR_HV, MSR_ME or MSR_LE */
+			imm = (instr & 0x10000)? 0x8002: 0xefffffffffffeffeUL;
+			op->val = imm;
+			return 0;
 #endif
+
 		case 19:	/* mfcr */
 			regs->gpr[rd] = regs->ccr;
 			regs->gpr[rd] &= 0xffffffffUL;
@@ -954,33 +983,43 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
 			goto instr_done;
 
 		case 339:	/* mfspr */
-			spr = (instr >> 11) & 0x3ff;
+			spr = ((instr >> 16) & 0x1f) | ((instr >> 6) & 0x3e0);
 			switch (spr) {
-			case 0x20:	/* mfxer */
+			case SPRN_XER:	/* mfxer */
 				regs->gpr[rd] = regs->xer;
 				regs->gpr[rd] &= 0xffffffffUL;
 				goto instr_done;
-			case 0x100:	/* mflr */
+			case SPRN_LR:	/* mflr */
 				regs->gpr[rd] = regs->link;
 				goto instr_done;
-			case 0x120:	/* mfctr */
+			case SPRN_CTR:	/* mfctr */
 				regs->gpr[rd] = regs->ctr;
 				goto instr_done;
+			default:
+				op->type = MFSPR;
+				op->reg = rd;
+				op->spr = spr;
+				return 0;
 			}
 			break;
 
 		case 467:	/* mtspr */
-			spr = (instr >> 11) & 0x3ff;
+			spr = ((instr >> 16) & 0x1f) | ((instr >> 6) & 0x3e0);
 			switch (spr) {
-			case 0x20:	/* mtxer */
+			case SPRN_XER:	/* mtxer */
 				regs->xer = (regs->gpr[rd] & 0xffffffffUL);
 				goto instr_done;
-			case 0x100:	/* mtlr */
+			case SPRN_LR:	/* mtlr */
 				regs->link = regs->gpr[rd];
 				goto instr_done;
-			case 0x120:	/* mtctr */
+			case SPRN_CTR:	/* mtctr */
 				regs->ctr = regs->gpr[rd];
 				goto instr_done;
+			default:
+				op->type = MTSPR;
+				op->val = regs->gpr[rd];
+				op->spr = spr;
+				return 0;
 			}
 			break;
 
@@ -1257,294 +1296,242 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
  * Cache instructions
  */
 		case 54:	/* dcbst */
-			ea = xform_ea(instr, regs, 0);
-			if (!address_ok(regs, ea, 8))
-				return 0;
-			err = 0;
-			__cacheop_user_asmx(ea, err, "dcbst");
-			if (err)
-				return 0;
-			goto instr_done;
+			op->type = MKOP(CACHEOP, DCBST, 0);
+			op->ea = xform_ea(instr, regs);
+			return 0;
 
 		case 86:	/* dcbf */
-			ea = xform_ea(instr, regs, 0);
-			if (!address_ok(regs, ea, 8))
-				return 0;
-			err = 0;
-			__cacheop_user_asmx(ea, err, "dcbf");
-			if (err)
-				return 0;
-			goto instr_done;
+			op->type = MKOP(CACHEOP, DCBF, 0);
+			op->ea = xform_ea(instr, regs);
+			return 0;
 
 		case 246:	/* dcbtst */
-			if (rd == 0) {
-				ea = xform_ea(instr, regs, 0);
-				prefetchw((void *) ea);
-			}
-			goto instr_done;
+			op->type = MKOP(CACHEOP, DCBTST, 0);
+			op->ea = xform_ea(instr, regs);
+			op->reg = rd;
+			return 0;
 
 		case 278:	/* dcbt */
-			if (rd == 0) {
-				ea = xform_ea(instr, regs, 0);
-				prefetch((void *) ea);
-			}
-			goto instr_done;
+			op->type = MKOP(CACHEOP, DCBTST, 0);
+			op->ea = xform_ea(instr, regs);
+			op->reg = rd;
+			return 0;
 
+		case 982:	/* icbi */
+			op->type = MKOP(CACHEOP, ICBI, 0);
+			op->ea = xform_ea(instr, regs);
+			return 0;
 		}
 		break;
 	}
 
