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95 lines
2.1 KiB
95 lines
2.1 KiB
// 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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