* [PATCH V3] MIPS: make userspace mapping young by default
@ 2020-09-19 7:47 Huang Pei
2020-09-28 6:39 ` Huang Pei
2020-10-02 12:35 ` Thomas Bogendoerfer
0 siblings, 2 replies; 4+ messages in thread
From: Huang Pei @ 2020-09-19 7:47 UTC (permalink / raw)
To: Thomas Bogendoerfer, ambrosehua
Cc: Bibo Mao, Andrew Morton, linux-mips, linux-arch, linux-mm,
Jiaxun Yang, Paul Burton, Li Xuefeng, Yang Tiezhu, Gao Juxin,
Fuxin Zhang, Huacai Chen
MIPS page fault path take 3 exceptions (1 TLB Miss + 2 TLB Invalid), but
the second TLB Invalid exception is just triggered by __update_tlb from
do_page_fault writing tlb without _PAGE_VALID set. With this patch, it
only take 1 TLB Miss + 1 TLB Invalid exceptions
This version removes pte_sw_mkyoung without polluting MM code and makes
page fault delay of MIPS on par with other architecture and covers both
no-RIXI and RIXI MIPS CPUS
[1]: https://lkml.kernel.org/lkml/1591416169-26666-1-git-send-email
-maobibo@loongson.cn/
---
V3:
- reformat with whitespace cleaned up following Thomas's advice
V2:
- remove unused asm-generic definition of pte_sw_mkyoung following Mao's
advice
---
Co-developed-by: Huang Pei <huangpei@loongson.cn>
Signed-off-by: Huang Pei <huangpei@loongson.cn>
Co-developed-by: Bibo Mao <maobibo@loonson.cn>
---
arch/mips/include/asm/pgtable.h | 10 ++++------
arch/mips/mm/cache.c | 25 +++++++++++++------------
include/linux/pgtable.h | 8 --------
mm/memory.c | 3 ---
4 files changed, 17 insertions(+), 29 deletions(-)
diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index dd7a0f552cac..931fb35730f0 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -27,11 +27,11 @@ struct vm_area_struct;
#define PAGE_NONE __pgprot(_PAGE_PRESENT | _PAGE_NO_READ | \
_page_cachable_default)
-#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
- _page_cachable_default)
+#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
+ __READABLE | _page_cachable_default)
#define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_NO_EXEC | \
- _page_cachable_default)
-#define PAGE_READONLY __pgprot(_PAGE_PRESENT | \
+ __READABLE | _page_cachable_default)
+#define PAGE_READONLY __pgprot(_PAGE_PRESENT | __READABLE | \
_page_cachable_default)
#define PAGE_KERNEL __pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
_PAGE_GLOBAL | _page_cachable_default)
@@ -414,8 +414,6 @@ static inline pte_t pte_mkyoung(pte_t pte)
return pte;
}
-#define pte_sw_mkyoung pte_mkyoung
-
#ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT
static inline int pte_huge(pte_t pte) { return pte_val(pte) & _PAGE_HUGE; }
diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
index 3e81ba000096..ed75f2871aad 100644
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -159,22 +159,23 @@ static inline void setup_protection_map(void)
{
if (cpu_has_rixi) {
protection_map[0] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
- protection_map[1] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
+ protection_map[1] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
protection_map[2] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
- protection_map[3] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
- protection_map[4] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
- protection_map[5] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
- protection_map[6] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
- protection_map[7] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
+ protection_map[3] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
+ protection_map[4] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
+ protection_map[5] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
+ protection_map[6] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
+ protection_map[7] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
protection_map[8] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
- protection_map[9] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
+ protection_map[9] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
protection_map[10] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | _PAGE_NO_READ);
- protection_map[11] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE);
- protection_map[12] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
- protection_map[13] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
- protection_map[14] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE);
- protection_map[15] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE);
+ protection_map[11] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | __READABLE);
+ protection_map[12] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
+ protection_map[13] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
+ protection_map[14] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
+ protection_map[15] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
+
} else {
protection_map[0] = PAGE_NONE;
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index e8cbc2e795d5..ef9c5fa8673e 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -377,14 +377,6 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
* To be differentiate with macro pte_mkyoung, this macro is used on platforms
* where software maintains page access bit.
