Re: [PATCH] MIPS: make userspace mapping young by default

maobibo
2020-09-07T08:51:06Z

Sorry for the late reply.

Would you like to remove definition of macro pte_sw_mkyoung in header
file include/linux/pgtable.h, since it is not used any more.

The others look good to me.

regards
bibo,mao

On 09/04/2020 04:49 PM, Huang Pei wrote:
> This version removes pte_sw_mkyoung without polluting MM code and covers
> both no-RIXI and RIXI MIPS CPUs and makes page fault delay of MIPS on par
> with other architecture
>
> 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. By making userspace
> mapping young by default, aka _PAGE_VALID and _PAGE_ACCESSED both set in
> prot, it only take 1 TLB Miss + 1 TLB Invalid exceptions
>
> [1]: https://lkml.kernel.org/lkml/1591416169-26666-1-git-send-email
> -maobibo@loongson.cn/
>
> Co-developed-by: Bibo Mao <maobibo@loonson.cn>
> Co-developed-by: Huang Pei <huangpei@loongson.cn>
> Signed-off-by: Huang Pei <huangpei@loongson.cn>
> ---
> arch/mips/include/asm/pgtable.h | 32 +++++++++++++++-----------------
> arch/mips/mm/cache.c | 25 +++++++++++++------------
> mm/memory.c | 3 ---
> 3 files changed, 28 insertions(+), 32 deletions(-)
>
> diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
> index dd7a0f552cac..aaafe3d6a0a1 100644
> --- a/arch/mips/include/asm/pgtable.h
> +++ b/arch/mips/include/asm/pgtable.h
> @@ -25,22 +25,22 @@
> struct mm_struct;
> 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_COPY __pgprot(_PAGE_PRESENT | _PAGE_NO_EXEC | \
> - _page_cachable_default)
> -#define PAGE_READONLY __pgprot(_PAGE_PRESENT | \
> - _page_cachable_default)
> -#define PAGE_KERNEL __pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
> - _PAGE_GLOBAL | _page_cachable_default)
> -#define PAGE_KERNEL_NC __pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
> - _PAGE_GLOBAL | _CACHE_CACHABLE_NONCOHERENT)
> -#define PAGE_USERIO __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
> - _page_cachable_default)
> +#define PAGE_NONE __pgprot(_PAGE_PRESENT | _PAGE_NO_READ | \
> + _page_cachable_default)
> +#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
> + __READABLE | _page_cachable_default)
> +#define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_NO_EXEC | \
> + __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)
> +#define PAGE_KERNEL_NC __pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
> + _PAGE_GLOBAL | _CACHE_CACHABLE_NONCOHERENT)
> +#define PAGE_USERIO __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
> + _page_cachable_default)
> #define PAGE_KERNEL_UNCACHED __pgprot(_PAGE_PRESENT | __READABLE | \
> - __WRITEABLE | _PAGE_GLOBAL | _CACHE_UNCACHED)
> + __WRITEABLE | _PAGE_GLOBAL | _CACHE_UNCACHED)
>
> /*
> * If _PAGE_NO_EXEC is not defined, we can't do page protection for
> @@ -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/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 */
>