lib/crc: Switch ARM and arm64 to 'ksimd' scoped guard API

Before modifying the prototypes of kernel_neon_begin() and
kernel_neon_end() to accommodate kernel mode FP/SIMD state buffers
allocated on the stack, move arm64 to the new 'ksimd' scoped guard API,
which encapsulates the calls to those functions.

For symmetry, do the same for 32-bit ARM too.

Reviewed-by: Eric Biggers <[e-mail]>
Reviewed-by: Jonathan Cameron <[e-mail]>
Acked-by: Catalin Marinas <[e-mail]>
Signed-off-by: Ard Biesheuvel <[e-mail]>

lib/crc/arm/crc-t10dif.h

···
  * Copyright (C) 2016 Linaro Ltd <[e-mail]>
  */
 
-#include <asm/neon.h>
 #include <asm/simd.h>
 
 static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);
···
 
 static inline u16 crc_t10dif_arch(u16 crc, const u8 *data, size_t length)
 {
-	if (length >= CRC_T10DIF_PMULL_CHUNK_SIZE) {
+	if (length >= CRC_T10DIF_PMULL_CHUNK_SIZE && likely(may_use_simd())) {
 		if (static_branch_likely(&have_pmull)) {
-			if (likely(may_use_simd())) {
-				kernel_neon_begin();
-				crc = crc_t10dif_pmull64(crc, data, length);
-				kernel_neon_end();
-				return crc;
-			}
+			scoped_ksimd()
+				return crc_t10dif_pmull64(crc, data, length);
 		} else if (length > CRC_T10DIF_PMULL_CHUNK_SIZE &&
-			   static_branch_likely(&have_neon) &&
-			   likely(may_use_simd())) {
+			   static_branch_likely(&have_neon)) {
 			u8 buf[16] __aligned(16);
 
-			kernel_neon_begin();
-			crc_t10dif_pmull8(crc, data, length, buf);
-			kernel_neon_end();
+			scoped_ksimd()
+				crc_t10dif_pmull8(crc, data, length, buf);
 
 			return crc_t10dif_generic(0, buf, sizeof(buf));
 		}

lib/crc/arm/crc32.h

···
 #include <linux/cpufeature.h>
 
 #include <asm/hwcap.h>
-#include <asm/neon.h>
 #include <asm/simd.h>
 
 static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_crc32);
···
 			len -= n;
 		}
 		n = round_down(len, 16);
-		kernel_neon_begin();
-		crc = crc32_pmull_le(p, n, crc);
-		kernel_neon_end();
+		scoped_ksimd()
+			crc = crc32_pmull_le(p, n, crc);
 		p += n;
 		len -= n;
 	}
···
 			len -= n;
 		}
 		n = round_down(len, 16);
-		kernel_neon_begin();
-		crc = crc32c_pmull_le(p, n, crc);
-		kernel_neon_end();
+		scoped_ksimd()
+			crc = crc32c_pmull_le(p, n, crc);
 		p += n;
 		len -= n;
 	}

lib/crc/arm64/crc-t10dif.h

···
 
 #include <linux/cpufeature.h>
 
-#include <asm/neon.h>
 #include <asm/simd.h>
 
 static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_asimd);
···
 
 static inline u16 crc_t10dif_arch(u16 crc, const u8 *data, size_t length)
 {
-	if (length >= CRC_T10DIF_PMULL_CHUNK_SIZE) {
+	if (length >= CRC_T10DIF_PMULL_CHUNK_SIZE && likely(may_use_simd())) {
 		if (static_branch_likely(&have_pmull)) {
-			if (likely(may_use_simd())) {
-				kernel_neon_begin();
-				crc = crc_t10dif_pmull_p64(crc, data, length);
-				kernel_neon_end();
-				return crc;
-			}
+			scoped_ksimd()
+				return crc_t10dif_pmull_p64(crc, data, length);
 		} else if (length > CRC_T10DIF_PMULL_CHUNK_SIZE &&
-			   static_branch_likely(&have_asimd) &&
-			   likely(may_use_simd())) {
+			   static_branch_likely(&have_asimd)) {
 			u8 buf[16];
 
-			kernel_neon_begin();
-			crc_t10dif_pmull_p8(crc, data, length, buf);
-			kernel_neon_end();
+			scoped_ksimd()
+				crc_t10dif_pmull_p8(crc, data, length, buf);
 
 			return crc_t10dif_generic(0, buf, sizeof(buf));
 		}

lib/crc/arm64/crc32.h

···
 
 #include <asm/alternative.h>
 #include <asm/cpufeature.h>
-#include <asm/neon.h>
 #include <asm/simd.h>
 
 // The minimum input length to consider the 4-way interleaved code path
···
 
 	if (len >= min_len && cpu_have_named_feature(PMULL) &&
 	    likely(may_use_simd())) {
-		kernel_neon_begin();
-		crc = crc32_le_arm64_4way(crc, p, len);
-		kernel_neon_end();
+		scoped_ksimd()
+			crc = crc32_le_arm64_4way(crc, p, len);
 
 		p += round_down(len, 64);
 		len %= 64;
···
 
 	if (len >= min_len && cpu_have_named_feature(PMULL) &&
 	    likely(may_use_simd())) {
-		kernel_neon_begin();
-		crc = crc32c_le_arm64_4way(crc, p, len);
-		kernel_neon_end();
+		scoped_ksimd()
+			crc = crc32c_le_arm64_4way(crc, p, len);
 
 		p += round_down(len, 64);
 		len %= 64;
···
 
 	if (len >= min_len && cpu_have_named_feature(PMULL) &&
 	    likely(may_use_simd())) {
-		kernel_neon_begin();
-		crc = crc32_be_arm64_4way(crc, p, len);
-		kernel_neon_end();
+		scoped_ksimd()
+			crc = crc32_be_arm64_4way(crc, p, len);
 
 		p += round_down(len, 64);
 		len %= 64;