[PATCH] x86/kexec: Annotate more noreturns

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

kexec_reloc() does not return.  Plumbing this property upwards lets us mark
machine_kexec() and machine_reboot_kexec() noreturn too.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <jbeulich@xxxxxxxx>
CC: Roger Pau Monné <roger@xxxxxxxxxxxxxx>
CC: Teddy Astie <teddy.astie@xxxxxxxxxx>

Rebase forward many years.
---
 xen/arch/x86/include/asm/machine_kexec.h | 7 ++++---
 xen/arch/x86/machine_kexec.c             | 5 ++---
 xen/common/kexec.c                       | 2 --
 xen/include/xen/kexec.h                  | 2 +-
 4 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/xen/arch/x86/include/asm/machine_kexec.h 
b/xen/arch/x86/include/asm/machine_kexec.h
index 3e189acf2464..f0bdc2f44109 100644
--- a/xen/arch/x86/include/asm/machine_kexec.h
+++ b/xen/arch/x86/include/asm/machine_kexec.h
@@ -4,10 +4,11 @@
 #define KEXEC_RELOC_FLAG_COMPAT 0x1 /* 32-bit image */
 
 #ifndef __ASSEMBLER__
+#include <xen/compiler.h>
 
-extern void kexec_reloc(unsigned long reloc_code, unsigned long reloc_pt,
-                        unsigned long ind_maddr, unsigned long entry_maddr,
-                        unsigned long flags);
+extern void noreturn kexec_reloc(
+    unsigned long reloc_code, unsigned long reloc_pt, unsigned long ind_maddr,
+    unsigned long entry_maddr, unsigned long flags);
 
 extern const char kexec_reloc_end[];
 
diff --git a/xen/arch/x86/machine_kexec.c b/xen/arch/x86/machine_kexec.c
index 038670922d47..0fb9ed50e780 100644
--- a/xen/arch/x86/machine_kexec.c
+++ b/xen/arch/x86/machine_kexec.c
@@ -142,15 +142,14 @@ void machine_kexec_unload(struct kexec_image *image)
     /* no-op. kimage_free() frees all control pages. */
 }
 
-void machine_reboot_kexec(struct kexec_image *image)
+void noreturn machine_reboot_kexec(struct kexec_image *image)
 {
     BUG_ON(smp_processor_id() != 0);
     smp_send_stop();
     machine_kexec(image);
-    BUG();
 }
 
-void machine_kexec(struct kexec_image *image)
+void noreturn machine_kexec(struct kexec_image *image)
 {
     int i;
     unsigned long reloc_flags = 0;
diff --git a/xen/common/kexec.c b/xen/common/kexec.c
index 8ccaef1e0258..da3bb95d0852 100644
--- a/xen/common/kexec.c
+++ b/xen/common/kexec.c
@@ -397,8 +397,6 @@ void kexec_crash(enum crash_reason reason)
     kexec_crash_save_cpu();
     machine_crash_shutdown();
     machine_kexec(kexec_image[KEXEC_IMAGE_CRASH_BASE + pos]);
-
-    BUG();
 }
 
 static long noreturn cf_check kexec_reboot(void *_image)
diff --git a/xen/include/xen/kexec.h b/xen/include/xen/kexec.h
index e0d793b04316..6bb3fde629a6 100644
--- a/xen/include/xen/kexec.h
+++ b/xen/include/xen/kexec.h
@@ -49,7 +49,7 @@ int machine_kexec_load(struct kexec_image *image);
 void machine_kexec_unload(struct kexec_image *image);
 void machine_kexec_reserved(xen_kexec_reserve_t *reservation);
 void noreturn machine_reboot_kexec(struct kexec_image *image);
-void machine_kexec(struct kexec_image *image);
+void noreturn machine_kexec(struct kexec_image *image);
 void kexec_crash(enum crash_reason reason);
 void kexec_crash_save_cpu(void);
 struct crash_xen_info *kexec_crash_save_info(void);
-- 
2.39.5