Some fixmap fixed address slots previously depended on PAGE_SIZE (i.e. to determine how many slots were required to cover a given size). Since we require the fixed address slots to be compile-time constant, let's work out the worst case number of required slots when page size is PAGE_SIZE_MIN instead. Additionally, let's determine the worst-case number of PTE tables we require and statically allocate enough memory. For compile-time page size builds, the end result is the same as it was previously. Signed-off-by: Ryan Roberts <ryan.roberts@xxxxxxx> --- ***NOTE*** Any confused maintainers may want to read the cover note here for context: https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@xxxxxxx/ arch/arm64/include/asm/fixmap.h | 12 ++++++++---- arch/arm64/mm/fixmap.c | 34 ++++++++++++++++++++++----------- 2 files changed, 31 insertions(+), 15 deletions(-) diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h index 9a496d54dfe6e..c73fd3c1334ff 100644 --- a/arch/arm64/include/asm/fixmap.h +++ b/arch/arm64/include/asm/fixmap.h @@ -43,7 +43,7 @@ enum fixed_addresses { * whether it crosses any page boundary. */ FIX_FDT_END, - FIX_FDT = FIX_FDT_END + DIV_ROUND_UP(MAX_FDT_SIZE, PAGE_SIZE) + 1, + FIX_FDT = FIX_FDT_END + DIV_ROUND_UP(MAX_FDT_SIZE, PAGE_SIZE_MIN) + 1, FIX_EARLYCON_MEM_BASE, FIX_TEXT_POKE0, @@ -79,7 +79,7 @@ enum fixed_addresses { * Temporary boot-time mappings, used by early_ioremap(), * before ioremap() is functional. */ -#define NR_FIX_BTMAPS (SZ_256K / PAGE_SIZE) +#define NR_FIX_BTMAPS (SZ_256K / PAGE_SIZE_MIN) #define FIX_BTMAPS_SLOTS 7 #define TOTAL_FIX_BTMAPS (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS) @@ -101,8 +101,12 @@ enum fixed_addresses { #define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT) #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) -#define FIXADDR_TOT_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) -#define FIXADDR_TOT_START (FIXADDR_TOP - FIXADDR_TOT_SIZE) +#define __FIXADDR_TOT_SIZE(page_shift) \ + (__end_of_fixed_addresses << (page_shift)) +#define __FIXADDR_TOT_START(page_shift) \ + (FIXADDR_TOP - __FIXADDR_TOT_SIZE(page_shift)) +#define FIXADDR_TOT_SIZE __FIXADDR_TOT_SIZE(PAGE_SHIFT) +#define FIXADDR_TOT_START __FIXADDR_TOT_START(PAGE_SHIFT) #define FIXMAP_PAGE_IO __pgprot(PROT_DEVICE_nGnRE) diff --git a/arch/arm64/mm/fixmap.c b/arch/arm64/mm/fixmap.c index 15ce3253ad359..a0dcf2375ccb4 100644 --- a/arch/arm64/mm/fixmap.c +++ b/arch/arm64/mm/fixmap.c @@ -17,27 +17,39 @@ #include <asm/tlbflush.h> /* ensure that the fixmap region does not grow down into the PCI I/O region */ -static_assert(FIXADDR_TOT_START > PCI_IO_END); +static_assert(__FIXADDR_TOT_START(PAGE_SHIFT_MAX) > PCI_IO_END); -#define NR_BM_PTE_TABLES \ - SPAN_NR_ENTRIES(FIXADDR_TOT_START, FIXADDR_TOP, PMD_SHIFT) -#define NR_BM_PMD_TABLES \ - SPAN_NR_ENTRIES(FIXADDR_TOT_START, FIXADDR_TOP, PUD_SHIFT) +#define FIXMAP_LEVEL(page_shift, lvl, vstart, vend) \ + SPAN_NR_ENTRIES(vstart, vend, PGTABLE_LEVEL_SHIFT(page_shift, lvl)) -static_assert(NR_BM_PMD_TABLES == 1); +#define FIXMAP_PAGES(page_shift, level) \ + FIXMAP_LEVEL(page_shift, level, \ + __FIXADDR_TOT_START(page_shift), FIXADDR_TOP) + +#define FIXMAP_SIZE(page_shift, level) \ + (FIXMAP_PAGES(page_shift, level) * (UL(1) << (page_shift))) + +#define FIXMAP_PTE_SIZE_MAX \ + MAX_IF_HAVE_PGSZ(FIXMAP_SIZE(ARM64_PAGE_SHIFT_4K, 2), \ + FIXMAP_SIZE(ARM64_PAGE_SHIFT_16K, 2), \ + FIXMAP_SIZE(ARM64_PAGE_SHIFT_64K, 2)) + +static_assert(FIXMAP_PAGES(ARM64_PAGE_SHIFT_4K, 1) == 1); +static_assert(FIXMAP_PAGES(ARM64_PAGE_SHIFT_16K, 1) == 1); +static_assert(FIXMAP_PAGES(ARM64_PAGE_SHIFT_64K, 1) == 1); #define __BM_TABLE_IDX(addr, shift) \ (((addr) >> (shift)) - (FIXADDR_TOT_START >> (shift))) #define BM_PTE_TABLE_IDX(addr) __BM_TABLE_IDX(addr, PMD_SHIFT) -static pte_t bm_pte[NR_BM_PTE_TABLES][PTRS_PER_PTE] __page_aligned_bss; -static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused; -static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused; +static pte_t bm_pte[FIXMAP_PTE_SIZE_MAX / sizeof(pte_t)] __page_aligned_bss; +static pmd_t bm_pmd[MAX_PTRS_PER_PMD] __page_aligned_bss __maybe_unused; +static pud_t bm_pud[MAX_PTRS_PER_PUD] __page_aligned_bss __maybe_unused; static inline pte_t *fixmap_pte(unsigned long addr) { - return &bm_pte[BM_PTE_TABLE_IDX(addr)][pte_index(addr)]; + return &bm_pte[BM_PTE_TABLE_IDX(addr) * PTRS_PER_PTE + pte_index(addr)]; } static void __init early_fixmap_init_pte(pmd_t *pmdp, unsigned long addr) @@ -46,7 +58,7 @@ static void __init early_fixmap_init_pte(pmd_t *pmdp, unsigned long addr) pte_t *ptep; if (pmd_none(pmd)) { - ptep = bm_pte[BM_PTE_TABLE_IDX(addr)]; + ptep = &bm_pte[BM_PTE_TABLE_IDX(addr) * PTRS_PER_PTE]; __pmd_populate(pmdp, __pa_symbol(ptep), PMD_TYPE_TABLE); } } -- 2.43.0
