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Message-ID: <509b9290-82e6-8b91-a852-67453ebd06c0@c-s.fr>
Date: Tue, 25 Sep 2018 18:48:40 +0200
From: Christophe LEROY <christophe.leroy@....fr>
To: "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>,
aneesh.kumar@...ux.vnet.ibm.com
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v4 16/20] powerpc/mm: Extend pte_fragment functionality to
nohash/32
Le 19/09/2018 à 05:03, Aneesh Kumar K.V a écrit :
> On 9/18/18 10:27 PM, Christophe Leroy wrote:
>> In order to allow the 8xx to handle pte_fragments, this patch
>> extends the use of pte_fragments to nohash/32 platforms.
>>
>> Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
>> ---
>> arch/powerpc/include/asm/mmu-40x.h | 1 +
>> arch/powerpc/include/asm/mmu-44x.h | 1 +
>> arch/powerpc/include/asm/mmu-8xx.h | 1 +
>> arch/powerpc/include/asm/mmu-book3e.h | 1 +
>> arch/powerpc/include/asm/mmu_context.h | 2 +-
>> arch/powerpc/include/asm/nohash/32/pgalloc.h | 43
>> +++++++++++-----------------
>> arch/powerpc/include/asm/nohash/32/pgtable.h | 7 +++--
>> arch/powerpc/include/asm/page.h | 6 +---
>> arch/powerpc/include/asm/pgtable.h | 8 ++++++
>> arch/powerpc/mm/Makefile | 3 ++
>> arch/powerpc/mm/mmu_context_nohash.c | 1 +
>> arch/powerpc/mm/pgtable-frag.c | 6 ++++
>> arch/powerpc/mm/pgtable_32.c | 8 ++++--
>> 13 files changed, 51 insertions(+), 37 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/mmu-40x.h
>> b/arch/powerpc/include/asm/mmu-40x.h
>> index 74f4edb5916e..7c77ceed71d6 100644
>> --- a/arch/powerpc/include/asm/mmu-40x.h
>> +++ b/arch/powerpc/include/asm/mmu-40x.h
>> @@ -58,6 +58,7 @@ typedef struct {
>> unsigned int id;
>> unsigned int active;
>> unsigned long vdso_base;
>> + void *pte_frag;
>> } mm_context_t;
>>
>> #endif /* !__ASSEMBLY__ */
>> diff --git a/arch/powerpc/include/asm/mmu-44x.h
>> b/arch/powerpc/include/asm/mmu-44x.h
>> index 295b3dbb2698..3d72e889ae7b 100644
>> --- a/arch/powerpc/include/asm/mmu-44x.h
>> +++ b/arch/powerpc/include/asm/mmu-44x.h
>> @@ -109,6 +109,7 @@ typedef struct {
>> unsigned int id;
>> unsigned int active;
>> unsigned long vdso_base;
>> + void *pte_frag;
>> } mm_context_t;
>>
>> #endif /* !__ASSEMBLY__ */
>> diff --git a/arch/powerpc/include/asm/mmu-8xx.h
>> b/arch/powerpc/include/asm/mmu-8xx.h
>> index fa05aa566ece..750cef6f65e3 100644
>> --- a/arch/powerpc/include/asm/mmu-8xx.h
>> +++ b/arch/powerpc/include/asm/mmu-8xx.h
>> @@ -179,6 +179,7 @@ typedef struct {
>> unsigned int id;
>> unsigned int active;
>> unsigned long vdso_base;
>> + void *pte_frag;
>> #ifdef CONFIG_PPC_MM_SLICES
>> u16 user_psize; /* page size index */
>> unsigned char low_slices_psize[SLICE_ARRAY_SIZE];
>> diff --git a/arch/powerpc/include/asm/mmu-book3e.h
>> b/arch/powerpc/include/asm/mmu-book3e.h
>> index e20072972e35..8e8aad5172ab 100644
>> --- a/arch/powerpc/include/asm/mmu-book3e.h
>> +++ b/arch/powerpc/include/asm/mmu-book3e.h
>> @@ -230,6 +230,7 @@ typedef struct {
>> unsigned int id;
>> unsigned int active;
>> unsigned long vdso_base;
>> + void *pte_frag;
>> } mm_context_t;
>>
>> /* Page size definitions, common between 32 and 64-bit
>> diff --git a/arch/powerpc/include/asm/mmu_context.h
>> b/arch/powerpc/include/asm/mmu_context.h
>> index b2f89b621b15..7f2c37a3f99d 100644
>> --- a/arch/powerpc/include/asm/mmu_context.h
>> +++ b/arch/powerpc/include/asm/mmu_context.h
>> @@ -222,7 +222,7 @@ static inline int arch_dup_mmap(struct mm_struct
>> *oldmm,
>> return 0;
>> }
>>
>> -#ifndef CONFIG_PPC_BOOK3S_64
>> +#if defined(CONFIG_PPC_BOOK3E_64) || defined(CONFIG_PPC_BOOK3S_32)
