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Diffstat (limited to 'arch/powerpc/kernel/align.c')
-rw-r--r--arch/powerpc/kernel/align.c189
1 files changed, 118 insertions, 71 deletions
diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c
index faaec9c6f78f..4734b5de599d 100644
--- a/arch/powerpc/kernel/align.c
+++ b/arch/powerpc/kernel/align.c
@@ -35,17 +35,19 @@ struct aligninfo {
#define INVALID { 0, 0 }
-#define LD 1 /* load */
-#define ST 2 /* store */
-#define SE 4 /* sign-extend value */
-#define F 8 /* to/from fp regs */
-#define U 0x10 /* update index register */
-#define M 0x20 /* multiple load/store */
-#define SW 0x40 /* byte swap int or ... */
-#define S 0x40 /* ... single-precision fp */
-#define SX 0x40 /* byte count in XER */
+/* Bits in the flags field */
+#define LD 0 /* load */
+#define ST 1 /* store */
+#define SE 2 /* sign-extend value */
+#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. */
+/* DSISR bits reported for a DCBZ instruction: */
#define DCBZ 0x5f /* 8xx/82xx dcbz faults when cache not enabled */
#define SWAP(a, b) (t = (a), (a) = (b), (b) = t)
@@ -256,12 +258,16 @@ static int emulate_dcbz(struct pt_regs *regs, unsigned char __user *addr)
#define REG_BYTE(rp, i) *((u8 *)(rp) + (i))
#endif
+#define SWIZ_PTR(p) ((unsigned char __user *)((p) ^ swiz))
+
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 int flags, unsigned int instr,
+ unsigned long swiz)
{
unsigned long *rptr;
- unsigned int nb0, i;
+ unsigned int nb0, i, bswiz;
+ unsigned long p;
/*
* We do not try to emulate 8 bytes multiple as they aren't really
@@ -280,9 +286,12 @@ static int emulate_multiple(struct pt_regs *regs, unsigned char __user *addr,
if (nb == 0)
return 1;
} else {
- if (__get_user(instr,
- (unsigned int __user *)regs->nip))
+ unsigned long pc = regs->nip ^ (swiz & 4);
+
+ if (__get_user(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;
@@ -300,7 +309,10 @@ static int emulate_multiple(struct pt_regs *regs, unsigned char __user *addr,
return -EFAULT; /* bad address */
rptr = &regs->gpr[reg];
- if (flags & LD) {
+ 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
@@ -311,26 +323,28 @@ static int emulate_multiple(struct pt_regs *regs, unsigned char __user *addr,
memset(&regs->gpr[0], 0,
((nb0 + 3) / 4) * sizeof(unsigned long));
- for (i = 0; i < nb; ++i)
- if (__get_user(REG_BYTE(rptr, i), addr + i))
+ for (i = 0; i < nb; ++i, ++p)
+ if (__get_user(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)
- if (__get_user(REG_BYTE(rptr, i), addr + i))
+ for (i = 0; i < nb0; ++i, ++p)
+ if (__get_user(REG_BYTE(rptr, i ^ bswiz),
+ SWIZ_PTR(p)))
return -EFAULT;
}
} else {
- for (i = 0; i < nb; ++i)
- if (__put_user(REG_BYTE(rptr, i), addr + i))
+ for (i = 0; i < nb; ++i, ++p)
+ if (__put_user(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)
- if (__put_user(REG_BYTE(rptr, i), addr + i))
+ for (i = 0; i < nb0; ++i, ++p)
+ if (__put_user(REG_BYTE(rptr, i ^ bswiz),
+ SWIZ_PTR(p)))
return -EFAULT;
}
}
@@ -352,7 +366,7 @@ int fix_alignment(struct pt_regs *regs)
unsigned int reg, areg;
unsigned int dsisr;
unsigned char __user *addr;
- unsigned char __user *p;
+ unsigned long p, swiz;
int ret, t;
union {
u64 ll;
@@ -380,11 +394,15 @@ int fix_alignment(struct pt_regs *regs)
* let's make one up from the instruction
*/
if (cpu_has_feature(CPU_FTR_NODSISRALIGN)) {
- unsigned int real_instr;
- if (unlikely(__get_user(real_instr,
- (unsigned int __user *)regs->nip)))
+ unsigned long pc = regs->nip;
+
+ if (cpu_has_feature(CPU_FTR_PPC_LE) && (regs->msr & MSR_LE))
+ pc ^= 4;
+ if (unlikely(__get_user(instr, (unsigned int __user *)pc)))
return -EFAULT;
- dsisr = make_dsisr(real_instr);
+ if (cpu_has_feature(CPU_FTR_REAL_LE) && (regs->msr & MSR_LE))
+ instr = cpu_to_le32(instr);
+ dsisr = make_dsisr(instr);
}
/* extract the operation and registers from the dsisr */
@@ -397,6 +415,24 @@ int fix_alignment(struct pt_regs *regs)
nb = aligninfo[instr].len;
flags = aligninfo[instr].flags;
+ /* Byteswap little endian loads and stores */
+ swiz = 0;
+ if (regs->msr & MSR_LE) {