 	/*
-	 * Following cases are for loads and stores, so bail out
-	 * if we're in little-endian mode.
+	 * Loads and stores.
 	 */
-	if (regs->msr & MSR_LE)
-		return 0;
-
-	/*
-	 * Save register RA in case it's an update form load or store
-	 * and the access faults.
-	 */
-	old_ra = regs->gpr[ra];
+	op->type = UNKNOWN;
+	op->update_reg = ra;
+	op->reg = rd;
+	op->val = regs->gpr[rd];
+	u = (instr >> 20) & UPDATE;
 
 	switch (opcode) {
 	case 31:
-		u = instr & 0x40;
+		u = instr & UPDATE;
+		op->ea = xform_ea(instr, regs);
 		switch ((instr >> 1) & 0x3ff) {
 		case 20:	/* lwarx */
-			ea = xform_ea(instr, regs, 0);
-			if (ea & 3)
-				break;		/* can't handle misaligned */
-			err = -EFAULT;
-			if (!address_ok(regs, ea, 4))
-				goto ldst_done;
-			err = 0;
-			__get_user_asmx(val, ea, err, "lwarx");
-			if (!err)
-				regs->gpr[rd] = val;
-			goto ldst_done;
+			op->type = MKOP(LARX, 0, 4);
+			break;
 
 		case 150:	/* stwcx. */
-			ea = xform_ea(instr, regs, 0);
-			if (ea & 3)
-				break;		/* can't handle misaligned */
-			err = -EFAULT;
-			if (!address_ok(regs, ea, 4))
-				goto ldst_done;
-			err = 0;
-			__put_user_asmx(regs->gpr[rd], ea, err, "stwcx.", cr);
-			if (!err)
-				regs->ccr = (regs->ccr & 0x0fffffff) |
-					(cr & 0xe0000000) |
-					((regs->xer >> 3) & 0x10000000);
-			goto ldst_done;
+			op->type = MKOP(STCX, 0, 4);
+			break;
 
 #ifdef __powerpc64__
 		case 84:	/* ldarx */
-			ea = xform_ea(instr, regs, 0);
-			if (ea & 7)
-				break;		/* can't handle misaligned */
-			err = -EFAULT;
-			if (!address_ok(regs, ea, 8))
-				goto ldst_done;
-			err = 0;
-			__get_user_asmx(val, ea, err, "ldarx");
-			if (!err)
-				regs->gpr[rd] = val;
-			goto ldst_done;
+			op->type = MKOP(LARX, 0, 8);
+			break;
 
 		case 214:	/* stdcx. */
-			ea = xform_ea(instr, regs, 0);
-			if (ea & 7)
-				break;		/* can't handle misaligned */
-			err = -EFAULT;
-			if (!address_ok(regs, ea, 8))
-				goto ldst_done;
-			err = 0;
-			__put_user_asmx(regs->gpr[rd], ea, err, "stdcx.", cr);
-			if (!err)
-				regs->ccr = (regs->ccr & 0x0fffffff) |
-					(cr & 0xe0000000) |
-					((regs->xer >> 3) & 0x10000000);
-			goto ldst_done;
+			op->type = MKOP(STCX, 0, 8);
+			break;
 
 		case 21:	/* ldx */
 		case 53:	/* ldux */
-			err = read_mem(&regs->gpr[rd], xform_ea(instr, regs, u),
-				       8, regs);
-			goto ldst_done;
+			op->type = MKOP(LOAD, u, 8);
+			break;
 #endif
 
 		case 23:	/* lwzx */
 		case 55:	/* lwzux */
-			err = read_mem(&regs->gpr[rd], xform_ea(instr, regs, u),
-				       4, regs);
-			goto ldst_done;
+			op->type = MKOP(LOAD, u, 4);
+			break;
 
 		case 87:	/* lbzx */
 		case 119:	/* lbzux */
-			err = read_mem(&regs->gpr[rd], xform_ea(instr, regs, u),
-				       1, regs);
-			goto ldst_done;
+			op->type = MKOP(LOAD, u, 1);
+			break;
 
 #ifdef CONFIG_ALTIVEC
 		case 103:	/* lvx */
 		case 359:	/* lvxl */
 			if (!(regs->msr & MSR_VEC))
-				break;
-			ea = xform_ea(instr, regs, 0);
-			err = do_vec_load(rd, do_lvx, ea, regs);
-			goto ldst_done;
+				goto vecunavail;
+			op->type = MKOP(LOAD_VMX, 0, 16);
+			break;
 
 		case 231:	/* stvx */
 		case 487:	/* stvxl */
 			if (!(regs->msr & MSR_VEC))
-				break;
-			ea = xform_ea(instr, regs, 0);
-			err = do_vec_store(rd, do_stvx, ea, regs);
-			goto ldst_done;
+				goto vecunavail;
+			op->type = MKOP(STORE_VMX, 0, 16);
+			break;
 #endif /* CONFIG_ALTIVEC */
 