>> static inline void arch_exit_mmap(struct mm_struct *mm)
>> {
>> }
>> diff --git a/arch/powerpc/include/asm/nohash/32/pgalloc.h
>> b/arch/powerpc/include/asm/nohash/32/pgalloc.h
>> index f3fec9052f31..e69423ad8e2e 100644
>> --- a/arch/powerpc/include/asm/nohash/32/pgalloc.h
>> +++ b/arch/powerpc/include/asm/nohash/32/pgalloc.h
>> @@ -27,6 +27,9 @@ extern void __bad_pte(pmd_t *pmd);
>> extern struct kmem_cache *pgtable_cache[];
>> #define PGT_CACHE(shift) pgtable_cache[shift]
>>
>> +pte_t *pte_fragment_alloc(struct mm_struct *mm, unsigned long vmaddr,
>> int kernel);
>> +void pte_fragment_free(unsigned long *table, int kernel);
>> +
>> static inline pgd_t *pgd_alloc(struct mm_struct *mm)
>> {
>> return kmem_cache_alloc(PGT_CACHE(PGD_INDEX_SIZE),
>> @@ -58,11 +61,10 @@ static inline void pmd_populate_kernel(struct
>> mm_struct *mm, pmd_t *pmdp,
>> static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmdp,
>> pgtable_t pte_page)
>> {
>> - *pmdp = __pmd((page_to_pfn(pte_page) << PAGE_SHIFT) | _PMD_USER |
>> - _PMD_PRESENT);
>> + *pmdp = __pmd(__pa(pte_page) | _PMD_USER | _PMD_PRESENT);
>> }
>>
>> -#define pmd_pgtable(pmd) pmd_page(pmd)
>> +#define pmd_pgtable(pmd) ((pgtable_t)pmd_page_vaddr(pmd))
>> #else
>>
>> static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t
>> *pmdp,
>> @@ -74,49 +76,38 @@ static inline void pmd_populate_kernel(struct
>> mm_struct *mm, pmd_t *pmdp,
>> static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmdp,
>> pgtable_t pte_page)
>> {
>> - *pmdp = __pmd((unsigned long)lowmem_page_address(pte_page) |
>> _PMD_PRESENT);
>> + *pmdp = __pmd((unsigned long)pte_page | _PMD_PRESENT);
>> }
>>
>> -#define pmd_pgtable(pmd) pmd_page(pmd)
>> +#define pmd_pgtable(pmd) ((pgtable_t)pmd_page_vaddr(pmd))
>> #endif
>>
>> -static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
>> unsigned long address)
>> +static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
>> + unsigned long address)
>> {
>> - return (pte_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
>> + return (pte_t *)pte_fragment_alloc(mm, address, 1);
>> }
>>
>> -static inline pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned
>> long address)
>> +static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
>> + unsigned long address)
>> {
>> - struct page *ptepage;
>> -
>> - gfp_t flags = GFP_KERNEL | __GFP_ZERO | __GFP_ACCOUNT;
>> -
>> - ptepage = alloc_pages(flags, 0);
>> - if (!ptepage)
>> - return NULL;
>> - if (!pgtable_page_ctor(ptepage)) {
>> - __free_page(ptepage);
>> - return NULL;
>> - }
>> - return ptepage;
>> + return (pgtable_t)pte_fragment_alloc(mm, address, 0);
>> }
>>
>> static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
>> {
>> - free_page((unsigned long)pte);
>> + pte_fragment_free((unsigned long *)pte, 1);
>> }
>>
>> static inline void pte_free(struct mm_struct *mm, pgtable_t ptepage)
>> {
>> - pgtable_page_dtor(ptepage);
>> - __free_page(ptepage);
>> + pte_fragment_free((unsigned long *)ptepage, 0);
>> }
>>
>> static inline void pgtable_free(void *table, unsigned index_size)
>> {
>> if (!index_size) {
>> - pgtable_page_dtor(virt_to_page(table));
>> - free_page((unsigned long)table);
>> + pte_fragment_free((unsigned long *)table, 0);
>> } else {
>> BUG_ON(index_size > MAX_PGTABLE_INDEX_SIZE);
>> kmem_cache_free(PGT_CACHE(index_size), table);
>> @@ -155,6 +146,6 @@ static inline void __pte_free_tlb(struct
>> mmu_gather *tlb, pgtable_t table,
>> unsigned long address)
>> {
>> tlb_flush_pgtable(tlb, address);
>> - pgtable_free_tlb(tlb, page_address(table), 0);
