7db57e7758
Mark switch cases where we are expecting to fall through.
Fixes errors such as below, seen with mpc85xx_defconfig:
arch/powerpc/kernel/align.c: In function 'emulate_spe':
arch/powerpc/kernel/align.c:178:8: error: this statement may fall through
ret |= __get_user_inatomic(temp.v[3], p++);
^~
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190730141917.21817-1-mpe@ellerman.id.au
358 lines
8.3 KiB
C
358 lines
8.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* align.c - handle alignment exceptions for the Power PC.
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*
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* Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au>
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* Copyright (c) 1998-1999 TiVo, Inc.
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* PowerPC 403GCX modifications.
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* Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu>
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* PowerPC 403GCX/405GP modifications.
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* Copyright (c) 2001-2002 PPC64 team, IBM Corp
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* 64-bit and Power4 support
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* Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp
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* <benh@kernel.crashing.org>
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* Merge ppc32 and ppc64 implementations
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*/
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <asm/processor.h>
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#include <linux/uaccess.h>
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#include <asm/cache.h>
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#include <asm/cputable.h>
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#include <asm/emulated_ops.h>
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#include <asm/switch_to.h>
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#include <asm/disassemble.h>
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#include <asm/cpu_has_feature.h>
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#include <asm/sstep.h>
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struct aligninfo {
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unsigned char len;
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unsigned char flags;
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};
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#define INVALID { 0, 0 }
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/* Bits in the flags field */
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#define LD 0 /* load */
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#define ST 1 /* store */
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#define SE 2 /* sign-extend value, or FP ld/st as word */
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#define SW 0x20 /* byte swap */
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#define E4 0x40 /* SPE endianness is word */
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#define E8 0x80 /* SPE endianness is double word */
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#ifdef CONFIG_SPE
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static struct aligninfo spe_aligninfo[32] = {
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{ 8, LD+E8 }, /* 0 00 00: evldd[x] */
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{ 8, LD+E4 }, /* 0 00 01: evldw[x] */
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{ 8, LD }, /* 0 00 10: evldh[x] */
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INVALID, /* 0 00 11 */
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{ 2, LD }, /* 0 01 00: evlhhesplat[x] */
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INVALID, /* 0 01 01 */
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{ 2, LD }, /* 0 01 10: evlhhousplat[x] */
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{ 2, LD+SE }, /* 0 01 11: evlhhossplat[x] */
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{ 4, LD }, /* 0 10 00: evlwhe[x] */
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INVALID, /* 0 10 01 */
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{ 4, LD }, /* 0 10 10: evlwhou[x] */
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{ 4, LD+SE }, /* 0 10 11: evlwhos[x] */
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{ 4, LD+E4 }, /* 0 11 00: evlwwsplat[x] */
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INVALID, /* 0 11 01 */
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{ 4, LD }, /* 0 11 10: evlwhsplat[x] */
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INVALID, /* 0 11 11 */
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{ 8, ST+E8 }, /* 1 00 00: evstdd[x] */
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{ 8, ST+E4 }, /* 1 00 01: evstdw[x] */
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{ 8, ST }, /* 1 00 10: evstdh[x] */
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INVALID, /* 1 00 11 */
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INVALID, /* 1 01 00 */
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INVALID, /* 1 01 01 */
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INVALID, /* 1 01 10 */
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INVALID, /* 1 01 11 */
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{ 4, ST }, /* 1 10 00: evstwhe[x] */
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INVALID, /* 1 10 01 */
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{ 4, ST }, /* 1 10 10: evstwho[x] */
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INVALID, /* 1 10 11 */
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{ 4, ST+E4 }, /* 1 11 00: evstwwe[x] */
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INVALID, /* 1 11 01 */
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{ 4, ST+E4 }, /* 1 11 10: evstwwo[x] */
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INVALID, /* 1 11 11 */
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};
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#define EVLDD 0x00
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#define EVLDW 0x01
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#define EVLDH 0x02
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#define EVLHHESPLAT 0x04
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#define EVLHHOUSPLAT 0x06
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#define EVLHHOSSPLAT 0x07
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#define EVLWHE 0x08
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#define EVLWHOU 0x0A
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#define EVLWHOS 0x0B
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#define EVLWWSPLAT 0x0C
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#define EVLWHSPLAT 0x0E
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#define EVSTDD 0x10
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#define EVSTDW 0x11
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#define EVSTDH 0x12
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#define EVSTWHE 0x18
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#define EVSTWHO 0x1A
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#define EVSTWWE 0x1C
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#define EVSTWWO 0x1E
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/*
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* Emulate SPE loads and stores.
