From a6bbf5d4d9d13509fd068de664238c16934962c6 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 14 Feb 2024 13:29:17 +0100 Subject: [PATCH] arm64: mm: Add definitions to support 5 levels of paging Add the required types and descriptor accessors to support 5 levels of paging in the common code. This is one of the prerequisites for supporting 52-bit virtual addressing with 4k pages. Note that this does not cover the code that handles kernel mappings or the fixmap. Signed-off-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20240214122845.2033971-76-ardb+git@google.com Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/pgalloc.h | 41 +++++++++++++ arch/arm64/include/asm/pgtable-hwdef.h | 22 ++++++- arch/arm64/include/asm/pgtable-types.h | 6 ++ arch/arm64/include/asm/pgtable.h | 82 +++++++++++++++++++++++++- arch/arm64/mm/mmu.c | 31 +++++++++- arch/arm64/mm/pgd.c | 15 ++++- 6 files changed, 188 insertions(+), 9 deletions(-) diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h index 237224484d0f6..cae8c648f4628 100644 --- a/arch/arm64/include/asm/pgalloc.h +++ b/arch/arm64/include/asm/pgalloc.h @@ -60,6 +60,47 @@ static inline void __p4d_populate(p4d_t *p4dp, phys_addr_t pudp, p4dval_t prot) } #endif /* CONFIG_PGTABLE_LEVELS > 3 */ +#if CONFIG_PGTABLE_LEVELS > 4 + +static inline void __pgd_populate(pgd_t *pgdp, phys_addr_t p4dp, pgdval_t prot) +{ + if (pgtable_l5_enabled()) + set_pgd(pgdp, __pgd(__phys_to_pgd_val(p4dp) | prot)); +} + +static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgdp, p4d_t *p4dp) +{ + pgdval_t pgdval = PGD_TYPE_TABLE; + + pgdval |= (mm == &init_mm) ? PGD_TABLE_UXN : PGD_TABLE_PXN; + __pgd_populate(pgdp, __pa(p4dp), pgdval); +} + +static inline p4d_t *p4d_alloc_one(struct mm_struct *mm, unsigned long addr) +{ + gfp_t gfp = GFP_PGTABLE_USER; + + if (mm == &init_mm) + gfp = GFP_PGTABLE_KERNEL; + return (p4d_t *)get_zeroed_page(gfp); +} + +static inline void p4d_free(struct mm_struct *mm, p4d_t *p4d) +{ + if (!pgtable_l5_enabled()) + return; + BUG_ON((unsigned long)p4d & (PAGE_SIZE-1)); + free_page((unsigned long)p4d); +} + +#define __p4d_free_tlb(tlb, p4d, addr) p4d_free((tlb)->mm, p4d) +#else +static inline void __pgd_populate(pgd_t *pgdp, phys_addr_t p4dp, pgdval_t prot) +{ + BUILD_BUG(); +} +#endif /* CONFIG_PGTABLE_LEVELS > 4 */ + extern pgd_t *pgd_alloc(struct mm_struct *mm); extern void pgd_free(struct mm_struct *mm, pgd_t *pgdp); diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h index 4426f48f2ae03..ef207a0d4f0d9 100644 --- a/arch/arm64/include/asm/pgtable-hwdef.h +++ b/arch/arm64/include/asm/pgtable-hwdef.h @@ -26,10 +26,10 @@ #define ARM64_HW_PGTABLE_LEVELS(va_bits) (((va_bits) - 4) / (PAGE_SHIFT - 3)) /* - * Size mapped by an entry at level n ( 0 <= n <= 3) + * Size mapped by an entry at level n ( -1 <= n <= 3) * We map (PAGE_SHIFT - 3) at all translation levels and PAGE_SHIFT bits * in the final page. The maximum number of translation levels supported by - * the architecture is 4. Hence, starting at level n, we have further + * the architecture is 5. Hence, starting at level n, we have further * ((4 - n) - 1) levels of translation excluding the offset within the page. * So, the total number of bits mapped by an entry at level n is : * @@ -62,9 +62,16 @@ #define PTRS_PER_PUD (1 << (PAGE_SHIFT - 3)) #endif +#if CONFIG_PGTABLE_LEVELS > 4 +#define P4D_SHIFT ARM64_HW_PGTABLE_LEVEL_SHIFT(0) +#define