[PATCH 1/6] x86/efi: find mem descriptor from phys address

[Ricardo Neri]

Several functions (efi_mem_type, efi_mem_attributes,
efi_lookup_mapped_addr) scan the memory map looking for the memory
descriptor to which a given physical address belongs for various
purposes.

The scan functionality is duplicated in all the three functions. The
common functionality is consolidated into a single function that three
functions mentioned above may call.

When checking the validity of the validity of the memory map, use
efi_enabled(), provided for this purpose.

Signed-off-by: Ricardo Neri <ricardo.neri-calderon@xxxxxxxxxxxxxxx>
---
 arch/x86/platform/efi/efi.c | 21 ++++++++++++++++++++-
 include/linux/efi.h         |  1 +
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 850da94..782d617 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -900,8 +900,27 @@ void __init efi_enter_virtual_mode(void)
 }
 
 /*
- * Convenience functions to obtain memory types and attributes
+ * Convenience functions to obtain memory descriptors,
+ * memory types and attributes
  */
+efi_memory_desc_t *efi_memory_descriptor(unsigned long phys_addr)
+{
+	efi_memory_desc_t *md;
+	void *p;
+
+	if (!efi_enabled(EFI_MEMMAP))
+		return NULL;
+
+	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
+		md = p;
+		if ((md->phys_addr <= phys_addr) &&
+		    (phys_addr < (md->phys_addr +
+				  (md->num_pages << EFI_PAGE_SHIFT))))
+			return md;
+	}
+	return NULL;
+}
+
 u32 efi_mem_type(unsigned long phys_addr)
 {
 	efi_memory_desc_t *md;
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 45cb4ff..b36b588 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -866,6 +866,7 @@ static inline efi_status_t efi_query_variable_store(u32 attributes, unsigned lon
 extern void __iomem *efi_lookup_mapped_addr(u64 phys_addr);
 extern int efi_config_init(efi_config_table_type_t *arch_tables);
 extern u64 efi_get_iobase (void);
+extern efi_memory_desc_t *efi_memory_descriptor(unsigned long phys_addr);
 extern u32 efi_mem_type (unsigned long phys_addr);
 extern u64 efi_mem_attributes (unsigned long phys_addr);
 extern u64 efi_mem_attribute (unsigned long phys_addr, unsigned long size);
-- 
1.9.1

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