b21d55e98a
Extract out the code patching code from kprobes so that it can be used from the jump label code. Additionally, the separated code: - Uses the IS_ENABLED() macros instead of the #ifdefs for THUMB2 support - Unifies the two separate functions in kprobes, providing one function that uses stop_machine() internally, and one that can be called from stop_machine() directly - Patches the text on all CPUs only on processors requiring software broadcasting of cache operations Acked-by: Jon Medhurst <tixy@yxit.co.uk> Tested-by: Jon Medhurst <tixy@yxit.co.uk> Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
76 lines
1.6 KiB
C
76 lines
1.6 KiB
C
#include <linux/kernel.h>
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#include <linux/kprobes.h>
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#include <linux/stop_machine.h>
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#include <asm/cacheflush.h>
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#include <asm/smp_plat.h>
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#include <asm/opcodes.h>
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#include "patch.h"
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struct patch {
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void *addr;
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unsigned int insn;
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};
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void __kprobes __patch_text(void *addr, unsigned int insn)
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{
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bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL);
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int size;
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if (thumb2 && __opcode_is_thumb16(insn)) {
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*(u16 *)addr = __opcode_to_mem_thumb16(insn);
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size = sizeof(u16);
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} else if (thumb2 && ((uintptr_t)addr & 2)) {
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u16 first = __opcode_thumb32_first(insn);
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u16 second = __opcode_thumb32_second(insn);
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u16 *addrh = addr;
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addrh[0] = __opcode_to_mem_thumb16(first);
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addrh[1] = __opcode_to_mem_thumb16(second);
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size = sizeof(u32);
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} else {
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if (thumb2)
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insn = __opcode_to_mem_thumb32(insn);
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else
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insn = __opcode_to_mem_arm(insn);
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*(u32 *)addr = insn;
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size = sizeof(u32);
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}
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flush_icache_range((uintptr_t)(addr),
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(uintptr_t)(addr) + size);
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}
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static int __kprobes patch_text_stop_machine(void *data)
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{
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struct patch *patch = data;
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__patch_text(patch->addr, patch->insn);
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return 0;
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}
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void __kprobes patch_text(void *addr, unsigned int insn)
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{
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struct patch patch = {
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.addr = addr,
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.insn = insn,
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};
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if (cache_ops_need_broadcast()) {
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stop_machine(patch_text_stop_machine, &patch, cpu_online_mask);
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} else {
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bool straddles_word = IS_ENABLED(CONFIG_THUMB2_KERNEL)
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&& __opcode_is_thumb32(insn)
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&& ((uintptr_t)addr & 2);
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if (straddles_word)
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stop_machine(patch_text_stop_machine, &patch, NULL);
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else
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__patch_text(addr, insn);
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}
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}
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