P4D_SIZE (_AC(1, UL) << P4D_SHIFT) +#define P4D_MASK (~(P4D_SIZE-1)) +#define PTRS_PER_P4D (1 << (PAGE_SHIFT - 3)) +#endif + /* * PGDIR_SHIFT determines the size a top-level page table entry can map - * (depending on the configuration, this level can be 0, 1 or 2). + * (depending on the configuration, this level can be -1, 0, 1 or 2). */ #define PGDIR_SHIFT ARM64_HW_PGTABLE_LEVEL_SHIFT(4 - CONFIG_PGTABLE_LEVELS) #define PGDIR_SIZE (_AC(1, UL) << PGDIR_SHIFT) @@ -87,6 +94,15 @@ /* * Hardware page table definitions. * + * Level -1 descriptor (PGD). + */ +#define PGD_TYPE_TABLE (_AT(pgdval_t, 3) << 0) +#define PGD_TABLE_BIT (_AT(pgdval_t, 1) << 1) +#define PGD_TYPE_MASK (_AT(pgdval_t, 3) << 0) +#define PGD_TABLE_PXN (_AT(pgdval_t, 1) << 59) +#define PGD_TABLE_UXN (_AT(pgdval_t, 1) << 60) + +/* * Level 0 descriptor (P4D). */ #define P4D_TYPE_TABLE (_AT(p4dval_t, 3) << 0) diff --git a/arch/arm64/include/asm/pgtable-types.h b/arch/arm64/include/asm/pgtable-types.h index b8f158ae25273..6d6d4065b0cb4 100644 --- a/arch/arm64/include/asm/pgtable-types.h +++ b/arch/arm64/include/asm/pgtable-types.h @@ -36,6 +36,12 @@ typedef struct { pudval_t pud; } pud_t; #define __pud(x) ((pud_t) { (x) } ) #endif +#if CONFIG_PGTABLE_LEVELS > 4 +typedef struct { p4dval_t p4d; } p4d_t; +#define p4d_val(x) ((x).p4d) +#define __p4d(x) ((p4d_t) { (x) } ) +#endif + typedef struct { pgdval_t pgd; } pgd_t; #define pgd_val(x) ((x).pgd) #define __pgd(x) ((pgd_t) { (x) } ) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 61de7b1516bc1..7eb2b933ed3c3 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -808,7 +808,6 @@ static inline pud_t *p4d_pgtable(p4d_t p4d) #else #define p4d_page_paddr(p4d) ({ BUILD_BUG(); 0;}) -#define pgd_page_paddr(pgd) ({ BUILD_BUG(); 0;}) /* Match pud_offset folding in */ #define pud_set_fixmap(addr) NULL @@ -819,6 +818,87 @@ static inline pud_t *p4d_pgtable(p4d_t p4d) #endif /* CONFIG_PGTABLE_LEVELS > 3 */ +#if CONFIG_PGTABLE_LEVELS > 4 + +static __always_inline bool pgtable_l5_enabled(void) +{ + if (!alternative_has_cap_likely(ARM64_ALWAYS_BOOT)) + return vabits_actual == VA_BITS; + return alternative_has_cap_unlikely(ARM64_HAS_VA52); +} + +static inline bool mm_p4d_folded(const struct mm_struct *mm) +{ + return !pgtable_l5_enabled(); +} +#define mm_p4d_folded mm_p4d_folded + +#define p4d_ERROR(e) \ + pr_err("%s:%d: bad p4d %016llx.\n", __FILE__, __LINE__, p4d_val(e)) + +#define pgd_none(pgd) (pgtable_l5_enabled() && !pgd_val(pgd)) +#define pgd_bad(pgd) (pgtable_l5_enabled() && !(pgd_val(pgd) & 2)) +#define pgd_present(pgd) (!pgd_none(pgd)) + +static inline void set_pgd(pgd_t *pgdp, pgd_t pgd) +{ + if (in_swapper_pgdir(pgdp)) { + set_swapper_pgd(pgdp, __pgd(pgd_val(pgd))); + return; + } + + WRITE_ONCE(*pgdp, pgd); + dsb(ishst); + isb(); +} + +static inline void pgd_clear(pgd_t *pgdp) +{ + if (pgtable_l5_enabled()) + set_pgd(pgdp, __pgd(0)); +} + +static inline phys_addr_t pgd_page_paddr(pgd_t pgd) +{ + return __pgd_to_phys(pgd); +} + +#define p4d_index(addr) (((addr) >> P4D_SHIFT) & (PTRS_PER_P4D - 1)) + +static inline p4d_t *pgd_to_folded_p4d(pgd_t *pgdp, unsigned long addr) +{ + return (p4d_t *)PTR_ALIGN_DOWN(pgdp, PAGE_SIZE) + p4d_index(addr); +} + +static inline phys_addr_t p4d_offset_phys(pgd_t *pgdp, unsigned long addr) +{ + BUG_ON(!pgtable_l5_enabled()); + + return pgd_page_paddr(READ_ONCE(*pgdp)) + p4d_index(addr) * sizeof(p4d_t); +} + +static inline +p4d_t *p4d_offset_lockless(pgd_t *pgdp, pgd_t pgd, unsigned long addr) +{ + if (!pgtable_l5_enabled()) + return pgd_to_folded_p4d(pgdp, addr); + return (p4d_t *)__va(pgd_page_paddr(pgd)) + p4d_index(addr); +} +#define p4d_offset_lockless p4d_offset_lockless + +static inline p4d_t *p4d_offset(pgd_t *pgdp, unsigned long addr) +{ + return p4d_offset_lockless(pgdp, READ_ONCE(*pgdp), addr); +} + +#define pgd_page(pgd) pfn_to_page(__phys_to_pfn(__pgd_to_phys(pgd))) + +#else + +static inline bool pgtable_l5_enabled(void) { return false; } + +#endif /* CONFIG_PGTABLE_LEVELS > 4 */ + #define pgd_ERROR(e) \ pr_err("%s:%d: bad pgd %016llx.\n", __FILE__, __LINE__, pgd_val(e)) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index ba00d02054477..d2e9dec38a15d 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1025,7 +1025,7 @@ static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr, if (CONFIG_PGTABLE_LEVELS <= 3) return; - if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK)) + if (!pgtable_range_aligned(start, end, floor, ceiling, P4D_MASK)) return; /* @@ -1048,8 +1048,8 @@ static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr, unsigned long end, unsigned long floor, unsigned long ceiling) { - unsigned long next; p4d_t *p4dp, p4d; + unsigned long i, next, start = addr; do { next = p4d_addr_end(addr, end); @@ -1061,6 +1061,27 @@ static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr, WARN_ON(!p4d_present(p4d)); free_empty_pud_table(p4dp, addr, next, floor, ceiling); } while (addr = next, addr < end); + + if (!pgtable_l5_enabled()) + return; + + if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK)) + return; + + /* + * Check whether we can free the p4d page if the rest of the + * entries are empty. Overlap with other regions have been + * handled by the floor/ceiling check. + */ + p4dp = p4d_offset(pgdp, 0UL); + for (i = 0; i < PTRS_PER_P4D; i++) { + if (!p4d_none(READ_ONCE(p4dp[i]))) + return; + } + + pgd_clear(pgdp); + __flush_tlb_kernel_pgtable(start); + free_hotplug_pgtable_page(virt_to_page(p4dp)); } static void free_empty_tables(unsigned long addr, unsigned long end, @@ -1145,6 +1166,12 @@ int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) return 1; } +#ifndef __PAGETABLE_P4D_FOLDED +void p4d_clear_huge(p4d_t *p4dp) +{ +} +#endif + int pud_clear_huge(pud_t *pudp) { if (!pud_sect(READ_ONCE(*pudp))) diff --git a/arch/arm64/mm/pgd.c b/arch/arm64/mm/pgd.c index 4a64089e5771c..3c4f8a279d2bc 100644 --- a/arch/arm64/mm/pgd.c +++ b/arch/arm64/mm/pgd.c @@ -17,11 +17,20 @@ static struct kmem_cache *pgd_cache __ro_after_init; +static bool pgdir_is_page_size(void) +{ + if (PGD_SIZE == PAGE_SIZE) + return true; + if (CONFIG_PGTABLE_LEVELS == 5) + return !pgtable_l5_enabled(); + return false; +} + pgd_t *pgd_alloc(struct mm_struct *mm) { gfp_t gfp = GFP_PGTABLE_USER; - if (PGD_SIZE == PAGE_SIZE) + if (pgdir_is_page_size()) return (pgd_t *)__get_free_page(gfp); else return kmem_cache_alloc(pgd_cache, gfp); @@ -29,7 +38,7 @@ pgd_t *pgd_alloc(struct mm_struct *mm) void pgd_free(struct mm_struct *mm, pgd_t *pgd) { - if (PGD_SIZE == PAGE_SIZE) + if (pgdir_is_page_size()) free_page((unsigned long)pgd); else kmem_cache_free(pgd_cache, pgd); @@ -37,7 +46,7 @@ void pgd_free(struct mm_struct *mm, pgd_t *pgd) void __init pgtable_cache_init(void) { - if (PGD_SIZE == PAGE_SIZE) + if (pgdir_is_page_size()) return; #ifdef CONFIG_ARM64_PA_BITS_52