kdump: define KEXEC_NOTE_BYTES arch specific for s390x

kdump only allocates memory for the prstatus ELF note.  For s390x,
besides of prstatus multiple ELF notes for various different register
types are stored.  Therefore the currently allocated memory is not
sufficient.  With this patch the KEXEC_NOTE_BYTES macro can be defined
by architecture code and for s390x it is set to the correct size now.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/s390/include/asm/kexec.h

@@ -42,6 +42,24 @@
 /* The native architecture */
 #define KEXEC_ARCH KEXEC_ARCH_S390
 
+/*
+ * Size for s390x ELF notes per CPU
+ *
+ * Seven notes plus zero note at the end: prstatus, fpregset, timer,
+ * tod_cmp, tod_reg, control regs, and prefix
+ */
+#define KEXEC_NOTE_BYTES \
+	(ALIGN(sizeof(struct elf_note), 4) * 8 + \
+	 ALIGN(sizeof("CORE"), 4) * 7 + \
+	 ALIGN(sizeof(struct elf_prstatus), 4) + \
+	 ALIGN(sizeof(elf_fpregset_t), 4) + \
+	 ALIGN(sizeof(u64), 4) + \
+	 ALIGN(sizeof(u64), 4) + \
+	 ALIGN(sizeof(u32), 4) + \
+	 ALIGN(sizeof(u64) * 16, 4) + \
+	 ALIGN(sizeof(u32), 4) \
+	)
+
 /* Provide a dummy definition to avoid build failures. */
 static inline void crash_setup_regs(struct pt_regs *newregs,
 					struct pt_regs *oldregs) { }

include/linux/kexec.h

@@ -50,9 +50,11 @@
  * note header.  For kdump, the code in vmcore.c runs in the context
  * of the second kernel to combine them into one note.
  */
+#ifndef KEXEC_NOTE_BYTES
 #define KEXEC_NOTE_BYTES ( (KEXEC_NOTE_HEAD_BYTES * 2) +		\
 			    KEXEC_CORE_NOTE_NAME_BYTES +		\
 			    KEXEC_CORE_NOTE_DESC_BYTES )
+#endif
 
 /*
  * This structure is used to hold the arguments that are used when loading