powerpc: Use instruction emulation infrastructure to handle alignment faults

This replaces almost all of the instruction emulation code in
fix_alignment() with calls to analyse_instr(), emulate_loadstore()
and emulate_dcbz().  The only emulation code left is the SPE
emulation code; analyse_instr() etc. do not handle SPE instructions
at present.

One result of this is that we can now handle alignment faults on
all the new VSX load and store instructions that were added in POWER9.
VSX loads/stores will take alignment faults for unaligned accesses
to cache-inhibited memory.

Another effect is that we no longer rely on the DAR and DSISR values
set by the processor.

With this, we now need to include the instruction emulation code
unconditionally.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 32 insertions, 771 deletions

diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c
index fd3c1fc..26b9994 100644
--- a/arch/powerpc/kernel/align.c
+++ b/arch/powerpc/kernel/align.c
@@ -27,6 +27,7 @@
 #include <asm/switch_to.h>
 #include <asm/disassemble.h>
 #include <asm/cpu_has_feature.h>
+#include <asm/sstep.h>
 
 struct aligninfo {
 	unsigned char len;
@@ -40,393 +41,9 @@ struct aligninfo {
 #define LD	0	/* load */
 #define ST	1	/* store */
 #define SE	2	/* sign-extend value, or FP ld/st as word */
-#define F	4	/* to/from fp regs */
-#define U	8	/* update index register */
-#define M	0x10	/* multiple load/store */
 #define SW	0x20	/* byte swap */
-#define S	0x40	/* single-precision fp or... */
-#define SX	0x40	/* ... byte count in XER */
-#define HARD	0x80	/* string, stwcx. */
 #define E4	0x40	/* SPE endianness is word */
 #define E8	0x80	/* SPE endianness is double word */
-#define SPLT	0x80	/* VSX SPLAT load */
-
-/* DSISR bits reported for a DCBZ instruction: */
-#define DCBZ	0x5f	/* 8xx/82xx dcbz faults when cache not enabled */
-
-/*
- * The PowerPC stores certain bits of the instruction that caused the
- * alignment exception in the DSISR register.  This array maps those
- * bits to information about the operand length and what the
- * instruction would do.
- */
-static struct aligninfo aligninfo[128] = {
-	{ 4, LD },		/* 00 0 0000: lwz / lwarx */
-	INVALID,		/* 00 0 0001 */
-	{ 4, ST },		/* 00 0 0010: stw */
-	INVALID,		/* 00 0 0011 */
-	{ 2, LD },		/* 00 0 0100: lhz */
-	{ 2, LD+SE },		/* 00 0 0101: lha */
-	{ 2, ST },		/* 00 0 0110: sth */
-	{ 4, LD+M },		/* 00 0 0111: lmw */
-	{ 4, LD+F+S },		/* 00 0 1000: lfs */
-	{ 8, LD+F },		/* 00 0 1001: lfd */
-	{ 4, ST+F+S },		/* 00 0 1010: stfs */
-	{ 8, ST+F },		/* 00 0 1011: stfd */
-	{ 16, LD },		/* 00 0 1100: lq */
-	{ 8, LD },		/* 00 0 1101: ld/ldu/lwa */
-	INVALID,		/* 00 0 1110 */
-	{ 8, ST },		/* 00 0 1111: std/stdu */
-	{ 4, LD+U },		/* 00 1 0000: lwzu */
-	INVALID,		/* 00 1 0001 */
-	{ 4, ST+U },		/* 00 1 0010: stwu */
-	INVALID,		/* 00 1 0011 */
-	{ 2, LD+U },		/* 00 1 0100: lhzu */
-	{ 2, LD+SE+U },		/* 00 1 0101: lhau */
-	{ 2, ST+U },		/* 00 1 0110: sthu */
-	{ 4, ST+M },		/* 00 1 0111: stmw */
-	{ 4, LD+F+S+U },	/* 00 1 1000: lfsu */
-	{ 8, LD+F+U },		/* 00 1 1001: lfdu */
-	{ 4, ST+F+S+U },	/* 00 1 1010: stfsu */
-	{ 8, ST+F+U },		/* 00 1 1011: stfdu */
-	{ 16, LD+F },		/* 00 1 1100: lfdp */
