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linux/arch/powerpc/kernel/align.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/* 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
*/
#include <linux/kernel.h>
#include <linux/mm.h>
#include <asm/processor.h>
#include <linux/uaccess.h>
#include <asm/cache.h>
#include <asm/cputable.h>
#include <asm/emulated_ops.h>
#include <asm/switch_to.h>
#include <asm/disassemble.h>
#include <asm/cpu_has_feature.h>
#include <asm/sstep.h>
struct aligninfo {
unsigned char len;
unsigned char flags;
};
#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 SW 0x20 /* byte swap */
#define E4 0x40 /* SPE endianness is word */
#define E8 0x80 /* SPE endianness is double word */
#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 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(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++);
/* fall through */
case 4:
ret |= __get_user_inatomic(temp.v[4], p++);
ret |= __get_user_inatomic(temp.v[5], p++);
/* fall through */
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:
data.ll = swab64(data.ll);
break;
case E4:
data.w[0] = swab32(data.w[0]);
data.w[1] = swab32(data.w[1]);
break;
/* Its half word endian */
default:
data.h[0] = swab16(data.h[0]);
data.h[1] = swab16(data.h[1]);
data.h[2] = swab16(data.h[2]);
data.h[3] = swab16(data.h[3]);
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++);
/* fall through */
case 4:
ret |= __put_user_inatomic(data.v[4], p++);
ret |= __put_user_inatomic(data.v[5], p++);
/* fall through */
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
*
* Return 1 on success
* Return 0 if unable to handle the interrupt
* Return -EFAULT if data address is bad
* Other negative return values indicate that the instruction can't
* be emulated, and the process should be given a SIGBUS.
*/
int fix_alignment(struct pt_regs *regs)
{
unsigned int instr;
struct instruction_op op;
int r, type;
/*
* We require a complete register set, if not, then our assembly
* is broken
*/
CHECK_FULL_REGS(regs);
if (unlikely(__get_user(instr, (unsigned int __user *)regs->nip)))
return -EFAULT;
if ((regs->msr & MSR_LE) != (MSR_KERNEL & MSR_LE)) {
/* We don't handle PPC little-endian any more... */
if (cpu_has_feature(CPU_FTR_PPC_LE))
return -EIO;
instr = swab32(instr);
}
#ifdef CONFIG_SPE
if ((instr >> 26) == 0x4) {
int reg = (instr >> 21) & 0x1f;
PPC_WARN_ALIGNMENT(spe, regs);
return emulate_spe(regs, reg, instr);
}
#endif
/*
* ISA 3.0 (such as P9) copy, copy_first, paste and paste_last alignment
* check.
*
* Send a SIGBUS to the process that caused the fault.
*
* We do not emulate these because paste may contain additional metadata
* when pasting to a co-processor. Furthermore, paste_last is the
* synchronisation point for preceding copy/paste sequences.
*/
if ((instr & 0xfc0006fe) == (PPC_INST_COPY & 0xfc0006fe))
return -EIO;
r = analyse_instr(&op, regs, instr);
if (r < 0)
return -EINVAL;
type = GETTYPE(op.type);
if (!OP_IS_LOAD_STORE(type)) {
if (op.type != CACHEOP + DCBZ)
return -EINVAL;
PPC_WARN_ALIGNMENT(dcbz, regs);
r = emulate_dcbz(op.ea, regs);
} else {
if (type == LARX || type == STCX)
return -EIO;
PPC_WARN_ALIGNMENT(unaligned, regs);
r = emulate_loadstore(regs, &op);
}
if (!r)
return 1;
return r;
}
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