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-rw-r--r--arch/ppc/kernel/align.c398
1 files changed, 398 insertions, 0 deletions
diff --git a/arch/ppc/kernel/align.c b/arch/ppc/kernel/align.c
new file mode 100644
index 00000000000..79c92947503
--- /dev/null
+++ b/arch/ppc/kernel/align.c
@@ -0,0 +1,398 @@
+/*
+ * 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.
+ */
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <asm/ptrace.h>
+#include <asm/processor.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <asm/cache.h>
+
+struct aligninfo {
+ unsigned char len;
+ unsigned char flags;
+};
+
+#if defined(CONFIG_4xx) || defined(CONFIG_POWER4) || defined(CONFIG_BOOKE)
+#define OPCD(inst) (((inst) & 0xFC000000) >> 26)
+#define RS(inst) (((inst) & 0x03E00000) >> 21)
+#define RA(inst) (((inst) & 0x001F0000) >> 16)
+#define IS_XFORM(code) ((code) == 31)
+#endif
+
+#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 S 0x40 /* single-precision fp, or byte-swap value */
+#define SX 0x40 /* byte count in XER */
+#define HARD 0x80 /* string, stwcx. */
+
+#define DCBZ 0x5f /* 8xx/82xx dcbz faults when cache not enabled */
+
+/*
+ * 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 */
+ INVALID, /* 00 0 1101: ld/ldu/lwa */
+ INVALID, /* 00 0 1110 */
+ INVALID, /* 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 */
+ INVALID, /* 01 0 0000: ldx */
+ INVALID, /* 01 0 0001 */
+ INVALID, /* 01 0 0010: stdx */
+ INVALID, /* 01 0 0011 */
+ INVALID, /* 01 0 0100 */
+ INVALID, /* 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 */
+ INVALID, /* 01 0 1101 */
+ INVALID, /* 01 0 1110 */
+ INVALID, /* 01 0 1111 */
+ INVALID, /* 01 1 0000: ldux */
+ INVALID, /* 01 1 0001 */
+ INVALID, /* 01 1 0010: stdux */
+ INVALID, /* 01 1 0011 */
+ INVALID, /* 01 1 0100 */
+ INVALID, /* 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 */
+ { 0, ST+HARD }, /* 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+S }, /* 10 0 1000: lwbrx */
+ INVALID, /* 10 0 1001 */
+ { 4, ST+S }, /* 10 0 1010: stwbrx */
+ INVALID, /* 10 0 1011 */
+ { 2, LD+S }, /* 10 0 1100: lhbrx */
+ INVALID, /* 10 0 1101 */
+ { 2, ST+S }, /* 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 */
+ INVALID, /* 11 0 1101: lmd */
+ INVALID, /* 11 0 1110 */
+ INVALID, /* 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 */
+};
+
+#define SWAP(a, b) (t = (a), (a) = (b), (b) = t)
+
+int
+fix_alignment(struct pt_regs *regs)
+{
+ int instr, nb, flags;
+#if defined(CONFIG_4xx) || defined(CONFIG_POWER4) || defined(CONFIG_BOOKE)
+ int opcode, f1, f2, f3;
+#endif
+ int i, t;
+ int reg, areg;
+ int offset, nb0;
+ unsigned char __user *addr;
+ unsigned char *rptr;
+ union {
+ long l;
+ float f;
+ double d;
+ unsigned char v[8];
+ } data;
+
+ CHECK_FULL_REGS(regs);
+
+#if defined(CONFIG_4xx) || defined(CONFIG_POWER4) || defined(CONFIG_BOOKE)
+ /* The 4xx-family & Book-E processors have no DSISR register,
+ * so we emulate it.
+ * The POWER4 has a DSISR register but doesn't set it on
+ * an alignment fault. -- paulus
+ */
+
+ if (__get_user(instr, (unsigned int __user *) regs->nip))
+ return 0;
+ opcode = OPCD(instr);
+ reg = RS(instr);
+ areg = RA(instr);
+
+ if (!IS_XFORM(opcode)) {
+ f1 = 0;
+ f2 = (instr & 0x04000000) >> 26;
+ f3 = (instr & 0x78000000) >> 27;
+ } else {
+ f1 = (instr & 0x00000006) >> 1;
+ f2 = (instr & 0x00000040) >> 6;
+ f3 = (instr & 0x00000780) >> 7;
+ }
+
+ instr = ((f1 << 5) | (f2 << 4) | f3);
+#else
+ reg = (regs->dsisr >> 5) & 0x1f; /* source/dest register */
+ areg = regs->dsisr & 0x1f; /* register to update */
+ instr = (regs->dsisr >> 10) & 0x7f;
+#endif
+
+ nb = aligninfo[instr].len;
+ if (nb == 0) {
+ long __user *p;
+ int i;
+
+ if (instr != DCBZ)
+ return 0; /* too hard or invalid instruction */
+ /*
+ * 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.
