efi/x86: libstub: Make DXE calls mixed mode safe

The newly added DXE calls use 64-bit quantities, which means we need to
marshall them explicitly when running in mixed mode. Currently, we get
away without it because we just bail when GetMemorySpaceDescriptor()
fails, which is guaranteed to happen due to the function argument mixup.

Let's fix this properly, though, by defining the macros that describe
how to marshall the arguments. While at it, drop an incorrect cast on a
status variable.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index bed74a0f2932..71943dce691e 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -270,6 +270,8 @@ static inline u32 efi64_convert_status(efi_status_t status)
 	return (u32)(status | (u64)status >> 32);
 }
 
+#define __efi64_split(val)		(val) & U32_MAX, (u64)(val) >> 32
+
 #define __efi64_argmap_free_pages(addr, size)				\
 	((addr), 0, (size))
 
@@ -317,6 +319,13 @@ static inline u32 efi64_convert_status(efi_status_t status)
 #define __efi64_argmap_hash_log_extend_event(prot, fl, addr, size, ev)	\
 	((prot), (fl), 0ULL, (u64)(addr), 0ULL, (u64)(size), 0ULL, ev)
 
+/* DXE services */
+#define __efi64_argmap_get_memory_space_descriptor(phys, desc) \
+	(__efi64_split(phys), (desc))
+
+#define __efi64_argmap_set_memory_space_descriptor(phys, size, flags) \
+	(__efi64_split(phys), __efi64_split(size), __efi64_split(flags))
+
 /*
  * The macros below handle the plumbing for the argument mapping. To add a
  * mapping for a specific EFI method, simply define a macro