Hi,
Le 4/12/21 à 3:08 AM, Jisheng Zhang a écrit :
Hi Jiuyang,
On Mon, 12 Apr 2021 00:05:30 +0000 Jiuyang Liu <l...@jiuyang.me> wrote:
This patch implements flush_cache_vmap for RISC-V, since it modifies PTE.
Without this patch, SFENCE.VMA won't be added to related codes, which
might introduce a bug in the out-of-order micro-architecture
implementations.
Signed-off-by: Jiuyang Liu <l...@jiuyang.me>
Reviewed-by: Alexandre Ghiti <a...@ghiti.fr>
Reviewed-by: Palmer Dabbelt <pal...@dabbelt.com>
IIRC, Palmer hasn't given this Reviewed-by tag.
---
Could you plz add version and changes? IIRC, this is the v3.
arch/riscv/include/asm/cacheflush.h | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/riscv/include/asm/cacheflush.h
b/arch/riscv/include/asm/cacheflush.h
index 23ff70350992..3fd528badc35 100644
--- a/arch/riscv/include/asm/cacheflush.h
+++ b/arch/riscv/include/asm/cacheflush.h
@@ -30,6 +30,12 @@ static inline void flush_dcache_page(struct page *page)
#define flush_icache_user_page(vma, pg, addr, len) \
flush_icache_mm(vma->vm_mm, 0)
+/*
+ * flush_cache_vmap is invoked after map_kernel_range() has installed the page
+ * table entries, which modifies PTE, SFENCE.VMA should be inserted.
Just my humble opinion, flush_cache_vmap() may not be necessary. vmalloc_fault
can take care of this, and finally sfence.vma is inserted in related path.
I believe Palmer and Jisheng are right, my initial proposal to implement
flush_cache_vmap is wrong.
But then, Jiuyang should not have noticed any problem here, so what's
wrong? @Jiuyang: Does implementing flush_cache_vmap fix your issue?
And regarding flush_cache_vunmap, from Jisheng call stack, it seems also
not necessary.
@Jiuyang: Can you tell us more about what you noticed?
Regards
+ */
+#define flush_cache_vmap(start, end) flush_tlb_all()
+
#ifndef CONFIG_SMP
#define flush_icache_all() local_flush_icache_all()
--
2.31.1
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