+ */
+ p = (long __user *) (regs->dar & -L1_CACHE_BYTES);
+ if (user_mode(regs)
+ && !access_ok(VERIFY_WRITE, p, L1_CACHE_BYTES))
+ return -EFAULT;
+ for (i = 0; i < L1_CACHE_BYTES / sizeof(long); ++i)
+ if (__put_user(0, p+i))
+ return -EFAULT;
+ return 1;
+ }
+
+ flags = aligninfo[instr].flags;
+ if ((flags & (LD|ST)) == 0)
+ return 0;
+
+ /* For the 4xx-family & Book-E processors, the 'dar' field of the
+ * pt_regs structure is overloaded and is really from the DEAR.
+ */
+
+ addr = (unsigned char __user *)regs->dar;
+
+ if (flags & M) {
+ /* 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 0;
+ 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;
+ }
+ rptr = (unsigned char *) &regs->gpr[reg];
+ if (flags & LD) {
+ for (i = 0; i < nb; ++i)
+ if (__get_user(rptr[i], addr+i))
+ return -EFAULT;
+ if (nb0 > 0) {
+ rptr = (unsigned char *) &regs->gpr[0];
+ addr += nb;
+ for (i = 0; i < nb0; ++i)
+ if (__get_user(rptr[i], addr+i))
+ return -EFAULT;
+ }
+ for (; (i & 3) != 0; ++i)
+ rptr[i] = 0;
+ } else {
+ for (i = 0; i < nb; ++i)
+ if (__put_user(rptr[i], addr+i))
+ return -EFAULT;
+ if (nb0 > 0) {
+ rptr = (unsigned char *) &regs->gpr[0];
+ addr += nb;
+ for (i = 0; i < nb0; ++i)
+ if (__put_user(rptr[i], addr+i))
+ return -EFAULT;
+ }
+ }
+ return 1;
+ }
+
+ offset = 0;
+ if (nb < 4) {
+ /* read/write the least significant bits */
+ data.l = 0;
+ offset = 4 - nb;
+ }
+
+ /* Verify the address of the operand */
+ if (user_mode(regs)) {
+ if (!access_ok((flags & ST? VERIFY_WRITE: VERIFY_READ), addr, nb))
+ return -EFAULT; /* bad address */
+ }
+
+ if (flags & F) {
+ preempt_disable();
+ if (regs->msr & MSR_FP)
+ giveup_fpu(current);
+ preempt_enable();
+ }
+
+ /* If we read the operand, copy it in, else get register values */
+ if (flags & LD) {
+ for (i = 0; i < nb; ++i)
+ if (__get_user(data.v[offset+i], addr+i))
+ return -EFAULT;
+ } else if (flags & F) {
+ data.d = current->thread.fpr[reg];
+ } else {
+ data.l = regs->gpr[reg];
+ }
+
+ switch (flags & ~U) {
+ case LD+SE: /* sign extend */
+ if (data.v[2] >= 0x80)
+ data.v[0] = data.v[1] = -1;
+ break;
+
+ case LD+S: /* byte-swap */
+ case ST+S:
+ if (nb == 2) {
+ SWAP(data.v[2], data.v[3]);
+ } else {
+ SWAP(data.v[0], data.v[3]);
+ SWAP(data.v[1], data.v[2]);
+ }
+ break;
+
+ /* Single-precision FP load and store require conversions... */
+ case LD+F+S:
+ preempt_disable();
+ enable_kernel_fp();
+ cvt_fd(&data.f, &data.d, &current->thread.fpscr);
+ preempt_enable();
+ break;
+ case ST+F+S:
+ preempt_disable();
+ enable_kernel_fp();
+ cvt_df(&data.d, &data.f, &current->thread.fpscr);
+ preempt_enable();
+ break;
+ }
+
+ if (flags & ST) {
+ for (i = 0; i < nb; ++i)
+ if (__put_user(data.v[offset+i], addr+i))
+ return -EFAULT;
+ } else if (flags & F) {
+ current->thread.fpr[reg] = data.d;
+ } else {
+ regs->gpr[reg] = data.l;
+ }
+
+ if (flags & U)
+ regs->gpr[areg] = regs->dar;
+
+ return 1;
+}
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