2021-05-24 06:53:24

by Guo Ren

[permalink] [raw]
Subject: [PATCH 1/3] riscv: Fixup _PAGE_GLOBAL in _PAGE_KERNEL

From: Guo Ren <[email protected]>

Kernel virtual address translation should avoid care asid 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.

Signed-off-by: Guo Ren <[email protected]>
Cc: Anup Patel <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
---
arch/riscv/include/asm/pgtable.h | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 78f2323..017da15 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -135,6 +135,7 @@
| _PAGE_PRESENT \
| _PAGE_ACCESSED \
| _PAGE_DIRTY \
+ | _PAGE_GLOBAL \
| _PAGE_CACHE)

#define PAGE_KERNEL __pgprot(_PAGE_KERNEL)
--
2.7.4


2021-05-24 06:53:39

by Guo Ren

[permalink] [raw]
Subject: [PATCH 2/3] riscv: Fixup PAGE_UP in asm/page.h

From: Guo Ren <[email protected]>

Current PAGE_UP implementation is wrong. PAGE_UP(0) should be
0x1000, but current implementation will give out 0.

Although the current PAGE_UP isn't used, it will soon be used in
tlb_flush optimization.

Signed-off-by: Guo Ren <[email protected]>
Cc: Anup Patel <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
---
arch/riscv/include/asm/page.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
index 6a7761c..c611b20 100644
--- a/arch/riscv/include/asm/page.h
+++ b/arch/riscv/include/asm/page.h
@@ -37,7 +37,7 @@

#ifndef __ASSEMBLY__

-#define PAGE_UP(addr) (((addr)+((PAGE_SIZE)-1))&(~((PAGE_SIZE)-1)))
+#define PAGE_UP(addr) (((addr)+(PAGE_SIZE))&(~((PAGE_SIZE)-1)))
#define PAGE_DOWN(addr) ((addr)&(~((PAGE_SIZE)-1)))

/* align addr on a size boundary - adjust address up/down if needed */
--
2.7.4

2021-05-24 06:54:07

by Guo Ren

[permalink] [raw]
Subject: [PATCH 3/3] riscv: Use use_asid_allocator flush TLB

From: Guo Ren <[email protected]>

Use static_branch_unlikely(&use_asid_allocator) to keep the origin
tlb flush style, so it's no effect on the existing machine. Here
are the optimized functions:
- flush_tlb_mm
- flush_tlb_page
- flush_tlb_range

All above are based on the below new implement functions:
- __sbi_tlb_flush_range_asid
- local_flush_tlb_range_asid

Signed-off-by: Guo Ren <[email protected]>
Cc: Anup Patel <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
---
arch/riscv/include/asm/mmu_context.h | 2 ++
arch/riscv/include/asm/tlbflush.h | 22 ++++++++++++++++++++
arch/riscv/mm/context.c | 2 +-
arch/riscv/mm/tlbflush.c | 40 +++++++++++++++++++++++++++++++++---
4 files changed, 62 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/include/asm/mmu_context.h b/arch/riscv/include/asm/mmu_context.h
index b065941..7030837 100644
--- a/arch/riscv/include/asm/mmu_context.h
+++ b/arch/riscv/include/asm/mmu_context.h
@@ -33,6 +33,8 @@ static inline int init_new_context(struct task_struct *tsk,
return 0;
}

+DECLARE_STATIC_KEY_FALSE(use_asid_allocator);
+
#include <asm-generic/mmu_context.h>

#endif /* _ASM_RISCV_MMU_CONTEXT_H */
diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h
index c84218a..9390319 100644
--- a/arch/riscv/include/asm/tlbflush.h
+++ b/arch/riscv/include/asm/tlbflush.h
@@ -8,6 +8,7 @@
#define _ASM_RISCV_TLBFLUSH_H

#include <linux/mm_types.h>
+#include <asm/page.h>
#include <asm/smp.h>
#include <asm/errata_list.h>

