1 /* <<
2 * High memory support for Xtensa architecture <<
3 * <<
4 * This file is subject to the terms and condi <<
5 * Public License. See the file "COPYING" in <<
6 * this archive for more details. <<
7 * <<
8 * Copyright (C) 2014 Cadence Design Systems I <<
9 */ <<
10 <<
11 #include <linux/export.h> <<
12 #include <linux/highmem.h> 1 #include <linux/highmem.h>
13 #include <asm/tlbflush.h> <<
14 2
15 #if DCACHE_WAY_SIZE > PAGE_SIZE !! 3 void *kmap(struct page *page)
16 unsigned int last_pkmap_nr_arr[DCACHE_N_COLORS !! 4 {
17 wait_queue_head_t pkmap_map_wait_arr[DCACHE_N_ !! 5 might_sleep();
>> 6 if (page < highmem_start_page)
>> 7 return page_address(page);
>> 8 return kmap_high(page);
>> 9 }
>> 10
>> 11 void kunmap(struct page *page)
>> 12 {
>> 13 if (in_interrupt())
>> 14 BUG();
>> 15 if (page < highmem_start_page)
>> 16 return;
>> 17 kunmap_high(page);
>> 18 }
18 19
19 static void __init kmap_waitqueues_init(void) !! 20 /*
>> 21 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
>> 22 * no global lock is needed and because the kmap code must perform a global TLB
>> 23 * invalidation when the kmap pool wraps.
>> 24 *
>> 25 * However when holding an atomic kmap is is not legal to sleep, so atomic
>> 26 * kmaps are appropriate for short, tight code paths only.
>> 27 */
>> 28 void *kmap_atomic(struct page *page, enum km_type type)
20 { 29 {
21 unsigned int i; !! 30 enum fixed_addresses idx;
>> 31 unsigned long vaddr;
>> 32
>> 33 inc_preempt_count();
>> 34 if (page < highmem_start_page)
>> 35 return page_address(page);
>> 36
>> 37 idx = type + KM_TYPE_NR*smp_processor_id();
>> 38 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
>> 39 #ifdef CONFIG_DEBUG_HIGHMEM
>> 40 if (!pte_none(*(kmap_pte-idx)))
>> 41 BUG();
>> 42 #endif
>> 43 set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
>> 44 __flush_tlb_one(vaddr);
22 45
23 for (i = 0; i < ARRAY_SIZE(pkmap_map_w !! 46 return (void*) vaddr;
24 init_waitqueue_head(pkmap_map_ <<
25 } 47 }
26 48
27 static inline enum fixed_addresses kmap_idx(in !! 49 void kunmap_atomic(void *kvaddr, enum km_type type)
28 { 50 {
29 int idx = (type + KM_MAX_IDX * smp_pro !! 51 #ifdef CONFIG_DEBUG_HIGHMEM
>> 52 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
>> 53 enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
>> 54
>> 55 if (vaddr < FIXADDR_START) { // FIXME
>> 56 dec_preempt_count();
>> 57 return;
>> 58 }
>> 59
>> 60 if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx))
>> 61 BUG();
30 62
31 /* 63 /*
32 * The fixmap operates top down, so th !! 64 * force other mappings to Oops if they'll try to access
33 * reverse as well. !! 65 * this pte without first remap it
34 */ 66 */
35 return idx + DCACHE_N_COLORS - 1 - col !! 67 pte_clear(kmap_pte-idx);
36 } !! 68 __flush_tlb_one(vaddr);
>> 69 #endif
37 70
38 enum fixed_addresses kmap_local_map_idx(int ty !! 71 dec_preempt_count();
39 { <<
40 return kmap_idx(type, DCACHE_ALIAS(pfn <<
41 } 72 }
42 73
43 enum fixed_addresses kmap_local_unmap_idx(int !! 74 struct page *kmap_atomic_to_page(void *ptr)
44 { 75 {
45 return kmap_idx(type, DCACHE_ALIAS(add !! 76 unsigned long idx, vaddr = (unsigned long)ptr;
46 } !! 77 pte_t *pte;
47 78
48 #else !! 79 if (vaddr < FIXADDR_START)
49 static inline void kmap_waitqueues_init(void) !! 80 return virt_to_page(ptr);
50 #endif <<
51 81
52 void __init kmap_init(void) !! 82 idx = virt_to_fix(vaddr);
53 { !! 83 pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
54 /* Check if this memory layout is brok !! 84 return pte_page(*pte);
55 * page table. <<
56 */ <<
57 BUILD_BUG_ON(PKMAP_BASE < TLBTEMP_BASE <<
58 kmap_waitqueues_init(); <<
59 } 85 }
>> 86
60 87
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