-	INVALID,		/* 00 1 1101 */
-	{ 16, ST+F },		/* 00 1 1110: stfdp */
-	INVALID,		/* 00 1 1111 */
-	{ 8, LD },		/* 01 0 0000: ldx */
-	INVALID,		/* 01 0 0001 */
-	{ 8, ST },		/* 01 0 0010: stdx */
-	INVALID,		/* 01 0 0011 */
-	INVALID,		/* 01 0 0100 */
-	{ 4, LD+SE },		/* 01 0 0101: lwax */
-	INVALID,		/* 01 0 0110 */
-	INVALID,		/* 01 0 0111 */
-	{ 4, LD+M+HARD+SX },	/* 01 0 1000: lswx */
-	{ 4, LD+M+HARD },	/* 01 0 1001: lswi */
-	{ 4, ST+M+HARD+SX },	/* 01 0 1010: stswx */
-	{ 4, ST+M+HARD },	/* 01 0 1011: stswi */
-	INVALID,		/* 01 0 1100 */
-	{ 8, LD+U },		/* 01 0 1101: ldu */
-	INVALID,		/* 01 0 1110 */
-	{ 8, ST+U },		/* 01 0 1111: stdu */
-	{ 8, LD+U },		/* 01 1 0000: ldux */
-	INVALID,		/* 01 1 0001 */
-	{ 8, ST+U },		/* 01 1 0010: stdux */
-	INVALID,		/* 01 1 0011 */
-	INVALID,		/* 01 1 0100 */
-	{ 4, LD+SE+U },		/* 01 1 0101: lwaux */
-	INVALID,		/* 01 1 0110 */
-	INVALID,		/* 01 1 0111 */
-	INVALID,		/* 01 1 1000 */
-	INVALID,		/* 01 1 1001 */
-	INVALID,		/* 01 1 1010 */
-	INVALID,		/* 01 1 1011 */
-	INVALID,		/* 01 1 1100 */
-	INVALID,		/* 01 1 1101 */
-	INVALID,		/* 01 1 1110 */
-	INVALID,		/* 01 1 1111 */
-	INVALID,		/* 10 0 0000 */
-	INVALID,		/* 10 0 0001 */
-	INVALID,		/* 10 0 0010: stwcx. */
-	INVALID,		/* 10 0 0011 */
-	INVALID,		/* 10 0 0100 */
-	INVALID,		/* 10 0 0101 */
-	INVALID,		/* 10 0 0110 */
-	INVALID,		/* 10 0 0111 */
-	{ 4, LD+SW },		/* 10 0 1000: lwbrx */
-	INVALID,		/* 10 0 1001 */
-	{ 4, ST+SW },		/* 10 0 1010: stwbrx */
-	INVALID,		/* 10 0 1011 */
-	{ 2, LD+SW },		/* 10 0 1100: lhbrx */
-	{ 4, LD+SE },		/* 10 0 1101  lwa */
-	{ 2, ST+SW },		/* 10 0 1110: sthbrx */
-	{ 16, ST },		/* 10 0 1111: stq */
-	INVALID,		/* 10 1 0000 */
-	INVALID,		/* 10 1 0001 */
-	INVALID,		/* 10 1 0010 */
-	INVALID,		/* 10 1 0011 */
-	INVALID,		/* 10 1 0100 */
-	INVALID,		/* 10 1 0101 */
-	INVALID,		/* 10 1 0110 */
-	INVALID,		/* 10 1 0111 */
-	INVALID,		/* 10 1 1000 */
-	INVALID,		/* 10 1 1001 */
-	INVALID,		/* 10 1 1010 */
-	INVALID,		/* 10 1 1011 */
-	INVALID,		/* 10 1 1100 */
-	INVALID,		/* 10 1 1101 */
-	INVALID,		/* 10 1 1110 */
-	{ 0, ST+HARD },		/* 10 1 1111: dcbz */
-	{ 4, LD },		/* 11 0 0000: lwzx */
-	INVALID,		/* 11 0 0001 */
-	{ 4, ST },		/* 11 0 0010: stwx */
-	INVALID,		/* 11 0 0011 */
-	{ 2, LD },		/* 11 0 0100: lhzx */
-	{ 2, LD+SE },		/* 11 0 0101: lhax */
-	{ 2, ST },		/* 11 0 0110: sthx */
-	INVALID,		/* 11 0 0111 */
-	{ 4, LD+F+S },		/* 11 0 1000: lfsx */
-	{ 8, LD+F },		/* 11 0 1001: lfdx */
-	{ 4, ST+F+S },		/* 11 0 1010: stfsx */
-	{ 8, ST+F },		/* 11 0 1011: stfdx */
-	{ 16, LD+F },		/* 11 0 1100: lfdpx */
-	{ 4, LD+F+SE },		/* 11 0 1101: lfiwax */
-	{ 16, ST+F },		/* 11 0 1110: stfdpx */
-	{ 4, ST+F },		/* 11 0 1111: stfiwx */
-	{ 4, LD+U },		/* 11 1 0000: lwzux */
-	INVALID,		/* 11 1 0001 */
-	{ 4, ST+U },		/* 11 1 0010: stwux */
-	INVALID,		/* 11 1 0011 */
-	{ 2, LD+U },		/* 11 1 0100: lhzux */
-	{ 2, LD+SE+U },		/* 11 1 0101: lhaux */
-	{ 2, ST+U },		/* 11 1 0110: sthux */
-	INVALID,		/* 11 1 0111 */
-	{ 4, LD+F+S+U },	/* 11 1 1000: lfsux */
-	{ 8, LD+F+U },		/* 11 1 1001: lfdux */
-	{ 4, ST+F+S+U },	/* 11 1 1010: stfsux */
-	{ 8, ST+F+U },		/* 11 1 1011: stfdux */
-	INVALID,		/* 11 1 1100 */
-	{ 4, LD+F },		/* 11 1 1101: lfiwzx */