@@ -22,9 +23,30 @@ static inline void local_flush_tlb_page(unsigned long addr)
{
ALT_FLUSH_TLB_PAGE(__asm__ __volatile__ ("sfence.vma %0" : : "r" (addr) : "memory"));
}
+
+static inline void local_flush_tlb_range_asid(unsigned long start, unsigned long size,
+ unsigned long asid)
+{
+ unsigned long page_add = PAGE_DOWN(start);
+ unsigned long page_end = PAGE_UP(start + size);
+
+ if (size == -1) {
+ __asm__ __volatile__ ("sfence.vma x0, %0" : : "r" (asid) : "memory");
+ return;
+ }
+
+ while(page_add < page_end) {
+ __asm__ __volatile__ ("sfence.vma %0, %1"
+ :
+ : "r" (page_add), "r" (asid)
+ : "memory");
+ page_add += PAGE_SIZE;
+ }
+}
#else /* CONFIG_MMU */
#define local_flush_tlb_all() do { } while (0)
#define local_flush_tlb_page(addr) do { } while (0)
+#define local_flush_tlb_range_asid(addr) do { } while (0)
#endif /* CONFIG_MMU */

#if defined(CONFIG_SMP) && defined(CONFIG_MMU)
diff --git a/arch/riscv/mm/context.c b/arch/riscv/mm/context.c
index 68aa312..45c1b04 100644
--- a/arch/riscv/mm/context.c
+++ b/arch/riscv/mm/context.c
@@ -18,7 +18,7 @@

#ifdef CONFIG_MMU

-static DEFINE_STATIC_KEY_FALSE(use_asid_allocator);
+DEFINE_STATIC_KEY_FALSE(use_asid_allocator);

static unsigned long asid_bits;
static unsigned long num_asids;
diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
index 720b443..69588dc 100644
--- a/arch/riscv/mm/tlbflush.c
+++ b/arch/riscv/mm/tlbflush.c
@@ -4,6 +4,7 @@
#include <linux/smp.h>
#include <linux/sched.h>
#include <asm/sbi.h>
+#include <asm/mmu_context.h>

void flush_tlb_all(void)
{
@@ -39,18 +40,51 @@ static void __sbi_tlb_flush_range(struct cpumask *cmask, unsigned long start,
put_cpu();
}

+static void __sbi_tlb_flush_range_asid(struct cpumask *cmask, unsigned long start,
+ unsigned long size, unsigned long asid)
+{
+ struct cpumask hmask;
+ unsigned int cpuid;
+
+ if (cpumask_empty(cmask))
+ return;
+
+ cpuid = get_cpu();
+
+ if (cpumask_any_but(cmask, cpuid) >= nr_cpu_ids) {
+ local_flush_tlb_range_asid(start, size, asid);
+ } else {
+ riscv_cpuid_to_hartid_mask(cmask, &hmask);
+ sbi_remote_sfence_vma_asid(cpumask_bits(&hmask), start, size, asid);
+ }
+
+ put_cpu();
+}
+
void flush_tlb_mm(struct mm_struct *mm)
{
- __sbi_tlb_flush_range(mm_cpumask(mm), 0, -1);
+ if (static_branch_unlikely(&use_asid_allocator))
+ __sbi_tlb_flush_range_asid(mm_cpumask(mm), 0, -1,
+ atomic_long_read(&mm->context.id));
+ else
+ __sbi_tlb_flush_range(mm_cpumask(mm), 0, -1);
}

void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
{
- __sbi_tlb_flush_range(mm_cpumask(vma->vm_mm), addr, PAGE_SIZE);
+ if (static_branch_unlikely(&use_asid_allocator))
+ __sbi_tlb_flush_range_asid(mm_cpumask(vma->vm_mm), addr, PAGE_SIZE,
+ atomic_long_read(&vma->vm_mm->context.id));
+ else
+ __sbi_tlb_flush_range(mm_cpumask(vma->vm_mm), addr, PAGE_SIZE);
}

void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end)
{
- __sbi_tlb_flush_range(mm_cpumask(vma->vm_mm), start, end - start);
+ if (static_branch_unlikely(&use_asid_allocator))
+ __sbi_tlb_flush_range_asid(mm_cpumask(vma->vm_mm), start, end - start,
+ atomic_long_read(&vma->vm_mm->context.id));
+ else
+ __sbi_tlb_flush_range(mm_cpumask(vma->vm_mm), start, end - start);
}
--
2.7.4

2021-05-24 08:04:23

by Anup Patel

[permalink] [raw]
Subject: Re: [PATCH 1/3] riscv: Fixup _PAGE_GLOBAL in _PAGE_KERNEL

On Mon, May 24, 2021 at 12:22 PM <[email protected]> wrote:
>
> From: Guo Ren <[email protected]>
>
> Kernel virtual address translation should avoid care asid 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.
>
> Signed-off-by: Guo Ren <[email protected]>
> Cc: Anup Patel <[email protected]>
> Cc: Palmer Dabbelt <[email protected]>

First of all thanks for doing this series, I had similar changes in mind
as follow-up to the ASID allocator.

