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authorMichael Neuling <mikey@neuling.org>2008-07-11 16:31:09 +1000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2008-07-15 12:29:25 +1000
commitcd6f37be7fdc9fea407379745350f6630b9d3cdd (patch)
treeca8c813d84c6db6ba6052a42c0fb4e8aff411422
parent7c29217096d83f657e6ee70479af09b46f4275f6 (diff)
powerpc: Add VSX load/store alignment exception handler
VSX loads and stores will take an alignment exception when the address is not on a 4 byte boundary. This add support for these alignment exceptions and will emulate the requested load or store. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
-rw-r--r--arch/powerpc/kernel/align.c58
1 files changed, 57 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c
index f22b5d0a4a9..367129789cc 100644
--- a/arch/powerpc/kernel/align.c
+++ b/arch/powerpc/kernel/align.c
@@ -48,6 +48,7 @@ struct aligninfo {
#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 */
@@ -637,6 +638,36 @@ 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)
+{
+ char *ptr = (char *) &current->thread.TS_FPR(reg);
+ int ret;
+
+ flush_vsx_to_thread(current);
+
+ if (flags & ST)
+ ret = __copy_to_user(addr, ptr, length);
+ else {
+ if (flags & SPLT){
+ ret = __copy_from_user(ptr, addr, length);
+ ptr += length;
+ }
+ ret |= __copy_from_user(ptr, addr, length);
+ }
+ if (flags & U)
+ regs->gpr[areg] = regs->dar;
+ if (ret)
+ return -EFAULT;
+ return 1;
+}
+#endif
+
/*
* Called on alignment exception. Attempts to fixup
*
@@ -647,7 +678,7 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg,
int fix_alignment(struct pt_regs *regs)
{
- unsigned int instr, nb, flags;
+ unsigned int instr, nb, flags, instruction = 0;
unsigned int reg, areg;
unsigned int dsisr;
unsigned char __user *addr;
@@ -689,6 +720,7 @@ int fix_alignment(struct pt_regs *regs)
if (cpu_has_feature(CPU_FTR_REAL_LE) && (regs->msr & MSR_LE))
instr = cpu_to_le32(instr);
dsisr = make_dsisr(instr);
+ instruction = instr;
}
/* extract the operation and registers from the dsisr */
@@ -728,6 +760,30 @@ int fix_alignment(struct pt_regs *regs)
/* DAR has the operand effective address */
addr = (unsigned char __user *)regs->dar;
+#ifdef CONFIG_VSX
+ if ((instruction & 0xfc00003e) == 0x7c000018) {
+ /* Additional register addressing bit (64 VSX vs 32 FPR/GPR */
+ reg |= (instruction & 0x1) << 5;
+ /* Simple inline decoder instead of a table */
+ if (instruction & 0x200)
+ nb = 16;
+ else if (instruction & 0x080)
+ nb = 8;
+ else
+ nb = 4;
+ flags = 0;
+ if (instruction & 0x100)
+ flags |= ST;
+ if (instruction & 0x040)
+ flags |= U;
+ /* splat load needs a special decoder */
+ if ((instruction & 0x400) == 0){
+ flags |= SPLT;
+ nb = 8;
+ }
+ return emulate_vsx(addr, reg, areg, regs, flags, nb);
+ }
+#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
*/