[PATCH v2] powerpc/32s: Don't flush all TLBs when flushing one page

From: Christophe Leroy
Date: Sat Feb 01 2020 - 03:04:44 EST


When flushing any memory range, the flushing function
flushes all TLBs.

When (start) and (end - 1) are in the same memory page,
flush that page instead.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
---
v2: Reworked the test as the previous one was always false (end - start was PAGE_SIZE - 1 for a single page)
---
arch/powerpc/mm/book3s32/tlb.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/mm/book3s32/tlb.c b/arch/powerpc/mm/book3s32/tlb.c
index 2fcd321040ff..724c0490fb17 100644
--- a/arch/powerpc/mm/book3s32/tlb.c
+++ b/arch/powerpc/mm/book3s32/tlb.c
@@ -79,11 +79,14 @@ static void flush_range(struct mm_struct *mm, unsigned long start,
int count;
unsigned int ctx = mm->context.id;

+ start &= PAGE_MASK;
if (!Hash) {
- _tlbia();
+ if (end - start <= PAGE_SIZE)
+ _tlbie(start);
+ else
+ _tlbia();
return;
}
- start &= PAGE_MASK;
if (start >= end)
return;
end = (end - 1) | ~PAGE_MASK;
--
2.25.0