Messages in this thread Patch in this message | | | Date | Mon, 11 Jan 2016 16:24:49 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH v3 06/21] arm64: pgtable: implement static [pte|pmd|pud]_offset variants |
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On Mon, Jan 11, 2016 at 02:18:59PM +0100, Ard Biesheuvel wrote: > The page table accessors pte_offset(), pud_offset() and pmd_offset() > rely on __va translations, so they can only be used after the linear > mapping has been installed. For the early fixmap and kasan init routines, > whose page tables are allocated statically in the kernel image, these > functions will return bogus values. So implement pmd_offset_kimg() and > pud_offset_kimg(), which can be used instead before any page tables have > been allocated dynamically. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
This looks good to me. One possible suggsetion below, but either way:
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
> --- > arch/arm64/include/asm/pgtable.h | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index 6129f6755081..7b4e16068c9f 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -449,6 +449,9 @@ static inline phys_addr_t pmd_page_paddr(pmd_t pmd) > > #define pmd_page(pmd) pfn_to_page(__phys_to_pfn(pmd_val(pmd) & PHYS_MASK)) > > +/* use ONLY for statically allocated translation tables */ > +#define pte_offset_kimg(dir,addr) ((pte_t *)__phys_to_kimg(pte_offset_phys((dir), (addr)))) > +
Given that we're probably only going to use this during one-off setup, maybe it's worth something like:
#define IN_KERNEL_IMAGE(p) ({ \ unsigned long __p = (unsigned long)p; \ KIMAGE_VADDR <= __p && __p < _end; \ })
#define pte_offset_kimg(dir,addr) ({ \ BUG_ON(!IN_KERNEL_IMAGE(dir)); \ ((pte_t *)__phys_to_kimg(pte_offset_phys((dir), (addr)))); \ })
That might be overkill, though, given all it does is turn one runtime failure into another runtime failure.
Mark.
> /* > * Conversion functions: convert a page and protection to a page entry, > * and a page entry and page directory to the page they refer to. > @@ -492,6 +495,9 @@ static inline phys_addr_t pud_page_paddr(pud_t pud) > > #define pud_page(pud) pfn_to_page(__phys_to_pfn(pud_val(pud) & PHYS_MASK)) > > +/* use ONLY for statically allocated translation tables */ > +#define pmd_offset_kimg(dir,addr) ((pmd_t *)__phys_to_kimg(pmd_offset_phys((dir), (addr)))) > + > #else > > #define pud_page_paddr(pud) ({ BUILD_BUG(); 0; }) > @@ -502,6 +508,8 @@ static inline phys_addr_t pud_page_paddr(pud_t pud) > #define pmd_set_fixmap_offset(pudp, addr) ((pmd_t *)pudp) > #define pmd_clear_fixmap() > > +#define pmd_offset_kimg(dir,addr) ((pmd_t *)dir) > + > #endif /* CONFIG_PGTABLE_LEVELS > 2 */ > > #if CONFIG_PGTABLE_LEVELS > 3 > @@ -540,6 +548,9 @@ static inline phys_addr_t pgd_page_paddr(pgd_t pgd) > > #define pgd_page(pgd) pfn_to_page(__phys_to_pfn(pgd_val(pgd) & PHYS_MASK)) > > +/* use ONLY for statically allocated translation tables */ > +#define pud_offset_kimg(dir,addr) ((pud_t *)__phys_to_kimg(pud_offset_phys((dir), (addr)))) > + > #else > > #define pgd_page_paddr(pgd) ({ BUILD_BUG(); 0;}) > @@ -550,6 +561,8 @@ static inline phys_addr_t pgd_page_paddr(pgd_t pgd) > #define pud_set_fixmap_offset(pgdp, addr) ((pud_t *)pgdp) > #define pud_clear_fixmap() > > +#define pud_offset_kimg(dir,addr) ((pud_t *)dir) > + > #endif /* CONFIG_PGTABLE_LEVELS > 3 */ > > #define pgd_ERROR(pgd) __pgd_error(__FILE__, __LINE__, pgd_val(pgd)) > -- > 2.5.0 >
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