Merge branch 'sh/for-2.6.33' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6

* 'sh/for-2.6.33' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6:
  sh: Remove superfluous setup_frame_reg call
  sh: Don't continue unwinding across interrupts
  sh: Setup frame pointer in handle_exception path
  sh: Correct the offset of the return address in ret_from_exception
  usb: r8a66597-hcd: Fix up spinlock recursion in root hub polling.
  usb: r8a66597-hcd: Flush the D-cache for the pipe-in transfer buffers.

3 files changed, 29 insertions, 2 deletions

diff --git a/arch/sh/kernel/cpu/sh3/entry.S b/arch/sh/kernel/cpu/sh3/entry.S
index 3f7e2a2..f6a389c 100644
--- a/arch/sh/kernel/cpu/sh3/entry.S
+++ b/arch/sh/kernel/cpu/sh3/entry.S
@@ -132,7 +132,6 @@ ENTRY(tlb_protection_violation_store)
 	 mov	#1, r5
 
 call_handle_tlbmiss:
-	setup_frame_reg
 	mov.l	1f, r0
 	mov	r5, r8
 	mov.l	@r0, r6
@@ -365,6 +364,8 @@ handle_exception:
 	 mov.l	@k2, k2		! read out vector and keep in k2
 
 handle_exception_special:
+	setup_frame_reg
+
 	! Setup return address and jump to exception handler
 	mov.l	7f, r9		! fetch return address
 	stc	r2_bank, r0	! k2 (vector)
diff --git a/arch/sh/kernel/dwarf.c b/arch/sh/kernel/dwarf.c
index 88d28ec..e511680 100644
--- a/arch/sh/kernel/dwarf.c
+++ b/arch/sh/kernel/dwarf.c
@@ -540,6 +540,8 @@ void dwarf_free_frame(struct dwarf_frame *frame)
 	mempool_free(frame, dwarf_frame_pool);
 }
 
+extern void ret_from_irq(void);
+
 /**
  *	dwarf_unwind_stack - unwind the stack
  *
@@ -678,6 +680,24 @@ struct dwarf_frame * dwarf_unwind_stack(unsigned long pc,
 	addr = frame->cfa + reg->addr;
 	frame->return_addr = __raw_readl(addr);
 
+	/*
+	 * Ah, the joys of unwinding through interrupts.
+	 *
+	 * Interrupts are tricky - the DWARF info needs to be _really_
+	 * accurate and unfortunately I'm seeing a lot of bogus DWARF
+	 * info. For example, I've seen interrupts occur in epilogues
+	 * just after the frame pointer (r14) had been restored. The
+	 * problem was that the DWARF info claimed that the CFA could be
+	 * reached by using the value of the frame pointer before it was
+	 * restored.
+	 *
+	 * So until the compiler can be trusted to produce reliable
+	 * DWARF info when it really matters, let's stop unwinding once
+	 * we've calculated the function that was interrupted.
+	 */
+	if (prev && prev->pc == (unsigned long)ret_from_irq)
+		frame->return_addr = 0;
+
 	return frame;
 
 bail:
diff --git a/arch/sh/kernel/entry-common.S b/arch/sh/kernel/entry-common.S
index f0abd58..2b15ae6 100644
--- a/arch/sh/kernel/entry-common.S
+++ b/arch/sh/kernel/entry-common.S
@@ -70,8 +70,14 @@ ret_from_exception:
 	CFI_STARTPROC simple
 	CFI_DEF_CFA r14, 0
 	CFI_REL_OFFSET 17, 64
-	CFI_REL_OFFSET 15, 0
+	CFI_REL_OFFSET 15, 60
 	CFI_REL_OFFSET 14, 56
+	CFI_REL_OFFSET 13, 52
+	CFI_REL_OFFSET 12, 48
+	CFI_REL_OFFSET 11, 44
+	CFI_REL_OFFSET 10, 40
+	CFI_REL_OFFSET 9, 36
+	CFI_REL_OFFSET 8, 32
 	preempt_stop()
 ENTRY(ret_from_irq)
 	!