From: Guo Ren <guoren@kernel.org> To: Palmer Dabbelt <palmerdabbelt@google.com> Cc: Anup Patel <Anup.Patel@wdc.com>, Arnd Bergmann <arnd@arndb.de>, Christoph Hellwig <hch@lst.de>, linux-riscv <linux-riscv@lists.infradead.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, linux-arch <linux-arch@vger.kernel.org>, linux-sunxi@lists.linux.dev, Guo Ren <guoren@linux.alibaba.com> Subject: Re: [PATCH V4 1/2] riscv: Fixup _PAGE_GLOBAL in _PAGE_KERNEL Date: Sun, 30 May 2021 13:33:52 +0800 [thread overview] Message-ID: <CAJF2gTSPQmWLon40GafUjEjeMfu3ZPsPREzE+4W5+0uWjj=F_A@mail.gmail.com> (raw) In-Reply-To: <mhng-60806045-5ac7-4057-b596-a4d9cb79b7be@palmerdabbelt-glaptop> On Sun, May 30, 2021 at 7:42 AM <palmerdabbelt@google.com> wrote: > > On Tue, 25 May 2021 22:49:20 PDT (-0700), guoren@kernel.org wrote: > > From: Guo Ren <guoren@linux.alibaba.com> > > > > Kernel virtual address translation should avoid to use ASIDs or it'll > > cause more TLB-miss and TLB-refill. Because the current ASID in satp > > belongs to the current process, but the target kernel va TLB entry's > > ASID still belongs to the previous process. > > Sorry, I still can't quite figure out what this is trying to say. I > went ahead and re-wrote the commit text to > > riscv: Use global mappings for kernel pages > > We map kernel pages into all addresses spages, so they can be marked as > global. This allows hardware to avoid flushing the kernel mappings when > moving between address spaces. Okay > > LMK if I'm misunderstanding something here, it's on for-next. > > > > > Signed-off-by: Guo Ren <guoren@linux.alibaba.com> > > Reviewed-by: Anup Patel <anup@brainfault.org> > > Reviewed-by: Christoph Hellwig <hch@lst.de> > > Cc: Palmer Dabbelt <palmerdabbelt@google.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) -- Best Regards Guo Ren ML: https://lore.kernel.org/linux-csky/
WARNING: multiple messages have this Message-ID (diff)
From: Guo Ren <guoren@kernel.org> To: Palmer Dabbelt <palmerdabbelt@google.com> Cc: Anup Patel <Anup.Patel@wdc.com>, Arnd Bergmann <arnd@arndb.de>, Christoph Hellwig <hch@lst.de>, linux-riscv <linux-riscv@lists.infradead.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, linux-arch <linux-arch@vger.kernel.org>, linux-sunxi@lists.linux.dev, Guo Ren <guoren@linux.alibaba.com> Subject: Re: [PATCH V4 1/2] riscv: Fixup _PAGE_GLOBAL in _PAGE_KERNEL Date: Sun, 30 May 2021 13:33:52 +0800 [thread overview] Message-ID: <CAJF2gTSPQmWLon40GafUjEjeMfu3ZPsPREzE+4W5+0uWjj=F_A@mail.gmail.com> (raw) In-Reply-To: <mhng-60806045-5ac7-4057-b596-a4d9cb79b7be@palmerdabbelt-glaptop> On Sun, May 30, 2021 at 7:42 AM <palmerdabbelt@google.com> wrote: > > On Tue, 25 May 2021 22:49:20 PDT (-0700), guoren@kernel.org wrote: > > From: Guo Ren <guoren@linux.alibaba.com> > > > > Kernel virtual address translation should avoid to use ASIDs or it'll > > cause more TLB-miss and TLB-refill. Because the current ASID in satp > > belongs to the current process, but the target kernel va TLB entry's > > ASID still belongs to the previous process. > > Sorry, I still can't quite figure out what this is trying to say. I > went ahead and re-wrote the commit text to > > riscv: Use global mappings for kernel pages > > We map kernel pages into all addresses spages, so they can be marked as > global. This allows hardware to avoid flushing the kernel mappings when > moving between address spaces. Okay > > LMK if I'm misunderstanding something here, it's on for-next. > > > > > Signed-off-by: Guo Ren <guoren@linux.alibaba.com> > > Reviewed-by: Anup Patel <anup@brainfault.org> > > Reviewed-by: Christoph Hellwig <hch@lst.de> > > Cc: Palmer Dabbelt <palmerdabbelt@google.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) -- Best Regards Guo Ren ML: https://lore.kernel.org/linux-csky/ _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2021-05-30 5:34 UTC|newest] Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-26 5:49 [PATCH V4 0/2] riscv: Fixup asid_allocator remaining issues guoren 2021-05-26 5:49 ` guoren 2021-05-26 5:49 ` [PATCH V4 1/2] riscv: Fixup _PAGE_GLOBAL in _PAGE_KERNEL guoren 2021-05-26 5:49 ` guoren 2021-05-29 23:42 ` palmerdabbelt 2021-05-29 23:42 ` palmerdabbelt 2021-05-30 5:33 ` Guo Ren [this message] 2021-05-30 5:33 ` Guo Ren 2021-05-30 5:33 ` Guo Ren 2021-05-26 5:49 ` [PATCH V4 2/2] riscv: Use use_asid_allocator flush TLB guoren 2021-05-26 5:49 ` guoren 2021-05-27 7:09 ` Christoph Hellwig 2021-05-27 7:09 ` Christoph Hellwig 2021-05-29 23:42 ` palmerdabbelt 2021-05-29 23:42 ` palmerdabbelt 2021-05-30 0:51 ` Guo Ren 2021-05-30 0:51 ` Guo Ren 2021-05-30 0:51 ` Guo Ren 2021-05-31 6:36 ` Christoph Hellwig 2021-05-31 6:36 ` Christoph Hellwig 2021-05-30 0:39 ` Guo Ren 2021-05-30 0:39 ` Guo Ren 2021-05-30 0:39 ` Guo Ren
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