1 files changed, 756 insertions, 0 deletions

diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c
new file mode 100644
index 000000000000..81f4a8a2d34b
--- /dev/null
+++ b/arch/arm/mm/alignment.c
@@ -0,0 +1,756 @@
+/*
+ *  linux/arch/arm/mm/alignment.c
+ *
+ *  Copyright (C) 1995  Linus Torvalds
+ *  Modifications for ARM processor (c) 1995-2001 Russell King
+ *  Thumb aligment fault fixups (c) 2004 MontaVista Software, Inc.
+ *  - Adapted from gdb/sim/arm/thumbemu.c -- Thumb instruction emulation.
+ *    Copyright (C) 1996, Cygnus Software Technologies Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/config.h>
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/ptrace.h>
+#include <linux/proc_fs.h>
+#include <linux/init.h>
+
+#include <asm/uaccess.h>
+#include <asm/unaligned.h>
+
+#include "fault.h"
+
+/*
+ * 32-bit misaligned trap handler (c) 1998 San Mehat (CCC) -July 1998
+ * /proc/sys/debug/alignment, modified and integrated into
+ * Linux 2.1 by Russell King
+ *
+ * Speed optimisations and better fault handling by Russell King.
+ *
+ * *** NOTE ***
+ * This code is not portable to processors with late data abort handling.
+ */
+#define CODING_BITS(i)  (i & 0x0e000000)
+
+#define LDST_I_BIT(i)   (i & (1 << 26))         /* Immediate constant   */
+#define LDST_P_BIT(i)   (i & (1 << 24))         /* Preindex             */
+#define LDST_U_BIT(i)   (i & (1 << 23))         /* Add offset           */
+#define LDST_W_BIT(i)   (i & (1 << 21))         /* Writeback            */
+#define LDST_L_BIT(i)   (i & (1 << 20))         /* Load                 */
+
+#define LDST_P_EQ_U(i)  ((((i) ^ ((i) >> 1)) & (1 << 23)) == 0)
+
+#define LDSTH_I_BIT(i)  (i & (1 << 22))         /* half-word immed      */
+#define LDM_S_BIT(i)    (i & (1 << 22))         /* write CPSR from SPSR */
+
+#define RN_BITS(i)      ((i >> 16) & 15)        /* Rn                   */
+#define RD_BITS(i)      ((i >> 12) & 15)        /* Rd                   */
+#define RM_BITS(i)      (i & 15)                /* Rm                   */
+
+#define REGMASK_BITS(i) (i & 0xffff)
+#define OFFSET_BITS(i)  (i & 0x0fff)
+
+#define IS_SHIFT(i)     (i & 0x0ff0)
+#define SHIFT_BITS(i)   ((i >> 7) & 0x1f)
+#define SHIFT_TYPE(i)   (i & 0x60)
+#define SHIFT_LSL       0x00
+#define SHIFT_LSR       0x20
+#define SHIFT_ASR       0x40
+#define SHIFT_RORRRX    0x60
+
+static unsigned long ai_user;
+static unsigned long ai_sys;
+static unsigned long ai_skipped;
+static unsigned long ai_half;
+static unsigned long ai_word;
+static unsigned long ai_multi;
+static int ai_usermode;
+
+#ifdef CONFIG_PROC_FS
+static const char *usermode_action[] = {
+        "ignored",
+        "warn",
+        "fixup",
+        "fixup+warn",
+        "signal",
+        "signal+warn"
+};
+
+static int
+proc_alignment_read(char *page, char **start, off_t off, int count, int *eof,
+                    void *data)
+{
+        char *p = page;
+        int len;
+
+        p += sprintf(p, "User:\t\t%lu\n", ai_user);
+        p += sprintf(p, "System:\t\t%lu\n", ai_sys);
+        p += sprintf(p, "Skipped:\t%lu\n", ai_skipped);
+        p += sprintf(p, "Half:\t\t%lu\n", ai_half);
+        p += sprintf(p, "Word:\t\t%lu\n", ai_word);
+        p += sprintf(p, "Multi:\t\t%lu\n", ai_multi);
+        p += sprintf(p, "User faults:\t%i (%s)\n", ai_usermode,
+                        usermode_action[ai_usermode]);
+
+        len = (p - page) - off;
+        if (len < 0)
+                len = 0;
+
+        *eof = (len <= count) ? 1 : 0;
+        *start = page + off;
+
+        return len;
+}
+
+static int proc_alignment_write(struct file *file, const char __user *buffer,
+                               unsigned long count, void *data)
+{
+        char mode;
+
+        if (count > 0) {
+                if (get_user(mode, buffer))
+                        return -EFAULT;
+                if (mode >= '0' && mode <= '5')
