| Message ID | 4aaabf1b-00c3-3365-e371-9d97dc0c06ab@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: mm: Use asid2idx() and asid feature macro for cleanup | expand |
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.
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.
On Tue, Dec 07, 2021 at 10:21:26AM +0800, Yunfeng Ye wrote: > On 2021/12/7 0:23, Catalin Marinas wrote: > > On Thu, Oct 28, 2021 at 08:27:23PM +0800, Yunfeng Ye wrote: > >> @@ -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) Yes, that would work.
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; } @@ -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); /* Set the equivalent of USER_ASID_BIT */ if (asid && arm64_kernel_unmapped_at_el0())
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(-)