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* Only Book-E has these instructions, and it does true little-endian,
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* so we don't need the address swizzling.
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*/
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static int emulate_spe(struct pt_regs *regs, unsigned int reg,
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unsigned int instr)
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{
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int ret;
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union {
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u64 ll;
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u32 w[2];
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u16 h[4];
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u8 v[8];
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} data, temp;
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unsigned char __user *p, *addr;
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unsigned long *evr = ¤t->thread.evr[reg];
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unsigned int nb, flags;
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instr = (instr >> 1) & 0x1f;
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/* DAR has the operand effective address */
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addr = (unsigned char __user *)regs->dar;
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nb = spe_aligninfo[instr].len;
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flags = spe_aligninfo[instr].flags;
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/* Verify the address of the operand */
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if (unlikely(user_mode(regs) &&
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!access_ok(addr, nb)))
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return -EFAULT;
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/* userland only */
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if (unlikely(!user_mode(regs)))
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return 0;
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flush_spe_to_thread(current);
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/* If we are loading, get the data from user space, else
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* get it from register values
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*/
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if (flags & ST) {
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data.ll = 0;
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switch (instr) {
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case EVSTDD:
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case EVSTDW:
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case EVSTDH:
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data.w[0] = *evr;
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data.w[1] = regs->gpr[reg];
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break;
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case EVSTWHE:
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data.h[2] = *evr >> 16;
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data.h[3] = regs->gpr[reg] >> 16;
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break;
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case EVSTWHO:
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data.h[2] = *evr & 0xffff;
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data.h[3] = regs->gpr[reg] & 0xffff;
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break;
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case EVSTWWE:
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data.w[1] = *evr;
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break;
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case EVSTWWO:
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data.w[1] = regs->gpr[reg];
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break;
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default:
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return -EINVAL;
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}
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} else {
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temp.ll = data.ll = 0;
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ret = 0;
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p = addr;
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switch (nb) {
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case 8:
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ret |= __get_user_inatomic(temp.v[0], p++);
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ret |= __get_user_inatomic(temp.v[1], p++);
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ret |= __get_user_inatomic(temp.v[2], p++);
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ret |= __get_user_inatomic(temp.v[3], p++);
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/* fall through */
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case 4:
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ret |= __get_user_inatomic(temp.v[4], p++);
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ret |= __get_user_inatomic(temp.v[5], p++);
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/* fall through */
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case 2:
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ret |= __get_user_inatomic(temp.v[6], p++);
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ret |= __get_user_inatomic(temp.v[7], p++);
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if (unlikely(ret))
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return -EFAULT;
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}
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switch (instr) {
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case EVLDD:
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case EVLDW:
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case EVLDH:
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data.ll = temp.ll;
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break;
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case EVLHHESPLAT:
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data.h[0] = temp.h[3];
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data.h[2] = temp.h[3];
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break;
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case EVLHHOUSPLAT:
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case EVLHHOSSPLAT:
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data.h[1] = temp.h[3];
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data.h[3] = temp.h[3];
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break;
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case EVLWHE:
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data.h[0] = temp.h[2];
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data.h[2] = temp.h[3];
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break;
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case EVLWHOU:
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case EVLWHOS:
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data.h[1] = temp.h[2];
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data.h[3] = temp.h[3];
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break;
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case EVLWWSPLAT:
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data.w[0] = temp.w[1];
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data.w[1] = temp.w[1];
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break;
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case EVLWHSPLAT:
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data.h[0] = temp.h[2];
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data.h[1] = temp.h[2];
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data.h[2] = temp.h[3];
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data.h[3] = temp.h[3];
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break;
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default:
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return -EINVAL;
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}
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}
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if (flags & SW) {
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switch (flags & 0xf0) {