I went through all three patches and at least I don't see any
obvious issue but I think we should try testing it more on a few
existing platforms.

Reviewed-by: Anup Patel <[email protected]>

Regards,
Anup

> ---
> arch/riscv/include/asm/pgtable.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> index 78f2323..017da15 100644
> --- a/arch/riscv/include/asm/pgtable.h
> +++ b/arch/riscv/include/asm/pgtable.h
> @@ -135,6 +135,7 @@
> | _PAGE_PRESENT \
> | _PAGE_ACCESSED \
> | _PAGE_DIRTY \
> + | _PAGE_GLOBAL \
> | _PAGE_CACHE)
>
> #define PAGE_KERNEL __pgprot(_PAGE_KERNEL)
> --
> 2.7.4
>

2021-05-24 08:14:08

by Anup Patel

[permalink] [raw]
Subject: Re: [PATCH 3/3] riscv: Use use_asid_allocator flush TLB

On Mon, May 24, 2021 at 12:22 PM <[email protected]> wrote:
>
> From: Guo Ren <[email protected]>
>
> Use static_branch_unlikely(&use_asid_allocator) to keep the origin
> tlb flush style, so it's no effect on the existing machine. Here
> are the optimized functions:
> - flush_tlb_mm
> - flush_tlb_page
> - flush_tlb_range
>
> All above are based on the below new implement functions:
> - __sbi_tlb_flush_range_asid
> - local_flush_tlb_range_asid
>
> Signed-off-by: Guo Ren <[email protected]>
> Cc: Anup Patel <[email protected]>
> Cc: Palmer Dabbelt <[email protected]>
> ---
> arch/riscv/include/asm/mmu_context.h | 2 ++
> arch/riscv/include/asm/tlbflush.h | 22 ++++++++++++++++++++
> arch/riscv/mm/context.c | 2 +-
> arch/riscv/mm/tlbflush.c | 40 +++++++++++++++++++++++++++++++++---
> 4 files changed, 62 insertions(+), 4 deletions(-)
>
> diff --git a/arch/riscv/include/asm/mmu_context.h b/arch/riscv/include/asm/mmu_context.h
> index b065941..7030837 100644
> --- a/arch/riscv/include/asm/mmu_context.h
> +++ b/arch/riscv/include/asm/mmu_context.h
> @@ -33,6 +33,8 @@ static inline int init_new_context(struct task_struct *tsk,
> return 0;
> }
>
> +DECLARE_STATIC_KEY_FALSE(use_asid_allocator);
> +
> #include <asm-generic/mmu_context.h>
>
> #endif /* _ASM_RISCV_MMU_CONTEXT_H */
> diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h
> index c84218a..9390319 100644
> --- a/arch/riscv/include/asm/tlbflush.h
> +++ b/arch/riscv/include/asm/tlbflush.h
> @@ -8,6 +8,7 @@
> #define _ASM_RISCV_TLBFLUSH_H
>
> #include <linux/mm_types.h>
> +#include <asm/page.h>
> #include <asm/smp.h>
> #include <asm/errata_list.h>
>
> @@ -22,9 +23,30 @@ static inline void local_flush_tlb_page(unsigned long addr)
> {
> ALT_FLUSH_TLB_PAGE(__asm__ __volatile__ ("sfence.vma %0" : : "r" (addr) : "memory"));
> }
> +
> +static inline void local_flush_tlb_range_asid(unsigned long start, unsigned long size,
> + unsigned long asid)
> +{
> + unsigned long page_add = PAGE_DOWN(start);
> + unsigned long page_end = PAGE_UP(start + size);

Your PATCH2 is not correct because PAGE_UP(x) should in-fact
return 0 when x == 0.

In fact, if both "start" and "size" are zero then both page_add and
page_end should be zero so that no "sfence.vma" is executed.

If you want at least one TLB entry to be invalidated when size == 0
then you can simply set "size = 1" when size is zero which will force
one TLB invalidation.

Please drop your PATCH2 and the rest of the things look good to me.