 #ifdef __powerpc64__
 		case 149:	/* stdx */
 		case 181:	/* stdux */
-			val = regs->gpr[rd];
-			err = write_mem(val, xform_ea(instr, regs, u), 8, regs);
-			goto ldst_done;
+			op->type = MKOP(STORE, u, 8);
+			break;
 #endif
 
 		case 151:	/* stwx */
 		case 183:	/* stwux */
-			val = regs->gpr[rd];
-			err = write_mem(val, xform_ea(instr, regs, u), 4, regs);
-			goto ldst_done;
+			op->type = MKOP(STORE, u, 4);
+			break;
 
 		case 215:	/* stbx */
 		case 247:	/* stbux */
-			val = regs->gpr[rd];
-			err = write_mem(val, xform_ea(instr, regs, u), 1, regs);
-			goto ldst_done;
+			op->type = MKOP(STORE, u, 1);
+			break;
 
 		case 279:	/* lhzx */
 		case 311:	/* lhzux */
-			err = read_mem(&regs->gpr[rd], xform_ea(instr, regs, u),
-				       2, regs);
-			goto ldst_done;
+			op->type = MKOP(LOAD, u, 2);
+			break;
 
 #ifdef __powerpc64__
 		case 341:	/* lwax */
 		case 373:	/* lwaux */
-			err = read_mem(&regs->gpr[rd], xform_ea(instr, regs, u),
-				       4, regs);
-			if (!err)
-				regs->gpr[rd] = (signed int) regs->gpr[rd];
-			goto ldst_done;
+			op->type = MKOP(LOAD, SIGNEXT | u, 4);
+			break;
 #endif
 
 		case 343:	/* lhax */
 		case 375:	/* lhaux */
-			err = read_mem(&regs->gpr[rd], xform_ea(instr, regs, u),
-				       2, regs);
-			if (!err)
-				regs->gpr[rd] = (signed short) regs->gpr[rd];
-			goto ldst_done;
+			op->type = MKOP(LOAD, SIGNEXT | u, 2);
+			break;
 
 		case 407:	/* sthx */
 		case 439:	/* sthux */
-			val = regs->gpr[rd];
-			err = write_mem(val, xform_ea(instr, regs, u), 2, regs);
-			goto ldst_done;
+			op->type = MKOP(STORE, u, 2);
+			break;
 
 #ifdef __powerpc64__
 		case 532:	/* ldbrx */
-			err = read_mem(&val, xform_ea(instr, regs, 0), 8, regs);
-			if (!err)
-				regs->gpr[rd] = byterev_8(val);
-			goto ldst_done;
+			op->type = MKOP(LOAD, BYTEREV, 8);
+			break;
 
 #endif
+		case 533:	/* lswx */
+			op->type = MKOP(LOAD_MULTI, 0, regs->xer & 0x7f);
+			break;
 
 		case 534:	/* lwbrx */
-			err = read_mem(&val, xform_ea(instr, regs, 0), 4, regs);
-			if (!err)
-				regs->gpr[rd] = byterev_4(val);
-			goto ldst_done;
+			op->type = MKOP(LOAD, BYTEREV, 4);
+			break;
+
+		case 597:	/* lswi */
+			if (rb == 0)
+				rb = 32;	/* # bytes to load */
+			op->type = MKOP(LOAD_MULTI, 0, rb);
+			op->ea = 0;
+			if (ra)
+				op->ea = truncate_if_32bit(regs->msr,
+							   regs->gpr[ra]);
+			break;
 
 #ifdef CONFIG_PPC_FPU
 		case 535:	/* lfsx */
 		case 567:	/* lfsux */
 			if (!(regs->msr & MSR_FP))
-				break;
-			ea = xform_ea(instr, regs, u);
-			err = do_fp_load(rd, do_lfs, ea, 4, regs);
-			goto ldst_done;
+				goto fpunavail;
+			op->type = MKOP(LOAD_FP, u, 4);
+			break;
 
 		case 599:	/* lfdx */
 		case 631:	/* lfdux */
 			if (!(regs->msr & MSR_FP))
-				break;
-			ea = xform_ea(instr, regs, u);
-			err = do_fp_load(rd, do_lfd, ea, 8, regs);
-			goto ldst_done;
+				goto fpunavail;
+			op->type = MKOP(LOAD_FP, u, 8);
+			break;
 
 		case 663:	/* stfsx */
 		case 695:	/* stfsux */
 			if (!(regs->msr & MSR_FP))
-				break;
-			ea = xform_ea(instr, regs, u);
-			err = do_fp_store(rd, do_stfs, ea, 4, regs);
-			goto ldst_done;
+				goto fpunavail;
+			op->type = MKOP(STORE_FP, u, 4);
+			break;
 
 		case 727:	/* stfdx */
 		case 759:	/* stfdux */
 			if (!(regs->msr & MSR_FP))
-				break;
-			ea = xform_ea(instr, regs, u);
-			err = do_fp_store(rd, do_stfd, ea, 8, regs);
-			goto ldst_done;
+				goto fpunavail;
+			op->type = MKOP(STORE_FP, u, 8);
+			break;
 #endif
 