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case E8:
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data.ll = swab64(data.ll);
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break;
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case E4:
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data.w[0] = swab32(data.w[0]);
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data.w[1] = swab32(data.w[1]);
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break;
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/* Its half word endian */
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default:
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data.h[0] = swab16(data.h[0]);
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data.h[1] = swab16(data.h[1]);
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data.h[2] = swab16(data.h[2]);
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data.h[3] = swab16(data.h[3]);
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break;
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}
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}
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if (flags & SE) {
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data.w[0] = (s16)data.h[1];
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data.w[1] = (s16)data.h[3];
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}
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/* Store result to memory or update registers */
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if (flags & ST) {
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ret = 0;
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p = addr;
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switch (nb) {
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case 8:
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ret |= __put_user_inatomic(data.v[0], p++);
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ret |= __put_user_inatomic(data.v[1], p++);
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ret |= __put_user_inatomic(data.v[2], p++);
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ret |= __put_user_inatomic(data.v[3], p++);
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/* fall through */
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case 4:
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ret |= __put_user_inatomic(data.v[4], p++);
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ret |= __put_user_inatomic(data.v[5], p++);
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/* fall through */
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case 2:
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ret |= __put_user_inatomic(data.v[6], p++);
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ret |= __put_user_inatomic(data.v[7], p++);
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}
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if (unlikely(ret))
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return -EFAULT;
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} else {
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*evr = data.w[0];
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regs->gpr[reg] = data.w[1];
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}
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return 1;
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}
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#endif /* CONFIG_SPE */
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/*
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* Called on alignment exception. Attempts to fixup
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*
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* Return 1 on success
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* Return 0 if unable to handle the interrupt
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* Return -EFAULT if data address is bad
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* Other negative return values indicate that the instruction can't
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* be emulated, and the process should be given a SIGBUS.
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*/
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int fix_alignment(struct pt_regs *regs)
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{
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unsigned int instr;
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struct instruction_op op;
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int r, type;
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/*
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* We require a complete register set, if not, then our assembly
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* is broken
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*/
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CHECK_FULL_REGS(regs);
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if (unlikely(__get_user(instr, (unsigned int __user *)regs->nip)))
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return -EFAULT;
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if ((regs->msr & MSR_LE) != (MSR_KERNEL & MSR_LE)) {
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/* We don't handle PPC little-endian any more... */
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if (cpu_has_feature(CPU_FTR_PPC_LE))
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return -EIO;
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instr = swab32(instr);
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}
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#ifdef CONFIG_SPE
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if ((instr >> 26) == 0x4) {
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int reg = (instr >> 21) & 0x1f;
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PPC_WARN_ALIGNMENT(spe, regs);
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return emulate_spe(regs, reg, instr);
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}
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#endif
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/*
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* ISA 3.0 (such as P9) copy, copy_first, paste and paste_last alignment
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* check.
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*
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* Send a SIGBUS to the process that caused the fault.
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*
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* We do not emulate these because paste may contain additional metadata
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* when pasting to a co-processor. Furthermore, paste_last is the
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* synchronisation point for preceding copy/paste sequences.
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*/
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if ((instr & 0xfc0006fe) == (PPC_INST_COPY & 0xfc0006fe))
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return -EIO;
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r = analyse_instr(&op, regs, instr);
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if (r < 0)
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return -EINVAL;
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type = GETTYPE(op.type);
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if (!OP_IS_LOAD_STORE(type)) {
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if (op.type != CACHEOP + DCBZ)
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return -EINVAL;
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PPC_WARN_ALIGNMENT(dcbz, regs);
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r = emulate_dcbz(op.ea, regs);
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} else {
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if (type == LARX || type == STCX)
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return -EIO;
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PPC_WARN_ALIGNMENT(unaligned, regs);
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r = emulate_loadstore(regs, &op);
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}
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if (!r)
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return 1;
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return r;
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}
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