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linux/arch/powerpc/kernel/align.c
Anton Blanchard 5c2e08231b powerpc: Never handle VSX alignment exceptions from kernel 
The VSX alignment handler needs to write out the existing VSX
state to memory before operating on it (flush_vsx_to_thread()).
If we take a VSX alignment exception in the kernel bad things
will happen. It looks like we could write the kernel state out
to the user process, or we could handle the kernel exception
using data from the user process (depending if MSR_VSX is set
or not).

Worse still, if the code to read or write the VSX state causes an
alignment exception, we will recurse forever. I ended up with
hundreds of megabytes of kernel stack to look through as a result.

Floating point and SPE code have similar issues but already include
a user check. Add the same check to emulate_vsx().

With this patch any unaligned VSX loads and stores in the kernel
will show up as a clear oops rather than silent corruption of
kernel or userspace VSX state, or worse, corruption of a potentially
unlimited amount of kernel memory.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-08-27 14:44:26 +10:00

988 lines
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/* align.c - handle alignment exceptions for the Power PC.
*
* Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au>
* Copyright (c) 1998-1999 TiVo, Inc.
* PowerPC 403GCX modifications.
* Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu>
* PowerPC 403GCX/405GP modifications.
* Copyright (c) 2001-2002 PPC64 team, IBM Corp
* 64-bit and Power4 support
* Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp
* <benh@kernel.crashing.org>
* Merge ppc32 and ppc64 implementations
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/mm.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/cache.h>
#include <asm/cputable.h>
#include <asm/emulated_ops.h>
#include <asm/switch_to.h>
struct aligninfo {
unsigned char len;
unsigned char flags;
};
#define IS_XFORM(inst) (((inst) >> 26) == 31)
#define IS_DSFORM(inst) (((inst) >> 26) >= 56)
#define INVALID { 0, 0 }
/* Bits in the flags field */
#define LD 0 /* load */
#define ST 1 /* store */
#define SE 2 /* sign-extend value, or FP ld/st as word */
#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. */
#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 */
#define SWAP(a, b) (t = (a), (a) = (b), (b) = t)
/*
* The PowerPC stores certain bits of the instruction that caused the
* alignment exception in the DSISR register. This array maps those
* bits to information about the operand length and what the
* instruction would do.
*/
static struct aligninfo aligninfo[128] = {
{ 4, LD }, /* 00 0 0000: lwz / lwarx */
INVALID, /* 00 0 0001 */
{ 4, ST }, /* 00 0 0010: stw */
INVALID, /* 00 0 0011 */
{ 2, LD }, /* 00 0 0100: lhz */
{ 2, LD+SE }, /* 00 0 0101: lha */
{ 2, ST }, /* 00 0 0110: sth */
{ 4, LD+M }, /* 00 0 0111: lmw */
{ 4, LD+F+S }, /* 00 0 1000: lfs */
{ 8, LD+F }, /* 00 0 1001: lfd */
{ 4, ST+F+S }, /* 00 0 1010: stfs */
{ 8, ST+F }, /* 00 0 1011: stfd */