Reviewed-by: Anup Patel <[email protected]>

Regards,
Anup

> +
> + if (size == -1) {
> + __asm__ __volatile__ ("sfence.vma x0, %0" : : "r" (asid) : "memory");
> + return;
> + }
> +
> + while(page_add < page_end) {
> + __asm__ __volatile__ ("sfence.vma %0, %1"
> + :
> + : "r" (page_add), "r" (asid)
> + : "memory");
> + page_add += PAGE_SIZE;
> + }
> +}
> #else /* CONFIG_MMU */
> #define local_flush_tlb_all() do { } while (0)
> #define local_flush_tlb_page(addr) do { } while (0)
> +#define local_flush_tlb_range_asid(addr) do { } while (0)
> #endif /* CONFIG_MMU */
>
> #if defined(CONFIG_SMP) && defined(CONFIG_MMU)
> diff --git a/arch/riscv/mm/context.c b/arch/riscv/mm/context.c
> index 68aa312..45c1b04 100644
> --- a/arch/riscv/mm/context.c
> +++ b/arch/riscv/mm/context.c
> @@ -18,7 +18,7 @@
>
> #ifdef CONFIG_MMU
>
> -static DEFINE_STATIC_KEY_FALSE(use_asid_allocator);
> +DEFINE_STATIC_KEY_FALSE(use_asid_allocator);
>
> static unsigned long asid_bits;
> static unsigned long num_asids;
> diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
> index 720b443..69588dc 100644
> --- a/arch/riscv/mm/tlbflush.c
> +++ b/arch/riscv/mm/tlbflush.c
> @@ -4,6 +4,7 @@
> #include <linux/smp.h>
> #include <linux/sched.h>
> #include <asm/sbi.h>
> +#include <asm/mmu_context.h>
>
> void flush_tlb_all(void)
> {
> @@ -39,18 +40,51 @@ static void __sbi_tlb_flush_range(struct cpumask *cmask, unsigned long start,
> put_cpu();
> }
>
> +static void __sbi_tlb_flush_range_asid(struct cpumask *cmask, unsigned long start,
> + unsigned long size, unsigned long asid)
> +{
> + struct cpumask hmask;
> + unsigned int cpuid;
> +
> + if (cpumask_empty(cmask))
> + return;
> +
> + cpuid = get_cpu();
> +
> + if (cpumask_any_but(cmask, cpuid) >= nr_cpu_ids) {
> + local_flush_tlb_range_asid(start, size, asid);
> + } else {
> + riscv_cpuid_to_hartid_mask(cmask, &hmask);
> + sbi_remote_sfence_vma_asid(cpumask_bits(&hmask), start, size, asid);
> + }
> +
> + put_cpu();
> +}
> +
> void flush_tlb_mm(struct mm_struct *mm)
> {
> - __sbi_tlb_flush_range(mm_cpumask(mm), 0, -1);
> + if (static_branch_unlikely(&use_asid_allocator))
> + __sbi_tlb_flush_range_asid(mm_cpumask(mm), 0, -1,
> + atomic_long_read(&mm->context.id));
> + else
> + __sbi_tlb_flush_range(mm_cpumask(mm), 0, -1);
> }
>
> void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
> {
> - __sbi_tlb_flush_range(mm_cpumask(vma->vm_mm), addr, PAGE_SIZE);
> + if (static_branch_unlikely(&use_asid_allocator))
> + __sbi_tlb_flush_range_asid(mm_cpumask(vma->vm_mm), addr, PAGE_SIZE,
> + atomic_long_read(&vma->vm_mm->context.id));
> + else
> + __sbi_tlb_flush_range(mm_cpumask(vma->vm_mm), addr, PAGE_SIZE);
> }
>
> void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
> unsigned long end)
> {
> - __sbi_tlb_flush_range(mm_cpumask(vma->vm_mm), start, end - start);
> + if (static_branch_unlikely(&use_asid_allocator))
> + __sbi_tlb_flush_range_asid(mm_cpumask(vma->vm_mm), start, end - start,
> + atomic_long_read(&vma->vm_mm->context.id));
> + else
> + __sbi_tlb_flush_range(mm_cpumask(vma->vm_mm), start, end - start);
> }
> --
> 2.7.4
>

2021-05-24 08:24:03

by Guo Ren

[permalink] [raw]
Subject: Re: [PATCH 1/3] riscv: Fixup _PAGE_GLOBAL in _PAGE_KERNEL

