]> git.baikalelectronics.ru Git - kernel.git/commit
powerpc/64s: Fix logic when handling unknown CPU features
authorMichael Ellerman <mpe@ellerman.id.au>
Mon, 11 Feb 2019 00:20:01 +0000 (11:20 +1100)
committerMichael Ellerman <mpe@ellerman.id.au>
Thu, 21 Feb 2019 13:10:15 +0000 (00:10 +1100)
commite4a77966e57765c85f71f9a037e98e6101100d37
tree183583a54fc6ce283d9d3adcd8e7c58a362ce9b2
parentde0a0808b402fcb3bff421b32b0fcbfc4a40a2b7
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: 6e3c768120a2 ("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>
arch/powerpc/kernel/dt_cpu_ftrs.c