From: Eric Biggers <ebiggers@kernel.org>
To: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
Ard Biesheuvel <ardb@kernel.org>,
"Jason A . Donenfeld" <Jason@zx2c4.com>,
Eric Biggers <ebiggers@kernel.org>
Subject: [PATCH 2/2] lib/crypto: x86/sha256: Remove unnecessary checks for nblocks==0
Date: Thu, 3 Jul 2025 19:39:58 -0700 [thread overview]
Message-ID: <20250704023958.73274-3-ebiggers@kernel.org> (raw)
In-Reply-To: <20250704023958.73274-1-ebiggers@kernel.org>
Since sha256_blocks() is called only with nblocks >= 1, remove
unnecessary checks for nblocks == 0 from the x86 SHA-256 assembly code.
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
lib/crypto/x86/sha256-avx-asm.S | 3 ---
lib/crypto/x86/sha256-avx2-asm.S | 1 -
lib/crypto/x86/sha256-ni-asm.S | 3 ---
lib/crypto/x86/sha256-ssse3-asm.S | 3 ---
4 files changed, 10 deletions(-)
diff --git a/lib/crypto/x86/sha256-avx-asm.S b/lib/crypto/x86/sha256-avx-asm.S
index 798a7f07fa013..c1aceb3ba3a3a 100644
--- a/lib/crypto/x86/sha256-avx-asm.S
+++ b/lib/crypto/x86/sha256-avx-asm.S
@@ -355,11 +355,10 @@ SYM_FUNC_START(sha256_transform_avx)
subq $STACK_SIZE, %rsp # allocate stack space
and $~15, %rsp # align stack pointer
shl $6, NUM_BLKS # convert to bytes
- jz .Ldone_hash
add INP, NUM_BLKS # pointer to end of data
mov NUM_BLKS, _INP_END(%rsp)
## load initial digest
mov 4*0(CTX), a
@@ -444,12 +443,10 @@ SYM_FUNC_START(sha256_transform_avx)
mov _INP(%rsp), INP
add $64, INP
cmp _INP_END(%rsp), INP
jne .Lloop0
-.Ldone_hash:
-
mov %rbp, %rsp
popq %rbp
popq %r15
popq %r14
popq %r13
diff --git a/lib/crypto/x86/sha256-avx2-asm.S b/lib/crypto/x86/sha256-avx2-asm.S
index 62a46993359e6..eb8836fb9695c 100644
--- a/lib/crypto/x86/sha256-avx2-asm.S
+++ b/lib/crypto/x86/sha256-avx2-asm.S
@@ -533,11 +533,10 @@ SYM_FUNC_START(sha256_transform_rorx)
subq $STACK_SIZE, %rsp
and $-32, %rsp # align rsp to 32 byte boundary
shl $6, NUM_BLKS # convert to bytes
- jz .Ldone_hash
lea -64(INP, NUM_BLKS), NUM_BLKS # pointer to last block
mov NUM_BLKS, _INP_END(%rsp)
cmp NUM_BLKS, INP
je .Lonly_one_block
diff --git a/lib/crypto/x86/sha256-ni-asm.S b/lib/crypto/x86/sha256-ni-asm.S
index 9ebbacbb9c13b..4bd9490ffc662 100644
--- a/lib/crypto/x86/sha256-ni-asm.S
+++ b/lib/crypto/x86/sha256-ni-asm.S
@@ -110,11 +110,10 @@
*/
.text
SYM_FUNC_START(sha256_ni_transform)
shl $6, NUM_BLKS /* convert to bytes */
- jz .Ldone_hash
add DATA_PTR, NUM_BLKS /* pointer to end of data */
/*
* load initial hash values
* Need to reorder these appropriately
@@ -161,12 +160,10 @@ SYM_FUNC_START(sha256_ni_transform)
pshufd $0x1B, STATE1, STATE1 /* DCBA */
movdqu STATE1, 0*16(STATE_PTR)
movdqu STATE0, 1*16(STATE_PTR)
-.Ldone_hash:
-
RET
SYM_FUNC_END(sha256_ni_transform)
.section .rodata.cst256.K256, "aM", @progbits, 256
.align 64
diff --git a/lib/crypto/x86/sha256-ssse3-asm.S b/lib/crypto/x86/sha256-ssse3-asm.S
index 3b602b7d43fad..0a2719661784c 100644
--- a/lib/crypto/x86/sha256-ssse3-asm.S
+++ b/lib/crypto/x86/sha256-ssse3-asm.S
@@ -363,11 +363,10 @@ SYM_FUNC_START(sha256_transform_ssse3)
subq $STACK_SIZE, %rsp
and $~15, %rsp
shl $6, NUM_BLKS # convert to bytes
- jz .Ldone_hash
add INP, NUM_BLKS
mov NUM_BLKS, _INP_END(%rsp) # pointer to end of data
## load initial digest
mov 4*0(CTX), a
@@ -456,12 +455,10 @@ SYM_FUNC_START(sha256_transform_ssse3)
mov _INP(%rsp), INP
add $64, INP
cmp _INP_END(%rsp), INP
jne .Lloop0
-.Ldone_hash:
-
mov %rbp, %rsp
popq %rbp
popq %r15
popq %r14
popq %r13
--
2.50.0
next prev parent reply other threads:[~2025-07-04 2:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-04 2:39 [PATCH 0/2] Small cleanups for x86 SHA-256 Eric Biggers
2025-07-04 2:39 ` [PATCH 1/2] lib/crypto: x86/sha256: Move static_call above kernel-mode FPU section Eric Biggers
2025-07-04 2:39 ` Eric Biggers [this message]
2025-07-04 13:26 ` [PATCH 0/2] Small cleanups for x86 SHA-256 Ard Biesheuvel
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