263 lines
6.2 KiB
C
263 lines
6.2 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2011-2012 Synopsys (www.synopsys.com)
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*
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* vineetg : May 2011
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* -Adapted (from .26 to .35)
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* -original contribution by Tim.yao@amlogic.com
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*/
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#include <linux/types.h>
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#include <linux/perf_event.h>
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#include <linux/ptrace.h>
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#include <linux/uaccess.h>
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#include <asm/disasm.h>
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#ifdef CONFIG_CPU_BIG_ENDIAN
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#define BE 1
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#define FIRST_BYTE_16 "swap %1, %1\n swape %1, %1\n"
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#define FIRST_BYTE_32 "swape %1, %1\n"
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#else
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#define BE 0
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#define FIRST_BYTE_16
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#define FIRST_BYTE_32
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#endif
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#define __get8_unaligned_check(val, addr, err) \
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__asm__( \
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"1: ldb.ab %1, [%2, 1]\n" \
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"2:\n" \
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" .section .fixup,\"ax\"\n" \
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" .align 4\n" \
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"3: mov %0, 1\n" \
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" j 2b\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .align 4\n" \
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" .long 1b, 3b\n" \
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" .previous\n" \
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: "=r" (err), "=&r" (val), "=r" (addr) \
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: "0" (err), "2" (addr))
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#define get16_unaligned_check(val, addr) \
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do { \
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unsigned int err = 0, v, a = addr; \
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__get8_unaligned_check(v, a, err); \
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val = v << ((BE) ? 8 : 0); \
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__get8_unaligned_check(v, a, err); \
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val |= v << ((BE) ? 0 : 8); \
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if (err) \
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goto fault; \
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} while (0)
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#define get32_unaligned_check(val, addr) \
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do { \
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unsigned int err = 0, v, a = addr; \
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__get8_unaligned_check(v, a, err); \
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val = v << ((BE) ? 24 : 0); \
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__get8_unaligned_check(v, a, err); \
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val |= v << ((BE) ? 16 : 8); \
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__get8_unaligned_check(v, a, err); \
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val |= v << ((BE) ? 8 : 16); \
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__get8_unaligned_check(v, a, err); \
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val |= v << ((BE) ? 0 : 24); \
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if (err) \
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goto fault; \
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} while (0)
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#define put16_unaligned_check(val, addr) \
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do { \
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unsigned int err = 0, v = val, a = addr;\
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\
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__asm__( \
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FIRST_BYTE_16 \
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"1: stb.ab %1, [%2, 1]\n" \
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" lsr %1, %1, 8\n" \
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"2: stb %1, [%2]\n" \
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"3:\n" \
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" .section .fixup,\"ax\"\n" \
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" .align 4\n" \
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"4: mov %0, 1\n" \
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" j 3b\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .align 4\n" \
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" .long 1b, 4b\n" \
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" .long 2b, 4b\n" \
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" .previous\n" \
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: "=r" (err), "=&r" (v), "=&r" (a) \
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: "0" (err), "1" (v), "2" (a)); \
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\
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if (err) \
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goto fault; \
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} while (0)
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#define put32_unaligned_check(val, addr) \
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do { \
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unsigned int err = 0, v = val, a = addr;\
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\
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__asm__( \
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FIRST_BYTE_32 \
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"1: stb.ab %1, [%2, 1]\n" \
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" lsr %1, %1, 8\n" \
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"2: stb.ab %1, [%2, 1]\n" \
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" lsr %1, %1, 8\n" \
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"3: stb.ab %1, [%2, 1]\n" \
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" lsr %1, %1, 8\n" \
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"4: stb %1, [%2]\n" \
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"5:\n" \
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" .section .fixup,\"ax\"\n" \
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" .align 4\n" \
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"6: mov %0, 1\n" \
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" j 5b\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .align 4\n" \
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" .long 1b, 6b\n" \
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" .long 2b, 6b\n" \
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" .long 3b, 6b\n" \
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" .long 4b, 6b\n" \
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" .previous\n" \
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: "=r" (err), "=&r" (v), "=&r" (a) \
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: "0" (err), "1" (v), "2" (a)); \
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\
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if (err) \
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goto fault; \
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} while (0)
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/* sysctl hooks */
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int unaligned_enabled __read_mostly = 1; /* Enabled by default */
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int no_unaligned_warning __read_mostly = 1; /* Only 1 warning by default */
