Messages in this thread | | | Subject | Re: [PATCH] implement flush_cache_vmap for RISC-V | From | Alex Ghiti <> | Date | Wed, 14 Apr 2021 03:03:13 -0400 |
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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 <liu@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 <liu@jiuyang.me> >> Reviewed-by: Alexandre Ghiti <alex@ghiti.fr> >> Reviewed-by: Palmer Dabbelt <palmer@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 > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv >
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