1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * arch/arm/mm/highmem.c -- ARM highmem support
  4 *
  5 * Author:	Nicolas Pitre
  6 * Created:	september 8, 2008
  7 * Copyright:	Marvell Semiconductors Inc.
  8 */
  9
 10#include <linux/module.h>
 11#include <linux/highmem.h>
 12#include <linux/interrupt.h>
 13#include <asm/fixmap.h>
 14#include <asm/cacheflush.h>
 15#include <asm/tlbflush.h>
 16#include "mm.h"
 17
 18static inline void set_fixmap_pte(int idx, pte_t pte)
 19{
 20	unsigned long vaddr = __fix_to_virt(idx);
 21	pte_t *ptep = virt_to_kpte(vaddr);
 22
 23	set_pte_ext(ptep, pte, 0);
 24	local_flush_tlb_kernel_page(vaddr);
 25}
 26
 27static inline pte_t get_fixmap_pte(unsigned long vaddr)
 28{
 29	pte_t *ptep = virt_to_kpte(vaddr);
 30
 31	return *ptep;
 32}
 33
 34void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
 35{
 36	unsigned int idx;
 37	unsigned long vaddr;
 38	void *kmap;
 39	int type;
 40
 41#ifdef CONFIG_DEBUG_HIGHMEM
 42	/*
 43	 * There is no cache coherency issue when non VIVT, so force the
 44	 * dedicated kmap usage for better debugging purposes in that case.
 45	 */
 46	if (!cache_is_vivt())
 47		kmap = NULL;
 48	else
 49#endif
 50		kmap = kmap_high_get(page);
 51	if (kmap)
 52		return kmap;
 53
 54	type = kmap_atomic_idx_push();
 55
 56	idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
 57	vaddr = __fix_to_virt(idx);
 58#ifdef CONFIG_DEBUG_HIGHMEM
 59	/*
 60	 * With debugging enabled, kunmap_atomic forces that entry to 0.
 61	 * Make sure it was indeed properly unmapped.
 62	 */
 63	BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
 64#endif
 65	/*
 66	 * When debugging is off, kunmap_atomic leaves the previous mapping
 67	 * in place, so the contained TLB flush ensures the TLB is updated
 68	 * with the new mapping.
 69	 */
 70	set_fixmap_pte(idx, mk_pte(page, prot));
 71
 72	return (void *)vaddr;
 73}
 74EXPORT_SYMBOL(kmap_atomic_high_prot);
 75
 76void kunmap_atomic_high(void *kvaddr)
 77{
 78	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
 79	int idx, type;
 80
 81	if (kvaddr >= (void *)FIXADDR_START) {
 82		type = kmap_atomic_idx();
 83		idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
 84
 85		if (cache_is_vivt())
 86			__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
 87#ifdef CONFIG_DEBUG_HIGHMEM
 88		BUG_ON(vaddr != __fix_to_virt(idx));
 89		set_fixmap_pte(idx, __pte(0));
 90#else
 91		(void) idx;  /* to kill a warning */
 92#endif
 93		kmap_atomic_idx_pop();
 94	} else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
 95		/* this address was obtained through kmap_high_get() */
 96		kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
 97	}
 98}
 99EXPORT_SYMBOL(kunmap_atomic_high);
100
101void *kmap_atomic_pfn(unsigned long pfn)
102{
103	unsigned long vaddr;
104	int idx, type;
105	struct page *page = pfn_to_page(pfn);
106
107	preempt_disable();
108	pagefault_disable();
109	if (!PageHighMem(page))
110		return page_address(page);
111
112	type = kmap_atomic_idx_push();
113	idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
114	vaddr = __fix_to_virt(idx);
115#ifdef CONFIG_DEBUG_HIGHMEM
116	BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
117#endif
118	set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot));
119
120	return (void *)vaddr;
121}