 #ifdef __powerpc64__
 		case 660:	/* stdbrx */
-			val = byterev_8(regs->gpr[rd]);
-			err = write_mem(val, xform_ea(instr, regs, 0), 8, regs);
-			goto ldst_done;
+			op->type = MKOP(STORE, BYTEREV, 8);
+			op->val = byterev_8(regs->gpr[rd]);
+			break;
 
 #endif
+		case 661:	/* stswx */
+			op->type = MKOP(STORE_MULTI, 0, regs->xer & 0x7f);
+			break;
+
 		case 662:	/* stwbrx */
-			val = byterev_4(regs->gpr[rd]);
-			err = write_mem(val, xform_ea(instr, regs, 0), 4, regs);
-			goto ldst_done;
+			op->type = MKOP(STORE, BYTEREV, 4);
+			op->val = byterev_4(regs->gpr[rd]);
+			break;
+
+		case 725:
+			if (rb == 0)
+				rb = 32;	/* # bytes to store */
+			op->type = MKOP(STORE_MULTI, 0, rb);
+			op->ea = 0;
+			if (ra)
+				op->ea = truncate_if_32bit(regs->msr,
+							   regs->gpr[ra]);
+			break;
 
 		case 790:	/* lhbrx */
-			err = read_mem(&val, xform_ea(instr, regs, 0), 2, regs);
-			if (!err)
-				regs->gpr[rd] = byterev_2(val);
-			goto ldst_done;
+			op->type = MKOP(LOAD, BYTEREV, 2);
+			break;
 
 		case 918:	/* sthbrx */
-			val = byterev_2(regs->gpr[rd]);
-			err = write_mem(val, xform_ea(instr, regs, 0), 2, regs);
-			goto ldst_done;
+			op->type = MKOP(STORE, BYTEREV, 2);
+			op->val = byterev_2(regs->gpr[rd]);
+			break;
 
 #ifdef CONFIG_VSX
 		case 844:	/* lxvd2x */
 		case 876:	/* lxvd2ux */
 			if (!(regs->msr & MSR_VSX))
-				break;
-			rd |= (instr & 1) << 5;
-			ea = xform_ea(instr, regs, u);
-			err = do_vsx_load(rd, do_lxvd2x, ea, regs);
-			goto ldst_done;
+				goto vsxunavail;
+			op->reg = rd | ((instr & 1) << 5);
+			op->type = MKOP(LOAD_VSX, u, 16);
+			break;
 
 		case 972:	/* stxvd2x */
 		case 1004:	/* stxvd2ux */
 			if (!(regs->msr & MSR_VSX))
-				break;
-			rd |= (instr & 1) << 5;
-			ea = xform_ea(instr, regs, u);
-			err = do_vsx_store(rd, do_stxvd2x, ea, regs);
-			goto ldst_done;
+				goto vsxunavail;
+			op->reg = rd | ((instr & 1) << 5);
+			op->type = MKOP(STORE_VSX, u, 16);
+			break;
 
 #endif /* CONFIG_VSX */
 		}
@@ -1552,178 +1539,123 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
 
 	case 32:	/* lwz */
 	case 33:	/* lwzu */
-		err = read_mem(&regs->gpr[rd], dform_ea(instr, regs), 4, regs);
-		goto ldst_done;
+		op->type = MKOP(LOAD, u, 4);
+		op->ea = dform_ea(instr, regs);
+		break;
 
 	case 34:	/* lbz */
 	case 35:	/* lbzu */
-		err = read_mem(&regs->gpr[rd], dform_ea(instr, regs), 1, regs);
-		goto ldst_done;
+		op->type = MKOP(LOAD, u, 1);
+		op->ea = dform_ea(instr, regs);
+		break;
 
