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author | Vineet Gupta <vgupta@kernel.org> | 2020-09-30 18:58:50 -0700 |
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committer | Vineet Gupta <vgupta@kernel.org> | 2021-08-26 13:43:19 -0700 |
commit | 2dde02ab6d1a725ddccc7144ff6bf5f55d37f916 (patch) | |
tree | 09c3c150d3ddd76c634e86f358eac40ed2efe920 /arch/arc/include/asm | |
parent | 9f3c76aedcbfee61dcdf299e708888141c7132fd (diff) | |
download | lwn-2dde02ab6d1a725ddccc7144ff6bf5f55d37f916.tar.gz lwn-2dde02ab6d1a725ddccc7144ff6bf5f55d37f916.zip |
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 <asm-generic/pgtable-nopud.h>
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 <rppt@linux.ibm.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
Diffstat (limited to 'arch/arc/include/asm')
-rw-r--r-- | arch/arc/include/asm/page.h | 11 | ||||
-rw-r--r-- | arch/arc/include/asm/pgalloc.h | 11 | ||||
-rw-r--r-- | arch/arc/include/asm/pgtable-levels.h | 63 | ||||
-rw-r--r-- | arch/arc/include/asm/processor.h | 2 |
4 files changed, 81 insertions, 6 deletions
diff --git a/arch/arc/include/asm/page.h b/arch/arc/include/asm/page.h index 28ed82b1800f..5d7899d87c08 100644 --- a/arch/arc/include/asm/page.h +++ b/arch/arc/include/asm/page.h @@ -41,6 +41,17 @@ typedef struct { #define pgd_val(x) ((x).pgd) #define __pgd(x) ((pgd_t) { (x) }) +#if CONFIG_PGTABLE_LEVELS > 2 + +typedef struct { + unsigned long pmd; +} pmd_t; + +#define pmd_val(x) ((x).pmd) +#define __pmd(x) ((pmd_t) { (x) }) + +#endif + typedef struct { #ifdef CONFIG_ARC_HAS_PAE40 unsigned long long pte; diff --git a/arch/arc/include/asm/pgalloc.h b/arch/arc/include/asm/pgalloc.h index 0cde9e5eefd7..781620d2e86f 100644 --- a/arch/arc/include/asm/pgalloc.h +++ b/arch/arc/include/asm/pgalloc.h @@ -70,6 +70,17 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm) return ret; } +#if CONFIG_PGTABLE_LEVELS > 2 + +static inline void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmdp) +{ + set_pud(pudp, __pud((unsigned long)pmdp)); +} + +#define __pmd_free_tlb(tlb, pmd, addr) pmd_free((tlb)->mm, pmd) + +#endif + #define __pte_free_tlb(tlb, pte, addr) pte_free((tlb)->mm, pte) #endif /* _ASM_ARC_PGALLOC_H */ diff --git a/arch/arc/include/asm/pgtable-levels.h b/arch/arc/include/asm/pgtable-levels.h index 561dedab79ed..5dd8c58f7d70 100644 --- a/arch/arc/include/asm/pgtable-levels.h +++ b/arch/arc/include/asm/pgtable-levels.h @@ -10,6 +10,8 @@ #ifndef _ASM_ARC_PGTABLE_LEVELS_H #define _ASM_ARC_PGTABLE_LEVELS_H +#if CONFIG_PGTABLE_LEVELS == 2 + /* * 2 level paging setup for software walked MMUv3 (ARC700) and MMUv4 (HS) * @@ -47,16 +49,38 @@ #endif -#define PGDIR_SIZE BIT(PGDIR_SHIFT) /* vaddr span, not PDG sz */ -#define PGDIR_MASK (~(PGDIR_SIZE - 1)) +#else /* CONFIG_PGTABLE_LEVELS != 2 */ + +/* + * A default 3 level paging testing setup in software walked MMU + * MMUv4 (8K page): <4> : <7> : <8> : <13> + */ +#define PGDIR_SHIFT 28 +#if CONFIG_PGTABLE_LEVELS > 2 +#define PMD_SHIFT 21 +#endif +#endif /* CONFIG_PGTABLE_LEVELS */ + +#define PGDIR_SIZE BIT(PGDIR_SHIFT) +#define PGDIR_MASK (~(PGDIR_SIZE - 1)) #define PTRS_PER_PGD BIT(32 - PGDIR_SHIFT) -#define PTRS_PER_PTE BIT(PGDIR_SHIFT - PAGE_SHIFT) +#if CONFIG_PGTABLE_LEVELS > 2 +#define PMD_SIZE BIT(PMD_SHIFT) +#define PMD_MASK (~(PMD_SIZE - 1)) +#define PTRS_PER_PMD BIT(PGDIR_SHIFT - PMD_SHIFT) +#endif + +#define PTRS_PER_PTE BIT(PMD_SHIFT - PAGE_SHIFT) #ifndef __ASSEMBLY__ +#if CONFIG_PGTABLE_LEVELS > 2 +#include <asm-generic/pgtable-nopud.h> +#else #include <asm-generic/pgtable-nopmd.h> +#endif /* * 1st level paging: pgd @@ -67,9 +91,35 @@ #define pgd_ERROR(e) \ pr_crit("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e)) +#if CONFIG_PGTABLE_LEVELS > 2 + +/* In 3 level paging, pud_* macros work on pgd */ +#define pud_none(x) (!pud_val(x)) +#define pud_bad(x) ((pud_val(x) & ~PAGE_MASK)) +#define pud_present(x) (pud_val(x)) +#define pud_clear(xp) do { pud_val(*(xp)) = 0; } while (0) +#define pud_pgtable(pud) ((pmd_t *)(pud_val(pud) & PAGE_MASK)) +#define pud_page(pud) virt_to_page(pud_pgtable(pud)) +#define set_pud(pudp, pud) (*(pudp) = pud) + /* - * Due to the strange way generic pgtable level folding works, in a 2 level - * setup, pmd_val() returns pgd, so these pmd_* macros actually work on pgd + * 2nd level paging: pmd + */ +#define pmd_ERROR(e) \ + pr_crit("%s:%d: bad pmd %08lx.\n", __FILE__, __LINE__, pmd_val(e)) + +#define pmd_pfn(pmd) ((pmd_val(pmd) & PMD_MASK) >> PAGE_SHIFT) +#define pfn_pmd(pfn,prot) __pmd(((pfn) << PAGE_SHIFT) | pgprot_val(prot)) +#define mk_pmd(page,prot) pfn_pmd(page_to_pfn(page),prot) + +#endif + +/* + * Due to the strange way generic pgtable level folding works, the pmd_* macros + * - are valid even for 2 levels (which supposedly only has pgd - pte) + * - behave differently for 2 vs. 3 + * In 2 level paging (pgd -> pte), pmd_* macros work on pgd + * In 3+ level paging (pgd -> pmd -> pte), pmd_* macros work on pmd */ #define pmd_none(x) (!pmd_val(x)) #define pmd_bad(x) ((pmd_val(x) & ~PAGE_MASK)) @@ -80,6 +130,9 @@ #define set_pmd(pmdp, pmd) (*(pmdp) = pmd) #define pmd_pgtable(pmd) ((pgtable_t) pmd_page_vaddr(pmd)) +/* + * 3rd level paging: pte + */ #define pte_ERROR(e) \ pr_crit("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e)) 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) |