Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH] arm64: mm: Use asid2idx() and asid feature macro for cleanup | From | Yunfeng Ye <> | Date | Tue, 7 Dec 2021 10:21:26 +0800 |
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On 2021/12/7 0:23, Catalin Marinas wrote: > 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. > The commit 0c8ea531b774 ("arm64: mm: Allocate ASIDs in pairs") introduce the asid2idx and idx2asid macro, but these macros is not really useful after the commit f88f42f853a8 ("arm64: context: Free up kernel ASIDs if KPTI is not in use").
I think "(asid & ~ASID_MASK)" can be instead by a macro, it is the same code with asid2idx(). Can it be renamed? (eg, ctxid2asid)
Thanks.
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