*/
-#ifndef pte_sw_mkyoung
-static inline pte_t pte_sw_mkyoung(pte_t pte)
-{
- return pte;
-}
-#define pte_sw_mkyoung pte_sw_mkyoung
-#endif
-
#ifndef pte_savedwrite
#define pte_savedwrite pte_write
#endif
diff --git a/mm/memory.c b/mm/memory.c
index 602f4283122f..5100ab5bcf77 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2705,7 +2705,6 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
}
flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
entry = mk_pte(new_page, vma->vm_page_prot);
- entry = pte_sw_mkyoung(entry);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
/*
* Clear the pte entry and flush it first, before updating the
@@ -3386,7 +3385,6 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
__SetPageUptodate(page);
entry = mk_pte(page, vma->vm_page_prot);
- entry = pte_sw_mkyoung(entry);
if (vma->vm_flags & VM_WRITE)
entry = pte_mkwrite(pte_mkdirty(entry));
@@ -3661,7 +3659,6 @@ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct page *page)
flush_icache_page(vma, page);
entry = mk_pte(page, vma->vm_page_prot);
- entry = pte_sw_mkyoung(entry);
if (write)
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
/* copy-on-write page */
--
2.17.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH V3] MIPS: make userspace mapping young by default
2020-09-19 7:47 [PATCH V3] MIPS: make userspace mapping young by default Huang Pei
@ 2020-09-28 6:39 ` Huang Pei
2020-10-02 12:35 ` Thomas Bogendoerfer
1 sibling, 0 replies; 4+ messages in thread
From: Huang Pei @ 2020-09-28 6:39 UTC (permalink / raw)
To: Thomas Bogendoerfer, ambrosehua
Cc: Bibo Mao, Andrew Morton, linux-mips, linux-arch, linux-mm,
Jiaxun Yang, Paul Burton, Li Xuefeng, Yang Tiezhu, Gao Juxin,
Fuxin Zhang, Huacai Chen
On Sat, Sep 19, 2020 at 03:47:31PM +0800, Huang Pei wrote:
Ping?
> MIPS page fault path take 3 exceptions (1 TLB Miss + 2 TLB Invalid), but
> the second TLB Invalid exception is just triggered by __update_tlb from
> do_page_fault writing tlb without _PAGE_VALID set. With this patch, it
> only take 1 TLB Miss + 1 TLB Invalid exceptions
>
> This version removes pte_sw_mkyoung without polluting MM code and makes
> page fault delay of MIPS on par with other architecture and covers both
> no-RIXI and RIXI MIPS CPUS
>
> [1]: https://lkml.kernel.org/lkml/1591416169-26666-1-git-send-email
> -maobibo@loongson.cn/
> ---
> V3:
> - reformat with whitespace cleaned up following Thomas's advice
> V2:
> - remove unused asm-generic definition of pte_sw_mkyoung following Mao's
> advice
> ---
> Co-developed-by: Huang Pei <huangpei@loongson.cn>
> Signed-off-by: Huang Pei <huangpei@loongson.cn>
> Co-developed-by: Bibo Mao <maobibo@loonson.cn>
> ---
> arch/mips/include/asm/pgtable.h | 10 ++++------
> arch/mips/mm/cache.c | 25 +++++++++++++------------
> include/linux/pgtable.h | 8 --------
> mm/memory.c | 3 ---
> 4 files changed, 17 insertions(+), 29 deletions(-)
>
> diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
> index dd7a0f552cac..931fb35730f0 100644
> --- a/arch/mips/include/asm/pgtable.h
> +++ b/arch/mips/include/asm/pgtable.h
> @@ -27,11 +27,11 @@ struct vm_area_struct;
>
> #define PAGE_NONE __pgprot(_PAGE_PRESENT | _PAGE_NO_READ | \
> _page_cachable_default)
> -#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
> - _page_cachable_default)
> +#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
> + __READABLE | _page_cachable_default)
> #define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_NO_EXEC | \
> - _page_cachable_default)
> -#define PAGE_READONLY __pgprot(_PAGE_PRESENT | \
> + __READABLE | _page_cachable_default)
> +#define PAGE_READONLY __pgprot(_PAGE_PRESENT | __READABLE | \
> _page_cachable_default)
