1/* 2 * High memory support for Xtensa architecture 3 * 4 * This file is subject to the terms and conditions of the GNU General 5 * Public License. See the file "COPYING" in the main directory of 6 * this archive for more details. 7 * 8 * Copyright (C) 2014 Cadence Design Systems Inc. 9 */ 10 11#include <linux/export.h> 12#include <linux/highmem.h> 13#include <asm/tlbflush.h> 14 15static pte_t *kmap_pte; 16 17#if DCACHE_WAY_SIZE > PAGE_SIZE 18unsigned int last_pkmap_nr_arr[DCACHE_N_COLORS]; 19wait_queue_head_t pkmap_map_wait_arr[DCACHE_N_COLORS]; 20 21static void __init kmap_waitqueues_init(void) 22{ 23 unsigned int i; 24 25 for (i = 0; i < ARRAY_SIZE(pkmap_map_wait_arr); ++i) 26 init_waitqueue_head(pkmap_map_wait_arr + i); 27} 28#else 29static inline void kmap_waitqueues_init(void) 30{ 31} 32#endif 33 34static inline enum fixed_addresses kmap_idx(int type, unsigned long color) 35{ 36 return (type + KM_TYPE_NR * smp_processor_id()) * DCACHE_N_COLORS + 37 color; 38} 39 40void *kmap_atomic_high_prot(struct page *page, pgprot_t prot) 41{ 42 enum fixed_addresses idx; 43 unsigned long vaddr; 44 45 idx = kmap_idx(kmap_atomic_idx_push(), 46 DCACHE_ALIAS(page_to_phys(page))); 47 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); 48#ifdef CONFIG_DEBUG_HIGHMEM 49 BUG_ON(!pte_none(*(kmap_pte + idx))); 50#endif 51 set_pte(kmap_pte + idx, mk_pte(page, prot)); 52 53 return (void *)vaddr; 54} 55EXPORT_SYMBOL(kmap_atomic_high_prot); 56 57void kunmap_atomic_high(void *kvaddr) 58{ 59 if (kvaddr >= (void *)FIXADDR_START && 60 kvaddr < (void *)FIXADDR_TOP) { 61 int idx = kmap_idx(kmap_atomic_idx(), 62 DCACHE_ALIAS((unsigned long)kvaddr)); 63 64 /* 65 * Force other mappings to Oops if they'll try to access this 66 * pte without first remap it. Keeping stale mappings around 67 * is a bad idea also, in case the page changes cacheability 68 * attributes or becomes a protected page in a hypervisor. 69 */ 70 pte_clear(&init_mm, kvaddr, kmap_pte + idx); 71 local_flush_tlb_kernel_range((unsigned long)kvaddr, 72 (unsigned long)kvaddr + PAGE_SIZE); 73 74 kmap_atomic_idx_pop(); 75 } 76} 77EXPORT_SYMBOL(kunmap_atomic_high); 78 79void __init kmap_init(void) 80{ 81 unsigned long kmap_vstart; 82 83 /* Check if this memory layout is broken because PKMAP overlaps 84 * page table. 85 */ 86 BUILD_BUG_ON(PKMAP_BASE < TLBTEMP_BASE_1 + TLBTEMP_SIZE); 87 /* cache the first kmap pte */ 88 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); 89 kmap_pte = virt_to_kpte(kmap_vstart); 90 kmap_waitqueues_init(); 91} 92