-	INVALID,		/* 11 1 1110 */
-	INVALID,		/* 11 1 1111 */
-};
-
-/*
- * The dcbz (data cache block zero) instruction
- * gives an alignment fault if used on non-cacheable
- * memory.  We handle the fault mainly for the
- * case when we are running with the cache disabled
- * for debugging.
- */
-static int emulate_dcbz(struct pt_regs *regs, unsigned char __user *addr)
-{
-	long __user *p;
-	int i, size;
-
-#ifdef __powerpc64__
-	size = ppc64_caches.l1d.block_size;
-#else
-	size = L1_CACHE_BYTES;
-#endif
-	p = (long __user *) (regs->dar & -size);
-	if (user_mode(regs) && !access_ok(VERIFY_WRITE, p, size))
-		return -EFAULT;
-	for (i = 0; i < size / sizeof(long); ++i)
-		if (__put_user_inatomic(0, p+i))
-			return -EFAULT;
-	return 1;
-}
-
-/*
- * Emulate load & store multiple instructions
- * On 64-bit machines, these instructions only affect/use the
- * bottom 4 bytes of each register, and the loads clear the
- * top 4 bytes of the affected register.
- */
-#ifdef __BIG_ENDIAN__
-#ifdef CONFIG_PPC64
-#define REG_BYTE(rp, i)		*((u8 *)((rp) + ((i) >> 2)) + ((i) & 3) + 4)
-#else
-#define REG_BYTE(rp, i)		*((u8 *)(rp) + (i))
-#endif
-#else
-#define REG_BYTE(rp, i)		(*(((u8 *)((rp) + ((i)>>2)) + ((i)&3))))
-#endif
-
-#define SWIZ_PTR(p)		((unsigned char __user *)((p) ^ swiz))
-
-#define __get_user_or_set_dar(_regs, _dest, _addr)		\
-	({							\
-		int rc = 0;					\
-		typeof(_addr) __addr = (_addr);			\
-		if (__get_user_inatomic(_dest, __addr)) {	\
-			_regs->dar = (unsigned long)__addr;	\
-			rc = -EFAULT;				\
-		}						\
-		rc;						\
-	})
-
-#define __put_user_or_set_dar(_regs, _src, _addr)		\
-	({							\
-		int rc = 0;					\
-		typeof(_addr) __addr = (_addr);			\
-		if (__put_user_inatomic(_src, __addr)) {	\
-			_regs->dar = (unsigned long)__addr;	\
-			rc = -EFAULT;				\
-		}						\
-		rc;						\
-	})
-
-static int emulate_multiple(struct pt_regs *regs, unsigned char __user *addr,
-			    unsigned int reg, unsigned int nb,
-			    unsigned int flags, unsigned int instr,
-			    unsigned long swiz)
-{
-	unsigned long *rptr;
-	unsigned int nb0, i, bswiz;
-	unsigned long p;
-
-	/*
-	 * We do not try to emulate 8 bytes multiple as they aren't really
-	 * available in our operating environments and we don't try to
-	 * emulate multiples operations in kernel land as they should never
-	 * be used/generated there at least not on unaligned boundaries
-	 */
-	if (unlikely((nb > 4) || !user_mode(regs)))
-		return 0;
-
-	/* lmw, stmw, lswi/x, stswi/x */
-	nb0 = 0;
-	if (flags & HARD) {
-		if (flags & SX) {
-			nb = regs->xer & 127;
-			if (nb == 0)
-				return 1;
-		} else {
-			unsigned long pc = regs->nip ^ (swiz & 4);
-
-			if (__get_user_or_set_dar(regs, instr,
-						  (unsigned int __user *)pc))
-				return -EFAULT;
-
-			if (swiz == 0 && (flags & SW))
-				instr = cpu_to_le32(instr);
-			nb = (instr >> 11) & 0x1f;
-			if (nb == 0)
-				nb = 32;
-		}
-		if (nb + reg * 4 > 128) {
-			nb0 = nb + reg * 4 - 128;
-			nb = 128 - reg * 4;
-		}
-#ifdef __LITTLE_ENDIAN__
-		/*
-		 *  String instructions are endian neutral but the code
-		 *  below is not.  Force byte swapping on so that the
-		 *  effects of swizzling are undone in the load/store
-		 *  loops below.
