[Blackfin] arch: Remove the circular buffering mechanism for exceptions

[safe/jmp/linux-2.6] / arch / blackfin / mach-common / entry.S

diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index a504c65..f2fb87e 100644 (file)
--- a/arch/blackfin/mach-common/entry.S
+++ b/arch/blackfin/mach-common/entry.S
@@ -38,6 +38,7 @@
 #include <linux/unistd.h>
 #include <asm/blackfin.h>
 #include <asm/errno.h>
+#include <asm/fixed_code.h>
 #include <asm/thread_info.h>  /* TIF_NEED_RESCHED */
 #include <asm/asm-offsets.h>
 #include <asm/trace.h>
@@ -52,15 +53,6 @@
 # define EX_SCRATCH_REG CYCLES
 #endif
 
-#if ANOMALY_05000281
-ENTRY(_safe_speculative_execution)
-       NOP;
-       NOP;
-       NOP;
-       jump _safe_speculative_execution;
-ENDPROC(_safe_speculative_execution)
-#endif
-
 #ifdef CONFIG_EXCPT_IRQ_SYSC_L1
 .section .l1.text
 #else
@@ -230,6 +222,26 @@ ENTRY(_ex_trap_c)
        [p4] = p5;
        csync;
 
+       p4.l = lo(DCPLB_FAULT_ADDR);
+       p4.h = hi(DCPLB_FAULT_ADDR);
+       r7 = [p4];
+       p5.h = _saved_dcplb_fault_addr;
+       p5.l = _saved_dcplb_fault_addr;
+       [p5] = r7;
+
+       r7 = [p4 + (ICPLB_FAULT_ADDR - DCPLB_FAULT_ADDR)];
+       p5.h = _saved_icplb_fault_addr;
+       p5.l = _saved_icplb_fault_addr;
+       [p5] = r7;
+
+       p4.l = __retx;
+       p4.h = __retx;
+       r6 = retx;
+       [p4] = r6;
+       p4.l = lo(SAFE_USER_INSTRUCTION);
+       p4.h = hi(SAFE_USER_INSTRUCTION);
+       retx = p4;
+
        /* Disable all interrupts, but make sure level 5 is enabled so
         * we can switch to that level.  Save the old mask.  */
        cli r6;
@@ -239,23 +251,6 @@ ENTRY(_ex_trap_c)
        r6 = 0x3f;
        sti r6;
 
-       /* Save the excause into a circular buffer, in case the instruction
-        * which caused this excecptions causes others.
-        */
-       P5.l = _in_ptr_excause;
-       P5.h = _in_ptr_excause;
-       R7 = [P5];
-       R7 += 4;
-       R6 = 0xF;
-       R7 = R7 & R6;
-       [P5] = R7;
-       R6.l = _excause_circ_buf;
-       R6.h = _excause_circ_buf;
-       R7 = R7 + R6;
-       p5 = R7;
-       R6 = SEQSTAT;
-       [P5] = R6;
-
        (R7:6,P5:4) = [sp++];
        ASTAT = [sp++];
        SP = EX_SCRATCH_REG;
@@ -312,6 +307,11 @@ ENDPROC(_double_fault)
 ENTRY(_exception_to_level5)
        SAVE_ALL_SYS
 
+       p4.l = __retx;
+       p4.h = __retx;
+       r6 = [p4];
+       [sp + PT_PC] = r6;
+
        /* Restore interrupt mask.  We haven't pushed RETI, so this
         * doesn't enable interrupts until we return from this handler.  */
        p4.l = _excpt_saved_imask;
@@ -333,42 +333,11 @@ ENTRY(_exception_to_level5)
        r0 = [p2];              /* Read current IPEND */
        [sp + PT_IPEND] = r0;   /* Store IPEND */
 
-       /* Pop the excause from the circular buffer and push it on the stack
-        * (in the right place - if you change the location of SEQSTAT, you
-        * must change this offset.
-        */
-.L_excep_to_5_again:
-       P5.l = _out_ptr_excause;
-       P5.h = _out_ptr_excause;
-       R7 = [P5];
-       R7 += 4;
-       R6 = 0xF;
-       R7 = R7 & R6;
-       [P5] = R7;
-       R6.l = _excause_circ_buf;
-       R6.h = _excause_circ_buf;
-       R7 = R7 + R6;
-       P5 = R7;
-       R1 = [P5];
-       [SP + PT_SEQSTAT] = r1;
-
        r0 = sp;        /* stack frame pt_regs pointer argument ==> r0 */
        SP += -12;
        call _trap_c;
        SP += 12;
 
-       /* See if anything else is in the exception buffer
-        * if there is, process it
-        */
-       P5.l = _out_ptr_excause;
-       P5.h = _out_ptr_excause;
-       P4.l = _in_ptr_excause;
-       P4.h = _in_ptr_excause;
-       R6 = [P5];
-       R7 = [P4];
-       CC = R6 == R7;
-       if ! CC JUMP .L_excep_to_5_again
-
        call _ret_from_exception;
        RESTORE_ALL_SYS
        rti;
@@ -732,8 +701,8 @@ ENTRY(_return_from_int)
        [p0] = p1;
        csync;
 #if ANOMALY_05000281
-       r0.l = _safe_speculative_execution;
-       r0.h = _safe_speculative_execution;
+       r0.l = lo(SAFE_USER_INSTRUCTION);
+       r0.h = hi(SAFE_USER_INSTRUCTION);
        reti = r0;
 #endif
        r0 = 0x801f (z);
@@ -746,8 +715,8 @@ ENDPROC(_return_from_int)
 
 ENTRY(_lower_to_irq14)
 #if ANOMALY_05000281
-       r0.l = _safe_speculative_execution;
-       r0.h = _safe_speculative_execution;
+       r0.l = lo(SAFE_USER_INSTRUCTION);
+       r0.h = hi(SAFE_USER_INSTRUCTION);
        reti = r0;
 #endif
        r0 = 0x401f;
@@ -814,20 +783,6 @@ _schedule_and_signal:
        rti;
 ENDPROC(_lower_to_irq14)
 
-/* Make sure when we start, that the circular buffer is initialized properly
- * R0 and P0 are call clobbered, so we can use them here.
- */
-ENTRY(_init_exception_buff)
-       r0 = 0;
-       p0.h = _in_ptr_excause;
-       p0.l = _in_ptr_excause;
-       [p0] = r0;
-       p0.h = _out_ptr_excause;
-       p0.l = _out_ptr_excause;
-       [p0] = r0;
-       rts;
-ENDPROC(_init_exception_buff)
-
 /* We handle this 100% in exception space - to reduce overhead
  * Only potiential problem is if the software buffer gets swapped out of the
  * CPLB table - then double fault. - so we don't let this happen in other places
@@ -1403,17 +1358,7 @@ _exception_stack_top:
 _last_cplb_fault_retx:
        .long 0;
 #endif
-/*
- * Single instructions can have multiple faults, which need to be
- * handled by traps.c, in irq5. We store the exception cause to ensure
- * we don't miss a double fault condition
- */
-ENTRY(_in_ptr_excause)
-       .long 0;
-ENTRY(_out_ptr_excause)
+       /* Used to save the real RETX when temporarily storing a safe
+        * return address.  */
+__retx:
        .long 0;
-ALIGN
-ENTRY(_excause_circ_buf)
-       .rept 4
-       .long 0
-       .endr