mirror of
https://github.com/git/git.git
synced 2024-11-08 14:09:26 +01:00
9dc523aa0e
Remove the PPC_SHA1 implementation added in a6ef3518f9a ([PATCH] PPC assembly implementation of SHA1, 2005-04-22). When this was added Apple consumer hardware used the PPC architecture, and the implementation was intended to improve SHA-1 speed there. Since it was added we've moved to using sha1collisiondetection by default, and anyone wanting hard-rolled non-DC SHA-1 implementation can use OpenSSL's via the OPENSSL_SHA1 knob. The PPC_SHA1 originally originally targeted 32 bit PPC, and later the 64 bit PPC 970 (a.k.a. Apple PowerPC G5). See 926172c5e48 (block-sha1: improve code on large-register-set machines, 2009-08-10) for a reference about the performance on G5 (a comment in block-sha1/sha1.c being removed here). I can't get it to do anything but segfault on both the BE and LE POWER machines in the GCC compile farm[1]. Anyone who's concerned about performance on PPC these days is likely to be using the IBM POWER processors. There have been proposals to entirely remove non-sha1collisiondetection implementations from the tree[2]. I think per [3] that would be a bit overzealous. I.e. there are various set-ups git's speed is going to be more important than the relatively implausible SHA-1 collision attack, or where such attacks are entirely mitigated by other means (e.g. by incoming objects being checked with DC_SHA1). But that really doesn't apply to PPC_SHA1 in particular, which seems to have outlived its usefulness. As this gets rid of the only in-tree *.S assembly file we can remove the small bits of logic from the Makefile needed to build objects from *.S (as opposed to *.c) The code being removed here was also throwing warnings with the "-pedantic" flag, it could have been fixed as 544d93bc3b4 (block-sha1: remove use of obsolete x86 assembly, 2022-03-10) did for block-sha1/*, but as noted above let's remove it instead. 1. https://cfarm.tetaneutral.net/machines/list/ Tested on gcc{110,112,135,203}, a mixture of POWER [789] ppc64 and ppc64le. All segfault in anything needing object hashing (e.g. t/t1007-hash-object.sh) when compiled with PPC_SHA1=Y. 2. https://lore.kernel.org/git/20200223223758.120941-1-mh@glandium.org/ 3. https://lore.kernel.org/git/20200224044732.GK1018190@coredump.intra.peff.net/ Acked-by: brian m. carlson" <sandals@crustytoothpaste.net> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com> |
||
|---|---|---|
| .. | ||
| sha1.c | ||
| sha1.h | ||