-		 */
-		flags ^= SW;
-#endif
-	} else {
-		/* lwm, stmw */
-		nb = (32 - reg) * 4;
-	}
-
-	if (!access_ok((flags & ST ? VERIFY_WRITE: VERIFY_READ), addr, nb+nb0))
-		return -EFAULT;	/* bad address */
-
-	rptr = &regs->gpr[reg];
-	p = (unsigned long) addr;
-	bswiz = (flags & SW)? 3: 0;
-
-	if (!(flags & ST)) {
-		/*
-		 * This zeroes the top 4 bytes of the affected registers
-		 * in 64-bit mode, and also zeroes out any remaining
-		 * bytes of the last register for lsw*.
-		 */
-		memset(rptr, 0, ((nb + 3) / 4) * sizeof(unsigned long));
-		if (nb0 > 0)
-			memset(&regs->gpr[0], 0,
-			       ((nb0 + 3) / 4) * sizeof(unsigned long));
-
-		for (i = 0; i < nb; ++i, ++p)
-			if (__get_user_or_set_dar(regs, REG_BYTE(rptr, i ^ bswiz),
-						  SWIZ_PTR(p)))
-				return -EFAULT;
-		if (nb0 > 0) {
-			rptr = &regs->gpr[0];
-			addr += nb;
-			for (i = 0; i < nb0; ++i, ++p)
-				if (__get_user_or_set_dar(regs,
-							  REG_BYTE(rptr, i ^ bswiz),
-							  SWIZ_PTR(p)))
-					return -EFAULT;
-		}
-
-	} else {
-		for (i = 0; i < nb; ++i, ++p)
-			if (__put_user_or_set_dar(regs, REG_BYTE(rptr, i ^ bswiz),
-						  SWIZ_PTR(p)))
-				return -EFAULT;
-		if (nb0 > 0) {
-			rptr = &regs->gpr[0];
-			addr += nb;
-			for (i = 0; i < nb0; ++i, ++p)
-				if (__put_user_or_set_dar(regs,
-							  REG_BYTE(rptr, i ^ bswiz),
-							  SWIZ_PTR(p)))
-					return -EFAULT;
-		}
-	}
-	return 1;
-}
-
-/*
- * Emulate floating-point pair loads and stores.
- * Only POWER6 has these instructions, and it does true little-endian,
- * so we don't need the address swizzling.
- */
-static int emulate_fp_pair(struct pt_regs *regs, unsigned char __user *addr,
-			   unsigned int reg, unsigned int flags)
-{
-	char *ptr0 = (char *) &current->thread.TS_FPR(reg);
-	char *ptr1 = (char *) &current->thread.TS_FPR(reg+1);
-	int i, sw = 0;
-
-	if (reg & 1)
-		return 0;	/* invalid form: FRS/FRT must be even */
-	if (flags & SW)
-		sw = 7;
-
-	for (i = 0; i < 8; ++i) {
-		if (!(flags & ST)) {
-			if (__get_user_or_set_dar(regs, ptr0[i^sw], addr + i))
-				return -EFAULT;
-			if (__get_user_or_set_dar(regs, ptr1[i^sw], addr + i + 8))
-				return -EFAULT;
-		} else {
-			if (__put_user_or_set_dar(regs, ptr0[i^sw], addr + i))
-				return -EFAULT;
-			if (__put_user_or_set_dar(regs, ptr1[i^sw], addr + i + 8))
-				return -EFAULT;
-		}
-	}
-
-	return 1;	/* exception handled and fixed up */
-}
-
-#ifdef CONFIG_PPC64
-static int emulate_lq_stq(struct pt_regs *regs, unsigned char __user *addr,
-			  unsigned int reg, unsigned int flags)
-{
-	char *ptr0 = (char *)&regs->gpr[reg];
-	char *ptr1 = (char *)&regs->gpr[reg+1];
-	int i, sw = 0;
-
-	if (reg & 1)
-		return 0;	/* invalid form: GPR must be even */
-	if (flags & SW)
-		sw = 7;
-
-	for (i = 0; i < 8; ++i) {
-		if (!(flags & ST)) {
-			if (__get_user_or_set_dar(regs, ptr0[i^sw], addr + i))
-				return -EFAULT;
-			if (__get_user_or_set_dar(regs, ptr1[i^sw], addr + i + 8))
-				return -EFAULT;
-		} else {
-			if (__put_user_or_set_dar(regs, ptr0[i^sw], addr + i))
-				return -EFAULT;
-			if (__put_user_or_set_dar(regs, ptr1[i^sw], addr + i + 8))
-				return -EFAULT;
-		}
-	}
-
-	return 1;	/* exception handled and fixed up */
-}
-#endif /* CONFIG_PPC64 */
 
