Remove hardcoding of hard_smp_processor_id on UP systems

With the advent of kdump, the assumption that the boot CPU when booting an UP
kernel is always the CPU with a particular hardware ID (often 0) (usually
referred to as BSP on some architectures) is not valid anymore.  The reason
being that the dump capture kernel boots on the crashed CPU (the CPU that
invoked crash_kexec), which may be or may not be that particular CPU.

Move definition of hard_smp_processor_id for the UP case to
architecture-specific code ("asm/smp.h") where it belongs, so that each
architecture can provide its own implementation.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Cc: "Luck, Tony" <tony.luck@intel.com>
Acked-by: Andi Kleen <ak@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/asm-um/smp.h b/include/asm-um/smp.h
index ca552261ed1f..84f8cf29324e 100644
--- a/include/asm-um/smp.h
+++ b/include/asm-um/smp.h
@@ -24,6 +24,10 @@ extern inline void smp_cpus_done(unsigned int maxcpus)
 
 extern struct task_struct *idle_threads[NR_CPUS];
 
+#else
+
+#define hard_smp_processor_id()         0
+
 #endif
 
 #endif