[PATCH 15/39] powerpc: Add little endian support to alignment handler
Anton Blanchard
anton at samba.org
Mon Sep 23 12:04:49 EST 2013
Handle most unaligned load and store faults in little
endian mode. Strings, multiples and VSX are not supported.
Signed-off-by: Anton Blanchard <anton at samba.org>
---
arch/powerpc/kernel/align.c | 93 ++++++++++++++++++++++++++++++---------------
1 file changed, 63 insertions(+), 30 deletions(-)
diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c
index 3049bd0..cce82b1 100644
--- a/arch/powerpc/kernel/align.c
+++ b/arch/powerpc/kernel/align.c
@@ -262,6 +262,7 @@ static int emulate_dcbz(struct pt_regs *regs, unsigned char __user *addr)
#define SWIZ_PTR(p) ((unsigned char __user *)((p) ^ swiz))
+#ifdef __BIG_ENDIAN__
static int emulate_multiple(struct pt_regs *regs, unsigned char __user *addr,
unsigned int reg, unsigned int nb,
unsigned int flags, unsigned int instr,
@@ -390,6 +391,7 @@ static int emulate_fp_pair(unsigned char __user *addr, unsigned int reg,
return -EFAULT;
return 1; /* exception handled and fixed up */
}
+#endif
#ifdef CONFIG_SPE
@@ -628,7 +630,7 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg,
}
#endif /* CONFIG_SPE */
-#ifdef CONFIG_VSX
+#if defined(CONFIG_VSX) && defined(__BIG_ENDIAN__)
/*
* Emulate VSX instructions...
*/
@@ -702,18 +704,28 @@ int fix_alignment(struct pt_regs *regs)
unsigned int dsisr;
unsigned char __user *addr;
unsigned long p, swiz;
- int ret;
- union {
+ int ret, 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;
@@ -772,8 +784,9 @@ int fix_alignment(struct pt_regs *regs)
/* Byteswap little endian loads and stores */
swiz = 0;
- if (regs->msr & MSR_LE) {
+ 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
@@ -786,11 +799,13 @@ int fix_alignment(struct pt_regs *regs)
*/
if (cpu_has_feature(CPU_FTR_PPC_LE))
swiz = 7;
+#endif
}
/* 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;
@@ -810,7 +825,7 @@ int fix_alignment(struct pt_regs *regs)
elsize = 8;
flags = 0;
- if (regs->msr & MSR_LE)
+ if ((regs->msr & MSR_LE) != (MSR_KERNEL & MSR_LE))
flags |= SW;
if (instruction & 0x100)
flags |= ST;
@@ -825,6 +840,9 @@ int fix_alignment(struct pt_regs *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
*/
@@ -839,9 +857,13 @@ int fix_alignment(struct pt_regs *regs)
* function
*/
if (flags & M) {
+#ifdef __BIG_ENDIAN__
PPC_WARN_ALIGNMENT(multiple, regs);
return emulate_multiple(regs, addr, reg, nb,
flags, instr, swiz);
+#else
+ return -EFAULT;
+#endif
}
/* Verify the address of the operand */
@@ -860,8 +882,12 @@ int fix_alignment(struct pt_regs *regs)
/* Special case for 16-byte FP loads and stores */
if (nb == 16) {
+#ifdef __BIG_ENDIAN__
PPC_WARN_ALIGNMENT(fp_pair, regs);
return emulate_fp_pair(addr, reg, flags);
+#else
+ return -EFAULT;
+#endif
}
PPC_WARN_ALIGNMENT(unaligned, regs);
@@ -870,24 +896,28 @@ int fix_alignment(struct pt_regs *regs)
* get it from register values
*/
if (!(flags & ST)) {
- data.ll = 0;
- ret = 0;
- p = (unsigned long) addr;
+ unsigned int start = 0;
+
switch (nb) {
- case 8:
- ret |= __get_user_inatomic(data.v[0], SWIZ_PTR(p++));
- ret |= __get_user_inatomic(data.v[1], SWIZ_PTR(p++));
- ret |= __get_user_inatomic(data.v[2], SWIZ_PTR(p++));
- ret |= __get_user_inatomic(data.v[3], SWIZ_PTR(p++));
case 4:
- ret |= __get_user_inatomic(data.v[4], SWIZ_PTR(p++));
- ret |= __get_user_inatomic(data.v[5], SWIZ_PTR(p++));
+ start = offsetof(union data, x32.low32);
+ break;
case 2:
- ret |= __get_user_inatomic(data.v[6], SWIZ_PTR(p++));
- ret |= __get_user_inatomic(data.v[7], SWIZ_PTR(p++));
- if (unlikely(ret))
- return -EFAULT;
+ start = offsetof(union data, x16.low16);
+ break;
}
+
+ data.ll = 0;
+ ret = 0;
+ p = (unsigned long)addr;
+
+ for (i = 0; i < nb; i++)
+ ret |= __get_user_inatomic(data.v[start + i],
+ SWIZ_PTR(p++));
+
+ if (unlikely(ret))
+ return -EFAULT;
+
} else if (flags & F) {
data.dd = current->thread.TS_FPR(reg);
if (flags & S) {
@@ -945,21 +975,24 @@ int fix_alignment(struct pt_regs *regs)
/* Store result to memory or update registers */
if (flags & ST) {
- ret = 0;
- p = (unsigned long) addr;
+ unsigned int start = 0;
+
switch (nb) {
- case 8:
- ret |= __put_user_inatomic(data.v[0], SWIZ_PTR(p++));
- ret |= __put_user_inatomic(data.v[1], SWIZ_PTR(p++));
- ret |= __put_user_inatomic(data.v[2], SWIZ_PTR(p++));
- ret |= __put_user_inatomic(data.v[3], SWIZ_PTR(p++));
case 4:
- ret |= __put_user_inatomic(data.v[4], SWIZ_PTR(p++));
- ret |= __put_user_inatomic(data.v[5], SWIZ_PTR(p++));
+ start = offsetof(union data, x32.low32);
+ break;
case 2:
- ret |= __put_user_inatomic(data.v[6], SWIZ_PTR(p++));
- ret |= __put_user_inatomic(data.v[7], SWIZ_PTR(p++));
+ start = offsetof(union data, x16.low16);
+ break;
}
+
+ ret = 0;
+ p = (unsigned long)addr;
+
+ for (i = 0; i < nb; i++)
+ ret |= __put_user_inatomic(data.v[start + i],
+ SWIZ_PTR(p++));
+
if (unlikely(ret))
return -EFAULT;
} else if (flags & F)
--
1.8.1.2
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