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183385f02f
Some CPUs report "illegal instruction" error for the crc test because they do not support the relevant optional feature . This can be fixed by introducing CPU feature detection for AArch64 . The difference with the x86 implementation is the dispatcher . It is based on the glibc function `getauxval(AT_HWCAP)` and `getauxval(AT_HWCAP2)` , not registers or instructions . On a heterogeneous system (big.LITTLE) , it is dangerous to detect CPU features using identification registers . And while it is possible to use architectural feature registers from userspace on recent kernels, this won't necessarily work with older platforms . Thus we use the HW_CAPs exported from the kernel (and visible in getauxval) as the solution. - According to kernel suggestion , getauxval should be used for this purpose . - [CPU Feature detection](https://github.com/torvalds/linux/blob/master/Documentation/arm64/cpu-feature-registers.rst) - According to AAPCS result/paramter registers should be saved/restore for function call - [AAPCS](http://infocenter.arm.com/help/topic/com.arm.doc.ihi0055b/IHI0055B_aapcs64.pdf) - [GLibc](https://sourceware.org/git/gitweb.cgi?p=glibc.git;a=blob;f=sysdeps/aarch64/dl-trampoline.S) Signed-off-by: Jerry Yu <jerry.h.yu@arm.com> Change-Id: Ic9abe0d2268ac95537e1abf10acc642fc58a5054
40 lines
1.9 KiB
C
40 lines
1.9 KiB
C
/**********************************************************************
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Copyright(c) 2019 Arm Corporation All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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* Neither the name of Arm Corporation nor the names of its
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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**********************************************************************/
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#include <aarch64_multibinary.h>
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DEFINE_INTERFACE_DISPATCHER(isal_zero_detect)
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{
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unsigned long auxval = getauxval(AT_HWCAP);
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if (auxval & HWCAP_ASIMD)
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return PROVIDER_INFO(mem_zero_detect_neon);
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return PROVIDER_BASIC(mem_zero_detect);
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}
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