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/*
* arch/arm/mm/highmem.c -- ARM highmem support
*
* Author: Nicolas Pitre
* Created: september 8, 2008
* Copyright: Marvell Semiconductors Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/highmem.h>
#include <linux/interrupt.h>
#include <asm/fixmap.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include "mm.h"
static inline void set_fixmap_pte(int idx, pte_t pte)
{
unsigned long vaddr = __fix_to_virt(idx);
pte_t *ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
set_pte_ext(ptep, pte, 0);
local_flush_tlb_kernel_page(vaddr);
}
static inline pte_t get_fixmap_pte(unsigned long vaddr)
{
pte_t *ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
return *ptep;
}
static unsigned int fixmap_idx(int type)
{
return FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
}
void *kmap(struct page *page)
{
might_sleep();
if (!PageHighMem(page))
return page_address(page);
return kmap_high(page);
}
EXPORT_SYMBOL(kmap);
void kunmap(struct page *page)
{
BUG_ON(in_interrupt());
if (!PageHighMem(page))
return;
kunmap_high(page);
}
EXPORT_SYMBOL(kunmap);
void *kmap_atomic(struct page *page)
{
pte_t pte = mk_pte(page, kmap_prot);
unsigned int idx;
unsigned long vaddr;
void *kmap;
int type;
preempt_disable_nort();
pagefault_disable();
if (!PageHighMem(page))
return page_address(page);
#ifdef CONFIG_DEBUG_HIGHMEM
/*
* There is no cache coherency issue when non VIVT, so force the
* dedicated kmap usage for better debugging purposes in that case.
*/
if (!cache_is_vivt())
kmap = NULL;
else
#endif
kmap = kmap_high_get(page);
if (kmap)
return kmap;
type = kmap_atomic_idx_push();
idx = fixmap_idx(type);
vaddr = __fix_to_virt(idx);
#ifdef CONFIG_DEBUG_HIGHMEM
/*
* With debugging enabled, kunmap_atomic forces that entry to 0.
* Make sure it was indeed properly unmapped.
*/
BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
#endif
/*
* When debugging is off, kunmap_atomic leaves the previous mapping
* in place, so the contained TLB flush ensures the TLB is updated
* with the new mapping.
*/
#ifdef CONFIG_PREEMPT_RT_FULL
current->kmap_pte[type] = pte;
#endif
set_fixmap_pte(idx, pte);
return (void *)vaddr;
}
EXPORT_SYMBOL(kmap_atomic);
void __kunmap_atomic(void *kvaddr)
{
unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
int idx, type;
if (kvaddr >= (void *)FIXADDR_START) {
type = kmap_atomic_idx();
idx = fixmap_idx(type);
if (cache_is_vivt())
__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
#ifdef CONFIG_PREEMPT_RT_FULL
current->kmap_pte[type] = __pte(0);
#endif
#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(vaddr != __fix_to_virt(idx));
#else
(void) idx; /* to kill a warning */
#endif
set_fixmap_pte(idx, __pte(0));
kmap_atomic_idx_pop();
} else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
/* this address was obtained through kmap_high_get() */
kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
}
pagefault_enable();
preempt_enable_nort();
}
EXPORT_SYMBOL(__kunmap_atomic);
void *kmap_atomic_pfn(unsigned long pfn)
{
pte_t pte = pfn_pte(pfn, kmap_prot);
unsigned long vaddr;
int idx, type;
struct page *page = pfn_to_page(pfn);
preempt_disable_nort();
pagefault_disable();
if (!PageHighMem(page))
return page_address(page);
type = kmap_atomic_idx_push();
idx = fixmap_idx(type);
vaddr = __fix_to_virt(idx);
#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
#endif
#ifdef CONFIG_PREEMPT_RT_FULL
current->kmap_pte[type] = pte;
#endif
set_fixmap_pte(idx, pte);
return (void *)vaddr;
}
#if defined CONFIG_PREEMPT_RT_FULL
void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p)
{
int i;
/*
* Clear @prev's kmap_atomic mappings
*/
for (i = 0; i < prev_p->kmap_idx; i++) {
int idx = fixmap_idx(i);
set_fixmap_pte(idx, __pte(0));
}
/*
* Restore @next_p's kmap_atomic mappings
*/
for (i = 0; i < next_p->kmap_idx; i++) {
int idx = fixmap_idx(i);
if (!pte_none(next_p->kmap_pte[i]))
set_fixmap_pte(idx, next_p->kmap_pte[i]);
}
}
#endif
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