[RFC PATCH v2 01/11] riscv: asid: Use global mappings for kernel pages

guoren
2021-06-06T09:05:10Z

From: Guo Ren <guoren@linux.alibaba.com>

We map kernel pages into all addresses space, so they can be marked as
global. This allows hardware to avoid flushing the kernel mappings when
moving between address spaces.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Liu Shaohua <liush@allwinnertech.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Liu Shaohua <liush@allwinnertech.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Drew Fustini <drew@beagleboard.org>
Cc: Maxime Ripard <maxime@cerno.tech>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Wei Fu <wefu@redhat.com>
Cc: Wei Wu <lazyparser@gmail.com>
---
arch/riscv/include/asm/pgtable.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 9469f46..346a3c6 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -134,7 +134,8 @@
| _PAGE_WRITE \
| _PAGE_PRESENT \
| _PAGE_ACCESSED \
- | _PAGE_DIRTY)
+ | _PAGE_DIRTY \
+ | _PAGE_GLOBAL)

#define PAGE_KERNEL __pgprot(_PAGE_KERNEL)
#define PAGE_KERNEL_READ __pgprot(_PAGE_KERNEL & ~_PAGE_WRITE)
--
2.7.4