elf: add ELF_CORE_COPY_KERNEL_REGS()

ELF core dump is used for both user land core dump and kernel crash
dump.  Depending on architecture, register might need to be accessed
differently for userland and kernel.  Allow architectures to define
ELF_CORE_COPY_KERNEL_REGS() and use different operation for kernel
register dump.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

include/linux/elfcore.h

@@ -111,6 +111,15 @@ static inline void elf_core_copy_regs(elf_gregset_t *elfregs, struct pt_regs *re
 #endif
 }
 
+static inline void elf_core_copy_kernel_regs(elf_gregset_t *elfregs, struct pt_regs *regs)
+{
+#ifdef ELF_CORE_COPY_KERNEL_REGS
+	ELF_CORE_COPY_KERNEL_REGS((*elfregs), regs);
+#else
+	elf_core_copy_regs(elfregs, regs);
+#endif
+}
+
 static inline int elf_core_copy_task_regs(struct task_struct *t, elf_gregset_t* elfregs)
 {
 #ifdef ELF_CORE_COPY_TASK_REGS

kernel/kexec.c

@@ -1130,7 +1130,7 @@ void crash_save_cpu(struct pt_regs *regs, int cpu)
 		return;
 	memset(&prstatus, 0, sizeof(prstatus));
 	prstatus.pr_pid = current->pid;
-	elf_core_copy_regs(&prstatus.pr_reg, regs);
+	elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
 	buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
 		      	      &prstatus, sizeof(prstatus));
 	final_note(buf);