 #ifdef CONFIG_SPE
 
@@ -665,138 +282,21 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg,
 }
 #endif /* CONFIG_SPE */
 
-#ifdef CONFIG_VSX
-/*
- * Emulate VSX instructions...
- */
-static int emulate_vsx(unsigned char __user *addr, unsigned int reg,
-		       unsigned int areg, struct pt_regs *regs,
-		       unsigned int flags, unsigned int length,
-		       unsigned int elsize)
-{
-	char *ptr;
-	unsigned long *lptr;
-	int ret = 0;
-	int sw = 0;
-	int i, j;
-
-	/* userland only */
-	if (unlikely(!user_mode(regs)))
-		return 0;
-
-	flush_vsx_to_thread(current);
-
-	if (reg < 32)
-		ptr = (char *) &current->thread.fp_state.fpr[reg][0];
-	else
-		ptr = (char *) &current->thread.vr_state.vr[reg - 32];
-
-	lptr = (unsigned long *) ptr;
-
-#ifdef __LITTLE_ENDIAN__
-	if (flags & SW) {
-		elsize = length;
-		sw = length-1;
-	} else {
-		/*
-		 * The elements are BE ordered, even in LE mode, so process
-		 * them in reverse order.
-		 */
-		addr += length - elsize;
-
-		/* 8 byte memory accesses go in the top 8 bytes of the VR */
-		if (length == 8)
-			ptr += 8;
-	}
-#else
-	if (flags & SW)
-		sw = elsize-1;
-#endif
-
-	for (j = 0; j < length; j += elsize) {
-		for (i = 0; i < elsize; ++i) {
-			if (flags & ST)
-				ret = __put_user_or_set_dar(regs, ptr[i^sw],
-							    addr + i);
-			else
-				ret = __get_user_or_set_dar(regs, ptr[i^sw],
-							    addr + i);
-
-			if (ret)
-				return ret;
-		}
-		ptr  += elsize;
-#ifdef __LITTLE_ENDIAN__
-		addr -= elsize;
-#else
-		addr += elsize;
-#endif
-	}
-
-#ifdef __BIG_ENDIAN__
-#define VSX_HI 0
-#define VSX_LO 1
-#else
-#define VSX_HI 1
-#define VSX_LO 0
-#endif
-
-	if (!ret) {
-		if (flags & U)
-			regs->gpr[areg] = regs->dar;
-
-		/* Splat load copies the same data to top and bottom 8 bytes */
-		if (flags & SPLT)
-			lptr[VSX_LO] = lptr[VSX_HI];
-		/* For 8 byte loads, zero the low 8 bytes */
-		else if (!(flags & ST) && (8 == length))
-			lptr[VSX_LO] = 0;
-	} else
-		return -EFAULT;
-
-	return 1;
-}
-#endif
-
 /*
  * Called on alignment exception. Attempts to fixup
  *
  * Return 1 on success
  * Return 0 if unable to handle the interrupt
  * Return -EFAULT if data address is bad
+ * Other negative return values indicate that the instruction can't
+ * be emulated, and the process should be given a SIGBUS.
  */
 
