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authorSzabolcs Nagy <szabolcs.nagy@arm.com>2018-06-28 14:43:07 +0100
committerSzabolcs Nagy <szabolcs.nagy@arm.com>2018-07-06 15:57:18 +0100
commitd0cd79807157e399ff58e67cb51651f90442122e (patch)
tree55f969d52e7d9fc03652ddbb925dbdc63f59d242 /include
parentddb3c626b0a159de3547d901420198b626c29554 (diff)
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aarch64: Remove HWCAP_CPUID from HWCAP_IMPORTANT
This partially reverts

commit f82e9672ad89ea1ef40bbe1af71478e255e87c5e
Author:     Siddhesh Poyarekar <siddhesh@sourceware.org>

    aarch64: Allow overriding HWCAP_CPUID feature check using HWCAP_MASK

The idea was to make it possible to disable cpuid based ifunc resolution
in glibc by changing the hwcap mask which the user could already control.

However the hwcap mask has an orthogonal role: it specifies additional
library search paths for the dynamic linker.  So "cpuid" got added to
the search paths when it was set in the default mask (HWCAP_IMPORTANT),
which is not useful behaviour, the hwcap masking should not be reused
in the cpu features code.

Meanwhile there is a tunable to set the cpu explicitly so it is possible
to disable the cpuid based dispatch without using a hwcap mask:

  GLIBC_TUNABLES=glibc.tune.cpu=generic

	* sysdeps/unix/sysv/linux/aarch64/cpu-features.c (init_cpu_features):
	Use dl_hwcap without masking.
	* sysdeps/unix/sysv/linux/aarch64/dl-procinfo.h (HWCAP_IMPORTANT):
	Remove HWCAP_CPUID.
Diffstat (limited to 'include')
0 files changed, 0 insertions, 0 deletions