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// SPDX-License-Identifier: GPL-2.0
/*
* highmem.c: virtual kernel memory mappings for high memory
*
* PowerPC version, stolen from the i386 version.
*
* Used in CONFIG_HIGHMEM systems for memory pages which
* are not addressable by direct kernel virtual addresses.
*
* Copyright (C) 1999 Gerhard Wichert, Siemens AG
* Gerhard.Wichert@pdb.siemens.de
*
*
* Redesigned the x86 32-bit VM architecture to deal with
* up to 16 Terrabyte physical memory. With current x86 CPUs
* we now support up to 64 Gigabytes physical RAM.
*
* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
*
* Reworked for PowerPC by various contributors. Moved from
* highmem.h by Benjamin Herrenschmidt (c) 2009 IBM Corp.
*/
#include <linux/export.h>
#include <linux/highmem.h>
/*
* The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
* gives a more generic (and caching) interface. But kmap_atomic can
* be used in IRQ contexts, so in some (very limited) cases we need
* it.
*/
#include <asm/tlbflush.h>
void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
{
unsigned long vaddr;
int idx, type;
type = kmap_atomic_idx_push();
idx = type + KM_TYPE_NR*smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(!pte_none(*(kmap_pte-idx)));
#endif
set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot));
local_flush_tlb_page(NULL, vaddr);
return (void *) vaddr;
}
EXPORT_SYMBOL(kmap_atomic_high_prot);
void kunmap_atomic_high(void *kvaddr)
{
unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
int type;
unsigned int idx;
if (vaddr < __fix_to_virt(FIX_KMAP_END))
return;
type = kmap_atomic_idx();
idx = type + KM_TYPE_NR * smp_processor_id();
#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
#endif
/*
* force other mappings to Oops if they'll try to access
* this pte without first remap it
*/
pte_clear(&init_mm, vaddr, kmap_pte-idx);
local_flush_tlb_page(NULL, vaddr);
kmap_atomic_idx_pop();
}
EXPORT_SYMBOL(kunmap_atomic_high);
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