sh: Rework irqflags tracing to fix up CONFIG_PROVE_LOCKING.

This cleans up the irqflags tracing code quite a bit and ties it
in to various missing callsites that caused an imbalance when
CONFIG_PROVE_LOCKING was enabled.

Previously this was catching on:

 987 #ifdef CONFIG_PROVE_LOCKING
 988     DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled);
 989     DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
 990 #endif
 991     retval = -EAGAIN;

with hardirqs being doubly enabled, and subsequently bailing out
with the following call trace:

	Call trace:
	[<88035224>] __lock_acquire+0x616/0x6a6
	[<88015a8c>] do_fork+0xf8/0x2b0
	[<880331ec>] trace_hardirqs_on_caller+0xd4/0x114
	[<88241074>] _spin_unlock_irq+0x20/0x64
	[<88035224>] __lock_acquire+0x616/0x6a6
	[<8800386c>] kernel_thread+0x48/0x70
	[<88024ecc>] ____call_usermodehelper+0x0/0x110
	[<88024ecc>] ____call_usermodehelper+0x0/0x110
	[<88003894>] kernel_thread_helper+0x0/0x14
	[<88024bac>] __call_usermodehelper+0x38/0x70
	[<88025dc0>] worker_thread+0x150/0x274
	[<88035b9c>] lock_release+0x0/0x198
	[<88024b74>] __call_usermodehelper+0x0/0x70
	[<88028cf0>] autoremove_wake_function+0x0/0x30
	[<88028bf2>] kthread+0x3e/0x70
	[<88025c70>] worker_thread+0x0/0x274
	[<8800389c>] kernel_thread_helper+0x8/0x14
	[<88028bb4>] kthread+0x0/0x70
	[<88003894>] kernel_thread_helper+0x0/0x14

Reported-by: Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

2 files changed, 20 insertions, 50 deletions

diff --git a/arch/sh/kernel/entry-common.S b/arch/sh/kernel/entry-common.S
index d62175650c5..fc26ccd8278 100644
--- a/arch/sh/kernel/entry-common.S
+++ b/arch/sh/kernel/entry-common.S
@@ -45,7 +45,7 @@
  */
 
 #if defined(CONFIG_PREEMPT)
-#  define preempt_stop()	cli
+#  define preempt_stop()	cli ; TRACE_IRQS_OFF
 #else
 #  define preempt_stop()
 #  define resume_kernel		__restore_all
@@ -55,11 +55,7 @@
 	.align	2
 ENTRY(exception_error)
 	!
-#ifdef CONFIG_TRACE_IRQFLAGS
-	mov.l	2f, r0
-	jsr	@r0
-	 nop
-#endif
+	TRACE_IRQS_ON
 	sti
 	mov.l	1f, r0
 	jmp	@r0
@@ -67,22 +63,23 @@ ENTRY(exception_error)
 
 	.align	2
 1:	.long	do_exception_error
-#ifdef CONFIG_TRACE_IRQFLAGS
-2:	.long	trace_hardirqs_on
-#endif
 
 	.align	2
 ret_from_exception:
 	preempt_stop()
-#ifdef CONFIG_TRACE_IRQFLAGS
-	mov.l	4f, r0
-	jsr	@r0
-	 nop
-#endif
 ENTRY(ret_from_irq)
 	!
 	mov	#OFF_SR, r0
 	mov.l	@(r0,r15), r0	! get status register
+
+	shlr2	r0
+	and	#0x3c, r0
+	cmp/eq	#0x3c, r0
+	bt	9f
+	TRACE_IRQS_ON
+9:
+	mov	#OFF_SR, r0
+	mov.l	@(r0,r15), r0	! get status register
 	shll	r0
 	shll	r0		! kernel space?
 	get_current_thread_info r8, r0
@@ -125,11 +122,7 @@ noresched:
 ENTRY(resume_userspace)
 	! r8: current_thread_info
 	cli
-#ifdef CONFIG_TRACE_IRQFLAGS
-	mov.l	5f, r0
-	jsr	@r0
-	 nop
-#endif
+	TRACE_IRQS_OfF
 	mov.l	@(TI_FLAGS,r8), r0		! current_thread_info->flags
 	tst	#(_TIF_WORK_MASK & 0xff), r0
 	bt/s	__restore_all
@@ -156,11 +149,7 @@ work_resched:
 	jsr	@r1				! schedule
 	 nop
 	cli
-#ifdef CONFIG_TRACE_IRQFLAGS
-	mov.l	5f, r0
-	jsr	@r0
-	 nop
-#endif
+	TRACE_IRQS_OFF
 	!
 	mov.l	@(TI_FLAGS,r8), r0		! current_thread_info->flags
 	tst	#(_TIF_WORK_MASK & 0xff), r0
@@ -172,10 +161,6 @@ work_resched:
 1:	.long	schedule
 2:	.long	do_notify_resume
 3:	.long	resume_userspace
-#ifdef CONFIG_TRACE_IRQFLAGS
-4:	.long	trace_hardirqs_on
-5:	.long	trace_hardirqs_off
-#endif
 
