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author | 2008-10-30 19:37:09 -0700 | |
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committer | 2008-10-31 10:12:38 +0100 | |
commit | fd9409343521eac22b6ed51686128a643c7c976b (patch) | |
tree | d70e3f009a29a7bbfe68b956608854db416bc2af /arch/x86/mm/iomap_32.c | |
parent | Merge branch 'for-linus' of git://neil.brown.name/md (diff) | |
download | linux-fd9409343521eac22b6ed51686128a643c7c976b.tar.gz linux-fd9409343521eac22b6ed51686128a643c7c976b.tar.bz2 linux-fd9409343521eac22b6ed51686128a643c7c976b.zip |
x86: add iomap_atomic*()/iounmap_atomic() on 32-bit using fixmaps
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>
Diffstat (limited to 'arch/x86/mm/iomap_32.c')
-rw-r--r-- | arch/x86/mm/iomap_32.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c new file mode 100644 index 000000000000..d0151d8ce452 --- /dev/null +++ b/arch/x86/mm/iomap_32.c @@ -0,0 +1,59 @@ +/* + * Copyright © 2008 Ingo Molnar + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. + */ + +#include <asm/iomap.h> +#include <linux/module.h> + +/* Map 'pfn' using fixed map 'type' and protections 'prot' + */ +void * +iomap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot) +{ + enum fixed_addresses idx; + unsigned long vaddr; + + pagefault_disable(); + + idx = type + KM_TYPE_NR*smp_processor_id(); + vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); + set_pte(kmap_pte-idx, pfn_pte(pfn, prot)); + arch_flush_lazy_mmu_mode(); + + return (void*) vaddr; +} +EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn); + +void +iounmap_atomic(void *kvaddr, enum km_type type) +{ + unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; + enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id(); + + /* + * Force other mappings to Oops if they'll try to access this pte + * without first remap it. Keeping stale mappings around is a bad idea + * also, in case the page changes cacheability attributes or becomes + * a protected page in a hypervisor. + */ + if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx)) + kpte_clear_flush(kmap_pte-idx, vaddr); + + arch_flush_lazy_mmu_mode(); + pagefault_enable(); +} +EXPORT_SYMBOL_GPL(iounmap_atomic); |