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[POWERPC] Handle alignment faults on SPE load/store instructions
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This adds code to handle alignment traps generated by the following
SPE (signal processing engine) load/store instructions, by emulating
the instruction in the kernel (as is done for other instructions that
generate alignment traps):

evldd[x]         Vector Load Double Word into Double Word [Indexed]
evldw[x]         Vector Load Double into Two Words [Indexed]
evldh[x]         Vector Load Double into Four Half Words [Indexed]
evlhhesplat[x]   Vector Load Half Word into Half Words Even and Splat [Indexed]
evlhhousplat[x]  Vector Load Half Word into Half Word Odd Unsigned and Splat [Indexed]
evlhhossplat[x]  Vector Load Half Word into Half Word Odd Signed and Splat [Indexed]
evlwhe[x]        Vector Load Word into Two Half Words Even [Indexed]
evlwhou[x]       Vector Load Word into Two Half Words Odd Unsigned (zero-extended) [Indexed]
evlwhos[x]       Vector Load Word into Two Half Words Odd Signed (with sign extension) [Indexed]
evlwwsplat[x]    Vector Load Word into Word and Splat [Indexed]
evlwhsplat[x]    Vector Load Word into Two Half Words and Splat [Indexed]
evstdd[x]        Vector Store Double of Double [Indexed]
evstdw[x]        Vector Store Double of Two Words [Indexed]
evstdh[x]        Vector Store Double of Four Half Words [Indexed]
evstwhe[x]       Vector Store Word of Two Half Words from Even [Indexed]
evstwho[x]       Vector Store Word of Two Half Words from Odd [Indexed]
evstwwe[x]       Vector Store Word of Word from Even [Indexed]
evstwwo[x]       Vector Store Word of Word from Odd [Indexed]

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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Kumar Gala committed Sep 14, 2007
1 parent f923473 commit 26caeb2
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250 changes: 250 additions & 0 deletions arch/powerpc/kernel/align.c
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Original file line number Diff line number Diff line change
Expand Up @@ -46,6 +46,8 @@ struct aligninfo {
#define S 0x40 /* single-precision fp or... */
#define SX 0x40 /* ... byte count in XER */
#define HARD 0x80 /* string, stwcx. */
#define E4 0x40 /* SPE endianness is word */
#define E8 0x80 /* SPE endianness is double word */

/* DSISR bits reported for a DCBZ instruction: */
#define DCBZ 0x5f /* 8xx/82xx dcbz faults when cache not enabled */
Expand Down Expand Up @@ -392,6 +394,248 @@ static int emulate_fp_pair(struct pt_regs *regs, unsigned char __user *addr,
return 1; /* exception handled and fixed up */
}

#ifdef CONFIG_SPE

static struct aligninfo spe_aligninfo[32] = {
{ 8, LD+E8 }, /* 0 00 00: evldd[x] */
{ 8, LD+E4 }, /* 0 00 01: evldw[x] */
{ 8, LD }, /* 0 00 10: evldh[x] */
INVALID, /* 0 00 11 */
{ 2, LD }, /* 0 01 00: evlhhesplat[x] */
INVALID, /* 0 01 01 */
{ 2, LD }, /* 0 01 10: evlhhousplat[x] */
{ 2, LD+SE }, /* 0 01 11: evlhhossplat[x] */
{ 4, LD }, /* 0 10 00: evlwhe[x] */
INVALID, /* 0 10 01 */
{ 4, LD }, /* 0 10 10: evlwhou[x] */
{ 4, LD+SE }, /* 0 10 11: evlwhos[x] */
{ 4, LD+E4 }, /* 0 11 00: evlwwsplat[x] */
INVALID, /* 0 11 01 */
{ 4, LD }, /* 0 11 10: evlwhsplat[x] */
INVALID, /* 0 11 11 */

{ 8, ST+E8 }, /* 1 00 00: evstdd[x] */
{ 8, ST+E4 }, /* 1 00 01: evstdw[x] */
{ 8, ST }, /* 1 00 10: evstdh[x] */
INVALID, /* 1 00 11 */
INVALID, /* 1 01 00 */
INVALID, /* 1 01 01 */
INVALID, /* 1 01 10 */
INVALID, /* 1 01 11 */
{ 4, ST }, /* 1 10 00: evstwhe[x] */
INVALID, /* 1 10 01 */
{ 4, ST }, /* 1 10 10: evstwho[x] */
INVALID, /* 1 10 11 */
{ 4, ST+E4 }, /* 1 11 00: evstwwe[x] */
INVALID, /* 1 11 01 */
{ 4, ST+E4 }, /* 1 11 10: evstwwo[x] */
INVALID, /* 1 11 11 */
};

#define EVLDD 0x00
#define EVLDW 0x01
#define EVLDH 0x02
#define EVLHHESPLAT 0x04
#define EVLHHOUSPLAT 0x06
#define EVLHHOSSPLAT 0x07
#define EVLWHE 0x08
#define EVLWHOU 0x0A
#define EVLWHOS 0x0B
#define EVLWWSPLAT 0x0C
#define EVLWHSPLAT 0x0E
#define EVSTDD 0x10
#define EVSTDW 0x11
#define EVSTDH 0x12
#define EVSTWHE 0x18
#define EVSTWHO 0x1A
#define EVSTWWE 0x1C
#define EVSTWWO 0x1E

