sparc64: Don't MAGIC_SYSRQ ifdef smp_fetch_global_regs and support code.

Based upon a report and initial patch by Friedrich Oslage.

The intention is to provide this facility for
__trigger_all_cpu_backtrace even if MAGIC_SYSRQ is not set.

The only part that should have MAGIC_SYSRQ ifdef protection is the
sparc_globalreg_op sysrq regitration and immediate code.

Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc64/kernel/smp.c

@@ -858,9 +858,7 @@ void smp_tsb_sync(struct mm_struct *mm)
 extern unsigned long xcall_flush_tlb_mm;
 extern unsigned long xcall_flush_tlb_pending;
 extern unsigned long xcall_flush_tlb_kernel_range;
-#ifdef CONFIG_MAGIC_SYSRQ
 extern unsigned long xcall_fetch_glob_regs;
-#endif
 extern unsigned long xcall_receive_signal;
 extern unsigned long xcall_new_mmu_context_version;
 #ifdef CONFIG_KGDB
@@ -1005,12 +1003,10 @@ void kgdb_roundup_cpus(unsigned long flags)
 }
 #endif
 
-#ifdef CONFIG_MAGIC_SYSRQ
 void smp_fetch_global_regs(void)
 {
 	smp_cross_call(&xcall_fetch_glob_regs, 0, 0, 0);
 }
-#endif
 
 /* We know that the window frames of the user have been flushed
  * to the stack before we get here because all callers of us

arch/sparc64/mm/ultra.S

@@ -480,7 +480,6 @@ xcall_sync_tick:
 	b		rtrap_xcall
 	 ldx		[%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
 
-#ifdef CONFIG_MAGIC_SYSRQ
 	.globl		xcall_fetch_glob_regs
 xcall_fetch_glob_regs:
 	sethi		%hi(global_reg_snapshot), %g1
@@ -511,7 +510,6 @@ xcall_fetch_glob_regs:
 	membar		#StoreStore
 	stx		%g3, [%g1 + GR_SNAP_THREAD]
 	retry
-#endif /* CONFIG_MAGIC_SYSRQ */
 
 #ifdef DCACHE_ALIASING_POSSIBLE
 	.align		32