1#include <linux/compiler.h>
  2#include <linux/module.h>
 
  3#include <linux/highmem.h>
  4#include <linux/sched.h>
  5#include <linux/smp.h>
  6#include <asm/fixmap.h>
  7#include <asm/tlbflush.h>
  8
  9static pte_t *kmap_pte;
 10
 11unsigned long highstart_pfn, highend_pfn;
 12
 13void *kmap(struct page *page)
 14{
 15	void *addr;
 16
 17	might_sleep();
 18	if (!PageHighMem(page))
 19		return page_address(page);
 20	addr = kmap_high(page);
 21	flush_tlb_one((unsigned long)addr);
 22
 23	return addr;
 24}
 25EXPORT_SYMBOL(kmap);
 26
 27void kunmap(struct page *page)
 28{
 29	BUG_ON(in_interrupt());
 30	if (!PageHighMem(page))
 31		return;
 32	kunmap_high(page);
 33}
 34EXPORT_SYMBOL(kunmap);
 35
 36/*
 37 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
 38 * no global lock is needed and because the kmap code must perform a global TLB
 39 * invalidation when the kmap pool wraps.
 40 *
 41 * However when holding an atomic kmap is is not legal to sleep, so atomic
 42 * kmaps are appropriate for short, tight code paths only.
 43 */
 44
 45void *kmap_atomic(struct page *page)
 46{
 47	unsigned long vaddr;
 48	int idx, type;
 49
 50	preempt_disable();
 51	pagefault_disable();
 52	if (!PageHighMem(page))
 53		return page_address(page);
 54
 55	type = kmap_atomic_idx_push();
 56	idx = type + KM_TYPE_NR*smp_processor_id();
 57	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
 58#ifdef CONFIG_DEBUG_HIGHMEM
 59	BUG_ON(!pte_none(*(kmap_pte - idx)));
 60#endif
 61	set_pte(kmap_pte-idx, mk_pte(page, PAGE_KERNEL));
 62	local_flush_tlb_one((unsigned long)vaddr);
 63
 64	return (void*) vaddr;
 65}
 66EXPORT_SYMBOL(kmap_atomic);
 67
 68void __kunmap_atomic(void *kvaddr)
 69{
 70	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
 71	int type __maybe_unused;
 72
 73	if (vaddr < FIXADDR_START) { // FIXME
 74		pagefault_enable();
 75		preempt_enable();
 76		return;
 77	}
 78
 79	type = kmap_atomic_idx();
 80#ifdef CONFIG_DEBUG_HIGHMEM
 81	{
 82		int idx = type + KM_TYPE_NR * smp_processor_id();
 83
 84		BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
 85
 86		/*
 87		 * force other mappings to Oops if they'll try to access
 88		 * this pte without first remap it
 89		 */
 90		pte_clear(&init_mm, vaddr, kmap_pte-idx);
 91		local_flush_tlb_one(vaddr);
 92	}
 93#endif
 94	kmap_atomic_idx_pop();
 95	pagefault_enable();
 96	preempt_enable();
 97}
 98EXPORT_SYMBOL(__kunmap_atomic);
 99
100/*
101 * This is the same as kmap_atomic() but can map memory that doesn't
102 * have a struct page associated with it.
103 */
104void *kmap_atomic_pfn(unsigned long pfn)
105{
106	unsigned long vaddr;
107	int idx, type;
108
109	preempt_disable();
110	pagefault_disable();
111
112	type = kmap_atomic_idx_push();
113	idx = type + KM_TYPE_NR*smp_processor_id();
114	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
115	set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
116	flush_tlb_one(vaddr);
117
118	return (void*) vaddr;
119}
120
121void __init kmap_init(void)
122{
123	unsigned long kmap_vstart;
124
125	/* cache the first kmap pte */
126	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
127	kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
128}

 1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/compiler.h>
 3#include <linux/init.h>
 4#include <linux/export.h>
 5#include <linux/highmem.h>
 6#include <linux/sched.h>
 7#include <linux/smp.h>
 8#include <asm/fixmap.h>
 9#include <asm/tlbflush.h>
10
 
 
11unsigned long highstart_pfn, highend_pfn;
12
13void kmap_flush_tlb(unsigned long addr)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
14{
15	flush_tlb_one(addr);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
16}
17EXPORT_SYMBOL(kmap_flush_tlb);