[PATCH v1 11/13] arm64: mm: More flags for __flush_tlb_range()

Ryan Roberts
2025-12-16T14:46:30Z

Refactor function variants with "_nosync", "_local" and "_nonotify" into
a single __always_inline implementation that takes flags and rely on
constant folding to select the parts that are actually needed at any
given callsite, based on the provided flags.

Flags all live in the tlbf_t (TLB flags) type; TLBF_NONE (0) continues
to provide the strongest semantics (i.e. evict from walk cache,
broadcast, synchronise and notify). Each flag reduces the strength in
some way; TLBF_NONOTIFY, TLBF_NOSYNC and TLBF_NOBROADCAST are added to
complement the existing TLBF_NOWALKCACHE.

The result is a clearer, simpler, more powerful API.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---
arch/arm64/include/asm/tlbflush.h | 101 ++++++++++++++++++------------
arch/arm64/mm/contpte.c | 9 ++-
2 files changed, 68 insertions(+), 42 deletions(-)

diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
index 9a37a6a014dc..ee747e66bbef 100644
--- a/arch/arm64/include/asm/tlbflush.h
+++ b/arch/arm64/include/asm/tlbflush.h
@@ -107,6 +107,12 @@ static inline unsigned long get_trans_granule(void)

typedef void (*tlbi_op)(u64 arg);

+static __always_inline void vae1(u64 arg)
+{
+ __tlbi(vae1, arg);
+ __tlbi_user(vae1, arg);
+}
+
static __always_inline void vae1is(u64 arg)
{
__tlbi(vae1is, arg);
@@ -276,7 +282,10 @@ static inline void __tlbi_level(tlbi_op op, u64 addr, u32 level)
* no invalidation may take place. In the case where the level
* cannot be easily determined, the value TLBI_TTL_UNKNOWN will
* perform a non-hinted invalidation. flags may be TLBF_NONE (0) or
- * TLBF_NOWALKCACHE (elide eviction of walk cache entries).
+ * any combination of TLBF_NOWALKCACHE (elide eviction of walk
+ * cache entries), 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).
*
* local_flush_tlb_page(vma, addr)
* Local variant of flush_tlb_page(). Stale TLB entries may
@@ -286,12 +295,6 @@ static inline void __tlbi_level(tlbi_op op, u64 addr, u32 level)
* Same as local_flush_tlb_page() except MMU notifier will not be
* called.
*
- * local_flush_tlb_contpte(vma, addr)
- * Invalidate the virtual-address range
- * '[addr, addr+CONT_PTE_SIZE)' mapped with contpte on local CPU
- * for the user address space corresponding to 'vma->mm'. Stale
- * TLB entries may remain in remote CPUs.
- *
* 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
* API as used by munmap() and friends.
@@ -436,6 +439,12 @@ static inline void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
* operations can only span an even number of pages. We save this for last to
* ensure 64KB start alignment is maintained for the LPA2 case.
*/
+static __always_inline void rvae1(u64 arg)
+{
+ __tlbi(rvae1, arg);
+ __tlbi_user(rvae1, arg);
+}
+
static __always_inline void rvae1is(u64 arg)
{
__tlbi(rvae1is, arg);
@@ -531,16 +540,18 @@ static inline bool __flush_tlb_range_limit_excess(unsigned long pages,
typedef unsigned __bitwise tlbf_t;
#define TLBF_NONE ((__force tlbf_t)0)
#define TLBF_NOWALKCACHE ((__force tlbf_t)BIT(0))
+#define TLBF_NOSYNC ((__force tlbf_t)BIT(1))
+#define TLBF_NONOTIFY ((__force tlbf_t)BIT(2))
+#define TLBF_NOBROADCAST ((__force tlbf_t)BIT(3))

-static inline void __flush_tlb_range_nosync(struct mm_struct *mm,
- unsigned long start, unsigned long end,
- unsigned long stride, int tlb_level,
- tlbf_t flags)
+static __always_inline void ___flush_tlb_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end,
+ unsigned long stride, int tlb_level,
+ tlbf_t flags)
{
+ struct mm_struct *mm = vma->vm_mm;
unsigned long asid, pages;

- start = round_down(start, stride);
- end = round_up(end, stride);
pages = (end - start) >> PAGE_SHIFT;

if (__flush_tlb_range_limit_excess(pages, stride)) {
@@ -548,17 +559,41 @@ static inline void __flush_tlb_range_nosync(struct mm_struct *mm,
return;
}

- dsb(ishst);
+ if (!(flags & TLBF_NOBROADCAST))
+ dsb(ishst);
+ else
+ dsb(nshst);
+
asid = ASID(mm);