+                           ai_usermode = mode - '0';
+        }
+        return count;
+}
+
+#endif /* CONFIG_PROC_FS */
+
+union offset_union {
+        unsigned long un;
+          signed long sn;
+};
+
+#define TYPE_ERROR      0
+#define TYPE_FAULT      1
+#define TYPE_LDST       2
+#define TYPE_DONE       3
+
+#ifdef __ARMEB__
+#define BE              1
+#define FIRST_BYTE_16   "mov    %1, %1, ror #8\n"
+#define FIRST_BYTE_32   "mov    %1, %1, ror #24\n"
+#define NEXT_BYTE       "ror #24"
+#else
+#define BE              0
+#define FIRST_BYTE_16
+#define FIRST_BYTE_32
+#define NEXT_BYTE       "lsr #8"
+#endif
+
+#define __get8_unaligned_check(ins,val,addr,err)        \
+        __asm__(                                        \
+        "1:     "ins"   %1, [%2], #1\n"                 \
+        "2:\n"                                          \
+        "       .section .fixup,\"ax\"\n"               \
+        "       .align  2\n"                            \
+        "3:     mov     %0, #1\n"                       \
+        "       b       2b\n"                           \
+        "       .previous\n"                            \
+        "       .section __ex_table,\"a\"\n"            \
+        "       .align  3\n"                            \
+        "       .long   1b, 3b\n"                       \
+        "       .previous\n"                            \
+        : "=r" (err), "=&r" (val), "=r" (addr)          \
+        : "0" (err), "2" (addr))
+
+#define __get16_unaligned_check(ins,val,addr)                   \
+        do {                                                    \
+                unsigned int err = 0, v, a = addr;              \
+                __get8_unaligned_check(ins,v,a,err);            \
+                val =  v << ((BE) ? 8 : 0);                     \
+                __get8_unaligned_check(ins,v,a,err);            \
+                val |= v << ((BE) ? 0 : 8);                     \
+                if (err)                                        \
+                        goto fault;                             \
+        } while (0)
+
+#define get16_unaligned_check(val,addr) \
+        __get16_unaligned_check("ldrb",val,addr)
+
+#define get16t_unaligned_check(val,addr) \
+        __get16_unaligned_check("ldrbt",val,addr)
+
+#define __get32_unaligned_check(ins,val,addr)                   \
+        do {                                                    \
+                unsigned int err = 0, v, a = addr;              \
+                __get8_unaligned_check(ins,v,a,err);            \
+                val =  v << ((BE) ? 24 :  0);                   \
+                __get8_unaligned_check(ins,v,a,err);            \
+                val |= v << ((BE) ? 16 :  8);                   \
+                __get8_unaligned_check(ins,v,a,err);            \
+                val |= v << ((BE) ?  8 : 16);                   \
+                __get8_unaligned_check(ins,v,a,err);            \
+                val |= v << ((BE) ?  0 : 24);                   \
+                if (err)                                        \
+                        goto fault;                             \
+        } while (0)
+
+#define get32_unaligned_check(val,addr) \
+        __get32_unaligned_check("ldrb",val,addr)
+
+#define get32t_unaligned_check(val,addr) \
+        __get32_unaligned_check("ldrbt",val,addr)
+
+#define __put16_unaligned_check(ins,val,addr)                   \
+        do {                                                    \
+                unsigned int err = 0, v = val, a = addr;        \
+                __asm__( FIRST_BYTE_16                          \
+                "1:     "ins"   %1, [%2], #1\n"                 \
+                "       mov     %1, %1, "NEXT_BYTE"\n"          \
+                "2:     "ins"   %1, [%2]\n"                     \