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static void fixup_load(struct disasm_state *state, struct pt_regs *regs,
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struct callee_regs *cregs)
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{
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int val;
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/* register write back */
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if ((state->aa == 1) || (state->aa == 2)) {
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set_reg(state->wb_reg, state->src1 + state->src2, regs, cregs);
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if (state->aa == 2)
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state->src2 = 0;
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}
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if (state->zz == 0) {
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get32_unaligned_check(val, state->src1 + state->src2);
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} else {
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get16_unaligned_check(val, state->src1 + state->src2);
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if (state->x)
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val = (val << 16) >> 16;
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}
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if (state->pref == 0)
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set_reg(state->dest, val, regs, cregs);
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return;
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fault: state->fault = 1;
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}
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static void fixup_store(struct disasm_state *state, struct pt_regs *regs,
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struct callee_regs *cregs)
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{
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/* register write back */
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if ((state->aa == 1) || (state->aa == 2)) {
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set_reg(state->wb_reg, state->src2 + state->src3, regs, cregs);
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if (state->aa == 3)
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state->src3 = 0;
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} else if (state->aa == 3) {
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if (state->zz == 2) {
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set_reg(state->wb_reg, state->src2 + (state->src3 << 1),
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regs, cregs);
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} else if (!state->zz) {
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set_reg(state->wb_reg, state->src2 + (state->src3 << 2),
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regs, cregs);
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} else {
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goto fault;
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}
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}
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/* write fix-up */
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if (!state->zz)
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put32_unaligned_check(state->src1, state->src2 + state->src3);
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else
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put16_unaligned_check(state->src1, state->src2 + state->src3);
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return;
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fault: state->fault = 1;
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}
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/*
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* Handle an unaligned access
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* Returns 0 if successfully handled, 1 if some error happened
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*/
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int misaligned_fixup(unsigned long address, struct pt_regs *regs,
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struct callee_regs *cregs)
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{
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struct disasm_state state;
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char buf[TASK_COMM_LEN];
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/* handle user mode only and only if enabled by sysadmin */
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if (!user_mode(regs) || !unaligned_enabled)
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return 1;
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if (no_unaligned_warning) {
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pr_warn_once("%s(%d) made unaligned access which was emulated"
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" by kernel assist\n. This can degrade application"
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" performance significantly\n. To enable further"
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" logging of such instances, please \n"
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" echo 0 > /proc/sys/kernel/ignore-unaligned-usertrap\n",
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get_task_comm(buf, current), task_pid_nr(current));
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} else {
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/* Add rate limiting if it gets down to it */
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pr_warn("%s(%d): unaligned access to/from 0x%lx by PC: 0x%lx\n",
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get_task_comm(buf, current), task_pid_nr(current),
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address, regs->ret);
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}
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disasm_instr(regs->ret, &state, 1, regs, cregs);
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if (state.fault)
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goto fault;
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/* ldb/stb should not have unaligned exception */
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if ((state.zz == 1) || (state.di))
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goto fault;
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if (!state.write)
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fixup_load(&state, regs, cregs);
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else
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fixup_store(&state, regs, cregs);
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if (state.fault)
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goto fault;
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/* clear any remnants of delay slot */
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if (delay_mode(regs)) {
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regs->ret = regs->bta & ~1U;
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regs->status32 &= ~STATUS_DE_MASK;
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} else {
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regs->ret += state.instr_len;
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/* handle zero-overhead-loop */
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if ((regs->ret == regs->lp_end) && (regs->lp_count)) {
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regs->ret = regs->lp_start;
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regs->lp_count--;
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}
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}
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perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, address);
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return 0;
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fault:
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pr_err("Alignment trap: fault in fix-up %08lx at [<%08lx>]\n",
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state.words[0], address);
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return 1;
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}
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