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>

5 files changed, 96 insertions, 53 deletions

diff --git a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug
index b440fd936714..a6dce41296e7 100644
--- a/arch/sh/Kconfig.debug
+++ b/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
diff --git a/arch/sh/include/asm/entry-macros.S b/arch/sh/include/asm/entry-macros.S
index 3a4752a65722..1bdd93891cd7 100644
--- a/arch/sh/include/asm/entry-macros.S
+++ b/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
diff --git a/arch/sh/kernel/entry-common.S b/arch/sh/kernel/entry-common.S
index d62175650c54..fc26ccd82789 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 77dfecb64373..e27a19e1f46e 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);
diff --git a/drivers/serial/sh-sci.c b/drivers/serial/sh-sci.c
index 8e2feb563347..4cbb87ad070a 100644
--- a/drivers/serial/sh-sci.c
+++ b/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;
 }