linux_dsm_epyc7002/arch/powerpc
Michael Ellerman 8cfaf10691 powerpc/64s: Fix logic when handling unknown CPU features
In cpufeatures_process_feature(), if a provided CPU feature is unknown and
enable_unknown is false, we erroneously print that the feature is being
enabled and return true, even though no feature has been enabled, and
may also set feature bits based on the last entry in the match table.

Fix this so that we only set feature bits from the match table if we have
actually enabled a feature from that table, and when failing to enable an
unknown feature, always print the "not enabling" message and return false.

Coincidentally, some older gccs (<GCC 7), when invoked with
-fsanitize-coverage=trace-pc, cause a spurious uninitialised variable
warning in this function:

  arch/powerpc/kernel/dt_cpu_ftrs.c: In function ‘cpufeatures_process_feature’:
  arch/powerpc/kernel/dt_cpu_ftrs.c:686:7: warning: ‘m’ may be used uninitialized in this function [-Wmaybe-uninitialized]
    if (m->cpu_ftr_bit_mask)

An upcoming patch will enable support for kcov, which requires this option.
This patch avoids the warning.

Fixes: 5a61ef74f2 ("powerpc/64s: Support new device tree binding for discovering CPU features")
Reported-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
[ajd: add commit message]
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
2019-02-22 00:10:15 +11:00
..
boot powerpc/dts: Standardize DTS status assignments from "ok" to "okay" 2019-02-22 00:10:15 +11:00
configs powerpc/configs: Add PPC4xx_OCM to ppc40x_defconfig 2018-12-30 14:00:47 +11:00
crypto powerpc updates for 4.19 2018-08-17 11:32:50 -07:00
include powerpc/book3s: Remove pgd/pud/pmd_set() interfaces 2019-02-22 00:10:15 +11:00
kernel powerpc/64s: Fix logic when handling unknown CPU features 2019-02-22 00:10:15 +11:00
kvm Merge branch 'topic/ppc-kvm' into next 2019-02-22 00:09:56 +11:00
lib Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
math-emu powerpc: math-emu: remove unneeded header search paths 2019-01-14 20:39:27 +11:00
mm powerpc/64s/hash: Fix assert_slb_presence() use of the slbfee. instruction 2019-02-22 00:10:14 +11:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2018-12-10 18:00:43 -08:00
oprofile Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
perf Merge branch 'fixes' into next 2019-02-19 19:56:26 +11:00
platforms powerpc/pseries: export timebase register sample in lparcfg 2019-02-22 00:10:15 +11:00
purgatory powerpc updates for 4.19 2018-08-17 11:32:50 -07:00
sysdev Merge branch 'topic/dma' into next 2019-02-21 23:15:10 +11:00
tools powerpc/tools/checkpatch: Ignore DT_SPLIT_BINDING_PATCH 2018-12-04 19:45:01 +11:00
xmon powerpc/xmon: fix dump_segments() 2018-12-19 18:56:32 +11:00
Kbuild powerpc: Add -Werror at arch/powerpc level 2018-10-19 00:56:17 +11:00
Kconfig powerpc: Make PPC_64K_PAGES depend on only 44x or PPC_BOOK3S_64 2019-02-22 00:10:15 +11:00
Kconfig.debug powerpc: remove redundant 'default n' from Kconfig-s 2018-10-13 22:21:25 +11:00
Makefile powerpc: remove redundant header search path additions 2019-01-14 20:39:27 +11:00
Makefile.postlink License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00