boringssl/crypto/cpu-ppc64le.c
Adam Langley b18cb6a5d0 Make the POWER hardware capability value a global in crypto.c.
(Thanks to Sam Panzer for the patch.)

At least some linkers will drop constructor functions if no symbols from
that translation unit are used elsewhere in the program. On POWER, since
the cached capability value isn't a global in crypto.o (like other
platforms), the constructor function is getting discarded.

The C++11 spec says (3.6.2, paragraph 4):

    It is implementation-defined whether the dynamic initialization of a
    non-local variable with static storage duration is done before the
    first statement of main. If the initialization is deferred to some
    point in time after the first statement of main, it shall occur
    before the first odr-use (3.2) of any function or variable defined
    in the same translation unit as the variable to be initialized.

Compilers appear to interpret that to mean they are allowed to drop
(i.e. indefinitely defer) constructors that occur in translation units
that are never used, so they can avoid initializing some part of a
library if it's dropped on the floor.

This change makes the hardware capability value for POWER a global in
crypto.c, which should prevent the constructor function from being
ignored.

Change-Id: I43ebe492d0ac1491f6f6c2097971a277f923dd3e
Reviewed-on: https://boringssl-review.googlesource.com/14664
Commit-Queue: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
2017-04-04 18:19:19 +00:00

39 lines
1.3 KiB
C

/* Copyright (c) 2016, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <openssl/cpu.h>
#if defined(OPENSSL_PPC64LE)
#include <sys/auxv.h>
#include "internal.h"
#if !defined(PPC_FEATURE2_HAS_VCRYPTO)
/* PPC_FEATURE2_HAS_VCRYPTO was taken from section 4.1.2.3 of the “OpenPOWER
* ABI for Linux Supplement”. */
#define PPC_FEATURE2_HAS_VCRYPTO 0x02000000
#endif
void OPENSSL_cpuid_setup(void) {
OPENSSL_ppc64le_hwcap2 = getauxval(AT_HWCAP2);
}
int CRYPTO_is_PPC64LE_vcrypto_capable(void) {
return (OPENSSL_ppc64le_hwcap2 & PPC_FEATURE2_HAS_VCRYPTO) != 0;
}
#endif /* OPENSSL_PPC64LE */