From 2dde02ab6d1a725ddccc7144ff6bf5f55d37f916 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Wed, 30 Sep 2020 18:58:50 -0700 Subject: ARC: mm: support 3 levels of page tables ARCv2 MMU is software walked and Linux implements 2 levels of paging: pgd/pte. Forthcoming hw will have multiple levels, so this change preps mm code for same. It is also fun to try multi levels even on soft-walked code to ensure generic mm code is robust to handle. overview ________ 2 levels {pgd, pte} : pmd is folded but pmd_* macros are valid and operate on pgd 3 levels {pgd, pmd, pte}: - pud is folded and pud_* macros point to pgd - pmd_* macros operate on actual pmd code changes ____________ 1. #include 2. Define CONFIG_PGTABLE_LEVELS 3 3a. Define PMD_SHIFT, PMD_SIZE, PMD_MASK, pmd_t 3b. Define pmd_val() which actually deals with pmd (pmd_offset(), pmd_index() are provided by generic code) 3c. pmd_alloc_one()/pmd_free() also provided by generic code (pmd_populate/pmd_free already exist) 4. Define pud_none(), pud_bad() macros based on generic pud_val() which internally pertains to pgd now. 4b. define pud_populate() to just setup pgd Acked-by: Mike Rapoport Signed-off-by: Vineet Gupta --- arch/arc/include/asm/processor.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arc/include/asm/processor.h') diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h index e4031ecd3c8c..f28afcf5c6d1 100644 --- a/arch/arc/include/asm/processor.h +++ b/arch/arc/include/asm/processor.h @@ -93,7 +93,7 @@ extern unsigned int get_wchan(struct task_struct *p); #define VMALLOC_START (PAGE_OFFSET - (CONFIG_ARC_KVADDR_SIZE << 20)) /* 1 PGDIR_SIZE each for fixmap/pkmap, 2 PGDIR_SIZE gutter (see asm/highmem.h) */ -#define VMALLOC_SIZE ((CONFIG_ARC_KVADDR_SIZE << 20) - PGDIR_SIZE * 4) +#define VMALLOC_SIZE ((CONFIG_ARC_KVADDR_SIZE << 20) - PMD_SIZE * 4) #define VMALLOC_END (VMALLOC_START + VMALLOC_SIZE) -- cgit v1.2.3