| 1 | |
| 2 | * This file is subject to the terms and conditions of the GNU General Public
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| 3 | * License. See the file "COPYING" in the main directory of this archive
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| 4 | * for more details.
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| 5 | *
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| 6 | * Copyright (c) 2010 Cavium Networks, Inc.
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| 7 |
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| 8 |
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| 9 | #include <linux/jump_label.h>
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| 10 | #include <linux/kernel.h>
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| 11 | #include <linux/memory.h>
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| 12 | #include <linux/mutex.h>
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| 13 | #include <linux/types.h>
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| 14 | #include <linux/cpu.h>
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| 15 |
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| 16 | #include <asm/cacheflush.h>
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| 17 | #include <asm/inst.h>
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| 18 |
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| 19 | |
| 20 | * Define parameters for the standard MIPS and the microMIPS jump
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| 21 | * instruction encoding respectively:
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| 22 | *
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| 23 | * - the ISA bit of the target, either 0 or 1 respectively,
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| 24 | *
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| 25 | * - the amount the jump target address is shifted right to fit in the
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| 26 | * immediate field of the machine instruction, either 2 or 1,
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| 27 | *
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| 28 | * - the mask determining the size of the jump region relative to the
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| 29 | * delay-slot instruction, either 256MB or 128MB,
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| 30 | *
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| 31 | * - the jump target alignment, either 4 or 2 bytes.
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| 32 |
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| 33 | #define J_ISA_BIT IS_ENABLED(CONFIG_CPU_MICROMIPS)
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| 34 | #define J_RANGE_SHIFT (2 - J_ISA_BIT)
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| 35 | #define J_RANGE_MASK ((1ul << (26 + J_RANGE_SHIFT)) - 1)
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| 36 | #define J_ALIGN_MASK ((1ul << J_RANGE_SHIFT) - 1)
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| 37 |
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| 38 | void arch_jump_label_transform(struct jump_entry *e,
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| 39 | enum jump_label_type type)
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| 40 | {
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| 41 | union mips_instruction *insn_p;
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| 42 | union mips_instruction insn;
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| 43 | long offset;
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| 44 |
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| 45 | insn_p = (union mips_instruction *)msk_isa16_mode(e->code);
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| 46 |
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| 47 |
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| 48 | BUG_ON((e->target & J_ALIGN_MASK) != J_ISA_BIT);
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| 49 |
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| 50 | if (type == JUMP_LABEL_JMP) {
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| 51 | if (!IS_ENABLED(CONFIG_CPU_MICROMIPS) && MIPS_ISA_REV >= 6) {
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| 52 | offset = e->target - ((unsigned long)insn_p + 4);
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| 53 | offset >>= 2;
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| 54 |
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| 55 | |
| 56 | * The branch offset must fit in the instruction's 26
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| 57 | * bit field.
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| 58 |
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| 59 | WARN_ON((offset >= (long)BIT(25)) ||
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| 60 | (offset < -(long)BIT(25)));
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| 61 |
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| 62 | insn.j_format.opcode = bc6_op;
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| 63 | insn.j_format.target = offset;
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| 64 | } else {
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| 65 | |
| 66 | * Jump only works within an aligned region its delay
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| 67 | * slot is in.
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| 68 |
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| 69 | WARN_ON((e->target & ~J_RANGE_MASK) !=
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| 70 | ((e->code + 4) & ~J_RANGE_MASK));
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| 71 |
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| 72 | insn.j_format.opcode = J_ISA_BIT ? mm_j32_op : j_op;
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| 73 | insn.j_format.target = e->target >> J_RANGE_SHIFT;
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| 74 | }
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| 75 | } else {
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| 76 | insn.word = 0;
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| 77 | }
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| 78 |
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| 79 | mutex_lock(&text_mutex);
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| 80 | if (IS_ENABLED(CONFIG_CPU_MICROMIPS)) {
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| 81 | insn_p->halfword[0] = insn.word >> 16;
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| 82 | insn_p->halfword[1] = insn.word;
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| 83 | } else
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| 84 | *insn_p = insn;
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| 85 |
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| 86 | flush_icache_range((unsigned long)insn_p,
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| 87 | (unsigned long)insn_p + sizeof(*insn_p));
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| 88 |
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| 89 | mutex_unlock(&text_mutex);
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| 90 | }
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| 91 |
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| 92 | #ifdef CONFIG_MODULES
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| 93 | void jump_label_apply_nops(struct module *mod)
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| 94 | {
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| 95 | struct jump_entry *iter_start = mod->jump_entries;
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| 96 | struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
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| 97 | struct jump_entry *iter;
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| 98 |
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| 99 |
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| 100 | if (iter_start == iter_stop)
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| 101 | return;
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| 102 |
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| 103 | for (iter = iter_start; iter < iter_stop; iter++) {
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| 104 |
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| 105 | if (jump_label_init_type(iter) == JUMP_LABEL_NOP)
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| 106 | arch_jump_label_transform(iter, JUMP_LABEL_NOP);
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| 107 | }
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| 108 | }
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| 109 | #endif
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