 int fix_alignment(struct pt_regs *regs)
 {
-	unsigned int instr, nb, flags, instruction = 0;
-	unsigned int reg, areg;
-	unsigned int dsisr;
-	unsigned char __user *addr;
-	unsigned long p, swiz;
-	int i;
-	union data {
-		u64 ll;
-		double dd;
-		unsigned char v[8];
-		struct {
-#ifdef __LITTLE_ENDIAN__
-			int	 low32;
-			unsigned hi32;
-#else
-			unsigned hi32;
-			int	 low32;
-#endif
-		} x32;
-		struct {
-#ifdef __LITTLE_ENDIAN__
-			short	      low16;
-			unsigned char hi48[6];
-#else
-			unsigned char hi48[6];
-			short	      low16;
-#endif
-		} x16;
-	} data;
+	unsigned int instr;
+	struct instruction_op op;
+	int r, type;
 
 	/*
 	 * We require a complete register set, if not, then our assembly
@@ -804,121 +304,23 @@ int fix_alignment(struct pt_regs *regs)
 	 */
 	CHECK_FULL_REGS(regs);
 
-	dsisr = regs->dsisr;
-
-	/* Some processors don't provide us with a DSISR we can use here,
-	 * let's make one up from the instruction
-	 */
-	if (cpu_has_feature(CPU_FTR_NODSISRALIGN)) {
-		unsigned long pc = regs->nip;
-
-		if (cpu_has_feature(CPU_FTR_PPC_LE) && (regs->msr & MSR_LE))
-			pc ^= 4;
-		if (unlikely(__get_user_inatomic(instr,
-						 (unsigned int __user *)pc)))
-			return -EFAULT;
-		if (cpu_has_feature(CPU_FTR_REAL_LE) && (regs->msr & MSR_LE))
-			instr = cpu_to_le32(instr);
-		dsisr = make_dsisr(instr);
-		instruction = instr;
+	if (unlikely(__get_user(instr, (unsigned int __user *)regs->nip)))
+		return -EFAULT;
+	if ((regs->msr & MSR_LE) != (MSR_KERNEL & MSR_LE)) {
+		/* We don't handle PPC little-endian any more... */
+		if (cpu_has_feature(CPU_FTR_PPC_LE))
+			return -EIO;
+		instr = swab32(instr);
 	}
 
-	/* extract the operation and registers from the dsisr */
-	reg = (dsisr >> 5) & 0x1f;	/* source/dest register */
-	areg = dsisr & 0x1f;		/* register to update */
-
 #ifdef CONFIG_SPE
 	if ((instr >> 26) == 0x4) {
+		int reg = (instr >> 21) & 0x1f;
 		PPC_WARN_ALIGNMENT(spe, regs);
 		return emulate_spe(regs, reg, instr);
 	}
 #endif
 
