[PATCH v8 15/38] x86/boot/e820: Add support to determine the E820 type of an address

From: Tom Lendacky
Date: Tue Jun 27 2017 - 11:03:27 EST


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

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

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;
}

/*