+                "3:\n"                                          \
+                "       .section .fixup,\"ax\"\n"               \
+                "       .align  2\n"                            \
+                "4:     mov     %0, #1\n"                       \
+                "       b       3b\n"                           \
+                "       .previous\n"                            \
+                "       .section __ex_table,\"a\"\n"            \
+                "       .align  3\n"                            \
+                "       .long   1b, 4b\n"                       \
+                "       .long   2b, 4b\n"                       \
+                "       .previous\n"                            \
+                : "=r" (err), "=&r" (v), "=&r" (a)              \
+                : "0" (err), "1" (v), "2" (a));                 \
+                if (err)                                        \
+                        goto fault;                             \
+        } while (0)
+
+#define put16_unaligned_check(val,addr)  \
+        __put16_unaligned_check("strb",val,addr)
+
+#define put16t_unaligned_check(val,addr) \
+        __put16_unaligned_check("strbt",val,addr)
+
+#define __put32_unaligned_check(ins,val,addr)                   \
+        do {                                                    \
+                unsigned int err = 0, v = val, a = addr;        \
+                __asm__( FIRST_BYTE_32                          \
+                "1:     "ins"   %1, [%2], #1\n"                 \
+                "       mov     %1, %1, "NEXT_BYTE"\n"          \
+                "2:     "ins"   %1, [%2], #1\n"                 \
+                "       mov     %1, %1, "NEXT_BYTE"\n"          \
+                "3:     "ins"   %1, [%2], #1\n"                 \
+                "       mov     %1, %1, "NEXT_BYTE"\n"          \
+                "4:     "ins"   %1, [%2]\n"                     \
+                "5:\n"                                          \
+                "       .section .fixup,\"ax\"\n"               \
+                "       .align  2\n"                            \
+                "6:     mov     %0, #1\n"                       \
+                "       b       5b\n"                           \
+                "       .previous\n"                            \
+                "       .section __ex_table,\"a\"\n"            \
+                "       .align  3\n"                            \
+                "       .long   1b, 6b\n"                       \
+                "       .long   2b, 6b\n"                       \
+                "       .long   3b, 6b\n"                       \
+                "       .long   4b, 6b\n"                       \
+                "       .previous\n"                            \
+                : "=r" (err), "=&r" (v), "=&r" (a)              \
+                : "0" (err), "1" (v), "2" (a));                 \
+                if (err)                                        \
+                        goto fault;                             \
+        } while (0)
+
+#define put32_unaligned_check(val,addr)  \
+        __put32_unaligned_check("strb", val, addr)
+
+#define put32t_unaligned_check(val,addr) \
+        __put32_unaligned_check("strbt", val, addr)
+
+static void
+do_alignment_finish_ldst(unsigned long addr, unsigned long instr, struct pt_regs *regs, union offset_union offset)
+{
+        if (!LDST_U_BIT(instr))
+                offset.un = -offset.un;
+
+        if (!LDST_P_BIT(instr))
+                addr += offset.un;
+
+        if (!LDST_P_BIT(instr) || LDST_W_BIT(instr))
+                regs->uregs[RN_BITS(instr)] = addr;
+}
+
+static int
+do_alignment_ldrhstrh(unsigned long addr, unsigned long instr, struct pt_regs *regs)
+{
+        unsigned int rd = RD_BITS(instr);
+
+        if ((instr & 0x01f00ff0) == 0x01000090)
