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>

Author: Stuart Menefy

arch/sh/Kconfig.debug

@@ -38,7 +38,7 @@ config EARLY_SCIF_CONSOLE_PORT
 	default "0xffe00000" if CPU_SUBTYPE_SH7780 || CPU_SUBTYPE_SH7763 || \
 				CPU_SUBTYPE_SH7722 || CPU_SUBTYPE_SH7366 || \
 				CPU_SUBTYPE_SH7343
-	default "0xffea0000" if CPU_SUBTYPE_SH7785
+	default "0xffeb0000" if CPU_SUBTYPE_SH7785
 	default "0xffeb0000" if CPU_SUBTYPE_SH7786
 	default "0xfffe8000" if CPU_SUBTYPE_SH7203
 	default "0xfffe9800" if CPU_SUBTYPE_SH7206 || CPU_SUBTYPE_SH7263

arch/sh/include/asm/entry-macros.S

@@ -31,6 +31,78 @@
 #endif	
 	.endm
 
+#ifdef CONFIG_TRACE_IRQFLAGS
+
+	.macro	TRACE_IRQS_ON
+	mov.l	r0, @-r15
+	mov.l	r1, @-r15
+	mov.l	r2, @-r15
+	mov.l	r3, @-r15
+	mov.l	r4, @-r15
+	mov.l	r5, @-r15
+	mov.l	r6, @-r15
+	mov.l	r7, @-r15
+
+	mov.l   7834f, r0
+	jsr	@r0
+	 nop
+
+	mov.l	@r15+, r7
+	mov.l	@r15+, r6
+	mov.l	@r15+, r5
+	mov.l	@r15+, r4
+	mov.l	@r15+, r3
+	mov.l	@r15+, r2
+	mov.l	@r15+, r1
+	mov.l	@r15+, r0
+	mov.l	7834f, r0
+
+	bra	7835f
+	 nop
+	.balign	4
+7834:	.long	trace_hardirqs_on
+7835:
+	.endm
+	.macro	TRACE_IRQS_OFF
+
+	mov.l	r0, @-r15
+	mov.l	r1, @-r15
+	mov.l	r2, @-r15
+	mov.l	r3, @-r15
+	mov.l	r4, @-r15
+	mov.l	r5, @-r15
+	mov.l	r6, @-r15
+	mov.l	r7, @-r15
+
+	mov.l	7834f, r0
+	jsr	@r0
+	 nop
+
+	mov.l	@r15+, r7
+	mov.l	@r15+, r6
+	mov.l	@r15+, r5
+	mov.l	@r15+, r4
+	mov.l	@r15+, r3
+	mov.l	@r15+, r2
+	mov.l	@r15+, r1
+	mov.l	@r15+, r0
+	mov.l	7834f, r0
+
+	bra	7835f
+	 nop
+	.balign	4
+7834:	.long	trace_hardirqs_off
+7835:
+	.endm
+
+#else
+	.macro	TRACE_IRQS_ON
+	.endm
+
+	.macro	TRACE_IRQS_OFF
+	.endm
+#endif
+
 #if defined(CONFIG_CPU_SH2A) || defined(CONFIG_CPU_SH4)
 # define PREF(x)	pref	@x
 #else

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
@@ -55,34 +55,31 @@
 	.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
 	 nop
 
 	.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

arch/sh/kernel/io_trapped.c

@@ -112,22 +112,23 @@ 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;
 			}
 
 			len = (res->end - res->start) + 1;
 			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);

drivers/serial/sh-sci.c

@@ -662,10 +662,11 @@ static irqreturn_t sci_rx_interrupt(int irq, void *port)
 static irqreturn_t sci_tx_interrupt(int irq, void *ptr)
 {
 	struct uart_port *port = ptr;
+	unsigned long flags;
 
-	spin_lock_irq(&port->lock);
+	spin_lock_irqsave(&port->lock, flags);
 	sci_transmit_chars(port);
-	spin_unlock_irq(&port->lock);
+	spin_unlock_irqrestore(&port->lock, flags);
 
 	return IRQ_HANDLED;
 }