Re: [PATCH v1 03/13] arm64: mm: Implicitly invalidate user ASID based on TLBI operation

Ryan Roberts
2026-01-05T17:13:56Z

On 05/01/2026 05:34, Linu Cherian wrote:
> Hi Ryan,
>
> On Tue, Dec 16, 2025 at 02:45:48PM +0000, Ryan Roberts wrote:
>> When kpti is enabled, separate ASIDs are used for userspace and
>> kernelspace, requiring ASID-qualified TLB invalidation by virtual
>> address to invalidate both of them.
>>
>> Push the logic for invalidating the two ASIDs down into the low-level
>> tlbi-op-specific functions and remove the burden from the caller to
>> handle the kpti-specific behaviour.
>>
>> Co-developed-by: Will Deacon <will@kernel.org>
>> Signed-off-by: Will Deacon <will@kernel.org>
>> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
>> ---
>> arch/arm64/include/asm/tlbflush.h | 27 ++++++++++-----------------
>> 1 file changed, 10 insertions(+), 17 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
>> index c5111d2afc66..31f43d953ce2 100644
>> --- a/arch/arm64/include/asm/tlbflush.h
>> +++ b/arch/arm64/include/asm/tlbflush.h
>> @@ -110,6 +110,7 @@ typedef void (*tlbi_op)(u64 arg);
>> static __always_inline void vae1is(u64 arg)
>> {
>> __tlbi(vae1is, arg);
>> + __tlbi_user(vae1is, arg);
>> }
>>
>> static __always_inline void vae2is(u64 arg)
>> @@ -126,6 +127,7 @@ static __always_inline void vale1(u64 arg)
>> static __always_inline void vale1is(u64 arg)
>> {
>> __tlbi(vale1is, arg);
>> + __tlbi_user(vale1is, arg);
>> }
>>
>> static __always_inline void vale2is(u64 arg)
>> @@ -162,11 +164,6 @@ static __always_inline void __tlbi_level(tlbi_op op, u64 addr, u32 level)
>> op(arg);
>> }
>>
>> -#define __tlbi_user_level(op, arg, level) do { \
>> - if (arm64_kernel_unmapped_at_el0()) \
>> - __tlbi_level(op, (arg | USER_ASID_FLAG), level); \
>> -} while (0)
>> -
>> /*
>> * This macro creates a properly formatted VA operand for the TLB RANGE. The
>> * value bit assignments are:
>> @@ -435,8 +432,6 @@ static inline void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
>> * @stride: Flush granularity
>> * @asid: The ASID of the task (0 for IPA instructions)
>> * @tlb_level: Translation Table level hint, if known
>> - * @tlbi_user: If 'true', call an additional __tlbi_user()
>> - * (typically for user ASIDs). 'flase' for IPA instructions
>> * @lpa2: If 'true', the lpa2 scheme is used as set out below
>> *
>> * When the CPU does not support TLB range operations, flush the TLB
>> @@ -462,6 +457,7 @@ static inline void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
>> static __always_inline void rvae1is(u64 arg)
>> {
>> __tlbi(rvae1is, arg);
>> + __tlbi_user(rvae1is, arg);
>> }
>>
>> static __always_inline void rvale1(u64 arg)
>> @@ -473,6 +469,7 @@ static __always_inline void rvale1(u64 arg)
>> static __always_inline void rvale1is(u64 arg)
>> {
>> __tlbi(rvale1is, arg);
>> + __tlbi_user(rvale1is, arg);
>> }
>>
>> static __always_inline void rvaale1is(u64 arg)
>> @@ -491,7 +488,7 @@ static __always_inline void __tlbi_range(tlbi_op op, u64 arg)
>> }
>>
>> #define __flush_tlb_range_op(op, start, pages, stride, \
>> - asid, tlb_level, tlbi_user, lpa2) \
>> + asid, tlb_level, lpa2) \
>> do { \
>> typeof(start) __flush_start = start; \
>> typeof(pages) __flush_pages = pages; \
>> @@ -506,8 +503,6 @@ do { \
>> (lpa2 && __flush_start != ALIGN(__flush_start, SZ_64K))) { \
>> addr = __TLBI_VADDR(__flush_start, asid); \
>> __tlbi_level(op, addr, tlb_level); \
>> - if (tlbi_user) \
>> - __tlbi_user_level(op, addr, tlb_level); \
>> __flush_start += stride; \
>> __flush_pages -= stride >> PAGE_SHIFT; \
>> continue; \
>> @@ -518,8 +513,6 @@ do { \
>> addr = __TLBI_VADDR_RANGE(__flush_start >> shift, asid, \
>> scale, num, tlb_level); \
>> __tlbi_range(r##op, addr); \
>> - if (tlbi_user) \
>> - __tlbi_user(r##op, addr); \
>> __flush_start += __TLBI_RANGE_PAGES(num, scale) << PAGE_SHIFT; \
>> __flush_pages -= __TLBI_RANGE_PAGES(num, scale);\
>> } \
>> @@ -528,7 +521,7 @@ do { \
>> } while (0)
>>
>> #define __flush_s2_tlb_range_op(op, start, pages, stride, tlb_level) \
>> - __flush_tlb_range_op(op, start, pages, stride, 0, tlb_level, false, kvm_lpa2_is_enabled());
>> + __flush_tlb_range_op(op, start, pages, stride, 0, tlb_level, kvm_lpa2_is_enabled());
>>
>> static inline bool __flush_tlb_range_limit_excess(unsigned long start,
>> unsigned long end, unsigned long pages, unsigned long stride)
>> @@ -568,10 +561,10 @@ static inline void __flush_tlb_range_nosync(struct mm_struct *mm,
>>
>> if (last_level)
>> __flush_tlb_range_op(vale1is, start, pages, stride, asid,
>> - tlb_level, true, lpa2_is_enabled());
>> + tlb_level, lpa2_is_enabled());
>> else
>> __flush_tlb_range_op(vae1is, start, pages, stride, asid,
>> - tlb_level, true, lpa2_is_enabled());
>> + tlb_level, lpa2_is_enabled());
>>
>> mmu_notifier_arch_invalidate_secondary_tlbs(mm, start, end);
>> }
>> @@ -630,7 +623,7 @@ static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end
>>
>> dsb(ishst);
>> __flush_tlb_range_op(vaale1is, start, pages, stride, 0,
>> - TLBI_TTL_UNKNOWN, false, lpa2_is_enabled());
>> + TLBI_TTL_UNKNOWN, lpa2_is_enabled());
>> dsb(ish);
>> isb();
>
>
>
> __flush_tlb_range_op call in local_flush_tlb_contpte is missed out.

Thanks; this is part of my botched rebase. I'll fix it in the next rev.

>
>
> --
> Linu Cherian