>> + pgtable_free_tlb(tlb, table, 0);
>> }
>> #endif /* _ASM_POWERPC_PGALLOC_32_H */
>> diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h
>> b/arch/powerpc/include/asm/nohash/32/pgtable.h
>> index d2908a8038e8..73e2b1fbdb36 100644
>> --- a/arch/powerpc/include/asm/nohash/32/pgtable.h
>> +++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
>> @@ -336,12 +336,12 @@ static inline int pte_young(pte_t pte)
>> */
>> #ifndef CONFIG_BOOKE
>> #define pmd_page_vaddr(pmd) \
>> - ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
>> + ((unsigned long)__va(pmd_val(pmd) & ~(PTE_TABLE_SIZE - 1)))
>> #define pmd_page(pmd) \
>> pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT)
>> #else
>> #define pmd_page_vaddr(pmd) \
>> - ((unsigned long) (pmd_val(pmd) & PAGE_MASK))
>> + ((unsigned long)(pmd_val(pmd) & ~(PTE_TABLE_SIZE - 1)))
>> #define pmd_page(pmd) \
>> pfn_to_page((__pa(pmd_val(pmd)) >> PAGE_SHIFT))
>> #endif
>> @@ -360,7 +360,8 @@ static inline int pte_young(pte_t pte)
>> (pmd_bad(*(dir)) ? NULL : (pte_t *)pmd_page_vaddr(*(dir)) + \
>> pte_index(addr))
>> #define pte_offset_map(dir, addr) \
>> - ((pte_t *) kmap_atomic(pmd_page(*(dir))) + pte_index(addr))
>> + ((pte_t *)(kmap_atomic(pmd_page(*(dir))) + \
>> + (pmd_page_vaddr(*(dir)) & ~PAGE_MASK)) + pte_index(addr))
>> #define pte_unmap(pte) kunmap_atomic(pte)
>>
>> /*
>> diff --git a/arch/powerpc/include/asm/page.h
>> b/arch/powerpc/include/asm/page.h
>> index f6a1265face2..27d1c16601ee 100644
>> --- a/arch/powerpc/include/asm/page.h
>> +++ b/arch/powerpc/include/asm/page.h
>> @@ -335,7 +335,7 @@ void arch_free_page(struct page *page, int order);
>> #endif
>>
>> struct vm_area_struct;
>> -#ifdef CONFIG_PPC_BOOK3S_64
>> +#if !defined(CONFIG_PPC_BOOK3E_64) && !defined(CONFIG_PPC_BOOK3S_32)
>> /*
>> * For BOOK3s 64 with 4k and 64K linux page size
>> * we want to use pointers, because the page table
>> @@ -343,12 +343,8 @@ struct vm_area_struct;
>> */
>> typedef pte_t *pgtable_t;
>> #else
>> -#if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_PPC64)
>> -typedef pte_t *pgtable_t;
>> -#else
>> typedef struct page *pgtable_t;
>> #endif
>> -#endif
>>
>
>
> Now that is getting complicated. Is there a way to move that to platform
> header instead of that complicated #if?
Ok, added two new patches for that in v5 (one distributes mmu-xxx.h in
platform dirs, the other moves pgtable_t typedefs in relevant files)
>
>> #include <asm-generic/memory_model.h>
>> #endif /* __ASSEMBLY__ */
>> diff --git a/arch/powerpc/include/asm/pgtable.h
>> b/arch/powerpc/include/asm/pgtable.h
>> index 8b38f7730211..1865a3e4ab8c 100644
>> --- a/arch/powerpc/include/asm/pgtable.h
>> +++ b/arch/powerpc/include/asm/pgtable.h
>> @@ -94,12 +94,20 @@ unsigned long vmalloc_to_phys(void *vmalloc_addr);
>> void pgtable_cache_add(unsigned int shift);
>> void pgtable_cache_init(void);
>>
>> +pte_t *early_alloc_pte(void);
>> +
>> #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_PPC32)
>> void mark_initmem_nx(void);
>> #else
>> static inline void mark_initmem_nx(void) { }
>> #endif
>>
>> +#ifndef PTE_FRAG_NR
>> +#define PTE_FRAG_NR 1
>> +#define PTE_FRAG_SIZE_SHIFT PAGE_SHIFT
>> +#define PTE_FRAG_SIZE PAGE_SIZE
>> +#endif
>> +
>
> IMHO we should avoid that. The #ifndef challenge is that we should
> always make sure the header inclusion is correct so that platform
> headers get included before. Why not move it to the platform that want
> to use pte fragmentation?
Ok, in v5 functions using it now defined static inline in platform
headers so moved them there are well.
