tile: support CONTEXT_TRACKING and thus NOHZ_FULL

Add the TIF_NOHZ flag appropriately.

Add call to user_exit() on entry to do_work_pending() and on entry
to syscalls via do_syscall_trace_enter(), and also the top of
do_syscall_trace_exit() just because it's done in x86.

Add call to user_enter() at the bottom of do_work_pending() once we
have no more work to do before returning to userspace.

Wrap all the trap code in exception_enter() / exception_exit().

Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/arch/tile/mm/fault.c b/arch/tile/mm/fault.c
index 0f61a73534e6..e83cc999da02 100644
--- a/arch/tile/mm/fault.c
+++ b/arch/tile/mm/fault.c
@@ -35,6 +35,7 @@
 #include <linux/syscalls.h>
 #include <linux/uaccess.h>
 #include <linux/kdebug.h>
+#include <linux/context_tracking.h>
 
 #include <asm/pgalloc.h>
 #include <asm/sections.h>
@@ -702,6 +703,7 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
                    unsigned long address, unsigned long write)
 {
         int is_page_fault;
+        enum ctx_state prev_state = exception_enter();
 
 #ifdef CONFIG_KPROBES
         /*
@@ -711,7 +713,7 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
          */
         if (notify_die(DIE_PAGE_FAULT, "page fault", regs, -1,
                        regs->faultnum, SIGSEGV) == NOTIFY_STOP)
-                return;
+                goto done;
 #endif
 
 #ifdef __tilegx__
@@ -750,7 +752,6 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
                                  current->comm, current->pid, pc, address);
                         show_regs(regs);
                         do_group_exit(SIGKILL);
-                        return;
                 }
         }
 #else
@@ -834,12 +835,15 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
                         async->is_fault = is_page_fault;
                         async->is_write = write;
                         async->address = address;
-                        return;
+                        goto done;
                 }
         }
 #endif
 
         handle_page_fault(regs, fault_num, is_page_fault, address, write);
+
+done:
+        exception_exit(prev_state);
 }