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https://github.com/torvalds/linux
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fd94093435
Impact: introduce new APIs, separate kmap code from CONFIG_HIGHMEM This takes the code used for CONFIG_HIGHMEM memory mappings except that it's designed for dynamic IO resource mapping. These fixmaps are available even with CONFIG_HIGHMEM turned off. Signed-off-by: Keith Packard <keithp@keithp.com> Signed-off-by: Eric Anholt <eric@anholt.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
59 lines
1.8 KiB
C
59 lines
1.8 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 <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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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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