> #define PAGE_KERNEL __pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
> _PAGE_GLOBAL | _page_cachable_default)
> @@ -414,8 +414,6 @@ static inline pte_t pte_mkyoung(pte_t pte)
> return pte;
> }
>
> -#define pte_sw_mkyoung pte_mkyoung
> -
> #ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT
> static inline int pte_huge(pte_t pte) { return pte_val(pte) & _PAGE_HUGE; }
>
> diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
> index 3e81ba000096..ed75f2871aad 100644
> --- a/arch/mips/mm/cache.c
> +++ b/arch/mips/mm/cache.c
> @@ -159,22 +159,23 @@ static inline void setup_protection_map(void)
> {
> if (cpu_has_rixi) {
> protection_map[0] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
> - protection_map[1] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
> + protection_map[1] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
> protection_map[2] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
> - protection_map[3] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
> - protection_map[4] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
> - protection_map[5] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
> - protection_map[6] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
> - protection_map[7] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
> + protection_map[3] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
> + protection_map[4] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
> + protection_map[5] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
> + protection_map[6] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
> + protection_map[7] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
>
> protection_map[8] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
> - protection_map[9] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
> + protection_map[9] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
> protection_map[10] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | _PAGE_NO_READ);
> - protection_map[11] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE);
> - protection_map[12] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
> - protection_map[13] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
> - protection_map[14] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE);
> - protection_map[15] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE);
> + protection_map[11] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | __READABLE);
> + protection_map[12] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
> + protection_map[13] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
> + protection_map[14] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
> + protection_map[15] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
> +
>
> } else {
> protection_map[0] = PAGE_NONE;
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index e8cbc2e795d5..ef9c5fa8673e 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -377,14 +377,6 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
> * To be differentiate with macro pte_mkyoung, this macro is used on platforms
> * where software maintains page access bit.
> */
> -#ifndef pte_sw_mkyoung
> -static inline pte_t pte_sw_mkyoung(pte_t pte)
> -{
> - return pte;
> -}
> -#define pte_sw_mkyoung pte_sw_mkyoung
> -#endif
> -
> #ifndef pte_savedwrite
> #define pte_savedwrite pte_write
> #endif
> diff --git a/mm/memory.c b/mm/memory.c
> index 602f4283122f..5100ab5bcf77 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -2705,7 +2705,6 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
> }
> flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
> entry = mk_pte(new_page, vma->vm_page_prot);
