/* * High memory support for Xtensa architecture * * This file is subject to the terms and conditions of the GNU General * Public License. See the file "COPYING" in the main directory of * this archive for more details. * * Copyright (C) 2014 Cadence Design Systems Inc. */ #include <linux/export.h> #include <linux/highmem.h> #include <asm/tlbflush.h> static pte_t *kmap_pte; #if DCACHE_WAY_SIZE > PAGE_SIZE unsigned int last_pkmap_nr_arr[DCACHE_N_COLORS]; wait_queue_head_t pkmap_map_wait_arr[DCACHE_N_COLORS]; static void __init kmap_waitqueues_init(void) { unsigned int i; for (i = 0; i < ARRAY_SIZE(pkmap_map_wait_arr); ++i) init_waitqueue_head(pkmap_map_wait_arr + i); } #else static inline void kmap_waitqueues_init(void) { } #endif static inline enum fixed_addresses kmap_idx(int type, unsigned long color) { return (type + KM_TYPE_NR * smp_processor_id()) * DCACHE_N_COLORS + color; } void *kmap_atomic(struct page *page) { enum fixed_addresses idx; unsigned long vaddr; preempt_disable(); pagefault_disable(); if (!PageHighMem(page)) return page_address(page); idx = kmap_idx(kmap_atomic_idx_push(), DCACHE_ALIAS(page_to_phys(page))); vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); #ifdef CONFIG_DEBUG_HIGHMEM BUG_ON(!pte_none(*(kmap_pte + idx))); #endif set_pte(kmap_pte + idx, mk_pte(page, PAGE_KERNEL_EXEC)); return (void *)vaddr; } EXPORT_SYMBOL(kmap_atomic); void __kunmap_atomic(void *kvaddr) { if (kvaddr >= (void *)FIXADDR_START && kvaddr < (void *)FIXADDR_TOP) { int idx = kmap_idx(kmap_atomic_idx(), DCACHE_ALIAS((unsigned long)kvaddr)); /* * Force other mappings to Oops if they'll try to access this * pte without first remap it. Keeping stale mappings around * is a bad idea also, in case the page changes cacheability * attributes or becomes a protected page in a hypervisor. */ pte_clear(&init_mm, kvaddr, kmap_pte + idx); local_flush_tlb_kernel_range((unsigned long)kvaddr, (unsigned long)kvaddr + PAGE_SIZE); kmap_atomic_idx_pop(); } pagefault_enable(); preempt_enable(); } EXPORT_SYMBOL(__kunmap_atomic); void __init kmap_init(void) { unsigned long kmap_vstart; /* cache the first kmap pte */ kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); kmap_pte = kmap_get_fixmap_pte(kmap_vstart); kmap_waitqueues_init(); }