>
>
>> #endif /* __ASSEMBLY__ */
>>
>> #endif /* _ASM_POWERPC_PGTABLE_H */
>> diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
>> index bd43b3ee52cb..e1deb15fe85e 100644
>> --- a/arch/powerpc/mm/Makefile
>> +++ b/arch/powerpc/mm/Makefile
>> @@ -18,6 +18,9 @@ obj-$(CONFIG_PPC_BOOK3E_64) += pgtable-book3e.o
>> obj-$(CONFIG_PPC_BOOK3S_64) += pgtable-hash64.o hash_utils_64.o
>> slb_low.o slb.o \
>> $(hash64-y) mmu_context_book3s64.o
>> pgtable-book3s64.o \
>> pgtable-frag.o
>> +ifndef CONFIG_PPC_BOOK3S_32
>> +obj-$(CONFIG_PPC32) += pgtable-frag.o
>> +endif
>> obj-$(CONFIG_PPC_RADIX_MMU) += pgtable-radix.o tlb-radix.o
>> obj-$(CONFIG_PPC_STD_MMU_32) += ppc_mmu_32.o hash_low_32.o
>> mmu_context_hash32.o
>> obj-$(CONFIG_PPC_STD_MMU) += tlb_hash$(BITS).o
>> diff --git a/arch/powerpc/mm/mmu_context_nohash.c
>> b/arch/powerpc/mm/mmu_context_nohash.c
>> index 4d80239ef83c..98f0ef463dc8 100644
>> --- a/arch/powerpc/mm/mmu_context_nohash.c
>> +++ b/arch/powerpc/mm/mmu_context_nohash.c
>> @@ -385,6 +385,7 @@ int init_new_context(struct task_struct *t, struct
>> mm_struct *mm)
>> #endif
>> mm->context.id = MMU_NO_CONTEXT;
>> mm->context.active = 0;
>> + mm->context.pte_frag = NULL;
>> return 0;
>> }
>>
>> diff --git a/arch/powerpc/mm/pgtable-frag.c
>> b/arch/powerpc/mm/pgtable-frag.c
>> index ab4910e92aaf..d554a1cbc56d 100644
>> --- a/arch/powerpc/mm/pgtable-frag.c
>> +++ b/arch/powerpc/mm/pgtable-frag.c
>> @@ -30,6 +30,7 @@ static void pte_frag_destroy(void *pte_frag)
>> }
>> }
>>
>> +#ifdef CONFIG_PPC_BOOK3S_64
>> static void pmd_frag_destroy(void *pmd_frag)
>> {
>> int count;
>> @@ -44,6 +45,7 @@ static void pmd_frag_destroy(void *pmd_frag)
>> __free_page(page);
>> }
>> }
>> +#endif
>>
>> static void destroy_pagetable_cache(struct mm_struct *mm)
>> {
>> @@ -53,15 +55,18 @@ static void destroy_pagetable_cache(struct
>> mm_struct *mm)
>> if (frag)
>> pte_frag_destroy(frag);
>>
>> +#ifdef CONFIG_PPC_BOOK3S_64
>> frag = mm->context.pmd_frag;
>> if (frag)
>> pmd_frag_destroy(frag);
>> +#endif
>> }
>>
>> void arch_exit_mmap(struct mm_struct *mm)
>> {
>> destroy_pagetable_cache(mm);
>>
>> +#ifdef CONFIG_PPC_BOOK3S_64
>> if (radix_enabled()) {
>> /*
>> * Radix doesn't have a valid bit in the process table
>> @@ -79,6 +84,7 @@ void arch_exit_mmap(struct mm_struct *mm)
>> */
>> process_tb[mm->context.id].prtb0 = 0;
>> }
>> +#endif
>> }
>>
>
> is there a way to avoid all that #ifdef? May be redo the frag code such
> that we have few helpers that is platform independent?
Yes, in v5 reworked to keep platform specific arch_exit_mmap() and
destroy_pagetable_cache().
Christophe
>
>> static pte_t *get_pte_from_cache(struct mm_struct *mm)
>> diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
>> index 7900b613e6e5..81e6b18d1955 100644
>> --- a/arch/powerpc/mm/pgtable_32.c
>> +++ b/arch/powerpc/mm/pgtable_32.c
>> @@ -195,12 +195,16 @@ EXPORT_SYMBOL(iounmap);
>> static __init pte_t *early_pte_alloc_kernel(pmd_t *pmdp, unsigned
>> long va)
>> {
>> if (!pmd_present(*pmdp)) {
>> - pte_t *ptep = __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE));
>> + pte_t *ptep = __va(memblock_alloc(PTE_FRAG_SIZE,
>> PTE_FRAG_SIZE));
>>
>> if (!ptep)
>> return NULL;
>>
>> - clear_page(ptep);
>> + if (PTE_FRAG_SIZE == PAGE_SIZE)
>> + clear_page(ptep);
>> + else
>> + memset(ptep, 0, PTE_FRAG_SIZE);
>> +
>> pmd_populate_kernel(&init_mm, pmdp, ptep);
>> }
>> return pte_offset_kernel(pmdp, va);
>>
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