sparc64: Implement HAVE_CONTEXT_TRACKING

Mark the places when the system are in user or are in kernel.
This is used to make full dynticks system (tickless) --
CONFIG_NO_HZ_FULL dependence.

Signed-off-by: Kirill Tkhai <tkhai@yandex.ru>
CC: David Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/mm/fault_64.c

@@ -21,6 +21,7 @@
 #include <linux/kprobes.h>
 #include <linux/kdebug.h>
 #include <linux/percpu.h>
+#include <linux/context_tracking.h>
 
 #include <asm/page.h>
 #include <asm/pgtable.h>
@@ -272,6 +273,7 @@ static void noinline __kprobes bogus_32bit_fault_address(struct pt_regs *regs,
 
 asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
 {
+	enum ctx_state prev_state = exception_enter();
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
 	unsigned int insn = 0;
@@ -282,7 +284,7 @@ asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
 	fault_code = get_thread_fault_code();
 
 	if (notify_page_fault(regs))
-		return;
+		goto exit_exception;
 
 	si_code = SEGV_MAPERR;
 	address = current_thread_info()->fault_address;
@@ -313,7 +315,7 @@ asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
 			/* Valid, no problems... */
 		} else {
 			bad_kernel_pc(regs, address);
-			return;
+			goto exit_exception;
 		}
 	} else
 		flags |= FAULT_FLAG_USER;
@@ -430,7 +432,7 @@ good_area:
 	fault = handle_mm_fault(mm, vma, address, flags);
 
 	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
-		return;
+		goto exit_exception;
 
 	if (unlikely(fault & VM_FAULT_ERROR)) {
 		if (fault & VM_FAULT_OOM)
@@ -482,6 +484,8 @@ good_area:
 
 	}
 #endif
+exit_exception:
+	exception_exit(prev_state);
 	return;
 
 	/*
@@ -494,7 +498,7 @@ bad_area:
 
 handle_kernel_fault:
 	do_kernel_fault(regs, si_code, fault_code, insn, address);
-	return;
+	goto exit_exception;
 
 /*
  * We ran out of memory, or some other thing happened to us that made
@@ -505,7 +509,7 @@ out_of_memory:
 	up_read(&mm->mmap_sem);
 	if (!(regs->tstate & TSTATE_PRIV)) {
 		pagefault_out_of_memory();
-		return;
+		goto exit_exception;
 	}
 	goto handle_kernel_fault;