[RFC PATCH 04/11] arm64: tlb: Justify non-leaf invalidation in flush_tlb_range()

Will Deacon
2018-08-24T15:53:41Z

Add a comment to explain why we can't get away with last-level
invalidation in flush_tlb_range()

Signed-off-by: Will Deacon <will.deacon@arm.com>
---
arch/arm64/include/asm/tlbflush.h | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
index e257f8655b84..ddbf1718669d 100644
--- a/arch/arm64/include/asm/tlbflush.h
+++ b/arch/arm64/include/asm/tlbflush.h
@@ -182,6 +182,10 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma,
static inline void flush_tlb_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
+ /*
+ * We cannot use leaf-only invalidation here, since we may be invalidating
+ * table entries as part of collapsing hugepages or moving page tables.
+ */
__flush_tlb_range(vma, start, end, false);
}

--
2.1.4