From: Ard Biesheuvel Date: Wed, 14 Feb 2024 12:29:20 +0000 (+0100) Subject: arm64: mm: Add 5 level paging support to fixmap and swapper handling X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=6ed8a3a094b43a27ac35e5c95a8004a1d83d1b79;p=linux.git arm64: mm: Add 5 level paging support to fixmap and swapper handling Add support for using 5 levels of paging in the fixmap, as well as in the kernel page table handling code which uses fixmaps internally. This also handles the case where a 5 level build runs on hardware that only supports 4 levels of paging. Signed-off-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20240214122845.2033971-79-ardb+git@google.com Signed-off-by: Catalin Marinas --- diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h index 8aabd45e9a13f..87e307804b99c 100644 --- a/arch/arm64/include/asm/fixmap.h +++ b/arch/arm64/include/asm/fixmap.h @@ -87,6 +87,7 @@ enum fixed_addresses { FIX_PTE, FIX_PMD, FIX_PUD, + FIX_P4D, FIX_PGD, __end_of_fixed_addresses diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 7eb2b933ed3c3..3d7fb3cde83d3 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -621,12 +621,12 @@ static inline bool pud_table(pud_t pud) { return true; } PUD_TYPE_TABLE) #endif -extern pgd_t init_pg_dir[PTRS_PER_PGD]; +extern pgd_t init_pg_dir[]; extern pgd_t init_pg_end[]; -extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; -extern pgd_t idmap_pg_dir[PTRS_PER_PGD]; -extern pgd_t tramp_pg_dir[PTRS_PER_PGD]; -extern pgd_t reserved_pg_dir[PTRS_PER_PGD]; +extern pgd_t swapper_pg_dir[]; +extern pgd_t idmap_pg_dir[]; +extern pgd_t tramp_pg_dir[]; +extern pgd_t reserved_pg_dir[]; extern void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd); @@ -891,12 +891,47 @@ static inline p4d_t *p4d_offset(pgd_t *pgdp, unsigned long addr) return p4d_offset_lockless(pgdp, READ_ONCE(*pgdp), addr); } +static inline p4d_t *p4d_set_fixmap(unsigned long addr) +{ + if (!pgtable_l5_enabled()) + return NULL; + return (p4d_t *)set_fixmap_offset(FIX_P4D, addr); +} + +static inline p4d_t *p4d_set_fixmap_offset(pgd_t *pgdp, unsigned long addr) +{ + if (!pgtable_l5_enabled()) + return pgd_to_folded_p4d(pgdp, addr); + return p4d_set_fixmap(p4d_offset_phys(pgdp, addr)); +} + +static inline void p4d_clear_fixmap(void) +{ + if (pgtable_l5_enabled()) + clear_fixmap(FIX_P4D); +} + +/* use ONLY for statically allocated translation tables */ +static inline p4d_t *p4d_offset_kimg(pgd_t *pgdp, u64 addr) +{ + if (!pgtable_l5_enabled()) + return pgd_to_folded_p4d(pgdp, addr); + return (p4d_t *)__phys_to_kimg(p4d_offset_phys(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; } +/* Match p4d_offset folding in */ +#define p4d_set_fixmap(addr) NULL +#define p4d_set_fixmap_offset(p4dp, addr) ((p4d_t *)p4dp) +#define p4d_clear_fixmap() + +#define p4d_offset_kimg(dir,addr) ((p4d_t *)dir) + #endif /* CONFIG_PGTABLE_LEVELS > 4 */ #define pgd_ERROR(e) \ diff --git a/arch/arm64/mm/fixmap.c b/arch/arm64/mm/fixmap.c index 9404f282f8298..d22506e9c7fda 100644 --- a/arch/arm64/mm/fixmap.c +++ b/arch/arm64/mm/fixmap.c @@ -104,7 +104,7 @@ void __init early_fixmap_init(void) unsigned long end = FIXADDR_TOP; pgd_t *pgdp = pgd_offset_k(addr); - p4d_t *p4dp = p4d_offset(pgdp, addr); + p4d_t *p4dp = p4d_offset_kimg(pgdp, addr); early_fixmap_init_pud(p4dp, addr, end); } diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index d30ae4d3fdd9e..8e5b3a7c5afd5 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -313,15 +313,14 @@ static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr, } while (addr = next, addr != end); } -static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end, +static void alloc_init_pud(p4d_t *p4dp, unsigned long addr, unsigned long end, phys_addr_t phys, pgprot_t prot, phys_addr_t (*pgtable_alloc)(int), int flags) { unsigned long next; - pud_t *pudp; - p4d_t *p4dp = p4d_offset(pgdp, addr); p4d_t p4d = READ_ONCE(*p4dp); + pud_t *pudp; if (p4d_none(p4d)) { p4dval_t p4dval = P4D_TYPE_TABLE | P4D_TABLE_UXN; @@ -369,6 +368,46 @@ static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end, pud_clear_fixmap(); } +static void alloc_init_p4d(pgd_t *pgdp, unsigned long addr, unsigned long end, + phys_addr_t phys, pgprot_t prot, + phys_addr_t (*pgtable_alloc)(int), + int flags) +{ + unsigned long next; + pgd_t pgd = READ_ONCE(*pgdp); + p4d_t *p4dp; + + if (pgd_none(pgd)) { + pgdval_t pgdval = PGD_TYPE_TABLE | PGD_TABLE_UXN; + phys_addr_t p4d_phys; + + if (flags & NO_EXEC_MAPPINGS) + pgdval |= PGD_TABLE_PXN; + BUG_ON(!pgtable_alloc); + p4d_phys = pgtable_alloc(P4D_SHIFT); + __pgd_populate(pgdp, p4d_phys, pgdval); + pgd = READ_ONCE(*pgdp); + } + BUG_ON(pgd_bad(pgd)); + + p4dp = p4d_set_fixmap_offset(pgdp, addr); + do { + p4d_t old_p4d = READ_ONCE(*p4dp); + + next = p4d_addr_end(addr, end); + + alloc_init_pud(p4dp, addr, next, phys, prot, + pgtable_alloc, flags); + + BUG_ON(p4d_val(old_p4d) != 0 && + p4d_val(old_p4d) != READ_ONCE(p4d_val(*p4dp))); + + phys += next - addr; + } while (p4dp++, addr = next, addr != end); + + p4d_clear_fixmap(); +} + static void __create_pgd_mapping_locked(pgd_t *pgdir, phys_addr_t phys, unsigned long virt, phys_addr_t size, pgprot_t prot, @@ -391,7 +430,7 @@ static void __create_pgd_mapping_locked(pgd_t *pgdir, phys_addr_t phys, do { next = pgd_addr_end(addr, end); - alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc, + alloc_init_p4d(pgdp, addr, next, phys, prot, pgtable_alloc, flags); phys += next - addr; } while (pgdp++, addr = next, addr != end);