arch/powerpc/crypto/aes_ctr.c

Source file repositories/reference/linux-study-clean/arch/powerpc/crypto/aes_ctr.c

File Facts

System
Linux kernel
Corpus path
arch/powerpc/crypto/aes_ctr.c
Extension
.c
Size
3935 bytes
Lines
154
Domain
Architecture Layer
Bucket
arch/powerpc
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 p8_aes_ctr_ctx {
	struct crypto_skcipher *fallback;
	struct p8_aes_key enc_key;
};

static int p8_aes_ctr_init(struct crypto_skcipher *tfm)
{
	struct p8_aes_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct crypto_skcipher *fallback;

	fallback = crypto_alloc_skcipher("ctr(aes)", 0,
					 CRYPTO_ALG_NEED_FALLBACK |
					 CRYPTO_ALG_ASYNC);
	if (IS_ERR(fallback)) {
		pr_err("Failed to allocate ctr(aes) fallback: %ld\n",
		       PTR_ERR(fallback));
		return PTR_ERR(fallback);
	}

	crypto_skcipher_set_reqsize(tfm, sizeof(struct skcipher_request) +
				    crypto_skcipher_reqsize(fallback));
	ctx->fallback = fallback;
	return 0;
}

static void p8_aes_ctr_exit(struct crypto_skcipher *tfm)
{
	struct p8_aes_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);

	crypto_free_skcipher(ctx->fallback);
}

static int p8_aes_ctr_setkey(struct crypto_skcipher *tfm, const u8 *key,
			     unsigned int keylen)
{
	struct p8_aes_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
	int ret;

	preempt_disable();
	pagefault_disable();
	enable_kernel_vsx();
	ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
	disable_kernel_vsx();
	pagefault_enable();
	preempt_enable();

	ret |= crypto_skcipher_setkey(ctx->fallback, key, keylen);

	return ret ? -EINVAL : 0;
}

static void p8_aes_ctr_final(const struct p8_aes_ctr_ctx *ctx,
			     struct skcipher_walk *walk)
{
	const u8 *src = walk->src.virt.addr;
	u8 *ctrblk = walk->iv;
	u8 keystream[AES_BLOCK_SIZE];
	u8 *dst = walk->dst.virt.addr;
	unsigned int nbytes = walk->nbytes;

	preempt_disable();
	pagefault_disable();
	enable_kernel_vsx();
	aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key);
	disable_kernel_vsx();
	pagefault_enable();
	preempt_enable();

	crypto_xor_cpy(dst, keystream, src, nbytes);
	crypto_inc(ctrblk, AES_BLOCK_SIZE);
}

static int p8_aes_ctr_crypt(struct skcipher_request *req)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	const struct p8_aes_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct skcipher_walk walk;
	unsigned int nbytes;
	int ret;

	if (!crypto_simd_usable()) {
		struct skcipher_request *subreq = skcipher_request_ctx(req);

		*subreq = *req;
		skcipher_request_set_tfm(subreq, ctx->fallback);
		return crypto_skcipher_encrypt(subreq);
	}

	ret = skcipher_walk_virt(&walk, req, false);
	while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {

Annotation

Implementation Notes