[PATCH v4 10/21] crypto/arm64: aes-ccm - Switch to 'ksimd' scoped guard API

[Ard Biesheuvel <ardb+git@google.com>]

From: Ard Biesheuvel <ardb@kernel.org>

Switch to the more abstract 'scoped_ksimd()' API, which will be modified
in a future patch to transparently allocate a kernel mode FP/SIMD state
buffer on the stack, so that kernel mode FP/SIMD code remains
preemptible in principe, but without the memory overhead that adds 528
bytes to the size of struct task_struct.

Reviewed-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/crypto/aes-ce-ccm-glue.c | 135 ++++++++++----------
 1 file changed, 66 insertions(+), 69 deletions(-)

diff --git a/arch/arm64/crypto/aes-ce-ccm-glue.c b/arch/arm64/crypto/aes-ce-ccm-glue.c
index 2eb4e76cabc3..c4fd648471f1 100644
--- a/arch/arm64/crypto/aes-ce-ccm-glue.c
+++ b/arch/arm64/crypto/aes-ce-ccm-glue.c
@@ -8,7 +8,6 @@
  * Author: Ard Biesheuvel <ardb@kernel.org>
  */
 
-#include <asm/neon.h>
 #include <linux/unaligned.h>
 #include <crypto/aes.h>
 #include <crypto/scatterwalk.h>
@@ -16,6 +15,8 @@
 #include <crypto/internal/skcipher.h>
 #include <linux/module.h>
 
+#include <asm/simd.h>
+
 #include "aes-ce-setkey.h"
 
 MODULE_IMPORT_NS("CRYPTO_INTERNAL");
@@ -184,40 +185,38 @@ static int ccm_encrypt(struct aead_request *req)
 	if (unlikely(err))
 		return err;
 
-	kernel_neon_begin();
-
-	if (req->assoclen)
-		ccm_calculate_auth_mac(req, mac);
-
-	do {
-		u32 tail = walk.nbytes % AES_BLOCK_SIZE;
-		const u8 *src = walk.src.virt.addr;
-		u8 *dst = walk.dst.virt.addr;
-		u8 buf[AES_BLOCK_SIZE];
-		u8 *final_iv = NULL;
-
-		if (walk.nbytes == walk.total) {
-			tail = 0;
-			final_iv = orig_iv;
-		}
-
-		if (unlikely(walk.nbytes < AES_BLOCK_SIZE))
-			src = dst = memcpy(&buf[sizeof(buf) - walk.nbytes],
-					   src, walk.nbytes);
-
-		ce_aes_ccm_encrypt(dst, src, walk.nbytes - tail,
-				   ctx->key_enc, num_rounds(ctx),
-				   mac, walk.iv, final_iv);
-
-		if (unlikely(walk.nbytes < AES_BLOCK_SIZE))
-			memcpy(walk.dst.virt.addr, dst, walk.nbytes);
-
-		if (walk.nbytes) {
-			err = skcipher_walk_done(&walk, tail);
-		}
-	} while (walk.nbytes);
-
-	kernel_neon_end();
+	scoped_ksimd() {
+		if (req->assoclen)
+			ccm_calculate_auth_mac(req, mac);
+
+		do {
+			u32 tail = walk.nbytes % AES_BLOCK_SIZE;
+			const u8 *src = walk.src.virt.addr;
+			u8 *dst = walk.dst.virt.addr;
+			u8 buf[AES_BLOCK_SIZE];
+			u8 *final_iv = NULL;
+
+			if (walk.nbytes == walk.total) {
+				tail = 0;
+				final_iv = orig_iv;
+			}
+
+			if (unlikely(walk.nbytes < AES_BLOCK_SIZE))
+				src = dst = memcpy(&buf[sizeof(buf) - walk.nbytes],
+						   src, walk.nbytes);
+
+			ce_aes_ccm_encrypt(dst, src, walk.nbytes - tail,
+					   ctx->key_enc, num_rounds(ctx),
+					   mac, walk.iv, final_iv);
+
+			if (unlikely(walk.nbytes < AES_BLOCK_SIZE))
+				memcpy(walk.dst.virt.addr, dst, walk.nbytes);
+
+			if (walk.nbytes) {
+				err = skcipher_walk_done(&walk, tail);
+			}
+		} while (walk.nbytes);
+	}
 
 	if (unlikely(err))
 		return err;
@@ -251,40 +250,38 @@ static int ccm_decrypt(struct aead_request *req)
 	if (unlikely(err))
 		return err;
 
-	kernel_neon_begin();
-
-	if (req->assoclen)
-		ccm_calculate_auth_mac(req, mac);
-
-	do {
-		u32 tail = walk.nbytes % AES_BLOCK_SIZE;
-		const u8 *src = walk.src.virt.addr;
-		u8 *dst = walk.dst.virt.addr;
-		u8 buf[AES_BLOCK_SIZE];
-		u8 *final_iv = NULL;
-
-		if (walk.nbytes == walk.total) {
-			tail = 0;
-			final_iv = orig_iv;
-		}
-
-		if (unlikely(walk.nbytes < AES_BLOCK_SIZE))
-			src = dst = memcpy(&buf[sizeof(buf) - walk.nbytes],
-					   src, walk.nbytes);
-
-		ce_aes_ccm_decrypt(dst, src, walk.nbytes - tail,
-				   ctx->key_enc, num_rounds(ctx),
-				   mac, walk.iv, final_iv);
-
-		if (unlikely(walk.nbytes < AES_BLOCK_SIZE))
-			memcpy(walk.dst.virt.addr, dst, walk.nbytes);
-
-		if (walk.nbytes) {
-			err = skcipher_walk_done(&walk, tail);
-		}
-	} while (walk.nbytes);
-
-	kernel_neon_end();
+	scoped_ksimd() {
+		if (req->assoclen)
+			ccm_calculate_auth_mac(req, mac);
+
+		do {
+			u32 tail = walk.nbytes % AES_BLOCK_SIZE;
+			const u8 *src = walk.src.virt.addr;
+			u8 *dst = walk.dst.virt.addr;
+			u8 buf[AES_BLOCK_SIZE];
+			u8 *final_iv = NULL;
+
+			if (walk.nbytes == walk.total) {
+				tail = 0;
+				final_iv = orig_iv;
+			}
+
+			if (unlikely(walk.nbytes < AES_BLOCK_SIZE))
+				src = dst = memcpy(&buf[sizeof(buf) - walk.nbytes],
+						   src, walk.nbytes);
+
+			ce_aes_ccm_decrypt(dst, src, walk.nbytes - tail,
+					   ctx->key_enc, num_rounds(ctx),
+					   mac, walk.iv, final_iv);
+
+			if (unlikely(walk.nbytes < AES_BLOCK_SIZE))
+				memcpy(walk.dst.virt.addr, dst, walk.nbytes);
+
+			if (walk.nbytes) {
+				err = skcipher_walk_done(&walk, tail);
+			}
+		} while (walk.nbytes);
+	}
 
 	if (unlikely(err))
 		return err;
-- 
2.51.1.930.gacf6e81ea2-goog