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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>
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In previous patches, extern was mechanically removed from function
declarations without care to formatting, causing parameter lists to be
misaligned. Manually format changed sections such that the parameter
lists should be realigned.
Viewing this patch with 'git diff -w' should produce no output.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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There has been a push to remove extern from function declarations.
Remove some instances of "extern" for function declarations which are
caught by Coccinelle. Note that Coccinelle has some difficulty with
processing functions with `__attribute__` or varargs so some `extern`
declarations are left behind to be dealt with in a future patch.
This was the Coccinelle patch used:
@@
type T;
identifier f;
@@
- extern
T f(...);
and it was run with:
$ git ls-files \*.{c,h} |
grep -v ^compat/ |
xargs spatch --sp-file contrib/coccinelle/noextern.cocci --in-place
Files under `compat/` are intentionally excluded as some are directly
copied from external sources and we should avoid churning them as much
as possible.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The git source uses git_SHA1_Update() and friends to call into the
code that computes the hashes. Traditionally, we used to map these
directly to underlying implementation of the SHA-1 hash (e.g.
SHA1_Update() from OpenSSL or blk_SHA1_Update() from block-sha1/).
This arrangement however makes it hard to tweak behaviour of the
underlying implementation without fully replacing. If we want to
introduce a tweaked_SHA1_Update() wrapper to implement the "Update"
in a slightly different way, for example, the implementation of the
wrapper still would want to call into the underlying implementation,
but tweaked_SHA1_Update() cannot call git_SHA1_Update() to get to
the underlying implementation (often but not always SHA1_Update()).
Add another level of indirection that maps platform_SHA1_Update()
and friends to their underlying implementations, and by default make
git_SHA1_Update() and friends map to platform_SHA1_* functions.
Doing it this way will later allow us to map git_SHA1_Update() to
tweaked_SHA1_Update(), and the latter can use platform_SHA1_Update()
in its implementation.
Signed-off-by: Atousa Pahlevan Duprat <apahlevan@ieee.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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On ARM I have the following compilation errors:
CC fast-import.o
In file included from cache.h:8,
from builtin.h:6,
from fast-import.c:142:
arm/sha1.h:14: error: conflicting types for 'SHA_CTX'
/usr/include/openssl/sha.h:105: error: previous declaration of 'SHA_CTX' was here
arm/sha1.h:16: error: conflicting types for 'SHA1_Init'
/usr/include/openssl/sha.h:115: error: previous declaration of 'SHA1_Init' was here
arm/sha1.h:17: error: conflicting types for 'SHA1_Update'
/usr/include/openssl/sha.h:116: error: previous declaration of 'SHA1_Update' was here
arm/sha1.h:18: error: conflicting types for 'SHA1_Final'
/usr/include/openssl/sha.h:117: error: previous declaration of 'SHA1_Final' was here
make: *** [fast-import.o] Error 1
This is because openssl header files are always included in
git-compat-util.h since commit 684ec6c63c whenever NO_OPENSSL is not
set, which somehow brings in <openssl/sha1.h> clashing with the custom
ARM version. Compilation of git is probably broken on PPC too for the
same reason.
Turns out that the only file requiring openssl/ssl.h and openssl/err.h
is imap-send.c. But only moving those problematic includes there
doesn't solve the issue as it also includes cache.h which brings in the
conflicting local SHA1 header file.
As suggested by Jeff King, the best solution is to rename our references
to SHA1 functions and structure to something git specific, and define those
according to the implementation used.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
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This uses "git-apply --whitespace=strip" to fix whitespace errors that have
crept in to our source files over time. There are a few files that need
to have trailing whitespaces (most notably, test vectors). The results
still passes the test, and build result in Documentation/ area is unchanged.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Signed-off-by: Junio C Hamano <junkio@cox.net>
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The only visible change is that git-blame doesn't understand
"--compability" anymore, but it does accept "--compatibility" instead,
which is already documented.
Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
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This is about 15% faster that the current sha1ppc.S on a G4, and
5% faster on a G5 when hashing 10 million bytes, unaligned.
(The G5 ratio seems to get better as the sizes fall.)
It's also somewhat smaller, due to using load-multiple instructions.
No copyright is claimed on the changes to Paul Mackerras' work below.
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The PPC SHA1 routine had an overflow which meant that it gave
incorrect results for input buffers >= 512MB. This fixes it by
ensuring that the update of the total length in bits is done using
64-bit arithmetic.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
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Here is a SHA1 implementation with the core written in PPC assembly.
On my 2GHz G5, it does 218MB/s, compared to 135MB/s for the openssl
version or 45MB/s for the mozilla version.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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