alpha: don't open-code trace_report_syscall_{enter,exit}

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/alpha/kernel/entry.S

@@ -418,11 +418,10 @@ $work_notifysig:
 strace:
 	/* set up signal stack, call syscall_trace */
 	bsr	$1, do_switch_stack
-	jsr	$26, syscall_trace
+	jsr	$26, syscall_trace_enter /* returns the syscall number */
 	bsr	$1, undo_switch_stack
 
-	/* get the system call number and the arguments back.. */
-	ldq	$0, 0($sp)
+	/* get the arguments back.. */
 	ldq	$16, SP_OFF+24($sp)
 	ldq	$17, SP_OFF+32($sp)
 	ldq	$18, SP_OFF+40($sp)
@@ -449,7 +448,7 @@ $strace_success:
 	stq	$0, 0($sp)		/* save return value */
 
 	bsr	$1, do_switch_stack
-	jsr	$26, syscall_trace
+	jsr	$26, syscall_trace_leave
 	bsr	$1, undo_switch_stack
 	br	$31, ret_from_sys_call
 
@@ -467,7 +466,7 @@ $strace_error:
 	bsr	$1, do_switch_stack
 	mov	$19, $9		/* save old syscall number */
 	mov	$20, $10	/* save old a3 */
-	jsr	$26, syscall_trace
+	jsr	$26, syscall_trace_leave
 	mov	$9, $19
 	mov	$10, $20
 	bsr	$1, undo_switch_stack
@@ -698,7 +697,7 @@ sys_sigreturn:
 	lda	$sp, -SWITCH_STACK_SIZE($sp)
 	jsr	$26, do_sigreturn
 	bne	$9, 1f
-	jsr	$26, syscall_trace
+	jsr	$26, syscall_trace_leave
 1:	br	$1, undo_switch_stack
 	br	ret_from_sys_call
 .end sys_sigreturn
@@ -715,7 +714,7 @@ sys_rt_sigreturn:
 	lda	$sp, -SWITCH_STACK_SIZE($sp)
 	jsr	$26, do_rt_sigreturn
 	bne	$9, 1f
-	jsr	$26, syscall_trace
+	jsr	$26, syscall_trace_leave
 1:	br	$1, undo_switch_stack
 	br	ret_from_sys_call
 .end sys_rt_sigreturn

arch/alpha/kernel/ptrace.c

@@ -13,6 +13,7 @@
 #include <linux/user.h>
 #include <linux/security.h>
 #include <linux/signal.h>
+#include <linux/tracehook.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
@@ -312,25 +313,18 @@ long arch_ptrace(struct task_struct *child, long request,
 	return ret;
 }
 
+asmlinkage unsigned long syscall_trace_enter(void)
+{
+	unsigned long ret = 0;
+	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
+	    tracehook_report_syscall_entry(current_pt_regs()))
+		ret = -1UL;
+	return ret ?: current_pt_regs()->r0;
+}
+
 asmlinkage void
-syscall_trace(void)
+syscall_trace_leave(void)
 {
-	if (!test_thread_flag(TIF_SYSCALL_TRACE))
-		return;
-	if (!(current->ptrace & PT_PTRACED))
-		return;
-	/* The 0x80 provides a way for the tracing parent to distinguish
-	   between a syscall stop and SIGTRAP delivery */
-	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
-				 ? 0x80 : 0));
-
-	/*
-	 * This isn't the same as continuing with a signal, but it will do
-	 * for normal use.  strace only continues with a signal if the
-	 * stopping signal is not SIGTRAP.  -brl
-	 */
-	if (current->exit_code) {
-		send_sig(current->exit_code, current, 1);
-		current->exit_code = 0;
-	}
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall_exit(current_pt_regs(), 0);
 }