96 lines
2.1 KiB
C
96 lines
2.1 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2018 Cadence Design Systems Inc.
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#include <linux/cpu.h>
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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/stop_machine.h>
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#include <linux/types.h>
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#include <asm/cacheflush.h>
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#define J_OFFSET_MASK 0x0003ffff
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#define J_SIGN_MASK (~(J_OFFSET_MASK >> 1))
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#if defined(__XTENSA_EL__)
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#define J_INSN 0x6
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#define NOP_INSN 0x0020f0
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#elif defined(__XTENSA_EB__)
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#define J_INSN 0x60000000
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#define NOP_INSN 0x0f020000
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#else
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#error Unsupported endianness.
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#endif
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struct patch {
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atomic_t cpu_count;
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unsigned long addr;
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size_t sz;
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const void *data;
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};
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static void local_patch_text(unsigned long addr, const void *data, size_t sz)
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{
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memcpy((void *)addr, data, sz);
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local_flush_icache_range(addr, addr + sz);
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}
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static int patch_text_stop_machine(void *data)
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{
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struct patch *patch = data;
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if (atomic_inc_return(&patch->cpu_count) == 1) {
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local_patch_text(patch->addr, patch->data, patch->sz);
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atomic_inc(&patch->cpu_count);
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} else {
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while (atomic_read(&patch->cpu_count) <= num_online_cpus())
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cpu_relax();
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__invalidate_icache_range(patch->addr, patch->sz);
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}
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return 0;
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}
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static void patch_text(unsigned long addr, const void *data, size_t sz)
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{
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if (IS_ENABLED(CONFIG_SMP)) {
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struct patch patch = {
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.cpu_count = ATOMIC_INIT(0),
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.addr = addr,
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.sz = sz,
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.data = data,
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};
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stop_machine_cpuslocked(patch_text_stop_machine,
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&patch, NULL);
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} else {
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unsigned long flags;
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local_irq_save(flags);
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local_patch_text(addr, data, sz);
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local_irq_restore(flags);
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}
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}
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void arch_jump_label_transform(struct jump_entry *e,
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enum jump_label_type type)
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{
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u32 d = (jump_entry_target(e) - (jump_entry_code(e) + 4));
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u32 insn;
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/* Jump only works within 128K of the J instruction. */
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BUG_ON(!((d & J_SIGN_MASK) == 0 ||
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(d & J_SIGN_MASK) == J_SIGN_MASK));
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if (type == JUMP_LABEL_JMP) {
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#if defined(__XTENSA_EL__)
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insn = ((d & J_OFFSET_MASK) << 6) | J_INSN;
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#elif defined(__XTENSA_EB__)
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insn = ((d & J_OFFSET_MASK) << 8) | J_INSN;
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#endif
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} else {
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insn = NOP_INSN;
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}
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patch_text(jump_entry_code(e), &insn, JUMP_LABEL_NOP_SIZE);
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}
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