mirror of https://gitee.com/openkylin/linux.git
224 lines
5.7 KiB
C
224 lines
5.7 KiB
C
/*
|
|
* 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"
|
|
|
|
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, enum km_type type)
|
|
{
|
|
unsigned int idx;
|
|
unsigned long vaddr;
|
|
void *kmap;
|
|
|
|
pagefault_disable();
|
|
if (!PageHighMem(page))
|
|
return page_address(page);
|
|
|
|
debug_kmap_atomic(type);
|
|
|
|
#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;
|
|
|
|
idx = type + KM_TYPE_NR * smp_processor_id();
|
|
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + 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(*(TOP_PTE(vaddr))));
|
|
#endif
|
|
set_pte_ext(TOP_PTE(vaddr), mk_pte(page, kmap_prot), 0);
|
|
/*
|
|
* When debugging is off, kunmap_atomic leaves the previous mapping
|
|
* in place, so this TLB flush ensures the TLB is updated with the
|
|
* new mapping.
|
|
*/
|
|
local_flush_tlb_kernel_page(vaddr);
|
|
|
|
return (void *)vaddr;
|
|
}
|
|
EXPORT_SYMBOL(kmap_atomic);
|
|
|
|
void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type)
|
|
{
|
|
unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
|
|
unsigned int idx = type + KM_TYPE_NR * smp_processor_id();
|
|
|
|
if (kvaddr >= (void *)FIXADDR_START) {
|
|
if (cache_is_vivt())
|
|
__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
|
|
#ifdef CONFIG_DEBUG_HIGHMEM
|
|
BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
|
|
set_pte_ext(TOP_PTE(vaddr), __pte(0), 0);
|
|
local_flush_tlb_kernel_page(vaddr);
|
|
#else
|
|
(void) idx; /* to kill a warning */
|
|
#endif
|
|
} 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();
|
|
}
|
|
EXPORT_SYMBOL(kunmap_atomic_notypecheck);
|
|
|
|
void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
|
|
{
|
|
unsigned int idx;
|
|
unsigned long vaddr;
|
|
|
|
pagefault_disable();
|
|
|
|
idx = type + KM_TYPE_NR * smp_processor_id();
|
|
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
|
|
#ifdef CONFIG_DEBUG_HIGHMEM
|
|
BUG_ON(!pte_none(*(TOP_PTE(vaddr))));
|
|
#endif
|
|
set_pte_ext(TOP_PTE(vaddr), pfn_pte(pfn, kmap_prot), 0);
|
|
local_flush_tlb_kernel_page(vaddr);
|
|
|
|
return (void *)vaddr;
|
|
}
|
|
|
|
struct page *kmap_atomic_to_page(const void *ptr)
|
|
{
|
|
unsigned long vaddr = (unsigned long)ptr;
|
|
pte_t *pte;
|
|
|
|
if (vaddr < FIXADDR_START)
|
|
return virt_to_page(ptr);
|
|
|
|
pte = TOP_PTE(vaddr);
|
|
return pte_page(*pte);
|
|
}
|
|
|
|
#ifdef CONFIG_CPU_CACHE_VIPT
|
|
|
|
#include <linux/percpu.h>
|
|
|
|
/*
|
|
* The VIVT cache of a highmem page is always flushed before the page
|
|
* is unmapped. Hence unmapped highmem pages need no cache maintenance
|
|
* in that case.
|
|
*
|
|
* However unmapped pages may still be cached with a VIPT cache, and
|
|
* it is not possible to perform cache maintenance on them using physical
|
|
* addresses unfortunately. So we have no choice but to set up a temporary
|
|
* virtual mapping for that purpose.
|
|
*
|
|
* Yet this VIPT cache maintenance may be triggered from DMA support
|
|
* functions which are possibly called from interrupt context. As we don't
|
|
* want to keep interrupt disabled all the time when such maintenance is
|
|
* taking place, we therefore allow for some reentrancy by preserving and
|
|
* restoring the previous fixmap entry before the interrupted context is
|
|
* resumed. If the reentrancy depth is 0 then there is no need to restore
|
|
* the previous fixmap, and leaving the current one in place allow it to
|
|
* be reused the next time without a TLB flush (common with DMA).
|
|
*/
|
|
|
|
static DEFINE_PER_CPU(int, kmap_high_l1_vipt_depth);
|
|
|
|
void *kmap_high_l1_vipt(struct page *page, pte_t *saved_pte)
|
|
{
|
|
unsigned int idx, cpu;
|
|
int *depth;
|
|
unsigned long vaddr, flags;
|
|
pte_t pte, *ptep;
|
|
|
|
if (!in_interrupt())
|
|
preempt_disable();
|
|
|
|
cpu = smp_processor_id();
|
|
depth = &per_cpu(kmap_high_l1_vipt_depth, cpu);
|
|
|
|
idx = KM_L1_CACHE + KM_TYPE_NR * cpu;
|
|
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
|
|
ptep = TOP_PTE(vaddr);
|
|
pte = mk_pte(page, kmap_prot);
|
|
|
|
raw_local_irq_save(flags);
|
|
(*depth)++;
|
|
if (pte_val(*ptep) == pte_val(pte)) {
|
|
*saved_pte = pte;
|
|
} else {
|
|
*saved_pte = *ptep;
|
|
set_pte_ext(ptep, pte, 0);
|
|
local_flush_tlb_kernel_page(vaddr);
|
|
}
|
|
raw_local_irq_restore(flags);
|
|
|
|
return (void *)vaddr;
|
|
}
|
|
|
|
void kunmap_high_l1_vipt(struct page *page, pte_t saved_pte)
|
|
{
|
|
unsigned int idx, cpu = smp_processor_id();
|
|
int *depth = &per_cpu(kmap_high_l1_vipt_depth, cpu);
|
|
unsigned long vaddr, flags;
|
|
pte_t pte, *ptep;
|
|
|
|
idx = KM_L1_CACHE + KM_TYPE_NR * cpu;
|
|
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
|
|
ptep = TOP_PTE(vaddr);
|
|
pte = mk_pte(page, kmap_prot);
|
|
|
|
BUG_ON(pte_val(*ptep) != pte_val(pte));
|
|
BUG_ON(*depth <= 0);
|
|
|
|
raw_local_irq_save(flags);
|
|
(*depth)--;
|
|
if (*depth != 0 && pte_val(pte) != pte_val(saved_pte)) {
|
|
set_pte_ext(ptep, saved_pte, 0);
|
|
local_flush_tlb_kernel_page(vaddr);
|
|
}
|
|
raw_local_irq_restore(flags);
|
|
|
|
if (!in_interrupt())
|
|
preempt_enable();
|
|
}
|
|
|
|
#endif /* CONFIG_CPU_CACHE_VIPT */
|