arm64: Use last level TLBI for user pte changes

The flush_tlb_page() function is used on user address ranges when PTEs
(or PMDs/PUDs for huge pages) were changed (attributes or clearing). For
such cases, it is more efficient to invalidate only the last level of
the TLB with the "tlbi vale1is" instruction.

In the TLB shoot-down case, the TLB caching of the intermediate page
table levels (pmd, pud, pgd) is handled by __flush_tlb_pgtable() via the
__(pte|pmd|pud)_free_tlb() functions and it is not deferred to
tlb_finish_mmu() (as of commit 285994a6 - "arm64: Invalidate the TLB
corresponding to intermediate page table levels"). The tlb_flush()
function only needs to invalidate the TLB for the last level of page
tables; the __flush_tlb_range() function gains a fourth argument for
last level TLBI.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/include/asm/tlb.h

@@ -41,7 +41,12 @@ static inline void tlb_flush(struct mmu_gather *tlb)
 		flush_tlb_mm(tlb->mm);
 	} else {
 		struct vm_area_struct vma = { .vm_mm = tlb->mm, };
-		flush_tlb_range(&vma, tlb->start, tlb->end);
+		/*
+		 * The intermediate page table levels are already handled by
+		 * the __(pte|pmd|pud)_free_tlb() functions, so last level
+		 * TLBI is sufficient here.
+		 */
+		__flush_tlb_range(&vma, tlb->start, tlb->end, true);
 	}
 }
 

arch/arm64/include/asm/tlbflush.h

@@ -87,7 +87,7 @@ static inline void flush_tlb_page(struct vm_area_struct *vma,
 		((unsigned long)ASID(vma->vm_mm) << 48);
 
 	dsb(ishst);
-	asm("tlbi	vae1is, %0" : : "r" (addr));
+	asm("tlbi	vale1is, %0" : : "r" (addr));
 	dsb(ish);
 }
 
@@ -97,8 +97,9 @@ static inline void flush_tlb_page(struct vm_area_struct *vma,
  */
 #define MAX_TLB_RANGE	(1024UL << PAGE_SHIFT)
 
-static inline void flush_tlb_range(struct vm_area_struct *vma,
-				   unsigned long start, unsigned long end)
+static inline void __flush_tlb_range(struct vm_area_struct *vma,
+				     unsigned long start, unsigned long end,
+				     bool last_level)
 {
 	unsigned long asid = (unsigned long)ASID(vma->vm_mm) << 48;
 	unsigned long addr;
@@ -112,11 +113,21 @@ static inline void flush_tlb_range(struct vm_area_struct *vma,
 	end = asid | (end >> 12);
 
 	dsb(ishst);
-	for (addr = start; addr < end; addr += 1 << (PAGE_SHIFT - 12))
+	for (addr = start; addr < end; addr += 1 << (PAGE_SHIFT - 12)) {
+		if (last_level)
+			asm("tlbi vale1is, %0" : : "r"(addr));
+		else
 			asm("tlbi vae1is, %0" : : "r"(addr));
+	}
 	dsb(ish);
 }
 
+static inline void flush_tlb_range(struct vm_area_struct *vma,
+				   unsigned long start, unsigned long end)
+{
+	__flush_tlb_range(vma, start, end, false);
+}
+
 static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end)
 {
 	unsigned long addr;