On 01/07/2019 07:40, Nicholas Piggin wrote: > walk_page_range() is going to be allowed to walk page tables other than > those of user space. For this it needs to know when it has reached a > 'leaf' entry in the page tables. This information will be provided by the > p?d_large() functions/macros. > > For arm64, we already have p?d_sect() macros which we can reuse for > p?d_large(). > > pud_sect() is defined as a dummy function when CONFIG_PGTABLE_LEVELS < 3 > or CONFIG_ARM64_64K_PAGES is defined. However when the kernel is > configured this way then architecturally it isn't allowed to have a > large page that this level, and any code using these page walking macros > is implicitly relying on the page size/number of levels being the same as > the kernel. So it is safe to reuse this for p?d_large() as it is an > architectural restriction. > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: Will Deacon <will.deacon@xxxxxxx> > Signed-off-by: Steven Price <steven.price@xxxxxxx> Hi Nicolas, This appears to my patch which I originally posted as part of converting x86/arm64 to use a generic page walk code[1]. I'm not sure that this patch makes much sense on its own, in particular it was working up to having a generic macro[2] which means the _large() macros could be used across all architectures. Also as a matter of courtesy please can you ensure the authorship information is preserved when posting other people's patches (there should be a From: line with my name on). You should also include your own Signed-off-by: line (see submitting-patches[3]) after mine. Apologies to anyone that has been following my patch series, I've been on holiday so not actively working on it. My aim is to combine the series with a generic ptdump implementation[4] which should improve the diff state. I should be able to post that in the next few weeks. Thanks, Steve [1] Series: https://patchwork.kernel.org/cover/10883885/ Last posting of this patch: https://patchwork.kernel.org/patch/10883899/ [2] https://patchwork.kernel.org/patch/10883965/ [3] https://www.kernel.org/doc/html/latest/process/submitting-patches.html#developer-s-certificate-of-origin-1-1 [4] RFC version here: https://lore.kernel.org/lkml/20190417143423.26665-1-steven.price@xxxxxxx/ > --- > arch/arm64/include/asm/pgtable.h | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index fca26759081a..0e973201bc16 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -417,6 +417,7 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, > PMD_TYPE_TABLE) > #define pmd_sect(pmd) ((pmd_val(pmd) & PMD_TYPE_MASK) == \ > PMD_TYPE_SECT) > +#define pmd_large(pmd) pmd_sect(pmd) > > #if defined(CONFIG_ARM64_64K_PAGES) || CONFIG_PGTABLE_LEVELS < 3 > #define pud_sect(pud) (0) > @@ -499,6 +500,7 @@ static inline void pte_unmap(pte_t *pte) { } > #define pud_none(pud) (!pud_val(pud)) > #define pud_bad(pud) (!(pud_val(pud) & PUD_TABLE_BIT)) > #define pud_present(pud) pte_present(pud_pte(pud)) > +#define pud_large(pud) pud_sect(pud) > #define pud_valid(pud) pte_valid(pud_pte(pud)) > > static inline void set_pud(pud_t *pudp, pud_t pud) >