+                goto swp;
+
+        if ((instr & 0x90) != 0x90 || (instr & 0x60) == 0)
+                goto bad;
+
+        ai_half += 1;
+
+        if (user_mode(regs))
+                goto user;
+
+        if (LDST_L_BIT(instr)) {
+                unsigned long val;
+                get16_unaligned_check(val, addr);
+
+                /* signed half-word? */
+                if (instr & 0x40)
+                        val = (signed long)((signed short) val);
+
+                regs->uregs[rd] = val;
+        } else
+                put16_unaligned_check(regs->uregs[rd], addr);
+
+        return TYPE_LDST;
+
+ user:
+        if (LDST_L_BIT(instr)) {
+                unsigned long val;
+                get16t_unaligned_check(val, addr);
+
+                /* signed half-word? */
+                if (instr & 0x40)
+                        val = (signed long)((signed short) val);
+
+                regs->uregs[rd] = val;
+        } else
+                put16t_unaligned_check(regs->uregs[rd], addr);
+
+        return TYPE_LDST;
+
+ swp:
+        printk(KERN_ERR "Alignment trap: not handling swp instruction\n");
+ bad:
+        return TYPE_ERROR;
+
+ fault:
+        return TYPE_FAULT;
+}
+
+static int
+do_alignment_ldrstr(unsigned long addr, unsigned long instr, struct pt_regs *regs)
+{
+        unsigned int rd = RD_BITS(instr);
+
+        ai_word += 1;
+
+        if ((!LDST_P_BIT(instr) && LDST_W_BIT(instr)) || user_mode(regs))
+                goto trans;
+
+        if (LDST_L_BIT(instr)) {
+                unsigned int val;
+                get32_unaligned_check(val, addr);
+                regs->uregs[rd] = val;
+        } else
+                put32_unaligned_check(regs->uregs[rd], addr);
+        return TYPE_LDST;
+
+ trans:
+        if (LDST_L_BIT(instr)) {
+                unsigned int val;
+                get32t_unaligned_check(val, addr);
+                regs->uregs[rd] = val;
+        } else
+                put32t_unaligned_check(regs->uregs[rd], addr);
+        return TYPE_LDST;
+
+ fault:
+        return TYPE_FAULT;
+}
+
+/*
+ * LDM/STM alignment handler.
+ *
+ * There are 4 variants of this instruction:
+ *
+ * B = rn pointer before instruction, A = rn pointer after instruction
+ *              ------ increasing address ----->
+ *              |    | r0 | r1 | ... | rx |    |
+ * PU = 01             B                    A
+ * PU = 11        B                    A
+ * PU = 00        A                    B
+ * PU = 10             A                    B
+ */
+static int
+do_alignment_ldmstm(unsigned long addr, unsigned long instr, struct pt_regs *regs)
+{
+        unsigned int rd, rn, correction, nr_regs, regbits;
+        unsigned long eaddr, newaddr;
+
+        if (LDM_S_BIT(instr))
+                goto bad;
+
+        correction = 4; /* processor implementation defined */
+        regs->ARM_pc += correction;
+
+        ai_multi += 1;
+
+        /* count the number of registers in the mask to be transferred */
+        nr_regs = hweight16(REGMASK_BITS(instr)) * 4;
+
+        rn = RN_BITS(instr);
+        newaddr = eaddr = regs->uregs[rn];
+
+        if (!LDST_U_BIT(instr))
+                nr_regs = -nr_regs;
+        newaddr += nr_regs;
+        if (!LDST_U_BIT(instr))
+                eaddr = newaddr;
+
+        if (LDST_P_EQ_U(instr)) /* U = P */
+                eaddr += 4;
+
+        /* 
+         * For alignment faults on the ARM922T/ARM920T the MMU  makes
+         * the FSR (and hence addr) equal to the updated base address
+         * of the multiple access rather than the restored value.
+         * Switch this message off if we've got a ARM92[02], otherwise
+         * [ls]dm alignment faults are noisy!
+         */
+#if !(defined CONFIG_CPU_ARM922T)  && !(defined CONFIG_CPU_ARM920T)
+        /*
+         * This is a "hint" - we already have eaddr worked out by the
+         * processor for us.