Hi Anup,

On Mon, May 24, 2021 at 4:03 PM Anup Patel <[email protected]> wrote:
>
> On Mon, May 24, 2021 at 12:22 PM <[email protected]> wrote:
> >
> > From: Guo Ren <[email protected]>
> >
> > Kernel virtual address translation should avoid care asid 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.
> >
> > Signed-off-by: Guo Ren <[email protected]>
> > Cc: Anup Patel <[email protected]>
> > Cc: Palmer Dabbelt <[email protected]>
>
> First of all thanks for doing this series, I had similar changes in mind
> as follow-up to the ASID allocator.
>
> I went through all three patches and at least I don't see any
> obvious issue but I think we should try testing it more on a few
> existing platforms.
We've tested it on Allwinner D1 C906 and C910 SMP*4 for a long time,
just hope it won't affect u540.

(In fact, C910 has used ASID allocator for more than two years with
our own kernel-tree. I remember we've talked about it in 2019
plumber.)

>
> Reviewed-by: Anup Patel <[email protected]>
>
> Regards,
> Anup
>
> > ---
> > arch/riscv/include/asm/pgtable.h | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> > index 78f2323..017da15 100644
> > --- a/arch/riscv/include/asm/pgtable.h
> > +++ b/arch/riscv/include/asm/pgtable.h
> > @@ -135,6 +135,7 @@
> > | _PAGE_PRESENT \
> > | _PAGE_ACCESSED \
> > | _PAGE_DIRTY \
> > + | _PAGE_GLOBAL \
> > | _PAGE_CACHE)
> >
> > #define PAGE_KERNEL __pgprot(_PAGE_KERNEL)
> > --
> > 2.7.4
> >



--
Best Regards
Guo Ren

ML: https://lore.kernel.org/linux-csky/

2021-05-24 10:44:09

by Anup Patel

[permalink] [raw]
Subject: Re: [PATCH 1/3] riscv: Fixup _PAGE_GLOBAL in _PAGE_KERNEL

On Mon, May 24, 2021 at 12:22 PM <[email protected]> wrote:
>
> From: Guo Ren <[email protected]>
>
> Kernel virtual address translation should avoid care asid 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.
>
> Signed-off-by: Guo Ren <[email protected]>
> Cc: Anup Patel <[email protected]>
> Cc: Palmer Dabbelt <[email protected]>
> ---
> arch/riscv/include/asm/pgtable.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> index 78f2323..017da15 100644
> --- a/arch/riscv/include/asm/pgtable.h
> +++ b/arch/riscv/include/asm/pgtable.h
> @@ -135,6 +135,7 @@
> | _PAGE_PRESENT \
> | _PAGE_ACCESSED \
> | _PAGE_DIRTY \
> + | _PAGE_GLOBAL \
> | _PAGE_CACHE)

It seems this patch is not based on the upstream kernel. The
_PAGE_CACHE seems to be from your other patch series.

Please rebase these patches on the latest upstream kernel without
dependency on any other patch series.

Regards,
Anup

>
> #define PAGE_KERNEL __pgprot(_PAGE_KERNEL)
> --
> 2.7.4
>

2021-05-24 12:03:44

by Guo Ren

[permalink] [raw]
Subject: Re: [PATCH 1/3] riscv: Fixup _PAGE_GLOBAL in _PAGE_KERNEL

On Mon, May 24, 2021 at 6:42 PM Anup Patel <[email protected]> wrote:
>
> On Mon, May 24, 2021 at 12:22 PM <[email protected]> wrote:
> >
> > From: Guo Ren <[email protected]>
> >
> > Kernel virtual address translation should avoid care asid 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.
> >
> > Signed-off-by: Guo Ren <[email protected]>
> > Cc: Anup Patel <[email protected]>
> > Cc: Palmer Dabbelt <[email protected]>
> > ---
> > arch/riscv/include/asm/pgtable.h | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> > index 78f2323..017da15 100644
> > --- a/arch/riscv/include/asm/pgtable.h
> > +++ b/arch/riscv/include/asm/pgtable.h
> > @@ -135,6 +135,7 @@
> > | _PAGE_PRESENT \
> > | _PAGE_ACCESSED \
> > | _PAGE_DIRTY \
> > + | _PAGE_GLOBAL \
> > | _PAGE_CACHE)
>
> It seems this patch is not based on the upstream kernel. The
> _PAGE_CACHE seems to be from your other patch series.
>
> Please rebase these patches on the latest upstream kernel without
> dependency on any other patch series.
Yes, it based on DMA_COHERENT. I'll rebase in PATCH V2, thx.

