From 39af22a79232373764904576f31572f1db76af10 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Wed, 15 Dec 2010 15:14:45 -0500 Subject: ARM: get rid of kmap_high_l1_vipt() Since commit 3e4d3af501 "mm: stack based kmap_atomic()", it is no longer necessary to carry an ad hoc version of kmap_atomic() added in commit 7e5a69e83b "ARM: 6007/1: fix highmem with VIPT cache and DMA" to cope with reentrancy. In fact, it is now actively wrong to rely on fixed kmap type indices (namely KM_L1_CACHE) as kmap_atomic() totally ignores them now and a concurrent instance of it may reuse any slot for any purpose. Signed-off-by: Nicolas Pitre --- arch/arm/mm/dma-mapping.c | 7 ++-- arch/arm/mm/flush.c | 7 ++-- arch/arm/mm/highmem.c | 87 ----------------------------------------------- 3 files changed, 8 insertions(+), 93 deletions(-) (limited to 'arch/arm/mm') diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index ac6a36142fc..809f1bf9fa2 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include @@ -480,10 +481,10 @@ static void dma_cache_maint_page(struct page *page, unsigned long offset, op(vaddr, len, dir); kunmap_high(page); } else if (cache_is_vipt()) { - pte_t saved_pte; - vaddr = kmap_high_l1_vipt(page, &saved_pte); + /* unmapped pages might still be cached */ + vaddr = kmap_atomic(page); op(vaddr + offset, len, dir); - kunmap_high_l1_vipt(page, saved_pte); + kunmap_atomic(vaddr); } } else { vaddr = page_address(page) + offset; diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c index 391ffae7509..c29f2839f1d 100644 --- a/arch/arm/mm/flush.c +++ b/arch/arm/mm/flush.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include @@ -180,10 +181,10 @@ void __flush_dcache_page(struct address_space *mapping, struct page *page) __cpuc_flush_dcache_area(addr, PAGE_SIZE); kunmap_high(page); } else if (cache_is_vipt()) { - pte_t saved_pte; - addr = kmap_high_l1_vipt(page, &saved_pte); + /* unmapped pages might still be cached */ + addr = kmap_atomic(page); __cpuc_flush_dcache_area(addr, PAGE_SIZE); - kunmap_high_l1_vipt(page, saved_pte); + kunmap_atomic(addr); } } diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c index c435fd9e1da..807c0573abb 100644 --- a/arch/arm/mm/highmem.c +++ b/arch/arm/mm/highmem.c @@ -140,90 +140,3 @@ struct page *kmap_atomic_to_page(const void *ptr) pte = TOP_PTE(vaddr); return pte_page(*pte); } - -#ifdef CONFIG_CPU_CACHE_VIPT - -#include - -/* - * 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; -} - -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 */ -- cgit v1.2.3-18-g5258