 	case 36:	/* stw */
-		val = regs->gpr[rd];
-		err = write_mem(val, dform_ea(instr, regs), 4, regs);
-		goto ldst_done;
-
 	case 37:	/* stwu */
-		val = regs->gpr[rd];
-		val3 = dform_ea(instr, regs);
-		/*
-		 * For PPC32 we always use stwu to change stack point with r1. So
-		 * this emulated store may corrupt the exception frame, now we
-		 * have to provide the exception frame trampoline, which is pushed
-		 * below the kprobed function stack. So we only update gpr[1] but
-		 * don't emulate the real store operation. We will do real store
-		 * operation safely in exception return code by checking this flag.
-		 */
-		if ((ra == 1) && !(regs->msr & MSR_PR) \
-			&& (val3 >= (regs->gpr[1] - STACK_INT_FRAME_SIZE))) {
-#ifdef CONFIG_PPC32
-			/*
-			 * Check if we will touch kernel sack overflow
-			 */
-			if (val3 - STACK_INT_FRAME_SIZE <= current->thread.ksp_limit) {
-				printk(KERN_CRIT "Can't kprobe this since Kernel stack overflow.\n");
-				err = -EINVAL;
-				break;
-			}
-#endif /* CONFIG_PPC32 */
-			/*
-			 * Check if we already set since that means we'll
-			 * lose the previous value.
-			 */
-			WARN_ON(test_thread_flag(TIF_EMULATE_STACK_STORE));
-			set_thread_flag(TIF_EMULATE_STACK_STORE);
-			err = 0;
-		} else
-			err = write_mem(val, val3, 4, regs);
-		goto ldst_done;
+		op->type = MKOP(STORE, u, 4);
+		op->ea = dform_ea(instr, regs);
+		break;
 
 	case 38:	/* stb */
 	case 39:	/* stbu */
-		val = regs->gpr[rd];
-		err = write_mem(val, dform_ea(instr, regs), 1, regs);
-		goto ldst_done;
+		op->type = MKOP(STORE, u, 1);
+		op->ea = dform_ea(instr, regs);
+		break;
 
 	case 40:	/* lhz */
 	case 41:	/* lhzu */
-		err = read_mem(&regs->gpr[rd], dform_ea(instr, regs), 2, regs);
-		goto ldst_done;
+		op->type = MKOP(LOAD, u, 2);
+		op->ea = dform_ea(instr, regs);
+		break;
 
 	case 42:	/* lha */
 	case 43:	/* lhau */
-		err = read_mem(&regs->gpr[rd], dform_ea(instr, regs), 2, regs);
-		if (!err)
-			regs->gpr[rd] = (signed short) regs->gpr[rd];
-		goto ldst_done;
+		op->type = MKOP(LOAD, SIGNEXT | u, 2);
+		op->ea = dform_ea(instr, regs);
+		break;
 
 	case 44:	/* sth */
 	case 45:	/* sthu */
-		val = regs->gpr[rd];
-		err = write_mem(val, dform_ea(instr, regs), 2, regs);
-		goto ldst_done;
+		op->type = MKOP(STORE, u, 2);
+		op->ea = dform_ea(instr, regs);
+		break;
 
 	case 46:	/* lmw */
-		ra = (instr >> 16) & 0x1f;
 		if (ra >= rd)
 			break;		/* invalid form, ra in range to load */
-		ea = dform_ea(instr, regs);
-		do {
-			err = read_mem(&regs->gpr[rd], ea, 4, regs);
-			if (err)
-				return 0;
-			ea += 4;
-		} while (++rd < 32);
-		goto instr_done;
+		op->type = MKOP(LOAD_MULTI, 0, 4 * (32 - rd));
+		op->ea = dform_ea(instr, regs);
+		break;
 
 	case 47:	/* stmw */
-		ea = dform_ea(instr, regs);
-		do {
-			err = write_mem(regs->gpr[rd], ea, 4, regs);
-			if (err)
-				return 0;
-			ea += 4;
-		} while (++rd < 32);
-		goto instr_done;
+		op->type = MKOP(STORE_MULTI, 0, 4 * (32 - rd));
+		op->ea = dform_ea(instr, regs);
+		break;
 
 #ifdef CONFIG_PPC_FPU
 	case 48:	/* lfs */
 	case 49:	/* lfsu */
 		if (!(regs->msr & MSR_FP))
-			break;
-		ea = dform_ea(instr, regs);
-		err = do_fp_load(rd, do_lfs, ea, 4, regs);
-		goto ldst_done;
+			goto fpunavail;
+		op->type = MKOP(LOAD_FP, u, 4);
+		op->ea = dform_ea(instr, regs);
+		break;
 
 	case 50:	/* lfd */
 	case 51:	/* lfdu */
 		if (!(regs->msr & MSR_FP))
-			break;
-		ea = dform_ea(instr, regs);
-		err = do_fp_load(rd, do_lfd, ea, 8, regs);
-		goto ldst_done;
+			goto fpunavail;
+		op->type = MKOP(LOAD_FP, u, 8);
+		op->ea = dform_ea(instr, regs);
+		break;
 