> - entry = pte_sw_mkyoung(entry);
> entry = maybe_mkwrite(pte_mkdirty(entry), vma);
> /*
> * Clear the pte entry and flush it first, before updating the
> @@ -3386,7 +3385,6 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
> __SetPageUptodate(page);
>
> entry = mk_pte(page, vma->vm_page_prot);
> - entry = pte_sw_mkyoung(entry);
> if (vma->vm_flags & VM_WRITE)
> entry = pte_mkwrite(pte_mkdirty(entry));
>
> @@ -3661,7 +3659,6 @@ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct page *page)
>
> flush_icache_page(vma, page);
> entry = mk_pte(page, vma->vm_page_prot);
> - entry = pte_sw_mkyoung(entry);
> if (write)
> entry = maybe_mkwrite(pte_mkdirty(entry), vma);
> /* copy-on-write page */
> --
> 2.17.1
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH V3] MIPS: make userspace mapping young by default
2020-09-19 7:47 [PATCH V3] MIPS: make userspace mapping young by default Huang Pei
2020-09-28 6:39 ` Huang Pei
@ 2020-10-02 12:35 ` Thomas Bogendoerfer
2020-10-08 3:30 ` Huang Pei
1 sibling, 1 reply; 4+ messages in thread
From: Thomas Bogendoerfer @ 2020-10-02 12:35 UTC (permalink / raw)
To: Huang Pei
Cc: ambrosehua, Bibo Mao, Andrew Morton, linux-mips, linux-arch,
linux-mm, Jiaxun Yang, Paul Burton, Li Xuefeng, Yang Tiezhu,
Gao Juxin, Fuxin Zhang, Huacai Chen
On Sat, Sep 19, 2020 at 03:47:31PM +0800, Huang Pei wrote:
> MIPS page fault path take 3 exceptions (1 TLB Miss + 2 TLB Invalid), but
> the second TLB Invalid exception is just triggered by __update_tlb from
> do_page_fault writing tlb without _PAGE_VALID set. With this patch, it
> only take 1 TLB Miss + 1 TLB Invalid exceptions
>
> This version removes pte_sw_mkyoung without polluting MM code and makes
> page fault delay of MIPS on par with other architecture and covers both
> no-RIXI and RIXI MIPS CPUS
>
> [1]: https://lkml.kernel.org/lkml/1591416169-26666-1-git-send-email
> -maobibo@loongson.cn/
> ---
> V3:
> - reformat with whitespace cleaned up following Thomas's advice
> V2:
> - remove unused asm-generic definition of pte_sw_mkyoung following Mao's
> advice
> ---
> Co-developed-by: Huang Pei <huangpei@loongson.cn>
> Signed-off-by: Huang Pei <huangpei@loongson.cn>
> Co-developed-by: Bibo Mao <maobibo@loonson.cn>
> ---
> arch/mips/include/asm/pgtable.h | 10 ++++------
> arch/mips/mm/cache.c | 25 +++++++++++++------------
> include/linux/pgtable.h | 8 --------
> mm/memory.c | 3 ---
> 4 files changed, 17 insertions(+), 29 deletions(-)
>
> diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
> index dd7a0f552cac..931fb35730f0 100644
> --- a/arch/mips/include/asm/pgtable.h
> +++ b/arch/mips/include/asm/pgtable.h
> @@ -27,11 +27,11 @@ struct vm_area_struct;
>
> #define PAGE_NONE __pgprot(_PAGE_PRESENT | _PAGE_NO_READ | \
> _page_cachable_default)
> -#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
> - _page_cachable_default)
> +#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
> + __READABLE | _page_cachable_default)
you are still doing a white space changes here.
> #define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_NO_EXEC | \
> - _page_cachable_default)
> -#define PAGE_READONLY __pgprot(_PAGE_PRESENT | \
> + __READABLE | _page_cachable_default)
> +#define PAGE_READONLY __pgprot(_PAGE_PRESENT | __READABLE | \
I've grepped for usage of PAGE_SHARED and PAGE_READONLY and found
arch/mips/kvm/mmu.c and arch/mips/kernel/vdso.c. I wonder
1. Is this usage correct or should we use protection_map[X] ?
2. Are this still correct after the change in this patch ?
Right now I'm in favour to fist clean up asm/pgtable.h to get rid
of all unneeded PAGE_XXX defines and make mm/cache.c rixi part
more readable before applying this patch.
