From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Mon, 16 Nov 2015 12:23:14 +0100 Subject: [PATCH v3 3/7] arm64: split off early mapping code from early_fixmap_init() In-Reply-To: <1447672998-20981-1-git-send-email-ard.biesheuvel@linaro.org> References: <1447672998-20981-1-git-send-email-ard.biesheuvel@linaro.org> Message-ID: <1447672998-20981-4-git-send-email-ard.biesheuvel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org This splits off and generalises the population of the statically allocated fixmap page tables so that we may reuse it later for the linear mapping once we move the kernel text mapping out of it. This also involves taking into account that table entries at any of the levels we are populating may have been populated already, since the fixmap mapping might not be disjoint up to the pgd level anymore from other early mappings. Signed-off-by: Ard Biesheuvel --- arch/arm64/include/asm/compiler.h | 2 + arch/arm64/kernel/vmlinux.lds.S | 12 ++-- arch/arm64/mm/mmu.c | 60 ++++++++++++++------ 3 files changed, 51 insertions(+), 23 deletions(-) diff --git a/arch/arm64/include/asm/compiler.h b/arch/arm64/include/asm/compiler.h index ee35fd0f2236..dd342af63673 100644 --- a/arch/arm64/include/asm/compiler.h +++ b/arch/arm64/include/asm/compiler.h @@ -27,4 +27,6 @@ */ #define __asmeq(x, y) ".ifnc " x "," y " ; .err ; .endif\n\t" +#define __pgdir __attribute__((section(".pgdir"),aligned(PAGE_SIZE))) + #endif /* __ASM_COMPILER_H */ diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index 1ee2c3937d4e..87a596246ec7 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -164,11 +164,13 @@ SECTIONS BSS_SECTION(0, 0, 0) - . = ALIGN(PAGE_SIZE); - idmap_pg_dir = .; - . += IDMAP_DIR_SIZE; - swapper_pg_dir = .; - . += SWAPPER_DIR_SIZE; + .pgdir (NOLOAD) : ALIGN(PAGE_SIZE) { + idmap_pg_dir = .; + . += IDMAP_DIR_SIZE; + swapper_pg_dir = .; + . += SWAPPER_DIR_SIZE; + *(.pgdir) + } _end = .; diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 32ddd893da9a..4f397a87c2be 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -396,6 +396,44 @@ static void __init __map_memblock(phys_addr_t start, phys_addr_t end) } #endif +struct bootstrap_pgtables { + pte_t pte[PTRS_PER_PTE]; + pmd_t pmd[PTRS_PER_PMD > 1 ? PTRS_PER_PMD : 0]; + pud_t pud[PTRS_PER_PUD > 1 ? PTRS_PER_PUD : 0]; +}; + +static void __init bootstrap_early_mapping(unsigned long addr, + struct bootstrap_pgtables *reg, + bool pte_level) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + + pgd = pgd_offset_k(addr); + if (pgd_none(*pgd)) { + clear_page(reg->pud); + memblock_reserve(__pa(reg->pud), PAGE_SIZE); + pgd_populate(&init_mm, pgd, reg->pud); + } + pud = pud_offset(pgd, addr); + if (pud_none(*pud)) { + clear_page(reg->pmd); + memblock_reserve(__pa(reg->pmd), PAGE_SIZE); + pud_populate(&init_mm, pud, reg->pmd); + } + + if (!pte_level) + return; + + pmd = pmd_offset(pud, addr); + if (pmd_none(*pmd)) { + clear_page(reg->pte); + memblock_reserve(__pa(reg->pte), PAGE_SIZE); + pmd_populate_kernel(&init_mm, pmd, reg->pte); + } +} + static void __init map_mem(void) { struct memblock_region *reg; @@ -598,14 +636,6 @@ void vmemmap_free(unsigned long start, unsigned long end) } #endif /* CONFIG_SPARSEMEM_VMEMMAP */ -static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss; -#if CONFIG_PGTABLE_LEVELS > 2 -static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss; -#endif -#if CONFIG_PGTABLE_LEVELS > 3 -static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss; -#endif - static inline pud_t * fixmap_pud(unsigned long addr) { pgd_t *pgd = pgd_offset_k(addr); @@ -635,21 +665,15 @@ static inline pte_t * fixmap_pte(unsigned long addr) void __init early_fixmap_init(void) { - pgd_t *pgd; - pud_t *pud; + static struct bootstrap_pgtables fixmap_bs_pgtables __pgdir; pmd_t *pmd; - unsigned long addr = FIXADDR_START; - pgd = pgd_offset_k(addr); - pgd_populate(&init_mm, pgd, bm_pud); - pud = pud_offset(pgd, addr); - pud_populate(&init_mm, pud, bm_pmd); - pmd = pmd_offset(pud, addr); - pmd_populate_kernel(&init_mm, pmd, bm_pte); + bootstrap_early_mapping(FIXADDR_START, &fixmap_bs_pgtables, true); + pmd = fixmap_pmd(FIXADDR_START); /* * The boot-ioremap range spans multiple pmds, for which - * we are not preparted: + * we are not prepared: */ BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); -- 1.9.1