70 строки
2.2 KiB
C
70 строки
2.2 KiB
C
/*
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* Copyright © 2008 Ingo Molnar
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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 as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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*/
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#include <asm/iomap.h>
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#include <asm/pat.h>
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#include <linux/module.h>
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/* Map 'pfn' using fixed map 'type' and protections 'prot'
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*/
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void *
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iomap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot)
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{
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enum fixed_addresses idx;
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unsigned long vaddr;
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pagefault_disable();
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/*
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* For non-PAT systems, promote PAGE_KERNEL_WC to PAGE_KERNEL_UC_MINUS.
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* PAGE_KERNEL_WC maps to PWT, which translates to uncached if the
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* MTRR is UC or WC. UC_MINUS gets the real intention, of the
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* user, which is "WC if the MTRR is WC, UC if you can't do that."
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*/
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if (!pat_enabled && pgprot_val(prot) == pgprot_val(PAGE_KERNEL_WC))
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prot = PAGE_KERNEL_UC_MINUS;
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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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set_pte(kmap_pte-idx, pfn_pte(pfn, prot));
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arch_flush_lazy_mmu_mode();
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return (void*) vaddr;
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}
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EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn);
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void
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iounmap_atomic(void *kvaddr, enum km_type type)
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{
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unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
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enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
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/*
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* Force other mappings to Oops if they'll try to access this pte
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* without first remap it. Keeping stale mappings around is a bad idea
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* also, in case the page changes cacheability attributes or becomes
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* a protected page in a hypervisor.
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*/
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if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx))
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kpte_clear_flush(kmap_pte-idx, vaddr);
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arch_flush_lazy_mmu_mode();
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pagefault_enable();
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}
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EXPORT_SYMBOL_GPL(iounmap_atomic);
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