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Always use adr with __thumb2__.

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Thumb2 addresses are a bit a mess, depending on whether a label is
interpreted as a function pointer value (for use with BX and BLX) or as
a program counter value (for use with PC-relative addressing). Clang's
integrated assembler mis-assembles this code. See
https://crbug.com/124610#c54 for details.

Instead, use the ADR pseudo-instruction which has clear semantics and
should be supported by every assembler that handles the OpenSSL Thumb2
code. (In other files, the ADR vs SUB conditionals are based on
__thumb2__ already. For some reason, this one is based on __APPLE__, I'm
guessing to deal with an older version of clang assembler.)

It's unclear to me which of clang or binutils is "correct" or if this is
even a well-defined notion beyond "whatever binutils does". But I will
note that https://github.com/openssl/openssl/pull/4669 suggests binutils
has also changed behavior around this before.

See also https://github.com/openssl/openssl/pull/5431 in OpenSSL.

Bug: chromium:124610
Change-Id: I5e7a0c8c0f54a3f65cc324ad599a41883675f368
Reviewed-on: https://boringssl-review.googlesource.com/26164
Commit-Queue: Steven Valdez <svaldez@google.com>
Reviewed-by: Steven Valdez <svaldez@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
This commit is contained in:
David Benjamin 2018-02-21 16:22:34 -05:00 committed by CQ bot account: commit-bot@chromium.org
parent 36714fc8ee
commit 672f6fc248
2 changed files with 6 additions and 6 deletions
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6
crypto/fipsmodule/aes/asm/aes-armv4.pl
View File

@ -208,7 +208,7 @@ asm_AES_encrypt:
adr r3,. adr r3,.
#endif #endif
stmdb sp!,{r1,r4-r12,lr} stmdb sp!,{r1,r4-r12,lr}
#ifdef __APPLE__ #if defined(__thumb2__) || defined(__APPLE__)
adr $tbl,AES_Te adr $tbl,AES_Te
#else #else
sub $tbl,r3,#asm_AES_encrypt-AES_Te @ Te sub $tbl,r3,#asm_AES_encrypt-AES_Te @ Te
@ -486,7 +486,7 @@ _armv4_AES_set_encrypt_key:
mov lr,r1 @ bits mov lr,r1 @ bits
mov $key,r2 @ key mov $key,r2 @ key
#ifdef __APPLE__ #if defined(__thumb2__) || defined(__APPLE__)
adr $tbl,AES_Te+1024 @ Te4 adr $tbl,AES_Te+1024 @ Te4
#else #else
sub $tbl,r3,#_armv4_AES_set_encrypt_key-AES_Te-1024 @ Te4 sub $tbl,r3,#_armv4_AES_set_encrypt_key-AES_Te-1024 @ Te4
@ -984,7 +984,7 @@ asm_AES_decrypt:
adr r3,. adr r3,.
#endif #endif
stmdb sp!,{r1,r4-r12,lr} stmdb sp!,{r1,r4-r12,lr}
#ifdef __APPLE__ #if defined(__thumb2__) || defined(__APPLE__)
adr $tbl,AES_Td adr $tbl,AES_Td
#else #else
sub $tbl,r3,#asm_AES_decrypt-AES_Td @ Td sub $tbl,r3,#asm_AES_decrypt-AES_Td @ Td

6
crypto/fipsmodule/aes/asm/bsaes-armv7.pl
View File

@ -742,7 +742,7 @@ $code.=<<___;
_bsaes_decrypt8: _bsaes_decrypt8:
adr $const,. adr $const,.
vldmia $key!, {@XMM[9]} @ round 0 key vldmia $key!, {@XMM[9]} @ round 0 key
#ifdef __APPLE__ #if defined(__thumb2__) || defined(__APPLE__)
adr $const,.LM0ISR adr $const,.LM0ISR
#else #else
add $const,$const,#.LM0ISR-_bsaes_decrypt8 add $const,$const,#.LM0ISR-_bsaes_decrypt8
@ -841,7 +841,7 @@ _bsaes_const:
_bsaes_encrypt8: _bsaes_encrypt8:
adr $const,. adr $const,.
vldmia $key!, {@XMM[9]} @ round 0 key vldmia $key!, {@XMM[9]} @ round 0 key
#ifdef __APPLE__ #if defined(__thumb2__) || defined(__APPLE__)
adr $const,.LM0SR adr $const,.LM0SR
#else #else
sub $const,$const,#_bsaes_encrypt8-.LM0SR sub $const,$const,#_bsaes_encrypt8-.LM0SR
@ -949,7 +949,7 @@ $code.=<<___;
_bsaes_key_convert: _bsaes_key_convert:
adr $const,. adr $const,.
vld1.8 {@XMM[7]}, [$inp]! @ load round 0 key vld1.8 {@XMM[7]}, [$inp]! @ load round 0 key
#ifdef __APPLE__ #if defined(__thumb2__) || defined(__APPLE__)
adr $const,.LM0 adr $const,.LM0
#else #else
sub $const,$const,#_bsaes_key_convert-.LM0 sub $const,$const,#_bsaes_key_convert-.LM0