 	.align	2
 syscall_exit_work:
@@ -184,11 +169,7 @@ syscall_exit_work:
 	tst	#(_TIF_WORK_SYSCALL_MASK & 0xff), r0
 	bt/s	work_pending
 	 tst	#_TIF_NEED_RESCHED, r0
-#ifdef CONFIG_TRACE_IRQFLAGS
-	mov.l	5f, r0
-	jsr	@r0
-	 nop
-#endif
+	TRACE_IRQS_ON
 	sti
 	mov	r15, r4
 	mov.l	8f, r0			! do_syscall_trace_leave
@@ -321,11 +302,7 @@ ENTRY(system_call)
 	bt/s	debug_trap		! it's a debug trap..
 	 nop
 
-#ifdef CONFIG_TRACE_IRQFLAGS
-	mov.l	5f, r10
-	jsr	@r10
-	 nop
-#endif
+	TRACE_IRQS_ON
 	sti
 
 	!
@@ -355,11 +332,7 @@ syscall_call:
 	!
 syscall_exit:
 	cli
-#ifdef CONFIG_TRACE_IRQFLAGS
-	mov.l	6f, r0
-	jsr	@r0
-	 nop
-#endif
+	TRACE_IRQS_OFF
 	!
 	get_current_thread_info r8, r0
 	mov.l	@(TI_FLAGS,r8), r0		! current_thread_info->flags
@@ -377,9 +350,5 @@ syscall_exit:
 #endif
 2:	.long	NR_syscalls
 3:	.long	sys_call_table
-#ifdef CONFIG_TRACE_IRQFLAGS
-5:	.long	trace_hardirqs_on
-6:	.long	trace_hardirqs_off
-#endif
 7:	.long	do_syscall_trace_enter
 8:	.long	do_syscall_trace_leave
diff --git a/arch/sh/kernel/io_trapped.c b/arch/sh/kernel/io_trapped.c
index 77dfecb6437..e27a19e1f46 100644
--- a/arch/sh/kernel/io_trapped.c
+++ b/arch/sh/kernel/io_trapped.c
@@ -112,14 +112,15 @@ void __iomem *match_trapped_io_handler(struct list_head *list,
 	struct trapped_io *tiop;
 	struct resource *res;
 	int k, len;
+	unsigned long flags;
 
-	spin_lock_irq(&trapped_lock);
+	spin_lock_irqsave(&trapped_lock, flags);
 	list_for_each_entry(tiop, list, list) {
 		voffs = 0;
 		for (k = 0; k < tiop->num_resources; k++) {
 			res = tiop->resource + k;
 			if (res->start == offset) {
-				spin_unlock_irq(&trapped_lock);
+				spin_unlock_irqrestore(&trapped_lock, flags);
 				return tiop->virt_base + voffs;
 			}
 
@@ -127,7 +128,7 @@ void __iomem *match_trapped_io_handler(struct list_head *list,
 			voffs += roundup(len, PAGE_SIZE);
 		}
 	}
-	spin_unlock_irq(&trapped_lock);
+	spin_unlock_irqrestore(&trapped_lock, flags);
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(match_trapped_io_handler);