10 files changed, 103 insertions, 44 deletions

diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig
index cdce8cc5b7b3..26ebb0e8c431 100644
--- a/arch/blackfin/Kconfig
+++ b/arch/blackfin/Kconfig
@@ -521,6 +521,52 @@ config BFIN_IDLE_LED_NUM
         help
           Select the LED (marked on the board) for you to blink.
 
+choice
+        prompt "Blackfin Exception Scratch Register"
+        default BFIN_SCRATCH_REG_RETN
+        help
+          Select the resource to reserve for the Exception handler:
+            - RETN: Non-Maskable Interrupt (NMI)
+            - RETE: Exception Return (JTAG/ICE)
+            - CYCLES: Performance counter
+
+          If you are unsure, please select "RETN".
+
+config BFIN_SCRATCH_REG_RETN
+        bool "RETN"
+        help
+          Use the RETN register in the Blackfin exception handler
+          as a stack scratch register.  This means you cannot
+          safely use NMI on the Blackfin while running Linux, but
+          you can debug the system with a JTAG ICE and use the
+          CYCLES performance registers.
+
+          If you are unsure, please select "RETN".
+
+config BFIN_SCRATCH_REG_RETE
+        bool "RETE"
+        help
+          Use the RETE register in the Blackfin exception handler
+          as a stack scratch register.  This means you cannot
+          safely use a JTAG ICE while debugging a Blackfin board,
+          but you can safely use the CYCLES performance registers
+          and the NMI.
+
+          If you are unsure, please select "RETN".
+
+config BFIN_SCRATCH_REG_CYCLES
+        bool "CYCLES"
+        help
+          Use the CYCLES register in the Blackfin exception handler
+          as a stack scratch register.  This means you cannot
+          safely use the CYCLES performance registers on a Blackfin
+          board at anytime, but you can debug the system with a JTAG
+          ICE and use the NMI.
+
+          If you are unsure, please select "RETN".
+
+endchoice
+
 #
 # Sorry - but you need to put the hex address here -
 #
diff --git a/arch/blackfin/kernel/irqchip.c b/arch/blackfin/kernel/irqchip.c
index 462ae41144c7..73647c158774 100644
--- a/arch/blackfin/kernel/irqchip.c
+++ b/arch/blackfin/kernel/irqchip.c
@@ -98,9 +98,8 @@ int show_interrupts(struct seq_file *p, void *v)
  */
 
 #ifdef CONFIG_DO_IRQ_L1
-asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)__attribute__((l1_text));
+__attribute__((l1_text))
 #endif
-
 asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 {
         struct pt_regs *old_regs;
diff --git a/arch/blackfin/mach-bf533/head.S b/arch/blackfin/mach-bf533/head.S
index 1d5b9dbbbaa7..3be6feefa8a9 100644
--- a/arch/blackfin/mach-bf533/head.S
+++ b/arch/blackfin/mach-bf533/head.S
@@ -53,10 +53,12 @@ __INIT
 ENTRY(__start)
         /* R0: argument of command line string, passed from uboot, save it */
         R7 = R0;
-        /* Set the SYSCFG register:
-         * Enable Cycle Counter and Nesting Of Interrupts (3rd Bit)
-         */
-        R0 = 0x36;
+        /* Enable Cycle Counter and Nesting Of Interrupts */
+#ifdef CONFIG_BFIN_SCRATCH_REG_CYCLES
+        R0 = SYSCFG_SNEN;
+#else
+        R0 = SYSCFG_SNEN | SYSCFG_CCEN;
+#endif
         SYSCFG = R0;
         R0 = 0;
 
diff --git a/arch/blackfin/mach-bf537/head.S b/arch/blackfin/mach-bf537/head.S
index 6dbcb77c8d36..0836bfdcc6c5 100644
--- a/arch/blackfin/mach-bf537/head.S
+++ b/arch/blackfin/mach-bf537/head.S
@@ -51,10 +51,12 @@ __INIT
 ENTRY(__start)
         /* R0: argument of command line string, passed from uboot, save it */
         R7 = R0;
-        /* Set the SYSCFG register:
-         * Enable Cycle Counter and Nesting Of Interrupts (3rd Bit)
-         */
-        R0 = 0x36;
+        /* Enable Cycle Counter and Nesting Of Interrupts */
+#ifdef CONFIG_BFIN_SCRATCH_REG_CYCLES
+        R0 = SYSCFG_SNEN;
+#else
+        R0 = SYSCFG_SNEN | SYSCFG_CCEN;
+#endif
         SYSCFG = R0;
         R0 = 0;
 
