x86/traps: Use SEND_SIG_PRIV instead of force_sig()

force_sig() is just force_sig_info(SEND_SIG_PRIV). Imho it should die,
we have too many ugly "send signal" helpers.

And do_trap() looks just ugly because it uses force_sig_info() or
force_sig() depending on info != NULL.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>

arch/x86/kernel/traps.c

@@ -168,10 +168,7 @@ do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
 	}
 #endif
 
-	if (info)
-		force_sig_info(signr, info, tsk);
-	else
-		force_sig(signr, tsk);
+	force_sig_info(signr, info ?: SEND_SIG_PRIV, tsk);
 }
 
 #define DO_ERROR(trapnr, signr, str, name)				\
@@ -305,7 +302,7 @@ do_general_protection(struct pt_regs *regs, long error_code)
 		pr_cont("\n");
 	}
 
-	force_sig(SIGSEGV, tsk);
+	force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
 exit:
 	exception_exit(prev_state);
 }
@@ -645,7 +642,7 @@ void math_state_restore(void)
 	 */
 	if (unlikely(restore_fpu_checking(tsk))) {
 		drop_init_fpu(tsk);
-		force_sig(SIGSEGV, tsk);
+		force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
 		return;
 	}