/*
* Emulate SPE loads and stores.
* Only Book-E has these instructions, and it does true little-endian,
* so we don't need the address swizzling.
*/
static int emulate_spe(struct pt_regs *regs, unsigned int reg,
unsigned int instr)
{
int t, ret;
union {
u64 ll;
u32 w[2];
u16 h[4];
u8 v[8];
} data, temp;
unsigned char __user *p, *addr;
unsigned long *evr = &current->thread.evr[reg];
unsigned int nb, flags;

instr = (instr >> 1) & 0x1f;

/* DAR has the operand effective address */
addr = (unsigned char __user *)regs->dar;

nb = spe_aligninfo[instr].len;
flags = spe_aligninfo[instr].flags;

/* Verify the address of the operand */
if (unlikely(user_mode(regs) &&
!access_ok((flags & ST ? VERIFY_WRITE : VERIFY_READ),
addr, nb)))
return -EFAULT;

/* userland only */
if (unlikely(!user_mode(regs)))
return 0;

flush_spe_to_thread(current);

/* If we are loading, get the data from user space, else
* get it from register values
*/
if (flags & ST) {
data.ll = 0;
switch (instr) {
case EVSTDD:
case EVSTDW:
case EVSTDH:
data.w[0] = *evr;
data.w[1] = regs->gpr[reg];
break;
case EVSTWHE:
data.h[2] = *evr >> 16;
data.h[3] = regs->gpr[reg] >> 16;
break;
case EVSTWHO:
data.h[2] = *evr & 0xffff;
data.h[3] = regs->gpr[reg] & 0xffff;
break;
case EVSTWWE:
data.w[1] = *evr;
break;
case EVSTWWO:
data.w[1] = regs->gpr[reg];
break;
default:
return -EINVAL;
}
} else {
temp.ll = data.ll = 0;
ret = 0;
p = addr;

switch (nb) {
case 8:
ret |= __get_user_inatomic(temp.v[0], p++);
ret |= __get_user_inatomic(temp.v[1], p++);
ret |= __get_user_inatomic(temp.v[2], p++);
ret |= __get_user_inatomic(temp.v[3], p++);
case 4:
ret |= __get_user_inatomic(temp.v[4], p++);
ret |= __get_user_inatomic(temp.v[5], p++);
case 2:
ret |= __get_user_inatomic(temp.v[6], p++);
ret |= __get_user_inatomic(temp.v[7], p++);
if (unlikely(ret))
return -EFAULT;
}

switch (instr) {
case EVLDD:
case EVLDW:
case EVLDH:
data.ll = temp.ll;
break;
case EVLHHESPLAT:
data.h[0] = temp.h[3];
data.h[2] = temp.h[3];
break;
case EVLHHOUSPLAT:
case EVLHHOSSPLAT:
data.h[1] = temp.h[3];
data.h[3] = temp.h[3];
break;
case EVLWHE:
data.h[0] = temp.h[2];
data.h[2] = temp.h[3];
break;
case EVLWHOU:
case EVLWHOS:
data.h[1] = temp.h[2];
data.h[3] = temp.h[3];
break;
case EVLWWSPLAT:
data.w[0] = temp.w[1];
data.w[1] = temp.w[1];
break;
case EVLWHSPLAT:
data.h[0] = temp.h[2];
data.h[1] = temp.h[2];
data.h[2] = temp.h[3];
data.h[3] = temp.h[3];
break;
default:
return -EINVAL;
}
}

if (flags & SW) {
switch (flags & 0xf0) {
case E8:
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 E4:

SWAP(data.v[0], data.v[3]);
SWAP(data.v[1], data.v[2]);
SWAP(data.v[4], data.v[7]);
SWAP(data.v[5], data.v[6]);
break;
/* Its half word endian */
default:
SWAP(data.v[0], data.v[1]);
SWAP(data.v[2], data.v[3]);
SWAP(data.v[4], data.v[5]);
SWAP(data.v[6], data.v[7]);
break;
}
}

if (flags & SE) {
data.w[0] = (s16)data.h[1];
data.w[1] = (s16)data.h[3];
}

/* Store result to memory or update registers */
if (flags & ST) {
ret = 0;
p = addr;
switch (nb) {
case 8:
ret |= __put_user_inatomic(data.v[0], p++);
ret |= __put_user_inatomic(data.v[1], p++);
ret |= __put_user_inatomic(data.v[2], p++);
ret |= __put_user_inatomic(data.v[3], p++);
case 4:
ret |= __put_user_inatomic(data.v[4], p++);
ret |= __put_user_inatomic(data.v[5], p++);
case 2:
ret |= __put_user_inatomic(data.v[6], p++);
ret |= __put_user_inatomic(data.v[7], p++);
}
if (unlikely(ret))
return -EFAULT;
} else {
*evr = data.w[0];
regs->gpr[reg] = data.w[1];
}

return 1;
}
#endif /* CONFIG_SPE */

/*
* Called on alignment exception. Attempts to fixup
Expand Down Expand Up @@ -450,6 +694,12 @@ int fix_alignment(struct pt_regs *regs)
/* extract the operation and registers from the dsisr */
reg = (dsisr >> 5) & 0x1f; /* source/dest register */
areg = dsisr & 0x1f; /* register to update */

#ifdef CONFIG_SPE
if ((instr >> 26) == 0x4)
return emulate_spe(regs, reg, instr);
#endif

instr = (dsisr >> 10) & 0x7f;
instr |= (dsisr >> 13) & 0x60;

Expand Down

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