- if (flags & TLBF_NOWALKCACHE)
- __flush_s1_tlb_range_op(vale1is, start, pages, stride,
- asid, tlb_level);
- else
+ switch (flags & (TLBF_NOWALKCACHE | TLBF_NOBROADCAST)) {
+ case TLBF_NONE:
__flush_s1_tlb_range_op(vae1is, start, pages, stride,
- asid, tlb_level);
+ asid, tlb_level);
+ break;
+ case TLBF_NOWALKCACHE:
+ __flush_s1_tlb_range_op(vale1is, start, pages, stride,
+ asid, tlb_level);
+ break;
+ case TLBF_NOBROADCAST:
+ __flush_s1_tlb_range_op(vae1, start, pages, stride,
+ asid, tlb_level);
+ break;
+ case TLBF_NOWALKCACHE | TLBF_NOBROADCAST:
+ __flush_s1_tlb_range_op(vale1, start, pages, stride,
+ asid, tlb_level);
+ break;
+ }

- mmu_notifier_arch_invalidate_secondary_tlbs(mm, start, end);
+ if (!(flags & TLBF_NONOTIFY))
+ mmu_notifier_arch_invalidate_secondary_tlbs(mm, start, end);
+
+ if (!(flags & TLBF_NOSYNC)) {
+ if (!(flags & TLBF_NOBROADCAST))
+ dsb(ish);
+ else
+ dsb(nsh);
+ }
}

static inline void __flush_tlb_range(struct vm_area_struct *vma,
@@ -566,24 +601,9 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma,
unsigned long stride, int tlb_level,
tlbf_t flags)
{
- __flush_tlb_range_nosync(vma->vm_mm, start, end, stride,
- tlb_level, flags);
- dsb(ish);
-}
-
-static inline void local_flush_tlb_contpte(struct vm_area_struct *vma,
- unsigned long addr)
-{
- unsigned long asid;
-
- addr = round_down(addr, CONT_PTE_SIZE);
-
- dsb(nshst);
- asid = ASID(vma->vm_mm);
- __flush_s1_tlb_range_op(vale1, addr, CONT_PTES, PAGE_SIZE, asid, 3);
- mmu_notifier_arch_invalidate_secondary_tlbs(vma->vm_mm, addr,
- addr + CONT_PTE_SIZE);
- dsb(nsh);
+ start = round_down(start, stride);
+ end = round_up(end, stride);
+ ___flush_tlb_range(vma, start, end, stride, tlb_level, flags);
}

static inline void flush_tlb_range(struct vm_area_struct *vma,
@@ -636,7 +656,10 @@ static inline void __flush_tlb_kernel_pgtable(unsigned long kaddr)
static inline void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *batch,
struct mm_struct *mm, unsigned long start, unsigned long end)
{
- __flush_tlb_range_nosync(mm, start, end, PAGE_SIZE, 3, TLBF_NOWALKCACHE);
+ struct vm_area_struct vma = { .vm_mm = mm, .vm_flags = 0 };
+
+ __flush_tlb_range(&vma, start, end, PAGE_SIZE, 3,
+ TLBF_NOWALKCACHE | TLBF_NOSYNC);
}

static inline bool __pte_flags_need_flush(ptdesc_t oldval, ptdesc_t newval)
diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c
index 1a12bb728ee1..ec17a0e70415 100644
--- a/arch/arm64/mm/contpte.c
+++ b/arch/arm64/mm/contpte.c
@@ -527,8 +527,8 @@ int contpte_ptep_clear_flush_young(struct vm_area_struct *vma,
* eliding the trailing DSB applies here.
*/
addr = ALIGN_DOWN(addr, CONT_PTE_SIZE);
- __flush_tlb_range_nosync(vma->vm_mm, addr, addr + CONT_PTE_SIZE,
- PAGE_SIZE, 3, TLBF_NOWALKCACHE);
+ __flush_tlb_range(vma, addr, addr + CONT_PTE_SIZE,
+ PAGE_SIZE, 3, TLBF_NOWALKCACHE | TLBF_NOSYNC);
}

return young;
@@ -623,7 +623,10 @@ int contpte_ptep_set_access_flags(struct vm_area_struct *vma,
__ptep_set_access_flags(vma, addr, ptep, entry, 0);

if (dirty)
- local_flush_tlb_contpte(vma, start_addr);
+ __flush_tlb_range(vma, start_addr,
+ start_addr + CONT_PTE_SIZE,
+ PAGE_SIZE, 3,
+ TLBF_NOWALKCACHE | TLBF_NOBROADCAST);
} else {
__contpte_try_unfold(vma->vm_mm, addr, ptep, orig_pte);
__ptep_set_access_flags(vma, addr, ptep, entry, dirty);
--
2.43.0