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

guoren at kernel.org guoren at kernel.org
Sun Jun 6 02:03:56 PDT 2021

From: Guo Ren <guoren at 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 at linux.alibaba.com>
Signed-off-by: Liu Shaohua <liush at allwinnertech.com>
Reviewed-by: Anup Patel <anup at brainfault.org>
Reviewed-by: Christoph Hellwig <hch at lst.de>
Signed-off-by: Liu Shaohua <liush at allwinnertech.com>
Cc: Chen-Yu Tsai <wens at csie.org>
Cc: Drew Fustini <drew at beagleboard.org>
Cc: Maxime Ripard <maxime at cerno.tech>
Cc: Palmer Dabbelt <palmerdabbelt at google.com>
Cc: Wei Fu <wefu at redhat.com>
Cc: Wei Wu <lazyparser at 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_DIRTY)
+				| _PAGE_DIRTY \
+				| _PAGE_GLOBAL)
 #define PAGE_KERNEL		__pgprot(_PAGE_KERNEL)

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