+         */
+        if (addr != eaddr) {
+                printk(KERN_ERR "LDMSTM: PC = %08lx, instr = %08lx, "
+                        "addr = %08lx, eaddr = %08lx\n",
+                         instruction_pointer(regs), instr, addr, eaddr);
+                show_regs(regs);
+        }
+#endif
+
+        if (user_mode(regs)) {
+                for (regbits = REGMASK_BITS(instr), rd = 0; regbits;
+                     regbits >>= 1, rd += 1)
+                        if (regbits & 1) {
+                                if (LDST_L_BIT(instr)) {
+                                        unsigned int val;
+                                        get32t_unaligned_check(val, eaddr);
+                                        regs->uregs[rd] = val;
+                                } else
+                                        put32t_unaligned_check(regs->uregs[rd], eaddr);
+                                eaddr += 4;
+                        }
+        } else {
+                for (regbits = REGMASK_BITS(instr), rd = 0; regbits;
+                     regbits >>= 1, rd += 1)
+                        if (regbits & 1) {
+                                if (LDST_L_BIT(instr)) {
+                                        unsigned int val;
+                                        get32_unaligned_check(val, eaddr);
+                                        regs->uregs[rd] = val;
+                                } else
+                                        put32_unaligned_check(regs->uregs[rd], eaddr);
+                                eaddr += 4;
+                        }
+        }
+
+        if (LDST_W_BIT(instr))
+                regs->uregs[rn] = newaddr;
+        if (!LDST_L_BIT(instr) || !(REGMASK_BITS(instr) & (1 << 15)))
+                regs->ARM_pc -= correction;
+        return TYPE_DONE;
+
+fault:
+        regs->ARM_pc -= correction;
+        return TYPE_FAULT;
+
+bad:
+        printk(KERN_ERR "Alignment trap: not handling ldm with s-bit set\n");
+        return TYPE_ERROR;
+}
+
+/*
+ * Convert Thumb ld/st instruction forms to equivalent ARM instructions so
+ * we can reuse ARM userland alignment fault fixups for Thumb.
+ *
+ * This implementation was initially based on the algorithm found in
+ * gdb/sim/arm/thumbemu.c. It is basically just a code reduction of same
+ * to convert only Thumb ld/st instruction forms to equivalent ARM forms.
+ *
+ * NOTES:
+ * 1. Comments below refer to ARM ARM DDI0100E Thumb Instruction sections.
+ * 2. If for some reason we're passed an non-ld/st Thumb instruction to
+ *    decode, we return 0xdeadc0de. This should never happen under normal
+ *    circumstances but if it does, we've got other problems to deal with
+ *    elsewhere and we obviously can't fix those problems here.
+ */
+
+static unsigned long
+thumb2arm(u16 tinstr)
+{
+        u32 L = (tinstr & (1<<11)) >> 11;
+
+        switch ((tinstr & 0xf800) >> 11) {
+        /* 6.5.1 Format 1: */
+        case 0x6000 >> 11:                              /* 7.1.52 STR(1) */
+        case 0x6800 >> 11:                              /* 7.1.26 LDR(1) */
+        case 0x7000 >> 11:                              /* 7.1.55 STRB(1) */
+        case 0x7800 >> 11:                              /* 7.1.30 LDRB(1) */
+                return 0xe5800000 |
+                        ((tinstr & (1<<12)) << (22-12)) |       /* fixup */
+                        (L<<20) |                               /* L==1? */
+                        ((tinstr & (7<<0)) << (12-0)) |         /* Rd */
+                        ((tinstr & (7<<3)) << (16-3)) |         /* Rn */
+                        ((tinstr & (31<<6)) >>                  /* immed_5 */
+                                (6 - ((tinstr & (1<<12)) ? 0 : 2)));
+        case 0x8000 >> 11:                              /* 7.1.57 STRH(1) */
+        case 0x8800 >> 11:                              /* 7.1.32 LDRH(1) */
+                return 0xe1c000b0 |
+                        (L<<20) |                               /* L==1? */
+                        ((tinstr & (7<<0)) << (12-0)) |         /* Rd */
+                        ((tinstr & (7<<3)) << (16-3)) |         /* Rn */
+                        ((tinstr & (7<<6)) >> (6-1)) |   /* immed_5[2:0] */
+                        ((tinstr & (3<<9)) >> (9-8));    /* immed_5[4:3] */
+
+        /* 6.5.1 Format 2: */
+        case 0x5000 >> 11:
+        case 0x5800 >> 11:
+                {
+                        static const u32 subset[8] = {
+                                0xe7800000,             /* 7.1.53 STR(2) */
+                                0xe18000b0,             /* 7.1.58 STRH(2) */
+                                0xe7c00000,             /* 7.1.56 STRB(2) */
+                                0xe19000d0,             /* 7.1.34 LDRSB */
+                                0xe7900000,             /* 7.1.27 LDR(2) */
+                                0xe19000b0,             /* 7.1.33 LDRH(2) */
+                                0xe7d00000,             /* 7.1.31 LDRB(2) */
+                                0xe19000f0              /* 7.1.35 LDRSH */
+                        };
+                        return subset[(tinstr & (7<<9)) >> 9] |
+                            ((tinstr & (7<<0)) << (12-0)) |     /* Rd */
+                            ((tinstr & (7<<3)) << (16-3)) |     /* Rn */
+                            ((tinstr & (7<<6)) >> (6-0));       /* Rm */
+                }
+
+        /* 6.5.1 Format 3: */
+        case 0x4800 >> 11:                              /* 7.1.28 LDR(3) */
+                /* NOTE: This case is not technically possible. We're
+                 *       loading 32-bit memory data via PC relative
+                 *       addressing mode. So we can and should eliminate
+                 *       this case. But I'll leave it here for now.
