Messages in this thread | | | Date | Mon, 6 Dec 2021 16:23:20 +0000 | From | Catalin Marinas <> | Subject | Re: [PATCH] arm64: mm: Use asid2idx() and asid feature macro for cleanup |
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On Thu, Oct 28, 2021 at 08:27:23PM +0800, Yunfeng Ye wrote: > Use asid2idx() and asid feature macro for cleanup. > > No functional change. > > Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com> > --- > arch/arm64/mm/context.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c > index cd72576ae2b7..076f14a75bd5 100644 > --- a/arch/arm64/mm/context.c > +++ b/arch/arm64/mm/context.c > @@ -50,10 +50,10 @@ static u32 get_cpu_asid_bits(void) > pr_warn("CPU%d: Unknown ASID size (%d); assuming 8-bit\n", > smp_processor_id(), fld); > fallthrough; > - case 0: > + case ID_AA64MMFR0_ASID_8: > asid = 8; > break; > - case 2: > + case ID_AA64MMFR0_ASID_16: > asid = 16; > }
I think this change is fine.
> @@ -162,7 +162,7 @@ static u64 new_context(struct mm_struct *mm) > u64 generation = atomic64_read(&asid_generation); > > if (asid != 0) { > - u64 newasid = generation | (asid & ~ASID_MASK); > + u64 newasid = generation | asid2idx(asid); > > /* > * If our current ASID was active during a rollover, we > @@ -306,7 +306,7 @@ unsigned long arm64_mm_context_get(struct mm_struct *mm) > out_unlock: > raw_spin_unlock_irqrestore(&cpu_asid_lock, flags); > > - asid &= ~ASID_MASK; > + asid = asid2idx(asid);
While functionally the code is the same, I don't think this was the intention of asid2idx(). It's meant to provide an index into asid_map, while the ASID_MASK lines isolate the asid number and add a new generation to it.
-- Catalin
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