[PATCH v8 17/38] efi: Update efi_mem_type() to return an error rather than 0

[Tom Lendacky]

The efi_mem_type() function currently returns a 0, which maps to
EFI_RESERVED_TYPE, if the function is unable to find a memmap entry for
the supplied physical address. Returning EFI_RESERVED_TYPE implies that
a memmap entry exists, when it doesn't.  Instead of returning 0, change
the function to return a negative error value when no memmap entry is
found.

Reviewed-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
 arch/ia64/kernel/efi.c      |    4 ++--
 arch/x86/platform/efi/efi.c |    6 +++---
 include/linux/efi.h         |    2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c
index 1212956..8141600 100644
--- a/arch/ia64/kernel/efi.c
+++ b/arch/ia64/kernel/efi.c
@@ -757,14 +757,14 @@ static void __init handle_palo(unsigned long phys_addr)
 	return 0;
 }
 
-u32
+int
 efi_mem_type (unsigned long phys_addr)
 {
 	efi_memory_desc_t *md = efi_memory_descriptor(phys_addr);
 
 	if (md)
 		return md->type;
-	return 0;
+	return -EINVAL;
 }
 
 u64
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index f084d87..6217b23 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -1035,12 +1035,12 @@ void __init efi_enter_virtual_mode(void)
 /*
  * Convenience functions to obtain memory types and attributes
  */
-u32 efi_mem_type(unsigned long phys_addr)
+int efi_mem_type(unsigned long phys_addr)
 {
 	efi_memory_desc_t *md;
 
 	if (!efi_enabled(EFI_MEMMAP))
-		return 0;
+		return -ENOTSUPP;
 
 	for_each_efi_memory_desc(md) {
 		if ((md->phys_addr <= phys_addr) &&
@@ -1048,7 +1048,7 @@ u32 efi_mem_type(unsigned long phys_addr)
 				  (md->num_pages << EFI_PAGE_SHIFT))))
 			return md->type;
 	}
-	return 0;
+	return -EINVAL;
 }
 
 static int __init arch_parse_efi_cmdline(char *str)
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 8e24f09..4e47f78 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -985,7 +985,7 @@ static inline void efi_esrt_init(void) { }
 extern int efi_config_parse_tables(void *config_tables, int count, int sz,
 				   efi_config_table_type_t *arch_tables);
 extern u64 efi_get_iobase (void);
-extern u32 efi_mem_type (unsigned long phys_addr);
+extern int 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);
 extern int __init efi_uart_console_only (void);