 	case 52:	/* stfs */
 	case 53:	/* stfsu */
 		if (!(regs->msr & MSR_FP))
-			break;
-		ea = dform_ea(instr, regs);
-		err = do_fp_store(rd, do_stfs, ea, 4, regs);
-		goto ldst_done;
+			goto fpunavail;
+		op->type = MKOP(STORE_FP, u, 4);
+		op->ea = dform_ea(instr, regs);
+		break;
 
 	case 54:	/* stfd */
 	case 55:	/* stfdu */
 		if (!(regs->msr & MSR_FP))
-			break;
-		ea = dform_ea(instr, regs);
-		err = do_fp_store(rd, do_stfd, ea, 8, regs);
-		goto ldst_done;
+			goto fpunavail;
+		op->type = MKOP(STORE_FP, u, 8);
+		op->ea = dform_ea(instr, regs);
+		break;
 #endif
 
 #ifdef __powerpc64__
 	case 58:	/* ld[u], lwa */
+		op->ea = dsform_ea(instr, regs);
 		switch (instr & 3) {
 		case 0:		/* ld */
-			err = read_mem(&regs->gpr[rd], dsform_ea(instr, regs),
-				       8, regs);
-			goto ldst_done;
+			op->type = MKOP(LOAD, 0, 8);
+			break;
 		case 1:		/* ldu */
-			err = read_mem(&regs->gpr[rd], dsform_ea(instr, regs),
-				       8, regs);
-			goto ldst_done;
+			op->type = MKOP(LOAD, UPDATE, 8);
+			break;
 		case 2:		/* lwa */
-			err = read_mem(&regs->gpr[rd], dsform_ea(instr, regs),
-				       4, regs);
-			if (!err)
-				regs->gpr[rd] = (signed int) regs->gpr[rd];
-			goto ldst_done;
+			op->type = MKOP(LOAD, SIGNEXT, 4);
+			break;
 		}
 		break;
 
 	case 62:	/* std[u] */
-		val = regs->gpr[rd];
+		op->ea = dsform_ea(instr, regs);
 		switch (instr & 3) {
 		case 0:		/* std */
-			err = write_mem(val, dsform_ea(instr, regs), 8, regs);
-			goto ldst_done;
+			op->type = MKOP(STORE, 0, 8);
+			break;
 		case 1:		/* stdu */
-			err = write_mem(val, dsform_ea(instr, regs), 8, regs);
-			goto ldst_done;
+			op->type = MKOP(STORE, UPDATE, 8);
+			break;
 		}
 		break;
 #endif /* __powerpc64__ */
 
 	}
-	err = -EINVAL;
-
- ldst_done:
-	if (err) {
-		regs->gpr[ra] = old_ra;
-		return 0;	/* invoke DSI if -EFAULT? */
-	}
- instr_done:
-	regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
-	return 1;
+	return 0;
 
