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-rw-r--r--arch/powerpc/kernel/align.c530
1 files changed, 530 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c
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+++ b/arch/powerpc/kernel/align.c
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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/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 = &regs->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(&regs->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 = &regs->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 = &regs->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, &current->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], &current->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;
+}
generated by cgit v0.10.2 at 2024-11-12 10:13:05 (GMT)