[PATCH] kdump: Define KEXEC_NOTE_BYTES arch specific for s390x

[PATCH] kdump: Define KEXEC_NOTE_BYTES arch specific for s390x

[Michael Holzheu]

From: Michael Holzheu <holzheu@linux.vnet.ibm.com>

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>
---
 arch/s390/include/asm/kexec.h |   18 ++++++++++++++++++
 include/linux/kexec.h         |    2 ++
 2 files changed, 20 insertions(+)

--- a/arch/s390/include/asm/kexec.h
+++ b/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) { }
--- a/include/linux/kexec.h
+++ b/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

Re: [PATCH] kdump: Define KEXEC_NOTE_BYTES arch specific for s390x

[Simon Horman]

On Wed, Jan 11, 2012 at 12:30:12PM +0100, Michael Holzheu wrote:
> From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
> 
> 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>

This seems reasonable to me.

Reviewed-by: Simon Horman <horms@verge.net.au>