-	instr = (dsisr >> 10) & 0x7f;
-	instr |= (dsisr >> 13) & 0x60;
-
-	/* Lookup the operation in our table */
-	nb = aligninfo[instr].len;
-	flags = aligninfo[instr].flags;
-
-	/*
-	 * Handle some cases which give overlaps in the DSISR values.
-	 */
-	if (IS_XFORM(instruction)) {
-		switch (get_xop(instruction)) {
-		case 532:	/* ldbrx */
-			nb = 8;
-			flags = LD+SW;
-			break;
-		case 660:	/* stdbrx */
-			nb = 8;
-			flags = ST+SW;
-			break;
-		case 20:	/* lwarx */
-		case 84:	/* ldarx */
-		case 116:	/* lharx */
-		case 276:	/* lqarx */
-			return 0;	/* not emulated ever */
-		}
-	}
-
-	/* Byteswap little endian loads and stores */
-	swiz = 0;
-	if ((regs->msr & MSR_LE) != (MSR_KERNEL & MSR_LE)) {
-		flags ^= SW;
-#ifdef __BIG_ENDIAN__
-		/*
-		 * So-called "PowerPC little endian" mode works by
-		 * swizzling addresses rather than by actually doing
-		 * any byte-swapping.  To emulate this, we XOR each
-		 * byte address with 7.  We also byte-swap, because
-		 * the processor's address swizzling depends on the
-		 * operand size (it xors the address with 7 for bytes,
-		 * 6 for halfwords, 4 for words, 0 for doublewords) but
-		 * we will xor with 7 and load/store each byte separately.
-		 */
-		if (cpu_has_feature(CPU_FTR_PPC_LE))
-			swiz = 7;
-#endif
-	}
-
-	/* DAR has the operand effective address */
-	addr = (unsigned char __user *)regs->dar;
-
-#ifdef CONFIG_VSX
-	if ((instruction & 0xfc00003e) == 0x7c000018) {
-		unsigned int elsize;
-
-		/* Additional register addressing bit (64 VSX vs 32 FPR/GPR) */
-		reg |= (instruction & 0x1) << 5;
-		/* Simple inline decoder instead of a table */
-		/* VSX has only 8 and 16 byte memory accesses */
-		nb = 8;
-		if (instruction & 0x200)
-			nb = 16;
-
-		/* Vector stores in little-endian mode swap individual
-		   elements, so process them separately */
-		elsize = 4;
-		if (instruction & 0x80)
-			elsize = 8;
-
-		flags = 0;
-		if ((regs->msr & MSR_LE) != (MSR_KERNEL & MSR_LE))
-			flags |= SW;
-		if (instruction & 0x100)
-			flags |= ST;
-		if (instruction & 0x040)
-			flags |= U;
-		/* splat load needs a special decoder */
-		if ((instruction & 0x400) == 0){
-			flags |= SPLT;
-			nb = 8;
-		}
-		PPC_WARN_ALIGNMENT(vsx, regs);
-		return emulate_vsx(addr, reg, areg, regs, flags, nb, elsize);
-	}
-#endif
 
 	/*
 	 * ISA 3.0 (such as P9) copy, copy_first, paste and paste_last alignment
@@ -930,168 +332,27 @@ int fix_alignment(struct pt_regs *regs)
 	 * when pasting to a co-processor. Furthermore, paste_last is the
 	 * synchronisation point for preceding copy/paste sequences.
 	 */
-	if ((instruction & 0xfc0006fe) == PPC_INST_COPY)
+	if ((instr & 0xfc0006fe) == PPC_INST_COPY)
 		return -EIO;
 
