/* * 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" 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) { unsigned int idx; unsigned long vaddr; void *kmap; int type; 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(FIX_KMAP_BEGIN + 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)))); #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. */ local_flush_tlb_kernel_page(vaddr); 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_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); #else (void) idx; /* to kill a warning */ #endif 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(); } EXPORT_SYMBOL(__kunmap_atomic); void *kmap_atomic_pfn(unsigned long pfn) { unsigned long vaddr; int idx, type; pagefault_disable(); type = kmap_atomic_idx_push(); idx = type + KM_TYPE_NR * smp_processor_id(); vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); #ifdef CONFIG_DEBUG_HIGHMEM BUG_ON(!pte_none(*(TOP_PTE(vaddr)))); #endif set_pte_ext(TOP_PTE(vaddr), pfn_pte(pfn, kmap_prot), 0); local_flush_tlb_kernel_page(vaddr); return (void *)vaddr; } 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); }