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39af22a792
Since commit3e4d3af501"mm: stack based kmap_atomic()", it is no longer necessary to carry an ad hoc version of kmap_atomic() added in commit7e5a69e83b"ARM: 6007/1: fix highmem with VIPT cache and DMA" to cope with reentrancy. In fact, it is now actively wrong to rely on fixed kmap type indices (namely KM_L1_CACHE) as kmap_atomic() totally ignores them now and a concurrent instance of it may reuse any slot for any purpose. Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
143 lines
3.3 KiB
C
143 lines
3.3 KiB
C
/*
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* arch/arm/mm/highmem.c -- ARM highmem support
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*
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* Author: Nicolas Pitre
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* Created: september 8, 2008
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* Copyright: Marvell Semiconductors Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/highmem.h>
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#include <linux/interrupt.h>
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#include <asm/fixmap.h>
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#include <asm/cacheflush.h>
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#include <asm/tlbflush.h>
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#include "mm.h"
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void *kmap(struct page *page)
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{
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might_sleep();
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if (!PageHighMem(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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EXPORT_SYMBOL(kmap);
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void kunmap(struct page *page)
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{
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BUG_ON(in_interrupt());
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if (!PageHighMem(page))
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return;
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kunmap_high(page);
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}
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EXPORT_SYMBOL(kunmap);
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void *__kmap_atomic(struct page *page)
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{
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unsigned int idx;
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unsigned long vaddr;
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void *kmap;
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int type;
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pagefault_disable();
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if (!PageHighMem(page))
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return page_address(page);
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#ifdef CONFIG_DEBUG_HIGHMEM
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/*
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* There is no cache coherency issue when non VIVT, so force the
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* dedicated kmap usage for better debugging purposes in that case.
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*/
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if (!cache_is_vivt())
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kmap = NULL;
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else
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#endif
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kmap = kmap_high_get(page);
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if (kmap)
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return kmap;
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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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#ifdef CONFIG_DEBUG_HIGHMEM
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/*
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* With debugging enabled, kunmap_atomic forces that entry to 0.
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* Make sure it was indeed properly unmapped.
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*/
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BUG_ON(!pte_none(*(TOP_PTE(vaddr))));
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#endif
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set_pte_ext(TOP_PTE(vaddr), mk_pte(page, kmap_prot), 0);
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/*
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* When debugging is off, kunmap_atomic leaves the previous mapping
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* in place, so this TLB flush ensures the TLB is updated with the
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* new mapping.
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*/
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local_flush_tlb_kernel_page(vaddr);
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return (void *)vaddr;
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}
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EXPORT_SYMBOL(__kmap_atomic);
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void __kunmap_atomic(void *kvaddr)
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{
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unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
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int idx, type;
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if (kvaddr >= (void *)FIXADDR_START) {
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type = kmap_atomic_idx();
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idx = type + KM_TYPE_NR * smp_processor_id();
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if (cache_is_vivt())
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__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
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#ifdef CONFIG_DEBUG_HIGHMEM
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BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
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set_pte_ext(TOP_PTE(vaddr), __pte(0), 0);
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local_flush_tlb_kernel_page(vaddr);
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#else
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(void) idx; /* to kill a warning */
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#endif
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kmap_atomic_idx_pop();
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} else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
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/* this address was obtained through kmap_high_get() */
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kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
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}
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pagefault_enable();
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}
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EXPORT_SYMBOL(__kunmap_atomic);
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void *kmap_atomic_pfn(unsigned long pfn)
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{
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unsigned long vaddr;
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int idx, type;
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pagefault_disable();
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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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#ifdef CONFIG_DEBUG_HIGHMEM
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BUG_ON(!pte_none(*(TOP_PTE(vaddr))));
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#endif
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set_pte_ext(TOP_PTE(vaddr), pfn_pte(pfn, kmap_prot), 0);
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local_flush_tlb_kernel_page(vaddr);
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return (void *)vaddr;
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}
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struct page *kmap_atomic_to_page(const void *ptr)
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{
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unsigned long vaddr = (unsigned long)ptr;
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pte_t *pte;
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if (vaddr < FIXADDR_START)
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return virt_to_page(ptr);
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pte = TOP_PTE(vaddr);
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return pte_page(*pte);
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}
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