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2cb7c9cb42
The existing code relies on pagefault_disable() implicitly disabling preemption, so that no schedule will happen between kmap_atomic() and kunmap_atomic(). Let's make this explicit, to prepare for pagefault_disable() not touching preemption anymore. Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: airlied@linux.ie Cc: akpm@linux-foundation.org Cc: benh@kernel.crashing.org Cc: bigeasy@linutronix.de Cc: borntraeger@de.ibm.com Cc: daniel.vetter@intel.com Cc: heiko.carstens@de.ibm.com Cc: herbert@gondor.apana.org.au Cc: hocko@suse.cz Cc: hughd@google.com Cc: mst@redhat.com Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: schwidefsky@de.ibm.com Cc: yang.shi@windriver.com Link: http://lkml.kernel.org/r/1431359540-32227-5-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
132 lines
3.0 KiB
C
132 lines
3.0 KiB
C
/* MN10300 Virtual kernel memory mappings for high memory
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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* - Derived from include/asm-i386/highmem.h
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#ifndef _ASM_HIGHMEM_H
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#define _ASM_HIGHMEM_H
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#ifdef __KERNEL__
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/highmem.h>
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#include <asm/kmap_types.h>
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#include <asm/pgtable.h>
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/* undef for production */
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#undef HIGHMEM_DEBUG
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/* declarations for highmem.c */
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extern unsigned long highstart_pfn, highend_pfn;
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extern pte_t *kmap_pte;
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extern pgprot_t kmap_prot;
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extern pte_t *pkmap_page_table;
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extern void __init kmap_init(void);
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/*
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* Right now we initialize only a single pte table. It can be extended
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* easily, subsequent pte tables have to be allocated in one physical
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* chunk of RAM.
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*/
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#define PKMAP_BASE 0xfe000000UL
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#define LAST_PKMAP 1024
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#define LAST_PKMAP_MASK (LAST_PKMAP - 1)
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#define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT)
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#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
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extern unsigned long kmap_high(struct page *page);
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extern void kunmap_high(struct page *page);
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static inline unsigned long kmap(struct page *page)
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{
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if (in_interrupt())
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BUG();
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if (page < highmem_start_page)
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return page_address(page);
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return kmap_high(page);
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}
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static inline void kunmap(struct page *page)
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{
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if (in_interrupt())
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BUG();
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if (page < highmem_start_page)
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return;
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kunmap_high(page);
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}
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/*
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* The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
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* gives a more generic (and caching) interface. But kmap_atomic can
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* be used in IRQ contexts, so in some (very limited) cases we need
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* it.
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*/
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static inline void *kmap_atomic(struct page *page)
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{
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unsigned long vaddr;
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int idx, type;
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preempt_disable();
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pagefault_disable();
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if (page < highmem_start_page)
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return page_address(page);
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type = kmap_atomic_idx_push();
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idx = type + KM_TYPE_NR * smp_processor_id();
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vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
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#if HIGHMEM_DEBUG
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if (!pte_none(*(kmap_pte - idx)))
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BUG();
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#endif
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set_pte(kmap_pte - idx, mk_pte(page, kmap_prot));
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local_flush_tlb_one(vaddr);
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return (void *)vaddr;
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}
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static inline void __kunmap_atomic(unsigned long vaddr)
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{
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int type;
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if (vaddr < FIXADDR_START) { /* FIXME */
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pagefault_enable();
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preempt_enable();
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return;
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}
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type = kmap_atomic_idx();
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#if HIGHMEM_DEBUG
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{
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unsigned int idx;
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idx = type + KM_TYPE_NR * smp_processor_id();
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if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx))
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BUG();
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/*
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* force other mappings to Oops if they'll try to access
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* this pte without first remap it
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*/
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pte_clear(kmap_pte - idx);
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local_flush_tlb_one(vaddr);
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}
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#endif
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kmap_atomic_idx_pop();
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pagefault_enable();
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preempt_enable();
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}
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#endif /* __KERNEL__ */
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#endif /* _ASM_HIGHMEM_H */
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