diff options
Diffstat (limited to 'arch/arm/mm/highmem.c')
| -rw-r--r-- | arch/arm/mm/highmem.c | 133 |
1 files changed, 28 insertions, 105 deletions
diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c index c435fd9e1da..45aeaaca905 100644 --- a/arch/arm/mm/highmem.c +++ b/arch/arm/mm/highmem.c @@ -18,6 +18,21 @@ #include <asm/tlbflush.h> #include "mm.h" +pte_t *fixmap_page_table; + +static inline void set_fixmap_pte(int idx, pte_t pte) +{ + unsigned long vaddr = __fix_to_virt(idx); + set_pte_ext(fixmap_page_table + idx, pte, 0); + local_flush_tlb_kernel_page(vaddr); +} + +static inline pte_t get_fixmap_pte(unsigned long vaddr) +{ + unsigned long idx = __virt_to_fix(vaddr); + return *(fixmap_page_table + idx); +} + void *kmap(struct page *page) { might_sleep(); @@ -36,7 +51,7 @@ void kunmap(struct page *page) } EXPORT_SYMBOL(kunmap); -void *__kmap_atomic(struct page *page) +void *kmap_atomic(struct page *page) { unsigned int idx; unsigned long vaddr; @@ -63,25 +78,24 @@ void *__kmap_atomic(struct page *page) type = kmap_atomic_idx_push(); idx = type + KM_TYPE_NR * smp_processor_id(); - vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); + 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(*(TOP_PTE(vaddr)))); + BUG_ON(!pte_none(*(fixmap_page_table + idx))); #endif - set_pte_ext(TOP_PTE(vaddr), mk_pte(page, kmap_prot), 0); /* * When debugging is off, kunmap_atomic leaves the previous mapping - * in place, so this TLB flush ensures the TLB is updated with the - * new mapping. + * in place, so the contained TLB flush ensures the TLB is updated + * with the new mapping. */ - local_flush_tlb_kernel_page(vaddr); + set_fixmap_pte(idx, mk_pte(page, kmap_prot)); return (void *)vaddr; } -EXPORT_SYMBOL(__kmap_atomic); +EXPORT_SYMBOL(kmap_atomic); void __kunmap_atomic(void *kvaddr) { @@ -95,9 +109,8 @@ void __kunmap_atomic(void *kvaddr) if (cache_is_vivt()) __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE); #ifdef CONFIG_DEBUG_HIGHMEM - BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); - set_pte_ext(TOP_PTE(vaddr), __pte(0), 0); - local_flush_tlb_kernel_page(vaddr); + BUG_ON(vaddr != __fix_to_virt(idx)); + set_fixmap_pte(idx, __pte(0)); #else (void) idx; /* to kill a warning */ #endif @@ -119,12 +132,11 @@ void *kmap_atomic_pfn(unsigned long pfn) type = kmap_atomic_idx_push(); idx = type + KM_TYPE_NR * smp_processor_id(); - vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); + vaddr = __fix_to_virt(idx); #ifdef CONFIG_DEBUG_HIGHMEM - BUG_ON(!pte_none(*(TOP_PTE(vaddr)))); + BUG_ON(!pte_none(*(fixmap_page_table + idx))); #endif - set_pte_ext(TOP_PTE(vaddr), pfn_pte(pfn, kmap_prot), 0); - local_flush_tlb_kernel_page(vaddr); + set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot)); return (void *)vaddr; } @@ -132,98 +144,9 @@ void *kmap_atomic_pfn(unsigned long pfn) struct page *kmap_atomic_to_page(const void *ptr) { unsigned long vaddr = (unsigned long)ptr; - pte_t *pte; if (vaddr < FIXADDR_START) return virt_to_page(ptr); - pte = TOP_PTE(vaddr); - return pte_page(*pte); -} - -#ifdef CONFIG_CPU_CACHE_VIPT - -#include <linux/percpu.h> - -/* - * The VIVT cache of a highmem page is always flushed before the page - * is unmapped. Hence unmapped highmem pages need no cache maintenance - * in that case. - * - * However unmapped pages may still be cached with a VIPT cache, and - * it is not possible to perform cache maintenance on them using physical - * addresses unfortunately. So we have no choice but to set up a temporary - * virtual mapping for that purpose. - * - * Yet this VIPT cache maintenance may be triggered from DMA support - * functions which are possibly called from interrupt context. As we don't - * want to keep interrupt disabled all the time when such maintenance is - * taking place, we therefore allow for some reentrancy by preserving and - * restoring the previous fixmap entry before the interrupted context is - * resumed. If the reentrancy depth is 0 then there is no need to restore - * the previous fixmap, and leaving the current one in place allow it to - * be reused the next time without a TLB flush (common with DMA). - */ - -static DEFINE_PER_CPU(int, kmap_high_l1_vipt_depth); - -void *kmap_high_l1_vipt(struct page *page, pte_t *saved_pte) -{ - unsigned int idx, cpu; - int *depth; - unsigned long vaddr, flags; - pte_t pte, *ptep; - - if (!in_interrupt()) - preempt_disable(); - - cpu = smp_processor_id(); - depth = &per_cpu(kmap_high_l1_vipt_depth, cpu); - - idx = KM_L1_CACHE + KM_TYPE_NR * cpu; - vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); - ptep = TOP_PTE(vaddr); - pte = mk_pte(page, kmap_prot); - - raw_local_irq_save(flags); - (*depth)++; - if (pte_val(*ptep) == pte_val(pte)) { - *saved_pte = pte; - } else { - *saved_pte = *ptep; - set_pte_ext(ptep, pte, 0); - local_flush_tlb_kernel_page(vaddr); - } - raw_local_irq_restore(flags); - - return (void *)vaddr; + return pte_page(get_fixmap_pte(vaddr)); } - -void kunmap_high_l1_vipt(struct page *page, pte_t saved_pte) -{ - unsigned int idx, cpu = smp_processor_id(); - int *depth = &per_cpu(kmap_high_l1_vipt_depth, cpu); - unsigned long vaddr, flags; - pte_t pte, *ptep; - - idx = KM_L1_CACHE + KM_TYPE_NR * cpu; - vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); - ptep = TOP_PTE(vaddr); - pte = mk_pte(page, kmap_prot); - - BUG_ON(pte_val(*ptep) != pte_val(pte)); - BUG_ON(*depth <= 0); - - raw_local_irq_save(flags); - (*depth)--; - if (*depth != 0 && pte_val(pte) != pte_val(saved_pte)) { - set_pte_ext(ptep, saved_pte, 0); - local_flush_tlb_kernel_page(vaddr); - } - raw_local_irq_restore(flags); - - if (!in_interrupt()) - preempt_enable(); -} - -#endif /* CONFIG_CPU_CACHE_VIPT */ |