diff --git a/arch/blackfin/mach-bf548/head.S b/arch/blackfin/mach-bf548/head.S
index 4c7d49f41187..937fbef26a51 100644
--- a/arch/blackfin/mach-bf548/head.S
+++ b/arch/blackfin/mach-bf548/head.S
@@ -50,9 +50,13 @@ ENTRY(__start)
 ENTRY(__stext)
         /* R0: argument of command line string, passed from uboot, save it */
         R7 = R0;
-        /* Set the SYSCFG register */
-        R0 = 0x36;
-        SYSCFG = R0;   /*Enable Cycle Counter and Nesting Of Interrupts(3rd Bit)*/
+        /* Enable Cycle Counter and Nesting Of Interrupts */
+#ifdef CONFIG_BFIN_SCRATCH_REG_CYCLES
+        R0 = SYSCFG_SNEN;
+#else
+        R0 = SYSCFG_SNEN | SYSCFG_CCEN;
+#endif
+        SYSCFG = R0;
         R0 = 0;
 
         /* Clear Out All the data and pointer  Registers*/
diff --git a/arch/blackfin/mach-bf561/head.S b/arch/blackfin/mach-bf561/head.S
index 8c9f73b8e579..139f4cff801b 100644
--- a/arch/blackfin/mach-bf561/head.S
+++ b/arch/blackfin/mach-bf561/head.S
@@ -51,10 +51,12 @@ __INIT
 ENTRY(__start)
         /* R0: argument of command line string, passed from uboot, save it */
         R7 = R0;
-        /* Set the SYSCFG register:
-         * Enable Cycle Counter and Nesting Of Interrupts (3rd Bit)
-         */
-        R0 = 0x36;
+        /* Enable Cycle Counter and Nesting Of Interrupts */
+#ifdef CONFIG_BFIN_SCRATCH_REG_CYCLES
+        R0 = SYSCFG_SNEN;
+#else
+        R0 = SYSCFG_SNEN | SYSCFG_CCEN;
+#endif
         SYSCFG = R0;
         R0 = 0;
 
diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index ab278a72f282..2188f81c6456 100644
--- a/arch/blackfin/mach-common/entry.S
+++ b/arch/blackfin/mach-common/entry.S
@@ -58,6 +58,14 @@
 
 #include <asm/mach-common/context.S>
 
+#if defined(CONFIG_BFIN_SCRATCH_REG_RETN)
+# define EX_SCRATCH_REG RETN
+#elif defined(CONFIG_BFIN_SCRATCH_REG_RETE)
+# define EX_SCRATCH_REG RETE
+#else
+# define EX_SCRATCH_REG CYCLES
+#endif
+
 #ifdef CONFIG_EXCPT_IRQ_SYSC_L1
 .section .l1.text
 #else
@@ -93,7 +101,7 @@ ENTRY(_ex_icplb)
         call __cplb_hdr;
         DEBUG_START_HWTRACE(p5, r7)
         RESTORE_ALL_SYS
-        SP = RETN;
+        SP = EX_SCRATCH_REG;
         rtx;
 ENDPROC(_ex_icplb)
 
@@ -102,7 +110,7 @@ ENTRY(_ex_syscall)
         (R7:6,P5:4) = [sp++];
         ASTAT = [sp++];
         raise 15;               /* invoked by TRAP #0, for sys call */
-        sp = retn;
+        sp = EX_SCRATCH_REG;
         rtx
 ENDPROC(_ex_syscall)
 
@@ -145,7 +153,7 @@ _return_from_exception:
 #endif
         (R7:6,P5:4) = [sp++];
         ASTAT = [sp++];
-        sp = retn;
+        sp = EX_SCRATCH_REG;
         rtx;
 ENDPROC(_ex_soft_bp)
 
