[v7,15/36] x86/boot/e820: Add support to determine the E820 type of an address

Commit Message

Tom Lendacky June 16, 2017, 6:52 p.m. UTC

Add a function that will return the E820 type associated with an address
range.

Reviewed-by: Borislav Petkov <[e-mail]>
Signed-off-by: Tom Lendacky <[e-mail]>
---
 arch/x86/include/asm/e820/api.h |    2 ++
 arch/x86/kernel/e820.c          |   26 +++++++++++++++++++++++---
 2 files changed, 25 insertions(+), 3 deletions(-)

Patch

diff --git a/arch/x86/include/asm/e820/api.h b/arch/x86/include/asm/e820/api.h
index 8e0f8b8..3641f5f 100644
--- a/arch/x86/include/asm/e820/api.h
+++ b/arch/x86/include/asm/e820/api.h
@@ -38,6 +38,8 @@ 
 extern void e820__reallocate_tables(void);
 extern void e820__register_nosave_regions(unsigned long limit_pfn);
 
+extern int  e820__get_entry_type(u64 start, u64 end);
+
 /*
  * Returns true iff the specified range [start,end) is completely contained inside
  * the ISA region.
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index d78a586..46c9b65 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -84,7 +84,8 @@  bool e820__mapped_any(u64 start, u64 end, enum e820_type type)
  * Note: this function only works correctly once the E820 table is sorted and
  * not-overlapping (at least for the range specified), which is the case normally.
  */
-bool __init e820__mapped_all(u64 start, u64 end, enum e820_type type)
+static struct e820_entry *__e820__mapped_all(u64 start, u64 end,
+					     enum e820_type type)
 {
 	int i;
 
@@ -110,9 +111,28 @@  bool __init e820__mapped_all(u64 start, u64 end, enum e820_type type)
 		 * coverage of the desired range exists:
 		 */
 		if (start >= end)
-			return 1;
+			return entry;
 	}
-	return 0;
+
+	return NULL;
+}
+
+/*
+ * This function checks if the entire range <start,end> is mapped with type.
+ */
+bool __init e820__mapped_all(u64 start, u64 end, enum e820_type type)
+{
+	return __e820__mapped_all(start, end, type);
+}
+
+/*
+ * This function returns the type associated with the range <start,end>.
+ */
+int e820__get_entry_type(u64 start, u64 end)
+{
+	struct e820_entry *entry = __e820__mapped_all(start, end, 0);
+
+	return entry ? entry->type : -EINVAL;
 }
 
 /*