INVALID, /* 00 0 1100 */
{ 8, LD }, /* 00 0 1101: ld/ldu/lwa */
INVALID, /* 00 0 1110 */
{ 8, ST }, /* 00 0 1111: std/stdu */
{ 4, LD+U }, /* 00 1 0000: lwzu */
INVALID, /* 00 1 0001 */
{ 4, ST+U }, /* 00 1 0010: stwu */
INVALID, /* 00 1 0011 */
{ 2, LD+U }, /* 00 1 0100: lhzu */
{ 2, LD+SE+U }, /* 00 1 0101: lhau */
{ 2, ST+U }, /* 00 1 0110: sthu */
{ 4, ST+M }, /* 00 1 0111: stmw */
{ 4, LD+F+S+U }, /* 00 1 1000: lfsu */
{ 8, LD+F+U }, /* 00 1 1001: lfdu */
{ 4, ST+F+S+U }, /* 00 1 1010: stfsu */
{ 8, ST+F+U }, /* 00 1 1011: stfdu */
{ 16, LD+F }, /* 00 1 1100: lfdp */
INVALID, /* 00 1 1101 */
{ 16, ST+F }, /* 00 1 1110: stfdp */
INVALID, /* 00 1 1111 */
{ 8, LD }, /* 01 0 0000: ldx */
INVALID, /* 01 0 0001 */
{ 8, ST }, /* 01 0 0010: stdx */
INVALID, /* 01 0 0011 */
INVALID, /* 01 0 0100 */
{ 4, LD+SE }, /* 01 0 0101: lwax */
INVALID, /* 01 0 0110 */
INVALID, /* 01 0 0111 */
{ 4, LD+M+HARD+SX }, /* 01 0 1000: lswx */
{ 4, LD+M+HARD }, /* 01 0 1001: lswi */
{ 4, ST+M+HARD+SX }, /* 01 0 1010: stswx */
{ 4, ST+M+HARD }, /* 01 0 1011: stswi */
INVALID, /* 01 0 1100 */
{ 8, LD+U }, /* 01 0 1101: ldu */
INVALID, /* 01 0 1110 */
{ 8, ST+U }, /* 01 0 1111: stdu */
{ 8, LD+U }, /* 01 1 0000: ldux */
INVALID, /* 01 1 0001 */
{ 8, ST+U }, /* 01 1 0010: stdux */
INVALID, /* 01 1 0011 */
INVALID, /* 01 1 0100 */
{ 4, LD+SE+U }, /* 01 1 0101: lwaux */
INVALID, /* 01 1 0110 */
INVALID, /* 01 1 0111 */
INVALID, /* 01 1 1000 */
INVALID, /* 01 1 1001 */
INVALID, /* 01 1 1010 */
INVALID, /* 01 1 1011 */
INVALID, /* 01 1 1100 */
INVALID, /* 01 1 1101 */
INVALID, /* 01 1 1110 */
INVALID, /* 01 1 1111 */
INVALID, /* 10 0 0000 */
INVALID, /* 10 0 0001 */
INVALID, /* 10 0 0010: stwcx. */
INVALID, /* 10 0 0011 */
INVALID, /* 10 0 0100 */
INVALID, /* 10 0 0101 */
INVALID, /* 10 0 0110 */
INVALID, /* 10 0 0111 */
{ 4, LD+SW }, /* 10 0 1000: lwbrx */
INVALID, /* 10 0 1001 */
{ 4, ST+SW }, /* 10 0 1010: stwbrx */
INVALID, /* 10 0 1011 */
{ 2, LD+SW }, /* 10 0 1100: lhbrx */
{ 4, LD+SE }, /* 10 0 1101 lwa */
{ 2, ST+SW }, /* 10 0 1110: sthbrx */
INVALID, /* 10 0 1111 */
INVALID, /* 10 1 0000 */
INVALID, /* 10 1 0001 */
INVALID, /* 10 1 0010 */
INVALID, /* 10 1 0011 */
INVALID, /* 10 1 0100 */
INVALID, /* 10 1 0101 */
INVALID, /* 10 1 0110 */
INVALID, /* 10 1 0111 */
INVALID, /* 10 1 1000 */
INVALID, /* 10 1 1001 */
INVALID, /* 10 1 1010 */
INVALID, /* 10 1 1011 */
INVALID, /* 10 1 1100 */
INVALID, /* 10 1 1101 */
INVALID, /* 10 1 1110 */
{ 0, ST+HARD }, /* 10 1 1111: dcbz */
{ 4, LD }, /* 11 0 0000: lwzx */
INVALID, /* 11 0 0001 */
{ 4, ST }, /* 11 0 0010: stwx */
INVALID, /* 11 0 0011 */
{ 2, LD }, /* 11 0 0100: lhzx */
{ 2, LD+SE }, /* 11 0 0101: lhax */
{ 2, ST }, /* 11 0 0110: sthx */
INVALID, /* 11 0 0111 */
{ 4, LD+F+S }, /* 11 0 1000: lfsx */
{ 8, LD+F }, /* 11 0 1001: lfdx */
{ 4, ST+F+S }, /* 11 0 1010: stfsx */
{ 8, ST+F }, /* 11 0 1011: stfdx */
{ 16, LD+F }, /* 11 0 1100: lfdpx */
{ 4, LD+F+SE }, /* 11 0 1101: lfiwax */
{ 16, ST+F }, /* 11 0 1110: stfdpx */
{ 4, ST+F }, /* 11 0 1111: stfiwx */
{ 4, LD+U }, /* 11 1 0000: lwzux */
INVALID, /* 11 1 0001 */
