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5f5e6d620f
* Fix getauxval comment (API 18 not 20)
getauxval is available in Android starting with API 18, not 20.
The comment about __ANDROID_API__ appears to have been copied from the
NDK's cpufeatures, which always uses dlopen/dlsym and doesn't assume it
can directly call getauxval, even if __ANDROID_API__ is new enough.
With this project, though, when __ANDROID_API__ is 18 or up, the
CMakeLists.txt file would detect that getauxval is available and define
HAVE_STRONG_GETAUXVAL.
* Broaden Qualcomm Krait idiv workaround
Some Qualcomm Krait CPUs have IDIV support but the kernel doesn't
report it. Previously, this code looked for two CPUs:
- 0x510006F2 (0x51/'Q', variant 0, part 0x06f, rev 2)
- 0x510006F3 (0x51/'Q', variant 0, part 0x06f, rev 3)
This check misses my 2013 Nexus 7 device, which has this CPU ID:
- 0x511006f0 (0x51/'Q', variant 1, part 0x06f, rev 0)
My Nexus 7 device doesn't report idiv through AT_HWCAP or through
/proc/cpuinfo (AT_HWCAP is 0x1b0d7).
Expand the check to anything with:
- implementer 0x51
- architecture 7
- part 0x4d or 0x6f
Part 0x4d appears to be a dual-core Krait (e.g. see
https://crbug.com/341598#c43).
This new matching behavior is a subset of what the upstream kernel
does (patch[1] contributed by CodeAurora), and also closely matches the
behavior of pytorch/cpuinfo.
[1] 120ecfafab