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH V3] MIPS: make userspace mapping young by default
2020-10-02 12:35 ` Thomas Bogendoerfer
@ 2020-10-08 3:30 ` Huang Pei
0 siblings, 0 replies; 4+ messages in thread
From: Huang Pei @ 2020-10-08 3:30 UTC (permalink / raw)
To: Thomas Bogendoerfer
Cc: ambrosehua, Bibo Mao, Andrew Morton, linux-mips, linux-arch,
linux-mm, Jiaxun Yang, Paul Burton, Li Xuefeng, Yang Tiezhu,
Gao Juxin, Fuxin Zhang, Huacai Chen
On Fri, Oct 02, 2020 at 02:35:03PM +0200, Thomas Bogendoerfer wrote:
Hi,
> On Sat, Sep 19, 2020 at 03:47:31PM +0800, Huang Pei wrote:
> > MIPS page fault path take 3 exceptions (1 TLB Miss + 2 TLB Invalid), but
> > the second TLB Invalid exception is just triggered by __update_tlb from
> > do_page_fault writing tlb without _PAGE_VALID set. With this patch, it
> > only take 1 TLB Miss + 1 TLB Invalid exceptions
> >
> > This version removes pte_sw_mkyoung without polluting MM code and makes
> > page fault delay of MIPS on par with other architecture and covers both
> > no-RIXI and RIXI MIPS CPUS
> >
> > [1]: https://lkml.kernel.org/lkml/1591416169-26666-1-git-send-email
> > -maobibo@loongson.cn/
> > ---
> > V3:
> > - reformat with whitespace cleaned up following Thomas's advice
> > V2:
> > - remove unused asm-generic definition of pte_sw_mkyoung following Mao's
> > advice
> > ---
> > Co-developed-by: Huang Pei <huangpei@loongson.cn>
> > Signed-off-by: Huang Pei <huangpei@loongson.cn>
> > Co-developed-by: Bibo Mao <maobibo@loonson.cn>
> > ---
> > arch/mips/include/asm/pgtable.h | 10 ++++------
> > arch/mips/mm/cache.c | 25 +++++++++++++------------
> > include/linux/pgtable.h | 8 --------
> > mm/memory.c | 3 ---
> > 4 files changed, 17 insertions(+), 29 deletions(-)
> >
> > diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
> > index dd7a0f552cac..931fb35730f0 100644
> > --- a/arch/mips/include/asm/pgtable.h
> > +++ b/arch/mips/include/asm/pgtable.h
> > @@ -27,11 +27,11 @@ struct vm_area_struct;
> >
> > #define PAGE_NONE __pgprot(_PAGE_PRESENT | _PAGE_NO_READ | \
> > _page_cachable_default)
> > -#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
> > - _page_cachable_default)
> > +#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
> > + __READABLE | _page_cachable_default)
>
> you are still doing a white space changes here.
>
> > #define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_NO_EXEC | \
> > - _page_cachable_default)
> > -#define PAGE_READONLY __pgprot(_PAGE_PRESENT | \
> > + __READABLE | _page_cachable_default)
> > +#define PAGE_READONLY __pgprot(_PAGE_PRESENT | __READABLE | \
>
sorry, my bad
> I've grepped for usage of PAGE_SHARED and PAGE_READONLY and found
> arch/mips/kvm/mmu.c and arch/mips/kernel/vdso.c. I wonder
>
for arch/mips/kvm/mmu.c, the comment says:
...
/* Also set valid and dirty, so refill handler doesn't have to */
*ptep = pte_mkyoung(pte_mkdirty(pfn_pte(pfn, PAGE_SHARED)));
...
the net effect is the same, dirty and valid, so I think it is ok;
for arch/mips/kernel/vdso.c, both mappings are kernel mapping, which
means the physical memory(or io memory) is already allocated and will not
be reclaimed by kernel.
> 1. Is this usage correct or should we use protection_map[X] ?
> 2. Are this still correct after the change in this patch ?
>
> Right now I'm in favour to fist clean up asm/pgtable.h to get rid
> of all unneeded PAGE_XXX defines and make mm/cache.c rixi part
> more readable before applying this patch.
>
I think we can clean up rixi part of mm/cache.c after this patch, or
within V4;
> Thomas.
>
> --
> Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
> good idea. [ RFC1925, 2.3 ]
^ permalink raw reply [flat|nested] 4+ messages in thread
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Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2020-09-19 7:47 [PATCH V3] MIPS: make userspace mapping young by default Huang Pei
2020-09-28 6:39 ` Huang Pei
2020-10-02 12:35 ` Thomas Bogendoerfer
2020-10-08 3:30 ` Huang Pei
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