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author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2005-11-18 14:09:41 +1100 |
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committer | Paul Mackerras <paulus@samba.org> | 2005-11-18 14:39:23 +1100 |
commit | 5daf9071b527089b1bd5d9cb3a5354b83121550e (patch) | |
tree | 3abf10c1f67975f3a7d0def22de261f395c325f1 /arch/powerpc/kernel/align.c | |
parent | 6defa38b3754c84cd3449447477aed81ea979407 (diff) | |
download | linux-5daf9071b527089b1bd5d9cb3a5354b83121550e.tar.gz linux-5daf9071b527089b1bd5d9cb3a5354b83121550e.tar.bz2 linux-5daf9071b527089b1bd5d9cb3a5354b83121550e.zip |
[PATCH] powerpc: merge align.c
This patch merges align.c, the result isn't quite what was in ppc64 nor
what was in ppc32 :) It should implement all the functionalities of both
though. Kumar, since you played with that in the past, I suppose you
have some test cases for verifying that it works properly before I dig
out the 601 machine ? :)
Since it's likely that I won't be able to test all scenario, code
inspection is much welcome.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel/align.c')
-rw-r--r-- | arch/powerpc/kernel/align.c | 530 |
1 files changed, 530 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c new file mode 100644 index 000000000000..faaec9c6f78f --- /dev/null +++ b/arch/powerpc/kernel/align.c @@ -0,0 +1,530 @@ +/* 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/system.h> +#include <asm/cache.h> +#include <asm/cputable.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 } + +#define LD 1 /* load */ +#define ST 2 /* store */ +#define SE 4 /* sign-extend value */ +#define F 8 /* to/from fp regs */ +#define U 0x10 /* update index register */ +#define M 0x20 /* multiple load/store */ +#define SW 0x40 /* byte swap int or ... */ +#define S 0x40 /* ... single-precision fp */ +#define SX 0x40 /* byte count in XER */ +#define HARD 0x80 /* string, stwcx. */ + +#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 */ + INVALID, /* 00 1 1100 */ + INVALID, /* 00 1 1101 */ + INVALID, /* 00 1 1110 */ + 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 */ + INVALID, /* 11 0 1100 */ + { 8, LD+M }, /* 11 0 1101: lmd */ + INVALID, /* 11 0 1110 */ + { 8, ST+M }, /* 11 0 1111: stmd */ + { 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 */ + INVALID, /* 11 1 1101 */ + 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(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 + +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 *rptr; + unsigned int nb0, i; + + /* + * 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 { + if (__get_user(instr, + (unsigned int __user *)regs->nip)) + return -EFAULT; + 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 = ®s->gpr[reg]; + if (flags & LD) { + /* + * 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(®s->gpr[0], 0, + ((nb0 + 3) / 4) * sizeof(unsigned long)); + + for (i = 0; i < nb; ++i) + if (__get_user(REG_BYTE(rptr, i), addr + i)) + return -EFAULT; + if (nb0 > 0) { + rptr = ®s->gpr[0]; + addr += nb; + for (i = 0; i < nb0; ++i) + if (__get_user(REG_BYTE(rptr, i), addr + i)) + return -EFAULT; + } + + } else { + for (i = 0; i < nb; ++i) + if (__put_user(REG_BYTE(rptr, i), addr + i)) + return -EFAULT; + if (nb0 > 0) { + rptr = ®s->gpr[0]; + addr += nb; + for (i = 0; i < nb0; ++i) + if (__put_user(REG_BYTE(rptr, i), addr + i)) + return -EFAULT; + } + } + return 1; +} + + +/* + * 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; + unsigned int reg, areg; + unsigned int dsisr; + unsigned char __user *addr; + unsigned char __user *p; + 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 int real_instr; + if (unlikely(__get_user(real_instr, + (unsigned int __user *)regs->nip))) + return -EFAULT; + dsisr = make_dsisr(real_instr); + } + + /* extract the operation and registers from the dsisr */ + reg = (dsisr >> 5) & 0x1f; /* source/dest register */ + areg = dsisr & 0x1f; /* register to update */ + instr = (dsisr >> 10) & 0x7f; + instr |= (dsisr >> 13) & 0x60; + + /* Lookup the operation in our table */ + nb = aligninfo[instr].len; + flags = aligninfo[instr].flags; + + /* DAR has the operand effective address */ + addr = (unsigned char __user *)regs->dar; + + /* 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) + return emulate_dcbz(regs, addr); + if (unlikely(nb == 0)) + return 0; + + /* Load/Store Multiple instructions are handled in their own + * function + */ + if (flags & M) + return emulate_multiple(regs, addr, reg, nb, flags, instr); + + /* 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); + } + + /* If we are loading, get the data from user space, else + * get it from register values + */ + if (flags & LD) { + data.ll = 0; + ret = 0; + p = addr; + switch (nb) { + case 8: + ret |= __get_user(data.v[0], p++); + ret |= __get_user(data.v[1], p++); + ret |= __get_user(data.v[2], p++); + ret |= __get_user(data.v[3], p++); + case 4: + ret |= __get_user(data.v[4], p++); + ret |= __get_user(data.v[5], p++); + case 2: + ret |= __get_user(data.v[6], p++); + ret |= __get_user(data.v[7], p++); + if (unlikely(ret)) + return -EFAULT; + } + } else if (flags & F) + data.dd = current->thread.fpr[reg]; + else + data.ll = regs->gpr[reg]; + + /* Perform other misc operations like sign extension, byteswap, + * or floating point single precision conversion + */ + switch (flags & ~U) { + case LD+SE: /* sign extend */ + if ( nb == 2 ) + data.ll = data.x16.low16; + else /* nb must be 4 */ + data.ll = data.x32.low32; + break; + case LD+S: /* byte-swap */ + case ST+S: + if (nb == 2) { + SWAP(data.v[6], data.v[7]); + } else { + SWAP(data.v[4], data.v[7]); + SWAP(data.v[5], data.v[6]); + } + break; + + /* Single-precision FP load and store require conversions... */ + case LD+F+S: +#ifdef CONFIG_PPC_FPU + preempt_disable(); + enable_kernel_fp(); + cvt_fd((float *)&data.v[4], &data.dd, ¤t->thread); + preempt_enable(); +#else + return 0; +#endif + break; + case ST+F+S: +#ifdef CONFIG_PPC_FPU + preempt_disable(); + enable_kernel_fp(); + cvt_df(&data.dd, (float *)&data.v[4], ¤t->thread); + preempt_enable(); +#else + return 0; +#endif + break; + } + + /* Store result to memory or update registers */ + if (flags & ST) { + ret = 0; + p = addr; + switch (nb) { + case 8: + ret |= __put_user(data.v[0], p++); + ret |= __put_user(data.v[1], p++); + ret |= __put_user(data.v[2], p++); + ret |= __put_user(data.v[3], p++); + case 4: + ret |= __put_user(data.v[4], p++); + ret |= __put_user(data.v[5], p++); + case 2: + ret |= __put_user(data.v[6], p++); + ret |= __put_user(data.v[7], p++); + } + if (unlikely(ret)) + return -EFAULT; + } else if (flags & F) + current->thread.fpr[reg] = data.dd; + else + regs->gpr[reg] = data.ll; + + /* Update RA as needed */ + if (flags & U) + regs->gpr[areg] = regs->dar; + + return 1; +} |