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Fix beeu_mod_inverse_vartime CFI annotations and preamble.

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This was also caught by the in-progress unwind tester. There are two
issues here.  First, .cfi_endproc must come after ret to fully cover the
function.  More importantly, this function is confused about whether it
has a frame pointer or not.

It looks like it does (movq %rsp, %rbp), and annotates accordingly, but
it does not actually use the frame pointer. It cannot. $y4 is rbp and
gets clobbered immediately after the preamble!

Remove this instruction and align the CFI annotations with a
frame-pointer-less function.

Bug: 181
Change-Id: I47b5f9798b3bcee1748e537b21c173d312a14b42
Reviewed-on: https://boringssl-review.googlesource.com/c/33947
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
This commit is contained in:
David Benjamin 2018-12-30 02:58:55 +00:00 committed by CQ bot account: commit-bot@chromium.org
parent a306b1b908
commit c2e8d016f5
1 changed files with 3 additions and 5 deletions
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8
crypto/fipsmodule/ec/asm/p256_beeu-x86_64-asm.pl
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@ -156,9 +156,6 @@ beeu_mod_inverse_vartime:
.cfi_startproc
push %rbp
.cfi_push rbp
movq %rsp, %rbp
.cfi_def_cfa_register rbp
push %r12
.cfi_push r12
push %r13
@ -173,6 +170,7 @@ beeu_mod_inverse_vartime:
.cfi_push rsi
sub \$$last_rsp_offset, %rsp
.cfi_adjust_cfa_offset $last_rsp_offset
movq $out, $out_rsp(%rsp)
# X=1, Y=0
@ -380,6 +378,7 @@ beeu_mod_inverse_vartime:
.Lbeeu_finish:
add \$$last_rsp_offset, %rsp
.cfi_adjust_cfa_offset -$last_rsp_offset
pop %rsi
.cfi_pop rsi
pop %rbx
@ -394,9 +393,8 @@ beeu_mod_inverse_vartime:
.cfi_pop r12
pop %rbp
.cfi_pop rbp
.cfi_def_cfa rsp, 8
.cfi_endproc
ret
.cfi_endproc
.size beeu_mod_inverse_vartime, .-beeu_mod_inverse_vartime
___