Commit 8a5d8bc4 authored by David Benjamin's avatar David Benjamin
Browse files

Always use adr with __thumb2__. 

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.

Reviewed-by: default avatarAndy Polyakov <appro@openssl.org>
Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5431)
parent 89f66fe2

crypto/aes/asm/aes-armv4.pl

+3 −3
Original line number Diff line number Diff line
@@ -203,7 +203,7 @@ AES_encrypt: 
	adr	r3,.

#endif

	stmdb   sp!,{r1,r4-r12,lr}

#ifdef	__APPLE__

#if defined(__thumb2__) || defined(__APPLE__)

	adr	$tbl,AES_Te

#else

	sub	$tbl,r3,#AES_encrypt-AES_Te	@ Te
@@ -481,7 +481,7 @@ _armv4_AES_set_encrypt_key: 
	mov	lr,r1			@ bits

	mov	$key,r2			@ key



#ifdef	__APPLE__

#if defined(__thumb2__) || defined(__APPLE__)

	adr	$tbl,AES_Te+1024				@ Te4

#else

	sub	$tbl,r3,#_armv4_AES_set_encrypt_key-AES_Te-1024	@ Te4
@@ -979,7 +979,7 @@ AES_decrypt: 
	adr	r3,.

#endif

	stmdb   sp!,{r1,r4-r12,lr}

#ifdef	__APPLE__

#if defined(__thumb2__) || defined(__APPLE__)

	adr	$tbl,AES_Td

#else

	sub	$tbl,r3,#AES_decrypt-AES_Td	@ Td

crypto/aes/asm/bsaes-armv7.pl

+3 −3
Original line number Diff line number Diff line
@@ -742,7 +742,7 @@ $code.=<<___; 
_bsaes_decrypt8:

	adr	$const,.

	vldmia	$key!, {@XMM[9]}		@ round 0 key

#ifdef	__APPLE__

#if defined(__thumb2__) || defined(__APPLE__)

	adr	$const,.LM0ISR

#else

	add	$const,$const,#.LM0ISR-_bsaes_decrypt8
@@ -841,7 +841,7 @@ _bsaes_const: 
_bsaes_encrypt8:

	adr	$const,.

	vldmia	$key!, {@XMM[9]}		@ round 0 key

#ifdef	__APPLE__

#if defined(__thumb2__) || defined(__APPLE__)

	adr	$const,.LM0SR

#else

	sub	$const,$const,#_bsaes_encrypt8-.LM0SR
@@ -949,7 +949,7 @@ $code.=<<___; 
_bsaes_key_convert:

	adr	$const,.

	vld1.8	{@XMM[7]},  [$inp]!		@ load round 0 key

#ifdef	__APPLE__

#if defined(__thumb2__) || defined(__APPLE__)

	adr	$const,.LM0

#else

	sub	$const,$const,#_bsaes_key_convert-.LM0