-	/* A size of 0 indicates an instruction we don't support, with
-	 * the exception of DCBZ which is handled as a special case here
-	 */
-	if (instr == DCBZ) {
-		PPC_WARN_ALIGNMENT(dcbz, regs);
-		return emulate_dcbz(regs, addr);
-	}
-	if (unlikely(nb == 0))
-		return 0;
-
-	/* Load/Store Multiple instructions are handled in their own
-	 * function
-	 */
-	if (flags & M) {
-		PPC_WARN_ALIGNMENT(multiple, regs);
-		return emulate_multiple(regs, addr, reg, nb,
-					flags, instr, swiz);
-	}
-
-	/* Verify the address of the operand */
-	if (unlikely(user_mode(regs) &&
-		     !access_ok((flags & ST ? VERIFY_WRITE : VERIFY_READ),
-				addr, nb)))
-		return -EFAULT;
-
-	/* Force the fprs into the save area so we can reference them */
-	if (flags & F) {
-		/* userland only */
-		if (unlikely(!user_mode(regs)))
-			return 0;
-		flush_fp_to_thread(current);
-	}
-
-	if (nb == 16) {
-		if (flags & F) {
-			/* Special case for 16-byte FP loads and stores */
-			PPC_WARN_ALIGNMENT(fp_pair, regs);
-			return emulate_fp_pair(regs, addr, reg, flags);
-		} else {
-#ifdef CONFIG_PPC64
-			/* Special case for 16-byte loads and stores */
-			PPC_WARN_ALIGNMENT(lq_stq, regs);
-			return emulate_lq_stq(regs, addr, reg, flags);
-#else
-			return 0;
-#endif
-		}
-	}
-
-	PPC_WARN_ALIGNMENT(unaligned, regs);
-
-	/* If we are loading, get the data from user space, else
-	 * get it from register values
-	 */
-	if (!(flags & ST)) {
-		unsigned int start = 0;
-
-		switch (nb) {
-		case 4:
-			start = offsetof(union data, x32.low32);
-			break;
-		case 2:
-			start = offsetof(union data, x16.low16);
-			break;
-		}
-
-		data.ll = 0;
-		p = (unsigned long)addr;
-
-		for (i = 0; i < nb; i++)
-			if (__get_user_or_set_dar(regs, data.v[start + i],
-						  SWIZ_PTR(p++)))
-				return -EFAULT;
-
-	} else if (flags & F) {
-		data.ll = current->thread.TS_FPR(reg);
-		if (flags & S) {
-			/* Single-precision FP store requires conversion... */
-#ifdef CONFIG_PPC_FPU
-			preempt_disable();
-			enable_kernel_fp();
-			cvt_df(&data.dd, (float *)&data.x32.low32);
-			disable_kernel_fp();
-			preempt_enable();
-#else
-			return 0;
-#endif
-		}
-	} else
-		data.ll = regs->gpr[reg];
-
-	if (flags & SW) {
-		switch (nb) {
-		case 8:
-			data.ll = swab64(data.ll);
-			break;
-		case 4:
-			data.x32.low32 = swab32(data.x32.low32);
-			break;
-		case 2:
-			data.x16.low16 = swab16(data.x16.low16);
-			break;
-		}
-	}
-
-	/* Perform other misc operations like sign extension
-	 * or floating point single precision conversion
-	 */
-	switch (flags & ~(U|SW)) {
-	case LD+SE:	/* sign extending integer loads */
-	case LD+F+SE:	/* sign extend for lfiwax */
-		if ( nb == 2 )
-			data.ll = data.x16.low16;
-		else	/* nb must be 4 */
-			data.ll = data.x32.low32;
-		break;
+	r = analyse_instr(&op, regs, instr);
+	if (r < 0)
+		return -EINVAL;
 
-	/* Single-precision FP load requires conversion... */
-	case LD+F+S:
-#ifdef CONFIG_PPC_FPU
-		preempt_disable();
-		enable_kernel_fp();
-		cvt_fd((float *)&data.x32.low32, &data.dd);
-		disable_kernel_fp();
-		preempt_enable();
-#else
-		return 0;
-#endif
-		break;
+	type = op.type & INSTR_TYPE_MASK;
+	if (!OP_IS_LOAD_STORE(type)) {
+		if (type != CACHEOP + DCBZ)
+			return -EINVAL;
+		PPC_WARN_ALIGNMENT(dcbz, regs);
+		r = emulate_dcbz(op.ea, regs);
+	} else {
+		if (type == LARX || type == STCX)
+			return -EIO;
+		PPC_WARN_ALIGNMENT(unaligned, regs);
+		r = emulate_loadstore(regs, &op);
 	}
 
-	/* Store result to memory or update registers */
-	if (flags & ST) {
-		unsigned int start = 0;
-
-		switch (nb) {
-		case 4:
-			start = offsetof(union data, x32.low32);
-			break;
-		case 2:
-			start = offsetof(union data, x16.low16);
-			break;
-		}
-
-		p = (unsigned long)addr;
-
-		for (i = 0; i < nb; i++)
-			if (__put_user_or_set_dar(regs, data.v[start + i],
-						  SWIZ_PTR(p++)))
-				return -EFAULT;
-
-	} else if (flags & F)
-		current->thread.TS_FPR(reg) = data.ll;
-	else
-		regs->gpr[reg] = data.ll;
-
-	/* Update RA as needed */
-	if (flags & U)
-		regs->gpr[areg] = regs->dar;
-
-	return 1;
+	if (!r)
+		return 1;
+	return r;
 }