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Diffstat (limited to 'arch/x86/mm/iomap_32.c')
-rw-r--r--arch/x86/mm/iomap_32.c58
1 files changed, 58 insertions, 0 deletions
diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c
index ca53224fc56c..d5e28424622c 100644
--- a/arch/x86/mm/iomap_32.c
+++ b/arch/x86/mm/iomap_32.c
@@ -20,6 +20,64 @@
#include <asm/pat.h>
#include <linux/module.h>
+#ifdef CONFIG_X86_PAE
+static int
+is_io_mapping_possible(resource_size_t base, unsigned long size)
+{
+ return 1;
+}
+#else
+static int
+is_io_mapping_possible(resource_size_t base, unsigned long size)
+{
+ /* There is no way to map greater than 1 << 32 address without PAE */
+ if (base + size > 0x100000000ULL)
+ return 0;
+
+ return 1;
+}
+#endif
+
+int
+reserve_io_memtype_wc(u64 base, unsigned long size, pgprot_t *prot)
+{
+ unsigned long ret_flag;
+
+ if (!is_io_mapping_possible(base, size))
+ goto out_err;
+
+ if (!pat_enabled) {
+ *prot = pgprot_noncached(PAGE_KERNEL);
+ return 0;
+ }
+
+ if (reserve_memtype(base, base + size, _PAGE_CACHE_WC, &ret_flag))
+ goto out_err;
+
+ if (ret_flag == _PAGE_CACHE_WB)
+ goto out_free;
+
+ if (kernel_map_sync_memtype(base, size, ret_flag))
+ goto out_free;
+
+ *prot = __pgprot(__PAGE_KERNEL | ret_flag);
+ return 0;
+
+out_free:
+ free_memtype(base, base + size);
+out_err:
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(reserve_io_memtype_wc);
+
+void
+free_io_memtype(u64 base, unsigned long size)
+{
+ if (pat_enabled)
+ free_memtype(base, base + size);
+}
+EXPORT_SYMBOL_GPL(free_io_memtype);
+
/* Map 'pfn' using fixed map 'type' and protections 'prot'
*/
void *