Merge remote-tracking branch 'samsung/for-next'

[karo-tx-linux.git] / arch / arc / kernel / entry-compact.S

diff --git a/arch/arc/kernel/entry-compact.S b/arch/arc/kernel/entry-compact.S
index 15d457b4403ae4a9ab55f455fd7e2ad1492e780c..431433929189c8b63e8b3efe41ef03030fa8b86f 100644 (file)
--- a/arch/arc/kernel/entry-compact.S
+++ b/arch/arc/kernel/entry-compact.S
@@ -86,7 +86,7 @@
  */
 
 ; ********* Critical System Events **********************
-VECTOR   res_service             ; 0x0, Restart Vector  (0x0)
+VECTOR   res_service             ; 0x0, Reset Vector   (0x0)
 VECTOR   mem_service             ; 0x8, Mem exception   (0x1)
 VECTOR   instr_service           ; 0x10, Instrn Error   (0x2)
 
@@ -142,26 +142,18 @@ int1_saved_reg:
        .zero 4
 
 /* Each Interrupt level needs its own scratch */
-#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
-
 ARCFP_DATA int2_saved_reg
        .type   int2_saved_reg, @object
        .size   int2_saved_reg, 4
 int2_saved_reg:
        .zero 4
 
-#endif
-
 ; ---------------------------------------------
        .section .text, "ax",@progbits
 
-res_service:           ; processor restart
-       flag    0x1     ; not implemented
-       nop
-       nop
 
-reserved:              ; processor restart
-       rtie            ; jump to processor initializations
+reserved:
+       flag 1          ; Unexpected event, halt
 
 ;##################### Interrupt Handling ##############################
 
@@ -175,12 +167,25 @@ ENTRY(handle_interrupt_level2)
 
        ;------------------------------------------------------
        ; if L2 IRQ interrupted a L1 ISR, disable preemption
+       ;
+       ; This is to avoid a potential L1-L2-L1 scenario
+       ;  -L1 IRQ taken
+       ;  -L2 interrupts L1 (before L1 ISR could run)
+       ;  -preemption off IRQ, user task in syscall picked to run
+       ;  -RTIE to userspace
+       ;       Returns from L2 context fine
+       ;       But both L1 and L2 re-enabled, so another L1 can be taken
+       ;       while prev L1 is still unserviced
+       ;
        ;------------------------------------------------------
 
+       ; L2 interrupting L1 implies both L2 and L1 active
+       ; However both A2 and A1 are NOT set in STATUS32, thus
+       ; need to check STATUS32_L2 to determine if L1 was active
+
        ld r9, [sp, PT_status32]        ; get statu32_l2 (saved in pt_regs)
        bbit0 r9, STATUS_A1_BIT, 1f     ; L1 not active when L2 IRQ, so normal
 
-       ; A1 is set in status32_l2
        ; bump thread_info->preempt_count (Disable preemption)
        GET_CURR_THR_INFO_FROM_SP   r10
        ld      r9, [r10, THREAD_INFO_PREEMPT_COUNT]
@@ -206,6 +211,31 @@ END(handle_interrupt_level2)
 
 #endif
 
+; ---------------------------------------------
+; User Mode Memory Bus Error Interrupt Handler
+; (Kernel mode memory errors handled via seperate exception vectors)
+; ---------------------------------------------
+ENTRY(mem_service)
+
+       INTERRUPT_PROLOGUE 2
+
+       mov r0, ilink2
+       mov r1, sp
+
+       ; User process needs to be killed with SIGBUS, but first need to get
+       ; out of the L2 interrupt context (drop to pure kernel mode) and jump
+       ; off to "C" code where SIGBUS in enqueued
+       lr  r3, [status32]
+       bclr r3, r3, STATUS_A2_BIT
+       or  r3, r3, (STATUS_E1_MASK|STATUS_E2_MASK)
+       sr  r3, [status32_l2]
+       mov ilink2, 1f
+       rtie
+1:
+       bl  do_memory_error
+       b   ret_from_exception
+END(mem_service)
+
 ; ---------------------------------------------
 ;  Level 1 ISR
 ; ---------------------------------------------
@@ -320,11 +350,10 @@ END(call_do_page_fault)
        ; Note that we use realtime STATUS32 (not pt_regs->status32) to
        ; decide that.
 
-       ; if Returning from Exception
-       btst   r10, STATUS_AE_BIT
-       bnz    .Lexcep_ret
+       and.f   0, r10, (STATUS_A1_MASK|STATUS_A2_MASK)
+       bz      .Lexcep_or_pure_K_ret
 
-       ; Not Exception so maybe Interrupts (Level 1 or 2)
+       ; Returning from Interrupts (Level 1 or 2)
 
 #ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
 
@@ -365,8 +394,7 @@ END(call_do_page_fault)
        st      r9, [r10, THREAD_INFO_PREEMPT_COUNT]
 
 149:
-       ;return from level 2
-       INTERRUPT_EPILOGUE 2
+       INTERRUPT_EPILOGUE 2    ; return from level 2 interrupt
 debug_marker_l2:
        rtie
 
@@ -374,15 +402,11 @@ not_level2_interrupt:
 
 #endif
 
-       bbit0  r10, STATUS_A1_BIT, .Lpure_k_mode_ret
-
-       ;return from level 1
-       INTERRUPT_EPILOGUE 1
+       INTERRUPT_EPILOGUE 1    ; return from level 1 interrupt
 debug_marker_l1:
        rtie
 
-.Lexcep_ret:
-.Lpure_k_mode_ret:
+.Lexcep_or_pure_K_ret:
 
        ;this case is for syscalls or Exceptions or pure kernel mode