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powerpc: Handle VSX alignment faults in little endian mode 

Things are complicated by the fact that VSX elements are big
endian ordered even in little endian mode. 8 byte loads and
stores also write to the top 8 bytes of the register.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Anton Blanchard 2013-09-23 12:04:50 +10:00 committed by Benjamin Herrenschmidt
parent 835e206a67
commit 52055d07ce
1 changed files with 33 additions and 8 deletions
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41
arch/powerpc/kernel/align.c
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@ -630,7 +630,7 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg,
}
#endif /* CONFIG_SPE */
#if defined(CONFIG_VSX) && defined(__BIG_ENDIAN__)
#ifdef CONFIG_VSX
/*
* Emulate VSX instructions...
*/
@ -658,8 +658,25 @@ static int emulate_vsx(unsigned char __user *addr, unsigned int reg,
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) {
@ -669,19 +686,31 @@ static int emulate_vsx(unsigned char __user *addr, unsigned int reg,
ret |= __get_user(ptr[i^sw], addr + i);
}
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[1] = lptr[0];
/* For 8 byte loads, zero the top 8 bytes */
lptr[VSX_LO] = lptr[VSX_HI];
/* For 8 byte loads, zero the low 8 bytes */
else if (!(flags & ST) && (8 == length))
lptr[1] = 0;
lptr[VSX_LO] = 0;
} else
return -EFAULT;
@ -805,7 +834,6 @@ int fix_alignment(struct pt_regs *regs)
/* DAR has the operand effective address */
addr = (unsigned char __user *)regs->dar;
#ifdef __BIG_ENDIAN__
#ifdef CONFIG_VSX
if ((instruction & 0xfc00003e) == 0x7c000018) {
unsigned int elsize;
@ -839,9 +867,6 @@ int fix_alignment(struct pt_regs *regs)
PPC_WARN_ALIGNMENT(vsx, regs);
return emulate_vsx(addr, reg, areg, regs, flags, nb, elsize);
}
#endif
#else
return -EFAULT;
#endif
/* A size of 0 indicates an instruction we don't support, with
* the exception of DCBZ which is handled as a special case here