From 40f47fa10a1d19c74f48a13d97b2eb19d5fb938d Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Sun, 11 Oct 2026 15:48:43 +0200 Subject: [PATCH] lib/crypto: x86/sha512: Follow the normal %rbp convention The SHA-512 assembly functions push callee-save GPRs to the stack *before* they set up the frame pointer (%rbp). (They are leaf functions, but they need to set up a frame pointer anyway because they allocate a 32-byte-aligned buffer on the stack.) As a result, during these functions, 8(%rbp) doesn't contain a return address like it is supposed to. This differs from the convention used by C code, and it interferes with the frame pointer unwinder (CONFIG_UNWINDER_FRAME_POINTER=y). Specifically, if a call trace is dumped in these functions, then all entries are populated purely from the fallback scan of the entire stack: RIP: 0010:sha512_transform_rorx+0x673/0xdf0 [...] Call Trace: ? sha512_blocks_avx2+0x37/0x60 ? __sha512_update+0x80/0x230 ? sha512+0x31/0x190 ? sha512+0x114/0x190 [...] ? do_syscall_64+0x6f/0x3e0 With this fix to follow the normal %rbp convention, the call trace is generated reliably: RIP: 0010:sha512_transform_rorx+0x90c/0xdf0 [...] Call Trace: sha512_blocks_avx2+0x37/0x60 __sha512_update+0x80/0x230 sha512+0x114/0x190 [...] do_syscall_64+0x6f/0x3e0 Reviewed-by: Ard Biesheuvel Link: https://patch.msgid.link/20261011134843.166585-4-ebiggers@kernel.org Signed-off-by: Eric Biggers --- lib/crypto/x86/sha512-avx-asm.S | 11 ++++++----- lib/crypto/x86/sha512-avx2-asm.S | 11 ++++++----- lib/crypto/x86/sha512-ssse3-asm.S | 11 ++++++----- 3 files changed, 18 insertions(+), 15 deletions(-) diff --git a/lib/crypto/x86/sha512-avx-asm.S b/lib/crypto/x86/sha512-avx-asm.S index 7732aa8fd850..a17dfedc1c51 100644 --- a/lib/crypto/x86/sha512-avx-asm.S +++ b/lib/crypto/x86/sha512-avx-asm.S @@ -276,6 +276,9 @@ frame_size = frame_WK + WK_SIZE ######################################################################## SYM_FUNC_START(sha512_transform_avx) + push %rbp + mov %rsp, %rbp + # Save GPRs push %rbx push %r12 @@ -284,8 +287,6 @@ SYM_FUNC_START(sha512_transform_avx) push %r15 # Allocate Stack Space - push %rbp - mov %rsp, %rbp sub $frame_size, %rsp and $~(0x20 - 1), %rsp @@ -348,9 +349,8 @@ SYM_FUNC_START(sha512_transform_avx) dec msglen jnz .Lupdateblock - # Restore Stack Pointer - mov %rbp, %rsp - pop %rbp + # Deallocate Stack Space + lea -40(%rbp), %rsp # Restore GPRs pop %r15 @@ -358,6 +358,7 @@ SYM_FUNC_START(sha512_transform_avx) pop %r13 pop %r12 pop %rbx + pop %rbp RET SYM_FUNC_END(sha512_transform_avx) diff --git a/lib/crypto/x86/sha512-avx2-asm.S b/lib/crypto/x86/sha512-avx2-asm.S index 22bdbfd899d0..2256d51297e1 100644 --- a/lib/crypto/x86/sha512-avx2-asm.S +++ b/lib/crypto/x86/sha512-avx2-asm.S @@ -568,6 +568,9 @@ frame_size = frame_CTX + CTX_SIZE ######################################################################## SYM_FUNC_START(sha512_transform_rorx) + push %rbp + mov %rsp, %rbp + # Save GPRs push %rbx push %r12 @@ -576,8 +579,6 @@ SYM_FUNC_START(sha512_transform_rorx) push %r15 # Allocate Stack Space - push %rbp - mov %rsp, %rbp sub $frame_size, %rsp and $~(0x20 - 1), %rsp @@ -667,9 +668,8 @@ SYM_FUNC_START(sha512_transform_rorx) cmp frame_INPEND(%rsp), INP jne .Lloop0 - # Restore Stack Pointer - mov %rbp, %rsp - pop %rbp + # Deallocate Stack Space + lea -40(%rbp), %rsp # Restore GPRs pop %r15 @@ -677,6 +677,7 @@ SYM_FUNC_START(sha512_transform_rorx) pop %r13 pop %r12 pop %rbx + pop %rbp vzeroupper RET diff --git a/lib/crypto/x86/sha512-ssse3-asm.S b/lib/crypto/x86/sha512-ssse3-asm.S index 4cae7445b2a8..1a37b7a735cf 100644 --- a/lib/crypto/x86/sha512-ssse3-asm.S +++ b/lib/crypto/x86/sha512-ssse3-asm.S @@ -275,6 +275,9 @@ frame_size = frame_WK + WK_SIZE ######################################################################## SYM_FUNC_START(sha512_transform_ssse3) + push %rbp + mov %rsp, %rbp + # Save GPRs push %rbx push %r12 @@ -283,8 +286,6 @@ SYM_FUNC_START(sha512_transform_ssse3) push %r15 # Allocate Stack Space - push %rbp - mov %rsp, %rbp sub $frame_size, %rsp and $~(0x20 - 1), %rsp @@ -347,9 +348,8 @@ SYM_FUNC_START(sha512_transform_ssse3) dec msglen jnz .Lupdateblock - # Restore Stack Pointer - mov %rbp, %rsp - pop %rbp + # Deallocate Stack Space + lea -40(%rbp), %rsp # Restore GPRs pop %r15 @@ -357,6 +357,7 @@ SYM_FUNC_START(sha512_transform_ssse3) pop %r13 pop %r12 pop %rbx + pop %rbp RET SYM_FUNC_END(sha512_transform_ssse3)