From mboxrd@z Thu Jan 1 00:00:00 1970 From: labbott@redhat.com (Laura Abbott) Date: Mon, 4 Jan 2016 14:38:42 -0800 Subject: [PATCHv2 14/18] arm64: mm: use fixmap when creating page tables In-Reply-To: <1451930211-22460-15-git-send-email-mark.rutland@arm.com> References: <1451930211-22460-1-git-send-email-mark.rutland@arm.com> <1451930211-22460-15-git-send-email-mark.rutland@arm.com> Message-ID: <568AF472.6060901@redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 01/04/2016 09:56 AM, Mark Rutland wrote: > As a prepratory step to allow us to allocate early page tables form "page tables from" > unmapped memory using memblock_alloc, modify the __create_mapping > callees to map and unmap the tables they modify using fixmap entries. > > All but the top-level pgd initialisation is performed via the fixmap. > Subsequent patches will inject the pgd physical address, and migrate to > using the FIX_PGD slot. > > Signed-off-by: Mark Rutland > Cc: Ard Biesheuvel > Cc: Catalin Marinas > Cc: Jeremy Linton > Cc: Laura Abbott > Cc: Will Deacon > --- > arch/arm64/include/asm/pgtable.h | 2 +- > arch/arm64/mm/mmu.c | 63 ++++++++++++++++++++++++++-------------- > 2 files changed, 42 insertions(+), 23 deletions(-) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index 824e7f0..6fbf9fa 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -534,7 +534,7 @@ static inline phys_addr_t pgd_page_paddr(pgd_t pgd) > #define pud_offset(dir, addr) ((pud_t *)__va(pud_offset_phys((dir), (addr)))) > > #define pud_fixmap(addr) ((pud_t *)set_fixmap_offset(FIX_PUD, addr)) > -#define pud_fixmap_offset(pgd, addr) pud_fixmap(pmd_offset_phys(pgd, addr)) > +#define pud_fixmap_offset(pgd, addr) pud_fixmap(pud_offset_phys(pgd, addr)) Was this supposed to be folded into a previous patch? > #define pud_fixmap_unmap() clear_fixmap(FIX_PUD) > > #define pgd_page(pgd) pfn_to_page(__phys_to_pfn(pgd_val(pgd) & PHYS_MASK)) > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 8879aed..bf09d44 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -63,19 +63,30 @@ pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, > } > EXPORT_SYMBOL(phys_mem_access_prot); > > -static void __init *early_pgtable_alloc(void) > +static phys_addr_t __init early_pgtable_alloc(void) > { > phys_addr_t phys; > void *ptr; > > phys = memblock_alloc(PAGE_SIZE, PAGE_SIZE); > BUG_ON(!phys); > - ptr = __va(phys); > + > + /* > + * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE > + * slot will be free, so we can (ab)use the FIX_PTE slot to initialise > + * any level of table. > + */ > + ptr = pte_fixmap(phys); > + > memset(ptr, 0, PAGE_SIZE); > > - /* Ensure the zeroed page is visible to the page table walker */ > - dsb(ishst); > - return ptr; > + /* > + * Implicit barriers also ensure the zeroed page is visible to the page > + * table walker > + */ > + pte_fixmap_unmap(); > + > + return phys; > } > > /* > @@ -99,24 +110,28 @@ static void split_pmd(pmd_t *pmd, pte_t *pte) > static void alloc_init_pte(pmd_t *pmd, unsigned long addr, > unsigned long end, unsigned long pfn, > pgprot_t prot, > - void *(*pgtable_alloc)(void)) > + phys_addr_t (*pgtable_alloc)(void)) > { > pte_t *pte; > > if (pmd_none(*pmd) || pmd_sect(*pmd)) { > - pte = pgtable_alloc(); > + phys_addr_t pte_phys = pgtable_alloc(); > + pte = pte_fixmap(pte_phys); > if (pmd_sect(*pmd)) > split_pmd(pmd, pte); > - __pmd_populate(pmd, __pa(pte), PMD_TYPE_TABLE); > + __pmd_populate(pmd, pte_phys, PMD_TYPE_TABLE); > flush_tlb_all(); > + pte_fixmap_unmap(); > } > BUG_ON(pmd_bad(*pmd)); > > - pte = pte_offset_kernel(pmd, addr); > + pte = pte_fixmap_offset(pmd, addr); > do { > set_pte(pte, pfn_pte(pfn, prot)); > pfn++; > } while (pte++, addr += PAGE_SIZE, addr != end); > + > + pte_fixmap_unmap(); > } > > static void split_pud(pud_t *old_pud, pmd_t *pmd) > @@ -134,7 +149,7 @@ static void split_pud(pud_t *old_pud, pmd_t *pmd) > static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud, > unsigned long addr, unsigned long end, > phys_addr_t phys, pgprot_t prot, > - void *(*pgtable_alloc)(void)) > + phys_addr_t (*pgtable_alloc)(void)) > { > pmd_t *pmd; > unsigned long next; > @@ -143,7 +158,8 @@ static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud, > * Check for initial section mappings in the pgd/pud and remove them. > */ > if (pud_none(*pud) || pud_sect(*pud)) { > - pmd = pgtable_alloc(); > + phys_addr_t pmd_phys = pgtable_alloc(); > + pmd = pmd_fixmap(pmd_phys); > if (pud_sect(*pud)) { > /* > * need to have the 1G of mappings continue to be > @@ -151,12 +167,13 @@ static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud, > */ > split_pud(pud, pmd); > } > - pud_populate(mm, pud, pmd); > + __pud_populate(pud, pmd_phys, PUD_TYPE_TABLE); > flush_tlb_all(); > + pmd_fixmap_unmap(); > } > BUG_ON(pud_bad(*pud)); > > - pmd = pmd_offset(pud, addr); > + pmd = pmd_fixmap_offset(pud, addr); > do { > next = pmd_addr_end(addr, end); > /* try section mapping first */ > @@ -182,6 +199,8 @@ static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud, > } > phys += next - addr; > } while (pmd++, addr = next, addr != end); > + > + pmd_fixmap_unmap(); > } > > static inline bool use_1G_block(unsigned long addr, unsigned long next, > @@ -199,18 +218,18 @@ static inline bool use_1G_block(unsigned long addr, unsigned long next, > static void alloc_init_pud(struct mm_struct *mm, pgd_t *pgd, > unsigned long addr, unsigned long end, > phys_addr_t phys, pgprot_t prot, > - void *(*pgtable_alloc)(void)) > + phys_addr_t (*pgtable_alloc)(void)) > { > pud_t *pud; > unsigned long next; > > if (pgd_none(*pgd)) { > - pud = pgtable_alloc(); > - pgd_populate(mm, pgd, pud); > + phys_addr_t pud_phys = pgtable_alloc(); > + __pgd_populate(pgd, pud_phys, PUD_TYPE_TABLE); > } > BUG_ON(pgd_bad(*pgd)); > > - pud = pud_offset(pgd, addr); > + pud = pud_fixmap_offset(pgd, addr); > do { > next = pud_addr_end(addr, end); > > @@ -243,6 +262,8 @@ static void alloc_init_pud(struct mm_struct *mm, pgd_t *pgd, > } > phys += next - addr; > } while (pud++, addr = next, addr != end); > + > + pud_fixmap_unmap(); > } > > /* > @@ -252,7 +273,7 @@ static void alloc_init_pud(struct mm_struct *mm, pgd_t *pgd, > static void __create_mapping(struct mm_struct *mm, pgd_t *pgd, > phys_addr_t phys, unsigned long virt, > phys_addr_t size, pgprot_t prot, > - void *(*pgtable_alloc)(void)) > + phys_addr_t (*pgtable_alloc)(void)) > { > unsigned long addr, length, end, next; > > @@ -275,14 +296,12 @@ static void __create_mapping(struct mm_struct *mm, pgd_t *pgd, > } while (pgd++, addr = next, addr != end); > } > > -static void *late_pgtable_alloc(void) > +static phys_addr_t late_pgtable_alloc(void) > { > void *ptr = (void *)__get_free_page(PGALLOC_GFP); > BUG_ON(!ptr); > - > - /* Ensure the zeroed page is visible to the page table walker */ > dsb(ishst); This dropped the comment but not the actual barrier, was that intentional? > - return ptr; > + return __pa(ptr); > } > > static void __init create_mapping(phys_addr_t phys, unsigned long virt, > Thanks, Laura