Hexagon: Signal and return path fixes

[platform/adaptation/renesas_rcar/renesas_kernel.git] / arch / hexagon / kernel / vm_entry.S

diff --git a/arch/hexagon/kernel/vm_entry.S b/arch/hexagon/kernel/vm_entry.S
index ffe4a42..053551e 100644 (file)
--- a/arch/hexagon/kernel/vm_entry.S
+++ b/arch/hexagon/kernel/vm_entry.S
@@ -274,6 +274,9 @@ event_dispatch:
        callr   r1
 
        /*
+        * Coming back from the C-world, our thread info pointer
+        * should be in the designated register (usually R19)
+        *
         * If we were in kernel mode, we don't need to check scheduler
         * or signals if CONFIG_PREEMPT is not set.  If set, then it has
         * to jump to a need_resched kind of block.
@@ -286,67 +289,43 @@ event_dispatch:
 #endif
 
        /*  "Nested control path" -- if the previous mode was kernel  */
-       R0 = memw(R29 + #_PT_ER_VMEST);
        {
-               P0 = tstbit(R0, #HVM_VMEST_UM_SFT);
-               if (!P0.new) jump:nt restore_all;
+               R0 = memw(R29 + #_PT_ER_VMEST);
+               R16.L = #LO(do_work_pending);
        }
-       /*
-        * Returning from system call, normally coming back from user mode
-        */
-return_from_syscall:
-       /*  Disable interrupts while checking TIF  */
-       R0 = #VM_INT_DISABLE
-       trap1(#HVM_TRAP1_VMSETIE)
-
-       /*
-        * Coming back from the C-world, our thread info pointer
-        * should be in the designated register (usually R19)
-        */
-#if CONFIG_HEXAGON_ARCH_VERSION < 4
-       R1.L = #LO(_TIF_ALLWORK_MASK)
        {
-               R1.H = #HI(_TIF_ALLWORK_MASK);
-               R0 = memw(THREADINFO_REG + #_THREAD_INFO_FLAGS);
-       }
-#else
-       {
-               R1 = ##_TIF_ALLWORK_MASK;
-               R0 = memw(THREADINFO_REG + #_THREAD_INFO_FLAGS);
+               P0 = tstbit(R0, #HVM_VMEST_UM_SFT);
+               if (!P0.new) jump:nt restore_all;
+               R16.H = #HI(do_work_pending);
+               R0 = #VM_INT_DISABLE;
        }
-#endif
 
        /*
-        * Compare against the "return to userspace" _TIF_WORK_MASK
+        * Check also the return from fork/system call, normally coming back from
+        * user mode
+        *
+        * R16 needs to have do_work_pending, and R0 should have VM_INT_DISABLE
         */
-       R1 = and(R1,R0);
-       { P0 = cmp.eq(R1,#0); if (!P0.new) jump:t work_pending;}
-       jump restore_all;  /*  we're outta here!  */
 
-work_pending:
+check_work_pending:
+       /*  Disable interrupts while checking TIF  */
+       trap1(#HVM_TRAP1_VMSETIE)
        {
-               P0 = tstbit(R1, #TIF_NEED_RESCHED);
-               if (!P0.new) jump:nt work_notifysig;
+               R0 = R29;  /*  regs should still be at top of stack  */
+               R1 = memw(THREADINFO_REG + #_THREAD_INFO_FLAGS);
+               callr R16;
        }
-       call schedule
-       jump return_from_syscall;  /*  check for more work  */
 
-work_notifysig:
-       /*  this is the part that's kind of fuzzy.  */
-       R1 = and(R0, #(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME));
-       {
-               P0 = cmp.eq(R1, #0);
-               if P0.new jump:t restore_all;
-       }
        {
-               R1 = R0;        /* unsigned long thread_info_flags */
-               R0 = R29;       /* regs should still be at top of stack  */
+               P0 = cmp.eq(R0, #0); if (!P0.new) jump:nt check_work_pending;
+               R0 = #VM_INT_DISABLE;
        }
-       call do_notify_resume
 
 restore_all:
-       /* Disable interrupts, if they weren't already, before reg restore.  */
-       R0 = #VM_INT_DISABLE
+       /*
+        * Disable interrupts, if they weren't already, before reg restore.
+        * R0 gets preloaded with #VM_INT_DISABLE before we get here.
+        */
        trap1(#HVM_TRAP1_VMSETIE)
 
        /*  do the setregs here for VM 0.5  */
@@ -371,6 +350,7 @@ restore_all:
        trap1(#HVM_TRAP1_VMRTE)
        /* Notreached */
 
+
        .globl _K_enter_genex
 _K_enter_genex:
        vm_event_entry(do_genex)
@@ -390,9 +370,12 @@ _K_enter_machcheck:
 
        .globl ret_from_fork
 ret_from_fork:
-       call schedule_tail
-       P0 = cmp.eq(R24, #0);
-       if P0 jump return_from_syscall
-       R0 = R25;
-       callr R24
-       jump return_from_syscall
+       {
+               call schedule_tail;
+               R16.H = #HI(do_work_pending);
+       }
+       {
+               R16.L = #LO(do_work_pending);
+               R0 = #VM_INT_DISABLE;
+               jump check_work_pending;
+       }