diff options
| -rw-r--r-- | arch/arm/Kconfig | 3 | ||||
| -rw-r--r-- | arch/arm/include/asm/fixmap.h | 15 | ||||
| -rw-r--r-- | arch/arm/kernel/setup.c | 4 | ||||
| -rw-r--r-- | arch/arm/mm/highmem.c | 6 | ||||
| -rw-r--r-- | arch/arm/mm/mmu.c | 88 |
5 files changed, 105 insertions, 11 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index a750c1425c3a..1bcda7cb2e04 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -188,6 +188,9 @@ config ARCH_HAS_ILOG2_U64 config ARCH_HAS_BANDGAP bool +config FIX_EARLYCON_MEM + def_bool y if MMU + config GENERIC_HWEIGHT bool default y diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h index 0415eae1df27..58cfe9f1a687 100644 --- a/arch/arm/include/asm/fixmap.h +++ b/arch/arm/include/asm/fixmap.h @@ -6,9 +6,13 @@ #define FIXADDR_TOP (FIXADDR_END - PAGE_SIZE) #include <asm/kmap_types.h> +#include <asm/pgtable.h> enum fixed_addresses { - FIX_KMAP_BEGIN, + FIX_EARLYCON_MEM_BASE, + __end_of_permanent_fixed_addresses, + + FIX_KMAP_BEGIN = __end_of_permanent_fixed_addresses, FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1, /* Support writing RO kernel text via kprobes, jump labels, etc. */ @@ -18,7 +22,16 @@ enum fixed_addresses { __end_of_fixed_addresses }; +#define FIXMAP_PAGE_COMMON (L_PTE_YOUNG | L_PTE_PRESENT | L_PTE_XN | L_PTE_DIRTY) + +#define FIXMAP_PAGE_NORMAL (FIXMAP_PAGE_COMMON | L_PTE_MT_WRITEBACK) + +/* Used by set_fixmap_(io|nocache), both meant for mapping a device */ +#define FIXMAP_PAGE_IO (FIXMAP_PAGE_COMMON | L_PTE_MT_DEV_SHARED | L_PTE_SHARED) +#define FIXMAP_PAGE_NOCACHE FIXMAP_PAGE_IO + void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot); +void __init early_fixmap_init(void); #include <asm-generic/fixmap.h> diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 6bbec6042052..e2ecee6b70ca 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -37,6 +37,7 @@ #include <asm/cpu.h> #include <asm/cputype.h> #include <asm/elf.h> +#include <asm/fixmap.h> #include <asm/procinfo.h> #include <asm/psci.h> #include <asm/sections.h> @@ -954,6 +955,9 @@ void __init setup_arch(char **cmdline_p) strlcpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE); *cmdline_p = cmd_line; + if (IS_ENABLED(CONFIG_FIX_EARLYCON_MEM)) + early_fixmap_init(); + parse_early_param(); #ifdef CONFIG_MMU diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c index ee8dfa793989..9df5f09585ca 100644 --- a/arch/arm/mm/highmem.c +++ b/arch/arm/mm/highmem.c @@ -79,7 +79,7 @@ void *kmap_atomic(struct page *page) type = kmap_atomic_idx_push(); - idx = type + KM_TYPE_NR * smp_processor_id(); + idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id(); vaddr = __fix_to_virt(idx); #ifdef CONFIG_DEBUG_HIGHMEM /* @@ -106,7 +106,7 @@ void __kunmap_atomic(void *kvaddr) if (kvaddr >= (void *)FIXADDR_START) { type = kmap_atomic_idx(); - idx = type + KM_TYPE_NR * smp_processor_id(); + idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id(); if (cache_is_vivt()) __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE); @@ -138,7 +138,7 @@ void *kmap_atomic_pfn(unsigned long pfn) return page_address(page); type = kmap_atomic_idx_push(); - idx = type + KM_TYPE_NR * smp_processor_id(); + idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id(); vaddr = __fix_to_virt(idx); #ifdef CONFIG_DEBUG_HIGHMEM BUG_ON(!pte_none(get_fixmap_pte(vaddr))); diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index 6ca7d9aa896f..fb9e817d08bb 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -357,6 +357,47 @@ const struct mem_type *get_mem_type(unsigned int type) } EXPORT_SYMBOL(get_mem_type); +static pte_t *(*pte_offset_fixmap)(pmd_t *dir, unsigned long addr); + +static pte_t bm_pte[PTRS_PER_PTE + PTE_HWTABLE_PTRS] + __aligned(PTE_HWTABLE_OFF + PTE_HWTABLE_SIZE) __initdata; + +static pte_t * __init pte_offset_early_fixmap(pmd_t *dir, unsigned long addr) +{ + return &bm_pte[pte_index(addr)]; +} + +static pte_t *pte_offset_late_fixmap(pmd_t *dir, unsigned long addr) +{ + return pte_offset_kernel(dir, addr); +} + +static inline pmd_t * __init fixmap_pmd(unsigned long addr) +{ + pgd_t *pgd = pgd_offset_k(addr); + pud_t *pud = pud_offset(pgd, addr); + pmd_t *pmd = pmd_offset(pud, addr); + + return pmd; +} + +void __init early_fixmap_init(void) +{ + pmd_t *pmd; + + /* + * The early fixmap range spans multiple pmds, for which + * we are not prepared: + */ + BUILD_BUG_ON((__fix_to_virt(__end_of_permanent_fixed_addresses) >> PMD_SHIFT) + != FIXADDR_TOP >> PMD_SHIFT); + + pmd = fixmap_pmd(FIXADDR_TOP); + pmd_populate_kernel(&init_mm, pmd, bm_pte); + + pte_offset_fixmap = pte_offset_early_fixmap; +} + /* * To avoid TLB flush broadcasts, this uses local_flush_tlb_kernel_range(). * As a result, this can only be called with preemption disabled, as under @@ -365,7 +406,7 @@ EXPORT_SYMBOL(get_mem_type); void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot) { unsigned long vaddr = __fix_to_virt(idx); - pte_t *pte = pte_offset_kernel(pmd_off_k(vaddr), vaddr); + pte_t *pte = pte_offset_fixmap(pmd_off_k(vaddr), vaddr); /* Make sure fixmap region does not exceed available allocation. */ BUILD_BUG_ON(FIXADDR_START + (__end_of_fixed_addresses * PAGE_SIZE) > @@ -855,7 +896,7 @@ static void __init create_mapping(struct map_desc *md) } if ((md->type == MT_DEVICE || md->type == MT_ROM) && - md->virtual >= PAGE_OFFSET && + md->virtual >= PAGE_OFFSET && md->virtual < FIXADDR_START && (md->virtual < VMALLOC_START || md->virtual >= VMALLOC_END)) { pr_warn("BUG: mapping for 0x%08llx at 0x%08lx out of vmalloc space\n", (long long)__pfn_to_phys((u64)md->pfn), md->virtual); @@ -1213,10 +1254,10 @@ void __init arm_mm_memblock_reserve(void) /* * Set up the device mappings. Since we clear out the page tables for all - * mappings above VMALLOC_START, we will remove any debug device mappings. - * This means you have to be careful how you debug this function, or any - * called function. This means you can't use any function or debugging - * method which may touch any device, otherwise the kernel _will_ crash. + * mappings above VMALLOC_START, except early fixmap, we might remove debug + * device mappings. This means earlycon can be used to debug this function + * Any other function or debugging method which may touch any device _will_ + * crash the kernel. */ static void __init devicemaps_init(const struct machine_desc *mdesc) { @@ -1231,7 +1272,10 @@ static void __init devicemaps_init(const struct machine_desc *mdesc) early_trap_init(vectors); - for (addr = VMALLOC_START; addr; addr += PMD_SIZE) + /* + * Clear page table except top pmd used by early fixmaps + */ + for (addr = VMALLOC_START; addr < (FIXADDR_TOP & PMD_MASK); addr += PMD_SIZE) pmd_clear(pmd_off_k(addr)); /* @@ -1483,6 +1527,35 @@ void __init early_paging_init(const struct machine_desc *mdesc) #endif +static void __init early_fixmap_shutdown(void) +{ + int i; + unsigned long va = fix_to_virt(__end_of_permanent_fixed_addresses - 1); + + pte_offset_fixmap = pte_offset_late_fixmap; + pmd_clear(fixmap_pmd(va)); + local_flush_tlb_kernel_page(va); + + for (i = 0; i < __end_of_permanent_fixed_addresses; i++) { + pte_t *pte; + struct map_desc map; + + map.virtual = fix_to_virt(i); + pte = pte_offset_early_fixmap(pmd_off_k(map.virtual), map.virtual); + + /* Only i/o device mappings are supported ATM */ + if (pte_none(*pte) || + (pte_val(*pte) & L_PTE_MT_MASK) != L_PTE_MT_DEV_SHARED) + continue; + + map.pfn = pte_pfn(*pte); + map.type = MT_DEVICE; + map.length = PAGE_SIZE; + + create_mapping(&map); + } +} + /* * paging_init() sets up the page tables, initialises the zone memory * maps, and sets up the zero page, bad page and bad page tables. @@ -1495,6 +1568,7 @@ void __init paging_init(const struct machine_desc *mdesc) prepare_page_table(); map_lowmem(); dma_contiguous_remap(); + early_fixmap_shutdown(); devicemaps_init(mdesc); kmap_init(); tcm_init(); |