76 lines
		
	
	
	
		
			1.6 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
		
		
			
		
	
	
			76 lines
		
	
	
	
		
			1.6 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
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								#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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