arch/arm64/kernel/patching.c

Source file repositories/reference/linux-study-clean/arch/arm64/kernel/patching.c

File Facts

System
Linux kernel
Corpus path
arch/arm64/kernel/patching.c
Extension
.c
Size
5397 bytes
Lines
239
Domain
Architecture Layer
Bucket
arch/arm64
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

struct aarch64_insn_patch {
	void		**text_addrs;
	u32		*new_insns;
	int		insn_cnt;
	atomic_t	cpu_count;
};

static int __kprobes aarch64_insn_patch_text_cb(void *arg)
{
	int i, ret = 0;
	struct aarch64_insn_patch *pp = arg;

	/* The last CPU becomes master */
	if (atomic_inc_return(&pp->cpu_count) == num_online_cpus()) {
		for (i = 0; ret == 0 && i < pp->insn_cnt; i++)
			ret = aarch64_insn_patch_text_nosync(pp->text_addrs[i],
							     pp->new_insns[i]);
		/* Notify other processors with an additional increment. */
		atomic_inc(&pp->cpu_count);
	} else {
		while (atomic_read(&pp->cpu_count) <= num_online_cpus())
			cpu_relax();
		isb();
	}

	return ret;
}

int __kprobes aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt)
{
	struct aarch64_insn_patch patch = {
		.text_addrs = addrs,
		.new_insns = insns,
		.insn_cnt = cnt,
		.cpu_count = ATOMIC_INIT(0),
	};

	if (cnt <= 0)
		return -EINVAL;

	return stop_machine_cpuslocked(aarch64_insn_patch_text_cb, &patch,
				       cpu_online_mask);
}

Annotation

Implementation Notes