[PATCH v1 12/13] arm64: mm: Wrap flush_tlb_page() around ___flush_tlb_range()

Ryan Roberts
2025-12-16T14:46:32Z

Flushing a page from the tlb is just a special case of flushing a range.
So let's rework flush_tlb_page() so that it simply wraps
___flush_tlb_range(). While at it, let's also update the API to take the
same flags that we use when flushing a range. This allows us to delete
all the ugly "_nosync", "_local" and "_nonotify" variants.

Thanks to constant folding, all of the complex looping and tlbi-by-range
options get eliminated so that the generated code for flush_tlb_page()
looks very similar to the previous version.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---
arch/arm64/include/asm/pgtable.h | 6 +--
arch/arm64/include/asm/tlbflush.h | 81 ++++++++++---------------------
arch/arm64/mm/fault.c | 2 +-
3 files changed, 29 insertions(+), 60 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 736747fbc843..b96a7ca465a1 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -136,10 +136,10 @@ static inline void arch_leave_lazy_mmu_mode(void)
* entries exist.
*/
#define flush_tlb_fix_spurious_fault(vma, address, ptep) \
- local_flush_tlb_page_nonotify(vma, address)
+ __flush_tlb_page(vma, address, TLBF_NOBROADCAST | TLBF_NONOTIFY)

#define flush_tlb_fix_spurious_fault_pmd(vma, address, pmdp) \
- local_flush_tlb_page_nonotify(vma, address)
+ __flush_tlb_page(vma, address, TLBF_NOBROADCAST | TLBF_NONOTIFY)

/*
* ZERO_PAGE is a global shared page that is always zero: used
@@ -1351,7 +1351,7 @@ static inline int __ptep_clear_flush_young(struct vm_area_struct *vma,
* context-switch, which provides a DSB to complete the TLB
* invalidation.
*/
- flush_tlb_page_nosync(vma, address);
+ __flush_tlb_page(vma, address, TLBF_NOSYNC);
}

return young;
diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
index ee747e66bbef..fa5aee990742 100644
--- a/arch/arm64/include/asm/tlbflush.h
+++ b/arch/arm64/include/asm/tlbflush.h
@@ -256,10 +256,7 @@ static inline void __tlbi_level(tlbi_op op, u64 addr, u32 level)
* unmapping pages from vmalloc/io space.
*
* flush_tlb_page(vma, addr)
- * Invalidate a single user mapping for address 'addr' in the
- * address space corresponding to 'vma->mm'. Note that this
- * operation only invalidates a single, last-level page-table
- * entry and therefore does not affect any walk-caches.
+ * Equivalent to __flush_tlb_page(..., flags=TLBF_NONE)
*
*
* Next, we have some undocumented invalidation routines that you probably
@@ -287,13 +284,14 @@ static inline void __tlbi_level(tlbi_op op, u64 addr, u32 level)
* TLBF_NOSYNC (don't issue trailing dsb) and TLBF_NOBROADCAST
* (only perform the invalidation for the local cpu).
*
- * local_flush_tlb_page(vma, addr)
- * Local variant of flush_tlb_page(). Stale TLB entries may
- * remain in remote CPUs.
- *
- * local_flush_tlb_page_nonotify(vma, addr)
- * Same as local_flush_tlb_page() except MMU notifier will not be
- * called.
+ * __flush_tlb_page(vma, addr, flags)
+ * Invalidate a single user mapping for address 'addr' in the
+ * address space corresponding to 'vma->mm'. Note that this
+ * operation only invalidates a single, last-level page-table entry
+ * and therefore does not affect any walk-caches. flags may contain
+ * any combination of TLBF_NONOTIFY (don't call mmu notifiers),
+ * TLBF_NOSYNC (don't issue trailing dsb) and TLBF_NOBROADCAST
+ * (only perform the invalidation for the local cpu).
*
* Finally, take a look at asm/tlb.h to see how tlb_flush() is implemented
* on top of these routines, since that is our interface to the mmu_gather
@@ -327,51 +325,6 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
mmu_notifier_arch_invalidate_secondary_tlbs(mm, 0, -1UL);
}

-static inline void __local_flush_tlb_page_nonotify_nosync(struct mm_struct *mm,
- unsigned long uaddr)
-{
- dsb(nshst);
- __tlbi_level_asid(vale1, uaddr, TLBI_TTL_UNKNOWN, ASID(mm));
-}
-
-static inline void local_flush_tlb_page_nonotify(struct vm_area_struct *vma,
- unsigned long uaddr)
-{
- __local_flush_tlb_page_nonotify_nosync(vma->vm_mm, uaddr);
- dsb(nsh);
-}
-
-static inline void local_flush_tlb_page(struct vm_area_struct *vma,
- unsigned long uaddr)
-{
- __local_flush_tlb_page_nonotify_nosync(vma->vm_mm, uaddr);
- mmu_notifier_arch_invalidate_secondary_tlbs(vma->vm_mm, uaddr & PAGE_MASK,
- (uaddr & PAGE_MASK) + PAGE_SIZE);
- dsb(nsh);
-}
-
-static inline void __flush_tlb_page_nosync(struct mm_struct *mm,
- unsigned long uaddr)
-{
- dsb(ishst);
- __tlbi_level_asid(vale1is, uaddr, TLBI_TTL_UNKNOWN, ASID(mm));
- mmu_notifier_arch_invalidate_secondary_tlbs(mm, uaddr & PAGE_MASK,
- (uaddr & PAGE_MASK) + PAGE_SIZE);
-}
-
-static inline void flush_tlb_page_nosync(struct vm_area_struct *vma,
- unsigned long uaddr)
-{
- return __flush_tlb_page_nosync(vma->vm_mm, uaddr);
-}
-
-static inline void flush_tlb_page(struct vm_area_struct *vma,
- unsigned long uaddr)
-{
- flush_tlb_page_nosync(vma, uaddr);
- dsb(ish);
-}
-
static inline bool arch_tlbbatch_should_defer(struct mm_struct *mm)
{
/*
@@ -618,6 +571,22 @@ static inline void flush_tlb_range(struct vm_area_struct *vma,
__flush_tlb_range(vma, start, end, PAGE_SIZE, TLBI_TTL_UNKNOWN, TLBF_NONE);
}

+static inline void __flush_tlb_page(struct vm_area_struct *vma,
+ unsigned long uaddr, tlbf_t flags)
+{
+ unsigned long start = round_down(uaddr, PAGE_SIZE);
+ unsigned long end = start + PAGE_SIZE;
+
+ ___flush_tlb_range(vma, start, end, PAGE_SIZE, TLBI_TTL_UNKNOWN,
+ TLBF_NOWALKCACHE | flags);
+}
+
+static inline void flush_tlb_page(struct vm_area_struct *vma,
+ unsigned long uaddr)
+{
+ __flush_tlb_page(vma, uaddr, TLBF_NONE);
+}
+
static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
const unsigned long stride = PAGE_SIZE;
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index be9dab2c7d6a..f91aa686f142 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -239,7 +239,7 @@ int __ptep_set_access_flags(struct vm_area_struct *vma,
* flush_tlb_fix_spurious_fault().
*/
if (dirty)
- local_flush_tlb_page(vma, address);
+ __flush_tlb_page(vma, address, TLBF_NOBROADCAST);
return 1;
}

--
2.43.0