From mboxrd@z Thu Jan 1 00:00:00 1970 From: labbott@redhat.com (Laura Abbott) Date: Mon, 4 Jan 2016 14:49:46 -0800 Subject: [PATCHv2 13/18] arm64: mm: add functions to walk tables in fixmap In-Reply-To: <1451930211-22460-14-git-send-email-mark.rutland@arm.com> References: <1451930211-22460-1-git-send-email-mark.rutland@arm.com> <1451930211-22460-14-git-send-email-mark.rutland@arm.com> Message-ID: <568AF70A.6020004@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 from > unmapped memory using memblock_alloc, add new p??_fixmap* functions that > can be used to walk page tables outside of the linear mapping by using > fixmap slots. > > Signed-off-by: Mark Rutland > Cc: Ard Biesheuvel > Cc: Catalin Marinas > Cc: Jeremy Linton > Cc: Laura Abbott > Cc: Will Deacon > --- > arch/arm64/include/asm/fixmap.h | 10 ++++++++++ > arch/arm64/include/asm/pgtable.h | 26 ++++++++++++++++++++++++++ > 2 files changed, 36 insertions(+) > > diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h > index 3097045..1a617d4 100644 > --- a/arch/arm64/include/asm/fixmap.h > +++ b/arch/arm64/include/asm/fixmap.h > @@ -62,6 +62,16 @@ enum fixed_addresses { > > FIX_BTMAP_END = __end_of_permanent_fixed_addresses, > FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1, > + > + /* > + * Used for kernel page table creation, so unmapped memory may be used > + * for tables. > + */ > + FIX_PTE, > + FIX_PMD, > + FIX_PUD, > + FIX_PGD, > + > __end_of_fixed_addresses > }; > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index f5742db..824e7f0 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -57,6 +57,7 @@ > > #ifndef __ASSEMBLY__ > > +#include > #include > > extern void __pte_error(const char *file, int line, unsigned long val); > @@ -442,6 +443,10 @@ static inline phys_addr_t pmd_page_paddr(pmd_t pmd) > #define pte_unmap(pte) do { } while (0) > #define pte_unmap_nested(pte) do { } while (0) > > +#define pte_fixmap(addr) ((pte_t *)set_fixmap_offset(FIX_PTE, addr)) > +#define pte_fixmap_offset(pmd, addr) pte_fixmap(pte_offset_phys(pmd, addr)) > +#define pte_fixmap_unmap() clear_fixmap(FIX_PTE) > + > #define pmd_page(pmd) pfn_to_page(__phys_to_pfn(pmd_val(pmd) & PHYS_MASK)) > > /* > @@ -481,12 +486,21 @@ static inline phys_addr_t pud_page_paddr(pud_t pud) > #define pmd_offset_phys(dir, addr) (pud_page_paddr(*(dir)) + pmd_index(addr) * sizeof(pmd_t)) > #define pmd_offset(dir, addr) ((pmd_t *)__va(pmd_offset_phys((dir), (addr)))) > > +#define pmd_fixmap(addr) ((pmd_t *)set_fixmap_offset(FIX_PMD, addr)) > +#define pmd_fixmap_offset(pud, addr) pmd_fixmap(pmd_offset_phys(pud, addr)) > +#define pmd_fixmap_unmap() clear_fixmap(FIX_PMD) > + > #define pud_page(pud) pfn_to_page(__phys_to_pfn(pud_val(pud) & PHYS_MASK)) > > #else > > #define pud_page_paddr(pud) ({ BUILD_BUG(); 0; }) > > +/* Match pmd_offset folding in */ > +#define pmd_fixmap(addr) NULL > +#define pmd_fixmap_offset(pudp, addr) ((pmd_t *)pudp) > +#define pmd_fixmap_unmap() > + > #endif /* CONFIG_PGTABLE_LEVELS > 2 */ > > #if CONFIG_PGTABLE_LEVELS > 3 > @@ -519,12 +533,21 @@ static inline phys_addr_t pgd_page_paddr(pgd_t pgd) > #define pud_offset_phys(dir, addr) (pgd_page_paddr(*(dir)) + pud_index(addr) * sizeof(pud_t)) > #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_unmap() clear_fixmap(FIX_PUD) > + > #define pgd_page(pgd) pfn_to_page(__phys_to_pfn(pgd_val(pgd) & PHYS_MASK)) > > #else > > #define pgd_page_paddr(pgd) ({ BUILD_BUG(); 0;}) > > +/* Match pud_offset folding in */ > +#define pud_fixmap(addr) NULL > +#define pud_fixmap_offset(pgdp, addr) ((pud_t *)pgdp) > +#define pud_fixmap_unmap() > + > #endif /* CONFIG_PGTABLE_LEVELS > 3 */ > > #define pgd_ERROR(pgd) __pgd_error(__FILE__, __LINE__, pgd_val(pgd)) > @@ -539,6 +562,9 @@ static inline phys_addr_t pgd_page_paddr(pgd_t pgd) > /* to find an entry in a kernel page-table-directory */ > #define pgd_offset_k(addr) pgd_offset(&init_mm, addr) > > +#define pgd_fixmap(addr) ((pgd_t *)set_fixmap_offset(FIX_PGD, addr)) > +#define pgd_fixmap_unmap() clear_fixmap(FIX_PGD) > + > static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) > { > const pteval_t mask = PTE_USER | PTE_PXN | PTE_UXN | PTE_RDONLY | > Bikeshed: p??_fixmap_offset doesn't make it obvious that this is an operation with a side effect. It seems more similar to p??_offset_kernel which is read only. Perhaps it's the lack of set/map in the name. Thanks, Laura