blackfin-retn-or-rete.patch

   1 Index: arch/blackfin/mach-common/entry.S
   2 ===================================================================
   3 --- arch/blackfin/mach-common/entry.S   (revision 3496)
   4 +++ arch/blackfin/mach-common/entry.S   (working copy)
   5 @@ -58,6 +58,12 @@
   6
   7  #include <asm/mach-common/context.S>
   8
   9 +#ifdef CONFIG_BFIN_SCRATCH_REG_RETN
  10 +# define EX_SCRATCH_REG RETN
  11 +#else
  12 +# define EX_SCRATCH_REG RETE
  13 +#endif
  14 +
  15  #ifdef CONFIG_EXCPT_IRQ_SYSC_L1
  16  .section .l1.text
  17  #else
  18 @@ -93,7 +99,7 @@ ENTRY(_ex_icplb)
  19         call __cplb_hdr;
  20         DEBUG_START_HWTRACE(p5, r7)
  21         RESTORE_ALL_SYS
  22 -       SP = RETN;
  23 +       SP = EX_SCRATCH_REG;
  24         rtx;
  25  ENDPROC(_ex_icplb)
  26
  27 @@ -102,7 +108,7 @@ ENTRY(_ex_syscall)
  28         (R7:6,P5:4) = [sp++];
  29         ASTAT = [sp++];
  30         raise 15;               /* invoked by TRAP #0, for sys call */
  31 -       sp = retn;
  32 +       sp = EX_SCRATCH_REG;
  33         rtx
  34  ENDPROC(_ex_syscall)
  35
  36 @@ -145,7 +151,7 @@ _return_from_exception:
  37  #endif
  38         (R7:6,P5:4) = [sp++];
  39         ASTAT = [sp++];
  40 -       sp = retn;
  41 +       sp = EX_SCRATCH_REG;
  42         rtx;
  43  ENDPROC(_ex_soft_bp)
  44
  45 @@ -204,7 +210,7 @@ ENTRY(_ex_trap_c)
  46         DEBUG_START_HWTRACE(p5, r7)
  47         (R7:6,P5:4) = [sp++];
  48         ASTAT = [sp++];
  49 -       SP = RETN;
  50 +       SP = EX_SCRATCH_REG;
  51         raise 5;
  52         rtx;
  53  ENDPROC(_ex_trap_c)
  54 @@ -279,7 +285,7 @@ ENTRY(_trap) /* Exception: 4th entry int
  55          * covered by a CPLB.  Switch to an exception stack; use RETN as a
  56          * scratch register (for want of a better option).
  57          */
  58 -       retn = sp;
  59 +       EX_SCRATCH_REG = sp;
  60         sp.l = _exception_stack_top;
  61         sp.h = _exception_stack_top;
  62         /* Try to deal with syscalls quickly.  */
  63 Index: arch/blackfin/Kconfig
  64 ===================================================================
  65 --- arch/blackfin/Kconfig       (revision 3496)
  66 +++ arch/blackfin/Kconfig       (working copy)
  67 @@ -520,6 +520,32 @@ config BFIN_IDLE_LED_NUM
  68         help
  69           Select the LED (marked on the board) for you to blink.
  70
  71 +choice
  72 +       prompt "Blackfin Exception Scratch Register"
  73 +       default BFIN_SCRATCH_REG_RETN
  74 +
  75 +config BFIN_SCRATCH_REG_RETN
  76 +       bool "RETN"
  77 +       help
  78 +         Use the RETN register in the Blackfin exception handler
  79 +         as a stack scratch register.  This means you cannot
  80 +         safely use NMI on the Blackfin while running Linux, but
  81 +         you can debug the system with a JTAG ICE.
  82 +
  83 +         If you are unsure, please select "RETN".
  84 +
  85 +config BFIN_SCRATCH_REG_RETE
  86 +       bool "RETE"
  87 +       help
  88 +         Use the RETE register in the Blackfin exception handler
  89 +         as a stack scratch register.  This means you cannot
  90 +         safely use a JTAG ICE while debugging a Blackfin board,
  91 +         but you can safely use the NMI.
  92 +
  93 +         If you are unsure, please select "RETN".
  94 +
  95 +endchoice
  96 +
  97  #
  98  # Sorry - but you need to put the hex address here -
  99  #