+ flags ^= SW;
+ /*
+ * 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;
+ }
+
/* DAR has the operand effective address */
addr = (unsigned char __user *)regs->dar;
@@ -412,7 +448,8 @@ int fix_alignment(struct pt_regs *regs)
* function
*/
if (flags & M)
- return emulate_multiple(regs, addr, reg, nb, flags, instr);
+ return emulate_multiple(regs, addr, reg, nb,
+ flags, instr, swiz);
/* Verify the address of the operand */
if (unlikely(user_mode(regs) &&
@@ -431,51 +468,71 @@ int fix_alignment(struct pt_regs *regs)
/* If we are loading, get the data from user space, else
* get it from register values
*/
- if (flags & LD) {
+ if (!(flags & ST)) {
data.ll = 0;
ret = 0;
- p = addr;
+ p = (unsigned long) addr;
switch (nb) {
case 8:
- ret |= __get_user(data.v[0], p++);
- ret |= __get_user(data.v[1], p++);
- ret |= __get_user(data.v[2], p++);
- ret |= __get_user(data.v[3], p++);
+ ret |= __get_user(data.v[0], SWIZ_PTR(p++));
+ ret |= __get_user(data.v[1], SWIZ_PTR(p++));
+ ret |= __get_user(data.v[2], SWIZ_PTR(p++));
+ ret |= __get_user(data.v[3], SWIZ_PTR(p++));
case 4:
- ret |= __get_user(data.v[4], p++);
- ret |= __get_user(data.v[5], p++);
+ ret |= __get_user(data.v[4], SWIZ_PTR(p++));
+ ret |= __get_user(data.v[5], SWIZ_PTR(p++));
case 2:
- ret |= __get_user(data.v[6], p++);
- ret |= __get_user(data.v[7], p++);
+ ret |= __get_user(data.v[6], SWIZ_PTR(p++));
+ ret |= __get_user(data.v[7], SWIZ_PTR(p++));
if (unlikely(ret))
return -EFAULT;
}
- } else if (flags & F)
+ } else if (flags & F) {
data.dd = current->thread.fpr[reg];
- else
+ if (flags & S) {
+ /* Single-precision FP store requires conversion... */
+#ifdef CONFIG_PPC_FPU
+ preempt_disable();
+ enable_kernel_fp();
+ cvt_df(&data.dd, (float *)&data.v[4], &current->thread);
+ preempt_enable();
+#else
+ return 0;
+#endif
+ }
+ } else
data.ll = regs->gpr[reg];
- /* Perform other misc operations like sign extension, byteswap,
+ if (flags & SW) {
+ switch (nb) {
+ case 8:
+ SWAP(data.v[0], data.v[7]);
+ SWAP(data.v[1], data.v[6]);
+ SWAP(data.v[2], data.v[5]);
+ SWAP(data.v[3], data.v[4]);
+ break;
+ case 4:
+ SWAP(data.v[4], data.v[7]);
+ SWAP(data.v[5], data.v[6]);
+ break;
+ case 2:
+ SWAP(data.v[6], data.v[7]);
+ break;
+ }
+ }
+
+ /* Perform other misc operations like sign extension
* or floating point single precision conversion
*/
- switch (flags & ~U) {
+ switch (flags & ~(U|SW)) {
case LD+SE: /* sign extend */
if ( nb == 2 )
data.ll = data.x16.low16;
else /* nb must be 4 */
data.ll = data.x32.low32;
break;
- case LD+S: /* byte-swap */
- case ST+S:
- if (nb == 2) {
- SWAP(data.v[6], data.v[7]);
- } else {
- SWAP(data.v[4], data.v[7]);
- SWAP(data.v[5], data.v[6]);
- }
- break;
- /* Single-precision FP load and store require conversions... */
+ /* Single-precision FP load requires conversion... */
case LD+F+S:
#ifdef CONFIG_PPC_FPU
preempt_disable();
@@ -486,34 +543,24 @@ int fix_alignment(struct pt_regs *regs)
return 0;
#endif
break;
- case ST+F+S:
-#ifdef CONFIG_PPC_FPU
- preempt_disable();
- enable_kernel_fp();
- cvt_df(&data.dd, (float *)&data.v[4], &current->thread);
- preempt_enable();
-#else
- return 0;
-#endif
- break;
}
/* Store result to memory or update registers */
if (flags & ST) {
ret = 0;
- p = addr;
+ p = (unsigned long) addr;
switch (nb) {
case 8:
- ret |= __put_user(data.v[0], p++);
- ret |= __put_user(data.v[1], p++);
- ret |= __put_user(data.v[2], p++);
- ret |= __put_user(data.v[3], p++);
+ ret |= __put_user(data.v[0], SWIZ_PTR(p++));
+ ret |= __put_user(data.v[1], SWIZ_PTR(p++));
+ ret |= __put_user(data.v[2], SWIZ_PTR(p++));
+ ret |= __put_user(data.v[3], SWIZ_PTR(p++));
case 4:
- ret |= __put_user(data.v[4], p++);
- ret |= __put_user(data.v[5], p++);
+ ret |= __put_user(data.v[4], SWIZ_PTR(p++));
+ ret |= __put_user(data.v[5], SWIZ_PTR(p++));
case 2:
- ret |= __put_user(data.v[6], p++);
- ret |= __put_user(data.v[7], p++);
+ ret |= __put_user(data.v[6], SWIZ_PTR(p++));
+ ret |= __put_user(data.v[7], SWIZ_PTR(p++));
}
if (unlikely(ret))
return -EFAULT;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.