{ 4, ST+U }, /* 11 1 0010: stwux */
INVALID, /* 11 1 0011 */
{ 2, LD+U }, /* 11 1 0100: lhzux */
{ 2, LD+SE+U }, /* 11 1 0101: lhaux */
{ 2, ST+U }, /* 11 1 0110: sthux */
INVALID, /* 11 1 0111 */
{ 4, LD+F+S+U }, /* 11 1 1000: lfsux */
{ 8, LD+F+U }, /* 11 1 1001: lfdux */
{ 4, ST+F+S+U }, /* 11 1 1010: stfsux */
{ 8, ST+F+U }, /* 11 1 1011: stfdux */
INVALID, /* 11 1 1100 */
{ 4, LD+F }, /* 11 1 1101: lfiwzx */
INVALID, /* 11 1 1110 */
INVALID, /* 11 1 1111 */
};
/*
* Create a DSISR value from the instruction
*/
static inline unsigned make_dsisr(unsigned instr)
{
unsigned dsisr;
/* bits 6:15 --> 22:31 */
dsisr = (instr & 0x03ff0000) >> 16;
if (IS_XFORM(instr)) {
/* bits 29:30 --> 15:16 */
dsisr |= (instr & 0x00000006) << 14;
/* bit 25 --> 17 */
dsisr |= (instr & 0x00000040) << 8;
/* bits 21:24 --> 18:21 */
dsisr |= (instr & 0x00000780) << 3;
} else {
/* bit 5 --> 17 */
dsisr |= (instr & 0x04000000) >> 12;
/* bits 1: 4 --> 18:21 */
dsisr |= (instr & 0x78000000) >> 17;
/* bits 30:31 --> 12:13 */
if (IS_DSFORM(instr))
dsisr |= (instr & 0x00000003) << 18;
}
return dsisr;
}
/*
* The dcbz (data cache block zero) instruction
* gives an alignment fault if used on non-cacheable
* memory. We handle the fault mainly for the
* case when we are running with the cache disabled
* for debugging.
*/
static int emulate_dcbz(struct pt_regs *regs, unsigned char __user *addr)
{
long __user *p;
int i, size;
#ifdef __powerpc64__
size = ppc64_caches.dline_size;
#else
size = L1_CACHE_BYTES;
#endif
p = (long __user *) (regs->dar & -size);
if (user_mode(regs) && !access_ok(VERIFY_WRITE, p, size))
return -EFAULT;
for (i = 0; i < size / sizeof(long); ++i)
if (__put_user_inatomic(0, p+i))
return -EFAULT;
return 1;
}
/*
* Emulate load & store multiple instructions
* On 64-bit machines, these instructions only affect/use the
* bottom 4 bytes of each register, and the loads clear the
* top 4 bytes of the affected register.
*/
#ifdef CONFIG_PPC64
#define REG_BYTE(rp, i) *((u8 *)((rp) + ((i) >> 2)) + ((i) & 3) + 4)
#else
#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 long swiz)
{
unsigned long *rptr;
unsigned int nb0, i, bswiz;
unsigned long p;
/*
* We do not try to emulate 8 bytes multiple as they aren't really
* available in our operating environments and we don't try to
* emulate multiples operations in kernel land as they should never
* be used/generated there at least not on unaligned boundaries
*/
if (unlikely((nb > 4) || !user_mode(regs)))
return 0;
/* lmw, stmw, lswi/x, stswi/x */
nb0 = 0;
if (flags & HARD) {
if (flags & SX) {
nb = regs->xer & 127;
if (nb == 0)
return 1;
} else {
unsigned long pc = regs->nip ^ (swiz & 4);
if (__get_user_inatomic(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;
}
if (nb + reg * 4 > 128) {
nb0 = nb + reg * 4 - 128;
nb = 128 - reg * 4;
}
} else {
/* lwm, stmw */
nb = (32 - reg) * 4;
}
if (!access_ok((flags & ST ? VERIFY_WRITE: VERIFY_READ), addr, nb+nb0))
return -EFAULT; /* bad address */
rptr = &regs->gpr[reg];
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
* bytes of the last register for lsw*.
