54 lines
1.4 KiB
C
54 lines
1.4 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2020 Emil Renner Berthing
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*
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* Based on arch/arm64/kernel/jump_label.c
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*/
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#include <linux/jump_label.h>
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#include <linux/kernel.h>
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#include <linux/memory.h>
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#include <linux/mutex.h>
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#include <asm/bug.h>
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#include <asm/patch.h>
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#define RISCV_INSN_NOP 0x00000013U
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#define RISCV_INSN_JAL 0x0000006fU
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void arch_jump_label_transform(struct jump_entry *entry,
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enum jump_label_type type)
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{
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void *addr = (void *)jump_entry_code(entry);
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u32 insn;
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if (type == JUMP_LABEL_JMP) {
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long offset = jump_entry_target(entry) - jump_entry_code(entry);
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if (WARN_ON(offset & 1 || offset < -524288 || offset >= 524288))
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return;
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insn = RISCV_INSN_JAL |
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(((u32)offset & GENMASK(19, 12)) << (12 - 12)) |
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(((u32)offset & GENMASK(11, 11)) << (20 - 11)) |
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(((u32)offset & GENMASK(10, 1)) << (21 - 1)) |
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(((u32)offset & GENMASK(20, 20)) << (31 - 20));
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} else {
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insn = RISCV_INSN_NOP;
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}
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mutex_lock(&text_mutex);
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patch_text_nosync(addr, &insn, sizeof(insn));
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mutex_unlock(&text_mutex);
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}
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void arch_jump_label_transform_static(struct jump_entry *entry,
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enum jump_label_type type)
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{
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/*
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* We use the same instructions in the arch_static_branch and
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* arch_static_branch_jump inline functions, so there's no
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* need to patch them up here.
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* The core will call arch_jump_label_transform when those
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* instructions need to be replaced.
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*/
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}
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