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powerpc: Handle VSX alignment faults correctly in little-endian mode 

This patch fixes the handling of VSX alignment faults in little-endian
mode (the current code assumes the processor is in big-endian mode).

The patch also makes the handlers clear the top 8 bytes of the register
when handling an 8 byte VSX load.

This is based on 2.6.32.

Signed-off-by: Neil Campbell <neilc@linux.vnet.ibm.com>
Cc: <stable@kernel.org>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Neil Campbell 2009-12-14 04:08:57 +00:00 committed by Benjamin Herrenschmidt
parent f04b10cddb
commit bb7f20b1c6
1 changed files with 46 additions and 17 deletions
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63
arch/powerpc/kernel/align.c
View File

@ -642,10 +642,14 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg,
*/
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 flags, unsigned int length,
unsigned int elsize)
{
char *ptr;
unsigned long *lptr;
int ret = 0;
int sw = 0;
int i, j;
flush_vsx_to_thread(current);
@ -654,19 +658,35 @@ static int emulate_vsx(unsigned char __user *addr, unsigned int reg,
else
ptr = (char *) &current->thread.vr[reg - 32];
if (flags & ST)
ret = __copy_to_user(addr, ptr, length);
else {
if (flags & SPLT){
ret = __copy_from_user(ptr, addr, length);
ptr += length;
lptr = (unsigned long *) ptr;
if (flags & SW)
sw = elsize-1;
for (j = 0; j < length; j += elsize) {
for (i = 0; i < elsize; ++i) {
if (flags & ST)
ret |= __put_user(ptr[i^sw], addr + i);
else
ret |= __get_user(ptr[i^sw], addr + i);
}
ret |= __copy_from_user(ptr, addr, length);
ptr += elsize;
addr += elsize;
}
if (flags & U)
regs->gpr[areg] = regs->dar;
if (ret)
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 */
else if (!(flags & ST) && (8 == length))
lptr[1] = 0;
} else
return -EFAULT;
return 1;
}
#endif
@ -767,16 +787,25 @@ int fix_alignment(struct pt_regs *regs)
#ifdef CONFIG_VSX
if ((instruction & 0xfc00003e) == 0x7c000018) {
/* Additional register addressing bit (64 VSX vs 32 FPR/GPR */
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;
else if (instruction & 0x080)
nb = 8;
else
nb = 4;
/* 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)
flags |= SW;
if (instruction & 0x100)
flags |= ST;
if (instruction & 0x040)
@ -787,7 +816,7 @@ int fix_alignment(struct pt_regs *regs)
nb = 8;
}
PPC_WARN_ALIGNMENT(vsx, regs);
return emulate_vsx(addr, reg, areg, regs, flags, nb);
return emulate_vsx(addr, reg, areg, regs, flags, nb, elsize);
}
#endif
/* A size of 0 indicates an instruction we don't support, with