mirror/openssl
2
0
Fork 0
mirror of https://github.com/openssl/openssl.git synced 2024-11-27 05:21:51 +08:00
Code Issues Packages Projects Releases Wiki Activity

chacha/asm/chacha-armv8.pl: preserve FP registers d8 and d9 correctly

Browse Source 
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 <paul.dale@oracle.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10497)
This commit is contained in:
Ard Biesheuvel 2019-11-21 18:13:41 +01:00 committed by Tomas Mraz
parent d86925e6bd
commit 07a470729c
1 changed files with 3 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
crypto/chacha/asm/chacha-armv8.pl
View File

@ -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]