Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/lib/crypto/arm64/sha256.h
29281 views
1
/* SPDX-License-Identifier: GPL-2.0-or-later */

2
/*

3
 * SHA-256 optimized for ARM64

4
 *

5
 * Copyright 2025 Google LLC

6
 */

7
#include <asm/neon.h>

8
#include <asm/simd.h>

9
#include <linux/cpufeature.h>

10


11
static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);

12
static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_ce);

13


14
asmlinkage void sha256_block_data_order(struct sha256_block_state *state,

15
					const u8 *data, size_t nblocks);

16
asmlinkage void sha256_block_neon(struct sha256_block_state *state,

17
				  const u8 *data, size_t nblocks);

18
asmlinkage size_t __sha256_ce_transform(struct sha256_block_state *state,

19
					const u8 *data, size_t nblocks);

20


21
static void sha256_blocks(struct sha256_block_state *state,

22
			  const u8 *data, size_t nblocks)

23
{

24
	if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) &&

25
	    static_branch_likely(&have_neon) && likely(may_use_simd())) {

26
		if (static_branch_likely(&have_ce)) {

27
			do {

28
				size_t rem;

29


30
				kernel_neon_begin();

31
				rem = __sha256_ce_transform(state,

32
							    data, nblocks);

33
				kernel_neon_end();

34
				data += (nblocks - rem) * SHA256_BLOCK_SIZE;

35
				nblocks = rem;

36
			} while (nblocks);

37
		} else {

38
			kernel_neon_begin();

39
			sha256_block_neon(state, data, nblocks);

40
			kernel_neon_end();

41
		}

42
	} else {

43
		sha256_block_data_order(state, data, nblocks);

44
	}

45
}

46


47
static_assert(offsetof(struct __sha256_ctx, state) == 0);

48
static_assert(offsetof(struct __sha256_ctx, bytecount) == 32);

49
static_assert(offsetof(struct __sha256_ctx, buf) == 40);

50
asmlinkage void sha256_ce_finup2x(const struct __sha256_ctx *ctx,

51
				  const u8 *data1, const u8 *data2, int len,

52
				  u8 out1[SHA256_DIGEST_SIZE],

53
				  u8 out2[SHA256_DIGEST_SIZE]);

54


55
#define sha256_finup_2x_arch sha256_finup_2x_arch

56
static bool sha256_finup_2x_arch(const struct __sha256_ctx *ctx,

57
				 const u8 *data1, const u8 *data2, size_t len,

58
				 u8 out1[SHA256_DIGEST_SIZE],

59
				 u8 out2[SHA256_DIGEST_SIZE])

60
{

61
	/*

62
	 * The assembly requires len >= SHA256_BLOCK_SIZE && len <= INT_MAX.

63
	 * Further limit len to 65536 to avoid spending too long with preemption

64
	 * disabled.  (Of course, in practice len is nearly always 4096 anyway.)

65
	 */

66
	if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) &&

67
	    static_branch_likely(&have_ce) && len >= SHA256_BLOCK_SIZE &&

68
	    len <= 65536 && likely(may_use_simd())) {

69
		kernel_neon_begin();

70
		sha256_ce_finup2x(ctx, data1, data2, len, out1, out2);

71
		kernel_neon_end();

72
		kmsan_unpoison_memory(out1, SHA256_DIGEST_SIZE);

73
		kmsan_unpoison_memory(out2, SHA256_DIGEST_SIZE);

74
		return true;

75
	}

76
	return false;

77
}

78


79
static bool sha256_finup_2x_is_optimized_arch(void)

80
{

81
	return static_key_enabled(&have_ce);

82
}

83


84
#ifdef CONFIG_KERNEL_MODE_NEON

85
#define sha256_mod_init_arch sha256_mod_init_arch

86
static void sha256_mod_init_arch(void)

87
{

88
	if (cpu_have_named_feature(ASIMD)) {

89
		static_branch_enable(&have_neon);

90
		if (cpu_have_named_feature(SHA2))

91
			static_branch_enable(&have_ce);

92
	}

93
}

94
#endif /* CONFIG_KERNEL_MODE_NEON */

95


96