>
> Regards,
> Anup
>
> >
> > #define PAGE_KERNEL __pgprot(_PAGE_KERNEL)
> > --
> > 2.7.4
> >



--
Best Regards
Guo Ren

ML: https://lore.kernel.org/linux-csky/

2021-05-25 06:39:46

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [PATCH 2/3] riscv: Fixup PAGE_UP in asm/page.h

On Mon, May 24, 2021 at 06:51:07AM +0000, [email protected] wrote:
> From: Guo Ren <[email protected]>
>
> Current PAGE_UP implementation is wrong. PAGE_UP(0) should be
> 0x1000, but current implementation will give out 0.
>
> Although the current PAGE_UP isn't used, it will soon be used in
> tlb_flush optimization.

Nak. Please just remove the PAGE_UP/PAGE_DOWN macros just like they
have been removed from other architectures long ago and use the
generic DIV_ROUND_UP macro for your new code like everyone else.

2021-05-25 09:30:48

by Guo Ren

[permalink] [raw]
Subject: Re: [PATCH 2/3] riscv: Fixup PAGE_UP in asm/page.h

On Tue, May 25, 2021 at 2:34 PM Christoph Hellwig <[email protected]> wrote:
>
> On Mon, May 24, 2021 at 06:51:07AM +0000, [email protected] wrote:
> > From: Guo Ren <[email protected]>
> >
> > Current PAGE_UP implementation is wrong. PAGE_UP(0) should be
> > 0x1000, but current implementation will give out 0.
> >
> > Although the current PAGE_UP isn't used, it will soon be used in
> > tlb_flush optimization.
>
> Nak. Please just remove the PAGE_UP/PAGE_DOWN macros just like they
> have been removed from other architectures long ago and use the
> generic DIV_ROUND_UP macro for your new code like everyone else.

This patch has been dropped because it's wrong, ref Anup's reply.

Remove PAGE_UP/DOWN is okay for me. How about:
static inline void local_flush_tlb_range_asid(unsigned long start,
unsigned long size,
unsigned long asid)
{
- unsigned long page_add = PAGE_DOWN(start);
- unsigned long page_end = PAGE_UP(start + size);
+ unsigned long page_add = _ALIGN_DOWN(start, PAGE_SIZE);
+ unsigned long page_end = _ALIGN_UP(start + size, PAGE_SIZE);

_ALIGN_XXX are also defined in arch/riscv/include/asm/page.h.

--
Best Regards
Guo Ren

ML: https://lore.kernel.org/linux-csky/

2021-05-25 10:33:28

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [PATCH 2/3] riscv: Fixup PAGE_UP in asm/page.h

On Tue, May 25, 2021 at 05:28:21PM +0800, Guo Ren wrote:
> On Tue, May 25, 2021 at 2:34 PM Christoph Hellwig <[email protected]> wrote:
> >
> > On Mon, May 24, 2021 at 06:51:07AM +0000, [email protected] wrote:
> > > From: Guo Ren <[email protected]>
> > >
> > > Current PAGE_UP implementation is wrong. PAGE_UP(0) should be
> > > 0x1000, but current implementation will give out 0.
> > >
> > > Although the current PAGE_UP isn't used, it will soon be used in
> > > tlb_flush optimization.
> >
> > Nak. Please just remove the PAGE_UP/PAGE_DOWN macros just like they
> > have been removed from other architectures long ago and use the
> > generic DIV_ROUND_UP macro for your new code like everyone else.
>
> This patch has been dropped because it's wrong, ref Anup's reply.
>
> Remove PAGE_UP/DOWN is okay for me. How about:
> static inline void local_flush_tlb_range_asid(unsigned long start,
> unsigned long size,
> unsigned long asid)
> {
> - unsigned long page_add = PAGE_DOWN(start);
> - unsigned long page_end = PAGE_UP(start + size);
> + unsigned long page_add = _ALIGN_DOWN(start, PAGE_SIZE);
> + unsigned long page_end = _ALIGN_UP(start + size, PAGE_SIZE);
>
> _ALIGN_XXX are also defined in arch/riscv/include/asm/page.h.

And these also are leftovers from days gone by and should be removed.

I think this should simply be:


unsigned long page_add = start & PAGE_MASK;
unsigned long page_end = PAGE_ALIGN(start + size);

(and page_add is a pretty horrible name as well..)