*/
memset(rptr, 0, ((nb + 3) / 4) * sizeof(unsigned long));
if (nb0 > 0)
memset(&regs->gpr[0], 0,
((nb0 + 3) / 4) * sizeof(unsigned long));
for (i = 0; i < nb; ++i, ++p)
if (__get_user_inatomic(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, ++p)
if (__get_user_inatomic(REG_BYTE(rptr,
i ^ bswiz),
SWIZ_PTR(p)))
return -EFAULT;
}
} else {
for (i = 0; i < nb; ++i, ++p)
if (__put_user_inatomic(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, ++p)
if (__put_user_inatomic(REG_BYTE(rptr,
i ^ bswiz),
SWIZ_PTR(p)))
return -EFAULT;
}
}
return 1;
}
/*
* Emulate floating-point pair loads and stores.
* Only POWER6 has these instructions, and it does true little-endian,
* so we don't need the address swizzling.
*/
static int emulate_fp_pair(unsigned char __user *addr, unsigned int reg,
unsigned int flags)
{
char *ptr0 = (char *) &current->thread.TS_FPR(reg);
char *ptr1 = (char *) &current->thread.TS_FPR(reg+1);
int i, ret, sw = 0;
if (!(flags & F))
return 0;
if (reg & 1)
return 0; /* invalid form: FRS/FRT must be even */
if (flags & SW)
sw = 7;
ret = 0;
for (i = 0; i < 8; ++i) {
if (!(flags & ST)) {
ret |= __get_user(ptr0[i^sw], addr + i);
ret |= __get_user(ptr1[i^sw], addr + i + 8);
} else {
ret |= __put_user(ptr0[i^sw], addr + i);
ret |= __put_user(ptr1[i^sw], addr + i + 8);
}
}
if (ret)
return -EFAULT;
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 */
#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,
unsigned int elsize)
{
char *ptr;
unsigned long *lptr;
int ret = 0;
int sw = 0;
int i, j;
/* userland only */
if (unlikely(!user_mode(regs)))
return 0;
flush_vsx_to_thread(current);
if (reg < 32)
ptr = (char *) &current->thread.TS_FPR(reg);
else
ptr = (char *) &current->thread.vr[reg - 32];
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);
}
ptr += elsize;
addr += elsize;
}
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
/*
* Called on alignment exception. Attempts to fixup
*
* Return 1 on success
* Return 0 if unable to handle the interrupt
* Return -EFAULT if data address is bad
*/
int fix_alignment(struct pt_regs *regs)
{
unsigned int instr, nb, flags, instruction = 0;
unsigned int reg, areg;
unsigned int dsisr;
unsigned char __user *addr;
unsigned long p, swiz;
int ret, t;
union {
u64 ll;
double dd;
unsigned char v[8];
struct {
unsigned hi32;
int low32;
} x32;
struct {
unsigned char hi48[6];
short low16;
} x16;
} data;
/*
* We require a complete register set, if not, then our assembly
* is broken
*/
CHECK_FULL_REGS(regs);
dsisr = regs->dsisr;
/* Some processors don't provide us with a DSISR we can use here,
* let's make one up from the instruction
*/
if (cpu_has_feature(CPU_FTR_NODSISRALIGN)) {
unsigned long pc = regs->nip;
if (cpu_has_feature(CPU_FTR_PPC_LE) && (regs->msr & MSR_LE))
pc ^= 4;
if (unlikely(__get_user_inatomic(instr,
(unsigned int __user *)pc)))
return -EFAULT;
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 */
reg = (dsisr >> 5) & 0x1f; /* source/dest register */
areg = dsisr & 0x1f; /* register to update */
#ifdef CONFIG_SPE
if ((instr >> 26) == 0x4) {
PPC_WARN_ALIGNMENT(spe, regs);
return emulate_spe(regs, reg, instr);
}
#endif
instr = (dsisr >> 10) & 0x7f;
