diff options
Diffstat (limited to 'kernel/arch/arm/mm/highmem.c')
| -rw-r--r-- | kernel/arch/arm/mm/highmem.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/kernel/arch/arm/mm/highmem.c b/kernel/arch/arm/mm/highmem.c new file mode 100644 index 000000000..4050e9d99 --- /dev/null +++ b/kernel/arch/arm/mm/highmem.c @@ -0,0 +1,195 @@ +/* + * arch/arm/mm/highmem.c -- ARM highmem support + * + * Author: Nicolas Pitre + * Created: september 8, 2008 + * Copyright: Marvell Semiconductors Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/module.h> +#include <linux/highmem.h> +#include <linux/interrupt.h> +#include <asm/fixmap.h> +#include <asm/cacheflush.h> +#include <asm/tlbflush.h> +#include "mm.h" + +static inline void set_fixmap_pte(int idx, pte_t pte) +{ + unsigned long vaddr = __fix_to_virt(idx); + pte_t *ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr); + + set_pte_ext(ptep, pte, 0); + local_flush_tlb_kernel_page(vaddr); +} + +static inline pte_t get_fixmap_pte(unsigned long vaddr) +{ + pte_t *ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr); + + return *ptep; +} + +void *kmap(struct page *page) +{ + might_sleep(); + if (!PageHighMem(page)) + return page_address(page); + return kmap_high(page); +} +EXPORT_SYMBOL(kmap); + +void kunmap(struct page *page) +{ + BUG_ON(in_interrupt()); + if (!PageHighMem(page)) + return; + kunmap_high(page); +} +EXPORT_SYMBOL(kunmap); + +void *kmap_atomic(struct page *page) +{ + pte_t pte = mk_pte(page, kmap_prot); + unsigned int idx; + unsigned long vaddr; + void *kmap; + int type; + + preempt_disable_nort(); + pagefault_disable(); + if (!PageHighMem(page)) + return page_address(page); + +#ifdef CONFIG_DEBUG_HIGHMEM + /* + * There is no cache coherency issue when non VIVT, so force the + * dedicated kmap usage for better debugging purposes in that case. + */ + if (!cache_is_vivt()) + kmap = NULL; + else +#endif + kmap = kmap_high_get(page); + if (kmap) + return kmap; + + type = kmap_atomic_idx_push(); + + idx = type + KM_TYPE_NR * smp_processor_id(); + vaddr = __fix_to_virt(idx); +#ifdef CONFIG_DEBUG_HIGHMEM + /* + * With debugging enabled, kunmap_atomic forces that entry to 0. + * Make sure it was indeed properly unmapped. + */ + BUG_ON(!pte_none(get_fixmap_pte(vaddr))); +#endif + /* + * When debugging is off, kunmap_atomic leaves the previous mapping + * in place, so the contained TLB flush ensures the TLB is updated + * with the new mapping. + */ +#ifdef CONFIG_PREEMPT_RT_FULL + current->kmap_pte[type] = pte; +#endif + set_fixmap_pte(idx, pte); + + return (void *)vaddr; +} +EXPORT_SYMBOL(kmap_atomic); + +void __kunmap_atomic(void *kvaddr) +{ + unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; + int idx, type; + + if (kvaddr >= (void *)FIXADDR_START) { + type = kmap_atomic_idx(); + idx = type + KM_TYPE_NR * smp_processor_id(); + + if (cache_is_vivt()) + __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE); +#ifdef CONFIG_PREEMPT_RT_FULL + current->kmap_pte[type] = __pte(0); +#endif +#ifdef CONFIG_DEBUG_HIGHMEM + BUG_ON(vaddr != __fix_to_virt(idx)); +#else + (void) idx; /* to kill a warning */ +#endif + set_fixmap_pte(idx, __pte(0)); + kmap_atomic_idx_pop(); + } else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) { + /* this address was obtained through kmap_high_get() */ + kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)])); + } + pagefault_enable(); + preempt_enable_nort(); +} +EXPORT_SYMBOL(__kunmap_atomic); + +void *kmap_atomic_pfn(unsigned long pfn) +{ + pte_t pte = pfn_pte(pfn, kmap_prot); + unsigned long vaddr; + int idx, type; + struct page *page = pfn_to_page(pfn); + + preempt_disable_nort(); + pagefault_disable(); + if (!PageHighMem(page)) + return page_address(page); + + type = kmap_atomic_idx_push(); + idx = type + KM_TYPE_NR * smp_processor_id(); + vaddr = __fix_to_virt(idx); +#ifdef CONFIG_DEBUG_HIGHMEM + BUG_ON(!pte_none(get_fixmap_pte(vaddr))); +#endif +#ifdef CONFIG_PREEMPT_RT_FULL + current->kmap_pte[type] = pte; +#endif + set_fixmap_pte(idx, pte); + + return (void *)vaddr; +} + +struct page *kmap_atomic_to_page(const void *ptr) +{ + unsigned long vaddr = (unsigned long)ptr; + + if (vaddr < FIXADDR_START) + return virt_to_page(ptr); + + return pte_page(get_fixmap_pte(vaddr)); +} + +#if defined CONFIG_PREEMPT_RT_FULL +void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p) +{ + int i; + + /* + * Clear @prev's kmap_atomic mappings + */ + for (i = 0; i < prev_p->kmap_idx; i++) { + int idx = i + KM_TYPE_NR * smp_processor_id(); + + set_fixmap_pte(idx, __pte(0)); + } + /* + * Restore @next_p's kmap_atomic mappings + */ + for (i = 0; i < next_p->kmap_idx; i++) { + int idx = i + KM_TYPE_NR * smp_processor_id(); + + if (!pte_none(next_p->kmap_pte[i])) + set_fixmap_pte(idx, next_p->kmap_pte[i]); + } +} +#endif |