+                 */
+                return 0xe59f0000 |
+                    ((tinstr & (7<<8)) << (12-8)) |             /* Rd */
+                    ((tinstr & 255) << (2-0));                  /* immed_8 */
+
+        /* 6.5.1 Format 4: */
+        case 0x9000 >> 11:                              /* 7.1.54 STR(3) */
+        case 0x9800 >> 11:                              /* 7.1.29 LDR(4) */
+                return 0xe58d0000 |
+                        (L<<20) |                               /* L==1? */
+                        ((tinstr & (7<<8)) << (12-8)) |         /* Rd */
+                        ((tinstr & 255) << 2);                  /* immed_8 */
+
+        /* 6.6.1 Format 1: */
+        case 0xc000 >> 11:                              /* 7.1.51 STMIA */
+        case 0xc800 >> 11:                              /* 7.1.25 LDMIA */
+                {
+                        u32 Rn = (tinstr & (7<<8)) >> 8;
+                        u32 W = ((L<<Rn) & (tinstr&255)) ? 0 : 1<<21;
+
+                        return 0xe8800000 | W | (L<<20) | (Rn<<16) |
+                                (tinstr&255);
+                }
+
+        /* 6.6.1 Format 2: */
+        case 0xb000 >> 11:                              /* 7.1.48 PUSH */
+        case 0xb800 >> 11:                              /* 7.1.47 POP */
+                if ((tinstr & (3 << 9)) == 0x0400) {
+                        static const u32 subset[4] = {
+                                0xe92d0000,     /* STMDB sp!,{registers} */
+                                0xe92d4000,     /* STMDB sp!,{registers,lr} */
+                                0xe8bd0000,     /* LDMIA sp!,{registers} */
+                                0xe8bd8000      /* LDMIA sp!,{registers,pc} */
+                        };
+                        return subset[(L<<1) | ((tinstr & (1<<8)) >> 8)] |
+                            (tinstr & 255);             /* register_list */
+                }
+                /* Else fall through for illegal instruction case */
+
+        default:
+                return 0xdeadc0de;
+        }
+}
+
+static int
+do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
+{
+        union offset_union offset;
+        unsigned long instr = 0, instrptr;
+        int (*handler)(unsigned long addr, unsigned long instr, struct pt_regs *regs);
+        unsigned int type;
+        mm_segment_t fs;
+        unsigned int fault;
+        u16 tinstr = 0;
+
+        instrptr = instruction_pointer(regs);
+
+        fs = get_fs();
+        set_fs(KERNEL_DS);
+        if thumb_mode(regs) {
+                fault = __get_user(tinstr, (u16 *)(instrptr & ~1));
+                if (!(fault))
+                        instr = thumb2arm(tinstr);
+        } else
+                fault = __get_user(instr, (u32 *)instrptr);
+        set_fs(fs);
+
+        if (fault) {
+                type = TYPE_FAULT;
+                goto bad_or_fault;
+        }
+
+        if (user_mode(regs))
+                goto user;
+
+        ai_sys += 1;
+
+ fixup:
+
+        regs->ARM_pc += thumb_mode(regs) ? 2 : 4;
+
+        switch (CODING_BITS(instr)) {
+        case 0x00000000:        /* ldrh or strh */
+                if (LDSTH_I_BIT(instr))
+                        offset.un = (instr & 0xf00) >> 4 | (instr & 15);
+                else
+                        offset.un = regs->uregs[RM_BITS(instr)];
+                handler = do_alignment_ldrhstrh;
+                break;
+
+        case 0x04000000:        /* ldr or str immediate */
+                offset.un = OFFSET_BITS(instr);
+                handler = do_alignment_ldrstr;
+                break;
+
+        case 0x06000000:        /* ldr or str register */
+                offset.un = regs->uregs[RM_BITS(instr)];
+
+                if (IS_SHIFT(instr)) {