  logical_done:
 	if (instr & 1)
@@ -1733,5 +1665,349 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
  arith_done:
 	if (instr & 1)
 		set_cr0(regs, rd);
-	goto instr_done;
+
+ instr_done:
+	regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
+	return 1;
+
+ priv:
+	op->type = INTERRUPT | 0x700;
+	op->val = SRR1_PROGPRIV;
+	return 0;
+
+ trap:
+	op->type = INTERRUPT | 0x700;
+	op->val = SRR1_PROGTRAP;
+	return 0;
+
+#ifdef CONFIG_PPC_FPU
+ fpunavail:
+	op->type = INTERRUPT | 0x800;
+	return 0;
+#endif
+
+#ifdef CONFIG_ALTIVEC
+ vecunavail:
+	op->type = INTERRUPT | 0xf20;
+	return 0;
+#endif
+
+#ifdef CONFIG_VSX
+ vsxunavail:
+	op->type = INTERRUPT | 0xf40;
+	return 0;
+#endif
+}
+EXPORT_SYMBOL_GPL(analyse_instr);
+
+/*
+ * For PPC32 we always use stwu with r1 to change the stack pointer.
+ * So this emulated store may corrupt the exception frame, now we
+ * have to provide the exception frame trampoline, which is pushed
+ * below the kprobed function stack. So we only update gpr[1] but
+ * don't emulate the real store operation. We will do real store
+ * operation safely in exception return code by checking this flag.
+ */
+static __kprobes int handle_stack_update(unsigned long ea, struct pt_regs *regs)
+{
+#ifdef CONFIG_PPC32
+	/*
+	 * Check if we will touch kernel stack overflow
+	 */
+	if (ea - STACK_INT_FRAME_SIZE <= current->thread.ksp_limit) {
+		printk(KERN_CRIT "Can't kprobe this since kernel stack would overflow.\n");
+		return -EINVAL;
+	}
+#endif /* CONFIG_PPC32 */
+	/*
+	 * Check if we already set since that means we'll
+	 * lose the previous value.
+	 */
+	WARN_ON(test_thread_flag(TIF_EMULATE_STACK_STORE));
+	set_thread_flag(TIF_EMULATE_STACK_STORE);
+	return 0;
+}
+
+static __kprobes void do_signext(unsigned long *valp, int size)
+{
+	switch (size) {
+	case 2:
+		*valp = (signed short) *valp;
+		break;
+	case 4:
+		*valp = (signed int) *valp;
+		break;
+	}
+}
+
+static __kprobes void do_byterev(unsigned long *valp, int size)
+{
+	switch (size) {
+	case 2:
+		*valp = byterev_2(*valp);
+		break;
+	case 4:
+		*valp = byterev_4(*valp);
+		break;
+#ifdef __powerpc64__
+	case 8:
+		*valp = byterev_8(*valp);
+		break;
+#endif
+	}
+}
+
+/*
+ * Emulate instructions that cause a transfer of control,
+ * loads and stores, and a few other instructions.
+ * Returns 1 if the step was emulated, 0 if not,
+ * or -1 if the instruction is one that should not be stepped,
+ * such as an rfid, or a mtmsrd that would clear MSR_RI.
+ */
+int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
+{
+	struct instruction_op op;
+	int r, err, size;
+	unsigned long val;
+	unsigned int cr;
+	int i, rd, nb;
+
+	r = analyse_instr(&op, regs, instr);
+	if (r != 0)
+		return r;
+
+	err = 0;
+	size = GETSIZE(op.type);
+	switch (op.type & INSTR_TYPE_MASK) {
+	case CACHEOP:
+		if (!address_ok(regs, op.ea, 8))
+			return 0;
+		switch (op.type & CACHEOP_MASK) {
+		case DCBST:
+			__cacheop_user_asmx(op.ea, err, "dcbst");
+			break;
+		case DCBF:
+			__cacheop_user_asmx(op.ea, err, "dcbf");
+			break;
+		case DCBTST:
+			if (op.reg == 0)
+				prefetchw((void *) op.ea);
+			break;
+		case DCBT:
+			if (op.reg == 0)
+				prefetch((void *) op.ea);
+			break;
+		case ICBI:
+			__cacheop_user_asmx(op.ea, err, "icbi");
+			break;
+		}
+		if (err)
+			return 0;
+		goto instr_done;
+
+	case LARX:
+		if (regs->msr & MSR_LE)
+			return 0;
+		if (op.ea & (size - 1))
+			break;		/* can't handle misaligned */
+		err = -EFAULT;
+		if (!address_ok(regs, op.ea, size))
+			goto ldst_done;
+		err = 0;
+		switch (size) {
+		case 4:
+			__get_user_asmx(val, op.ea, err, "lwarx");
+			break;
+		case 8:
+			__get_user_asmx(val, op.ea, err, "ldarx");
+			break;
+		default:
+			return 0;
+		}
+		if (!err)
+			regs->gpr[op.reg] = val;
+		goto ldst_done;
+
+	case STCX:
+		if (regs->msr & MSR_LE)
+			return 0;
+		if (op.ea & (size - 1))
+			break;		/* can't handle misaligned */
+		err = -EFAULT;
+		if (!address_ok(regs, op.ea, size))
+			goto ldst_done;
+		err = 0;
+		switch (size) {
