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lib/crypto: x86/sha512: Follow the normal %rbp convention

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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:
     <TASK>
     ? 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:
     <TASK>
     sha512_blocks_avx2+0x37/0x60
     __sha512_update+0x80/0x230
     sha512+0x114/0x190
     [...]
     do_syscall_64+0x6f/0x3e0

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://patch.msgid.link/20261011134843.166585-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
This commit is contained in:
Eric Biggers 2026-10-11 15:48:43 +02:00
parent cc76c9b82b
commit 40f47fa10a
3 changed files with 18 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
lib/crypto/x86/sha512-avx-asm.S
View File

@ -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)

11
lib/crypto/x86/sha512-avx2-asm.S
View File

@ -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

11
lib/crypto/x86/sha512-ssse3-asm.S
View File

@ -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)