@@ -204,7 +212,7 @@ ENTRY(_ex_trap_c)
         DEBUG_START_HWTRACE(p5, r7)
         (R7:6,P5:4) = [sp++];
         ASTAT = [sp++];
-        SP = RETN;
+        SP = EX_SCRATCH_REG;
         raise 5;
         rtx;
 ENDPROC(_ex_trap_c)
@@ -279,7 +287,7 @@ ENTRY(_trap) /* Exception: 4th entry into system event table(supervisor mode)*/
          * covered by a CPLB.  Switch to an exception stack; use RETN as a
          * scratch register (for want of a better option).
          */
-        retn = sp;
+        EX_SCRATCH_REG = sp;
         sp.l = _exception_stack_top;
         sp.h = _exception_stack_top;
         /* Try to deal with syscalls quickly.  */
diff --git a/arch/blackfin/mach-common/interrupt.S b/arch/blackfin/mach-common/interrupt.S
index 1d5ba5e3d91c..c6b32fe0f6e9 100644
--- a/arch/blackfin/mach-common/interrupt.S
+++ b/arch/blackfin/mach-common/interrupt.S
@@ -177,27 +177,15 @@ ENTRY(_evt_ivhw)
         jump .Lcommon_restore_context;
 #endif
 
-/* interrupt routine for evt2 - 2.  This is NMI.  */
-ENTRY(_evt_evt2)
-        SAVE_CONTEXT
-#ifdef CONFIG_FRAME_POINTER
-        fp = 0;
-#endif
-#if ANOMALY_05000283
-        cc = r7 == r7;
-        p5.h = 0xffc0;
-        p5.l = 0x0014;
-        if cc jump 1f;
-        r7.l = W[p5];
-1:
-#endif
-        r0 = IRQ_NMI;
-        r1 =  sp;
-        SP += -12;
-        call _asm_do_IRQ;
-        SP += 12;
-        RESTORE_CONTEXT
+/* Interrupt routine for evt2 (NMI).
+ * We don't actually use this, so just return.
+ * For inner circle type details, please see:
+ * http://docs.blackfin.uclinux.org/doku.php?id=linux:nmi
+ */
+ENTRY(_evt_nmi)
+.weak _evt_nmi
         rtn;
+ENDPROC(_evt_nmi)
 
 /* interrupt routine for core timer - 6 */
 ENTRY(_evt_timer)
diff --git a/arch/blackfin/mach-common/ints-priority-dc.c b/arch/blackfin/mach-common/ints-priority-dc.c
index 684d306ab6bb..2db3546fc874 100644
--- a/arch/blackfin/mach-common/ints-priority-dc.c
+++ b/arch/blackfin/mach-common/ints-priority-dc.c
@@ -362,7 +362,11 @@ void __init init_exception_vectors(void)
 {
         SSYNC();
 
-        bfin_write_EVT2(evt_evt2);
+        /* cannot program in software:
+         * evt0 - emulation (jtag)
+         * evt1 - reset
+         */
+        bfin_write_EVT2(evt_nmi);
         bfin_write_EVT3(trap);
         bfin_write_EVT5(evt_ivhw);
         bfin_write_EVT6(evt_timer);
diff --git a/arch/blackfin/mach-common/ints-priority-sc.c b/arch/blackfin/mach-common/ints-priority-sc.c
index a2016af65eb0..d3b7672b2b94 100644
--- a/arch/blackfin/mach-common/ints-priority-sc.c
+++ b/arch/blackfin/mach-common/ints-priority-sc.c
@@ -721,7 +721,11 @@ void __init init_exception_vectors(void)
 {
         SSYNC();
 
-        bfin_write_EVT2(evt_evt2);
+        /* cannot program in software:
+         * evt0 - emulation (jtag)
+         * evt1 - reset
+         */
+        bfin_write_EVT2(evt_nmi);
         bfin_write_EVT3(trap);
         bfin_write_EVT5(evt_ivhw);
         bfin_write_EVT6(evt_timer);