Hello Desnes, thanks for the patch. "Desnes A. Nunes do Rosario" <desn...@linux.ibm.com> writes:
> PowerVM systems running compatibility mode on a few Power8 revisions are
> still vulnerable to the hardware defect that loses PMU exceptions arriving
> prior to a context switch.
>
> The software fix for this issue is enabled through the CPU_FTR_PMAO_BUG
> cpu_feature bit, nevertheless this bit also needs to be set for PowerVM
> compatibility mode systems.
>
> Fixes: 68f2f0d431d9ea4 ("powerpc: Add a cpu feature CPU_FTR_PMAO_BUG")
> Signed-off-by: Desnes A. Nunes do Rosario <desn...@linux.ibm.com>
> ---
> arch/powerpc/kernel/cputable.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
> index e745abc5457a..5bfef6263dfb 100644
> --- a/arch/powerpc/kernel/cputable.c
> +++ b/arch/powerpc/kernel/cputable.c
> @@ -2198,6 +2198,8 @@ static struct cpu_spec * __init setup_cpu_spec(unsigned
> long offset,
> if (old.oprofile_cpu_type != NULL) {
> t->oprofile_cpu_type = old.oprofile_cpu_type;
> t->oprofile_type = old.oprofile_type;
> + if (old.cpu_features & CPU_FTR_PMAO_BUG)
> + t->cpu_features |= CPU_FTR_PMAO_BUG;
What are your thoughts about doing:
t->cpu_features |= old.cpu_features & CPU_FTR_PMAO_BUG;
Also, I would recommend adding a short comment on top of the added
lines explaining why it is needed.
Best regards,
Leonardo Bras
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