PR/55598 CVS commit: src/sys/crypto/chacha/arch/arm

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

The following reply was made to PR port-arm/55598; it has been noted by GNATS.

From: "Taylor R Campbell" <riastradh%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/55598 CVS commit: src/sys/crypto/chacha/arch/arm
Date: Sun, 23 Aug 2020 16:39:06 +0000

 Module Name:	src
 Committed By:	riastradh
 Date:		Sun Aug 23 16:39:06 UTC 2020
 
 Modified Files:
 	src/sys/crypto/chacha/arch/arm: chacha_neon_32.S
 
 Log Message:
 Adjust sp, not fp, to allocate a 32-byte temporary.
 
 Costs another couple MOV instructions, but we can't skimp on this --
 there's no red zone below sp for interrupts on arm, so we can't touch
 anything there.  So just use fp to save sp and then adjust sp itself,
 rather than using fp as a temporary register to point just below sp.
 
 Should fix PR port-arm/55598 -- previously the ChaCha self-test
 failed 33/10000 trials triggered by sysctl during running system;
 with the patch it has failed 0/10000 trials.
 
 (Presumably it happened more often at boot time, leading to 5/26
 failures in the test bed, because we just enabled interrupts and some
 devices are starting to deliver interrupts.)
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.3 -r1.4 src/sys/crypto/chacha/arch/arm/chacha_neon_32.S
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.