+                        unsigned int shiftval = SHIFT_BITS(instr);
+
+                        switch(SHIFT_TYPE(instr)) {
+                        case SHIFT_LSL:
+                                offset.un <<= shiftval;
+                                break;
+
+                        case SHIFT_LSR:
+                                offset.un >>= shiftval;
+                                break;
+
+                        case SHIFT_ASR:
+                                offset.sn >>= shiftval;
+                                break;
+
+                        case SHIFT_RORRRX:
+                                if (shiftval == 0) {
+                                        offset.un >>= 1;
+                                        if (regs->ARM_cpsr & PSR_C_BIT)
+                                                offset.un |= 1 << 31;
+                                } else
+                                        offset.un = offset.un >> shiftval |
+                                                          offset.un << (32 - shiftval);
+                                break;
+                        }
+                }
+                handler = do_alignment_ldrstr;
+                break;
+
+        case 0x08000000:        /* ldm or stm */
+                handler = do_alignment_ldmstm;
+                break;
+
+        default:
+                goto bad;
+        }
+
+        type = handler(addr, instr, regs);
+
+        if (type == TYPE_ERROR || type == TYPE_FAULT)
+                goto bad_or_fault;
+
+        if (type == TYPE_LDST)
+                do_alignment_finish_ldst(addr, instr, regs, offset);
+
+        return 0;
+
+ bad_or_fault:
+        if (type == TYPE_ERROR)
+                goto bad;
+        regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
+        /*
+         * We got a fault - fix it up, or die.
+         */
+        do_bad_area(current, current->mm, addr, fsr, regs);
+        return 0;
+
+ bad:
+        /*
+         * Oops, we didn't handle the instruction.
+         */
+        printk(KERN_ERR "Alignment trap: not handling instruction "
+                "%0*lx at [<%08lx>]\n",
+                thumb_mode(regs) ? 4 : 8,
+                thumb_mode(regs) ? tinstr : instr, instrptr);
+        ai_skipped += 1;
+        return 1;
+
+ user:
+        ai_user += 1;
+
+        if (ai_usermode & 1)
+                printk("Alignment trap: %s (%d) PC=0x%08lx Instr=0x%0*lx "
+                       "Address=0x%08lx FSR 0x%03x\n", current->comm,
+                        current->pid, instrptr,
+                        thumb_mode(regs) ? 4 : 8,
+                        thumb_mode(regs) ? tinstr : instr,
+                        addr, fsr);
+
+        if (ai_usermode & 2)
+                goto fixup;
+
+        if (ai_usermode & 4)
+                force_sig(SIGBUS, current);
+        else
+                set_cr(cr_no_alignment);
+
+        return 0;
+}
+
+/*
+ * This needs to be done after sysctl_init, otherwise sys/ will be
+ * overwritten.  Actually, this shouldn't be in sys/ at all since
+ * it isn't a sysctl, and it doesn't contain sysctl information.
+ * We now locate it in /proc/cpu/alignment instead.
+ */
+static int __init alignment_init(void)
+{
+#ifdef CONFIG_PROC_FS
+        struct proc_dir_entry *res;
+
+        res = proc_mkdir("cpu", NULL);
+        if (!res)
+                return -ENOMEM;
+
+        res = create_proc_entry("alignment", S_IWUSR | S_IRUGO, res);
+        if (!res)
+                return -ENOMEM;
+
+        res->read_proc = proc_alignment_read;
+        res->write_proc = proc_alignment_write;
+#endif
+
+        hook_fault_code(1, do_alignment, SIGILL, "alignment exception");
+        hook_fault_code(3, do_alignment, SIGILL, "alignment exception");
+
+        return 0;
+}
+
+fs_initcall(alignment_init);