diff options
Diffstat (limited to 'arch/powerpc/kernel/align.c')
-rw-r--r-- | arch/powerpc/kernel/align.c | 364 |
1 files changed, 364 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c new file mode 100644 index 000000000..3e37ece06 --- /dev/null +++ b/arch/powerpc/kernel/align.c @@ -0,0 +1,364 @@ +// 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> +#include <asm/inst.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, + ppc_inst_t ppc_instr) +{ + union { + u64 ll; + u32 w[2]; + u16 h[4]; + u8 v[8]; + } data, temp; + unsigned char __user *p, *addr; + unsigned long *evr = ¤t->thread.evr[reg]; + unsigned int nb, flags, instr; + + instr = ppc_inst_val(ppc_instr); + 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; + + /* 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; + p = addr; + + if (!user_read_access_begin(addr, nb)) + return -EFAULT; + + switch (nb) { + case 8: + unsafe_get_user(temp.v[0], p++, Efault_read); + unsafe_get_user(temp.v[1], p++, Efault_read); + unsafe_get_user(temp.v[2], p++, Efault_read); + unsafe_get_user(temp.v[3], p++, Efault_read); + fallthrough; + case 4: + unsafe_get_user(temp.v[4], p++, Efault_read); + unsafe_get_user(temp.v[5], p++, Efault_read); + fallthrough; + case 2: + unsafe_get_user(temp.v[6], p++, Efault_read); + unsafe_get_user(temp.v[7], p++, Efault_read); + } + user_read_access_end(); + + 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) { + p = addr; + + if (!user_write_access_begin(addr, nb)) + return -EFAULT; + + switch (nb) { + case 8: + unsafe_put_user(data.v[0], p++, Efault_write); + unsafe_put_user(data.v[1], p++, Efault_write); + unsafe_put_user(data.v[2], p++, Efault_write); + unsafe_put_user(data.v[3], p++, Efault_write); + fallthrough; + case 4: + unsafe_put_user(data.v[4], p++, Efault_write); + unsafe_put_user(data.v[5], p++, Efault_write); + fallthrough; + case 2: + unsafe_put_user(data.v[6], p++, Efault_write); + unsafe_put_user(data.v[7], p++, Efault_write); + } + user_write_access_end(); + } else { + *evr = data.w[0]; + regs->gpr[reg] = data.w[1]; + } + + return 1; + +Efault_read: + user_read_access_end(); + return -EFAULT; + +Efault_write: + user_write_access_end(); + return -EFAULT; +} +#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) +{ + ppc_inst_t instr; + struct instruction_op op; + int r, type; + + if (is_kernel_addr(regs->nip)) + r = copy_inst_from_kernel_nofault(&instr, (void *)regs->nip); + else + r = __get_user_instr(instr, (void __user *)regs->nip); + + if (unlikely(r)) + 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 = ppc_inst_swab(instr); + } + +#ifdef CONFIG_SPE + if (ppc_inst_primary_opcode(instr) == 0x4) { + int reg = (ppc_inst_val(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 ((ppc_inst_val(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); + WARN_ON_ONCE(!user_mode(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; +} |