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-rw-r--r--Documentation/x86/boot.txt3
-rw-r--r--arch/x86/boot/header.S9
-rw-r--r--arch/x86/include/uapi/asm/bootparam.h1
3 files changed, 12 insertions, 1 deletions
diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt
index f4f268c2b826..cb81741d3b0b 100644
--- a/Documentation/x86/boot.txt
+++ b/Documentation/x86/boot.txt
@@ -608,6 +608,9 @@ Protocol: 2.12+
- If 1, the kernel supports the 64-bit EFI handoff entry point
given at handover_offset + 0x200.
+ Bit 4 (read): XLF_EFI_KEXEC
+ - If 1, the kernel supports kexec EFI boot with EFI runtime support.
+
Field name: cmdline_size
Type: read
Offset/size: 0x238/4
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 9ec06a1f6d61..ec3b8ba68096 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -391,7 +391,14 @@ xloadflags:
#else
# define XLF23 0
#endif
- .word XLF0 | XLF1 | XLF23
+
+#if defined(CONFIG_X86_64) && defined(CONFIG_EFI) && defined(CONFIG_KEXEC)
+# define XLF4 XLF_EFI_KEXEC
+#else
+# define XLF4 0
+#endif
+
+ .word XLF0 | XLF1 | XLF23 | XLF4
cmdline_size: .long COMMAND_LINE_SIZE-1 #length of the command line,
#added with boot protocol
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index 64fe421aab65..225b0988043a 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -24,6 +24,7 @@
#define XLF_CAN_BE_LOADED_ABOVE_4G (1<<1)
#define XLF_EFI_HANDOVER_32 (1<<2)
#define XLF_EFI_HANDOVER_64 (1<<3)
+#define XLF_EFI_KEXEC (1<<4)
#ifndef __ASSEMBLY__