instr |= (dsisr >> 13) & 0x60;
/* Lookup the operation in our table */
nb = aligninfo[instr].len;
flags = aligninfo[instr].flags;
/* ldbrx/stdbrx overlap lfs/stfs in the DSISR unfortunately */
if (IS_XFORM(instruction) && ((instruction >> 1) & 0x3ff) == 532) {
nb = 8;
flags = LD+SW;
} else if (IS_XFORM(instruction) &&
((instruction >> 1) & 0x3ff) == 660) {
nb = 8;
flags = ST+SW;
}
/* 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;
#ifdef CONFIG_VSX
if ((instruction & 0xfc00003e) == 0x7c000018) {
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;
/* 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)
flags |= U;
/* splat load needs a special decoder */
if ((instruction & 0x400) == 0){
flags |= SPLT;
nb = 8;
}
PPC_WARN_ALIGNMENT(vsx, regs);
return emulate_vsx(addr, reg, areg, regs, flags, nb, elsize);
}
#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
*/
if (instr == DCBZ) {
PPC_WARN_ALIGNMENT(dcbz, regs);
return emulate_dcbz(regs, addr);
}
if (unlikely(nb == 0))
return 0;
/* Load/Store Multiple instructions are handled in their own
* function
*/
if (flags & M) {
PPC_WARN_ALIGNMENT(multiple, regs);
return emulate_multiple(regs, addr, reg, nb,
flags, instr, swiz);
}
/* Verify the address of the operand */
if (unlikely(user_mode(regs) &&
!access_ok((flags & ST ? VERIFY_WRITE : VERIFY_READ),
addr, nb)))
return -EFAULT;
/* Force the fprs into the save area so we can reference them */
if (flags & F) {
/* userland only */
if (unlikely(!user_mode(regs)))
return 0;
flush_fp_to_thread(current);
}
/* Special case for 16-byte FP loads and stores */
if (nb == 16) {
PPC_WARN_ALIGNMENT(fp_pair, regs);
return emulate_fp_pair(addr, reg, flags);
}
PPC_WARN_ALIGNMENT(unaligned, regs);
/* If we are loading, get the data from user space, else
* get it from register values
*/
if (!(flags & ST)) {
data.ll = 0;
ret = 0;
p = (unsigned long) addr;
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++));
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;
}
} else if (flags & F) {
data.dd = current->thread.TS_FPR(reg);
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]);
preempt_enable();
#else
return 0;
#endif
}
} else
data.ll = regs->gpr[reg];
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|SW)) {
case LD+SE: /* sign extending integer loads */
case LD+F+SE: /* sign extend for lfiwax */
if ( nb == 2 )
data.ll = data.x16.low16;
else /* nb must be 4 */
data.ll = data.x32.low32;
break;
/* Single-precision FP load requires conversion... */
case LD+F+S:
#ifdef CONFIG_PPC_FPU
preempt_disable();
enable_kernel_fp();
cvt_fd((float *)&data.v[4], &data.dd);
preempt_enable();
#else
return 0;
#endif
break;
}
/* Store result to memory or update registers */
if (flags & ST) {
ret = 0;
p = (unsigned long) addr;
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++));
case 2:
ret |= __put_user_inatomic(data.v[6], SWIZ_PTR(p++));
ret |= __put_user_inatomic(data.v[7], SWIZ_PTR(p++));
}
if (unlikely(ret))
return -EFAULT;
} else if (flags & F)
current->thread.TS_FPR(reg) = data.dd;
else
regs->gpr[reg] = data.ll;
/* Update RA as needed */
if (flags & U)
regs->gpr[areg] = regs->dar;
return 1;
}
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