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- Log -----------------------------------------------------------------
commit 07a470729c4ace678fba6aeeeaf506436aa856e2
Author: Ard Biesheuvel <[email protected]>
Date: Thu Nov 21 18:13:41 2019 +0100
chacha/asm/chacha-armv8.pl: preserve FP registers d8 and d9 correctly
Depending on the size of the input, we may take different paths through
the accelerated arm64 ChaCha20 routines, each of which use a different
subset of the FP registers, some of which need to be preserved and
restored, as required by the AArch64 calling convention (AAPCS64)
In some cases, (e.g., when the input size is 640 bytes), we call the 512
byte NEON path followed directly by the scalar path, and in this case,
we preserve and restore d8 and d9, only to clobber them again
immediately before handing over to the scalar path which does not touch
the FP registers at all, and hence does not restore them either.
Fix this by moving the restoration of d8 and d9 to a later stage in the
512 byte routine, either before calling the scalar path, or when exiting
the function.
Fixes #10470
CLA: trivial
Reviewed-by: Paul Dale <[email protected]>
Reviewed-by: Matt Caswell <[email protected]>
(Merged from https://github.com/openssl/openssl/pull/10497)
-----------------------------------------------------------------------
Summary of changes:
crypto/chacha/asm/chacha-armv8.pl | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/crypto/chacha/asm/chacha-armv8.pl
b/crypto/chacha/asm/chacha-armv8.pl
index aed873d57e..7868389f71 100755
--- a/crypto/chacha/asm/chacha-armv8.pl
+++ b/crypto/chacha/asm/chacha-armv8.pl
@@ -1232,8 +1232,7 @@ $code.=<<___;
adds $len,$len,#512
ushr $ONE,$ONE,#1 // 4 -> 2
- ldp d8,d9,[sp,#128+0] // meet ABI requirements
- ldp d10,d11,[sp,#128+16]
+ ldp d10,d11,[sp,#128+16] // meet ABI requirements
ldp d12,d13,[sp,#128+32]
ldp d14,d15,[sp,#128+48]
@@ -1250,6 +1249,7 @@ $code.=<<___;
ld1 {$CTR,$ROT24},[$key]
b.hs .Loop_outer_neon
+ ldp d8,d9,[sp,#0] // meet ABI requirements
eor @K[1],@K[1],@K[1]
eor @K[2],@K[2],@K[2]
eor @K[3],@K[3],@K[3]
@@ -1259,6 +1259,7 @@ $code.=<<___;
b .Loop_outer
.Ldone_512_neon:
+ ldp d8,d9,[sp,#128+0] // meet ABI requirements
ldp x19,x20,[x29,#16]
add sp,sp,#128+64
ldp x21,x22,[x29,#32]