+		case 4:
+			__put_user_asmx(op.val, op.ea, err, "stwcx.", cr);
+			break;
+		case 8:
+			__put_user_asmx(op.val, op.ea, err, "stdcx.", cr);
+			break;
+		default:
+			return 0;
+		}
+		if (!err)
+			regs->ccr = (regs->ccr & 0x0fffffff) |
+				(cr & 0xe0000000) |
+				((regs->xer >> 3) & 0x10000000);
+		goto ldst_done;
+
+	case LOAD:
+		if (regs->msr & MSR_LE)
+			return 0;
+		err = read_mem(&regs->gpr[op.reg], op.ea, size, regs);
+		if (!err) {
+			if (op.type & SIGNEXT)
+				do_signext(&regs->gpr[op.reg], size);
+			if (op.type & BYTEREV)
+				do_byterev(&regs->gpr[op.reg], size);
+		}
+		goto ldst_done;
+
+	case LOAD_FP:
+		if (regs->msr & MSR_LE)
+			return 0;
+		if (size == 4)
+			err = do_fp_load(op.reg, do_lfs, op.ea, size, regs);
+		else
+			err = do_fp_load(op.reg, do_lfd, op.ea, size, regs);
+		goto ldst_done;
+
+#ifdef CONFIG_ALTIVEC
+	case LOAD_VMX:
+		if (regs->msr & MSR_LE)
+			return 0;
+		err = do_vec_load(op.reg, do_lvx, op.ea & ~0xfUL, regs);
+		goto ldst_done;
+#endif
+#ifdef CONFIG_VSX
+	case LOAD_VSX:
+		if (regs->msr & MSR_LE)
+			return 0;
+		err = do_vsx_load(op.reg, do_lxvd2x, op.ea, regs);
+		goto ldst_done;
+#endif
+	case LOAD_MULTI:
+		if (regs->msr & MSR_LE)
+			return 0;
+		rd = op.reg;
+		for (i = 0; i < size; i += 4) {
+			nb = size - i;
+			if (nb > 4)
+				nb = 4;
+			err = read_mem(&regs->gpr[rd], op.ea, nb, regs);
+			if (err)
+				return 0;
+			if (nb < 4)	/* left-justify last bytes */
+				regs->gpr[rd] <<= 32 - 8 * nb;
+			op.ea += 4;
+			++rd;
+		}
+		goto instr_done;
+
+	case STORE:
+		if (regs->msr & MSR_LE)
+			return 0;
+		if ((op.type & UPDATE) && size == sizeof(long) &&
+		    op.reg == 1 && op.update_reg == 1 &&
+		    !(regs->msr & MSR_PR) &&
+		    op.ea >= regs->gpr[1] - STACK_INT_FRAME_SIZE) {
+			err = handle_stack_update(op.ea, regs);
+			goto ldst_done;
+		}
+		err = write_mem(op.val, op.ea, size, regs);
+		goto ldst_done;
+
+	case STORE_FP:
+		if (regs->msr & MSR_LE)
+			return 0;
+		if (size == 4)
+			err = do_fp_store(op.reg, do_stfs, op.ea, size, regs);
+		else
+			err = do_fp_store(op.reg, do_stfd, op.ea, size, regs);
+		goto ldst_done;
+
+#ifdef CONFIG_ALTIVEC
+	case STORE_VMX:
+		if (regs->msr & MSR_LE)
+			return 0;
+		err = do_vec_store(op.reg, do_stvx, op.ea & ~0xfUL, regs);
+		goto ldst_done;
+#endif
+#ifdef CONFIG_VSX
+	case STORE_VSX:
+		if (regs->msr & MSR_LE)
+			return 0;
+		err = do_vsx_store(op.reg, do_stxvd2x, op.ea, regs);
+		goto ldst_done;
+#endif
+	case STORE_MULTI:
+		if (regs->msr & MSR_LE)
+			return 0;
+		rd = op.reg;
+		for (i = 0; i < size; i += 4) {
+			val = regs->gpr[rd];
+			nb = size - i;
+			if (nb > 4)
+				nb = 4;
+			else
+				val >>= 32 - 8 * nb;
+			err = write_mem(val, op.ea, nb, regs);
+			if (err)
+				return 0;
+			op.ea += 4;
+			++rd;
+		}
+		goto instr_done;
+
+	case MFMSR:
+		regs->gpr[op.reg] = regs->msr & MSR_MASK;
+		goto instr_done;
+
+	case MTMSR:
+		val = regs->gpr[op.reg];
+		if ((val & MSR_RI) == 0)
+			/* can't step mtmsr[d] that would clear MSR_RI */
+			return -1;
+		/* here op.val is the mask of bits to change */
+		regs->msr = (regs->msr & ~op.val) | (val & op.val);
+		goto instr_done;
+
+#ifdef CONFIG_PPC64
+	case SYSCALL:	/* sc */
+		/*
+		 * N.B. this uses knowledge about how the syscall
+		 * entry code works.  If that is changed, this will
+		 * need to be changed also.
+		 */
+		if (regs->gpr[0] == 0x1ebe &&
+		    cpu_has_feature(CPU_FTR_REAL_LE)) {
+			regs->msr ^= MSR_LE;
+			goto instr_done;
+		}
+		regs->gpr[9] = regs->gpr[13];
+		regs->gpr[10] = MSR_KERNEL;
+		regs->gpr[11] = regs->nip + 4;
+		regs->gpr[12] = regs->msr & MSR_MASK;
+		regs->gpr[13] = (unsigned long) get_paca();
+		regs->nip = (unsigned long) &system_call_common;
+		regs->msr = MSR_KERNEL;
+		return 1;
+
+	case RFI:
+		return -1;
+#endif
+	}
+	return 0;
+
+ ldst_done:
+	if (err)
+		return 0;
+	if (op.type & UPDATE)
+		regs->gpr[op.update_reg] = op.ea;
+
+ instr_done:
+	regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
+	return 1;
 }