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#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/stop_machine.h>
#include <asm/cacheflush.h>
#include <asm/smp_plat.h>
#include <asm/opcodes.h>
#include "patch.h"
struct patch {
void *addr;
unsigned int insn;
};
void __kprobes __patch_text(void *addr, unsigned int insn)
{
bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL);
int size;
if (thumb2 && __opcode_is_thumb16(insn)) {
*(u16 *)addr = __opcode_to_mem_thumb16(insn);
size = sizeof(u16);
} else if (thumb2 && ((uintptr_t)addr & 2)) {
u16 first = __opcode_thumb32_first(insn);
u16 second = __opcode_thumb32_second(insn);
u16 *addrh = addr;
addrh[0] = __opcode_to_mem_thumb16(first);
addrh[1] = __opcode_to_mem_thumb16(second);
size = sizeof(u32);
} else {
if (thumb2)
insn = __opcode_to_mem_thumb32(insn);
else
insn = __opcode_to_mem_arm(insn);
*(u32 *)addr = insn;
size = sizeof(u32);
}
flush_icache_range((uintptr_t)(addr),
(uintptr_t)(addr) + size);
}
static int __kprobes patch_text_stop_machine(void *data)
{
struct patch *patch = data;
__patch_text(patch->addr, patch->insn);
return 0;
}
void __kprobes patch_text(void *addr, unsigned int insn)
{
struct patch patch = {
.addr = addr,
.insn = insn,
};
if (cache_ops_need_broadcast()) {
stop_machine(patch_text_stop_machine, &patch, cpu_online_mask);
} else {
bool straddles_word = IS_ENABLED(CONFIG_THUMB2_KERNEL)
&& __opcode_is_thumb32(insn)
&& ((uintptr_t)addr & 2);
if (straddles_word)
stop_machine(patch_text_stop_machine, &patch, NULL);
else
__patch_text(addr, insn);
}
}
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