Messages in this thread | | | Subject | Re: [PATCH] implement flush_cache_vmap and flush_cache_vunmap for RISC-V | From | Alex Ghiti <> | Date | Tue, 30 Mar 2021 03:02:50 -0400 |
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Hi Jiuyang,
Le 3/28/21 à 9:55 PM, Jiuyang Liu a écrit : > This patch implements flush_cache_vmap and flush_cache_vunmap for > RISC-V, since these functions might modify PTE. Without this patch, > SFENCE.VMA won't be added to related codes, which might introduce a bug > in some out-of-order micro-architecture implementations. > > Signed-off-by: Jiuyang Liu <liu@jiuyang.me> > --- > arch/riscv/include/asm/cacheflush.h | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/arch/riscv/include/asm/cacheflush.h b/arch/riscv/include/asm/cacheflush.h > index 23ff70350992..4adf25248c43 100644 > --- a/arch/riscv/include/asm/cacheflush.h > +++ b/arch/riscv/include/asm/cacheflush.h > @@ -8,6 +8,14 @@ > > #include <linux/mm.h> > > +/* > + * flush_cache_vmap and flush_cache_vunmap might modify PTE, needs SFENCE.VMA.
"might modify PTE" is not entirely true I think, this is what happens before using this function that might modify PTE, those functions ensure those modifications are made visible.
> + * - flush_cache_vmap is invoked after map_kernel_range() has installed the page table entries. > + * - flush_cache_vunmap is invoked before unmap_kernel_range() deletes the page table entries > + */ > +#define flush_cache_vmap(start, end) flush_tlb_all() > +#define flush_cache_vunmap(start, end) flush_tlb_all() > + > static inline void local_flush_icache_all(void) > { > asm volatile ("fence.i" ::: "memory"); >
FWIW, you can add:
Reviewed-by: Alexandre Ghiti <alex@ghiti.fr>
Thanks,
Alex
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