[IA64] Wire in the MCA/INIT handler stacks
Wire the MCA/INIT handler stacks into DTR[2] and track them in
IA64_KR(CURRENT_STACK). This gives the MCA/INIT handler stacks the
same TLB status as normal kernel stacks. Reload the old CURRENT_STACK
data on return from OS to SAL.
Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/kernel/mca_asm.S b/arch/ia64/kernel/mca_asm.S
index 499a065..db32fc1 100644
--- a/arch/ia64/kernel/mca_asm.S
+++ b/arch/ia64/kernel/mca_asm.S
@@ -489,24 +489,27 @@
;;
st8 [temp1]=r17,16 // pal_min_state
st8 [temp2]=r6,16 // prev_IA64_KR_CURRENT
+ mov r6=IA64_KR(CURRENT_STACK)
+ ;;
+ st8 [temp1]=r6,16 // prev_IA64_KR_CURRENT_STACK
+ st8 [temp2]=r0,16 // prev_task, starts off as NULL
mov r6=cr.ifa
;;
- st8 [temp1]=r0,16 // prev_task, starts off as NULL
- st8 [temp2]=r12,16 // cr.isr
+ st8 [temp1]=r12,16 // cr.isr
+ st8 [temp2]=r6,16 // cr.ifa
mov r12=cr.itir
;;
- st8 [temp1]=r6,16 // cr.ifa
- st8 [temp2]=r12,16 // cr.itir
+ st8 [temp1]=r12,16 // cr.itir
+ st8 [temp2]=r11,16 // cr.iipa
mov r12=cr.iim
;;
- st8 [temp1]=r11,16 // cr.iipa
- st8 [temp2]=r12,16 // cr.iim
- mov r6=cr.iha
+ st8 [temp1]=r12,16 // cr.iim
(p1) mov r12=IA64_MCA_COLD_BOOT
(p2) mov r12=IA64_INIT_WARM_BOOT
+ mov r6=cr.iha
;;
- st8 [temp1]=r6,16 // cr.iha
- st8 [temp2]=r12 // os_status, default is cold boot
+ st8 [temp2]=r6,16 // cr.iha
+ st8 [temp1]=r12 // os_status, default is cold boot
mov r6=IA64_MCA_SAME_CONTEXT
;;
st8 [temp1]=r6 // context, default is same context
@@ -823,9 +826,12 @@
ld8 r12=[temp1],16 // sal_ra
ld8 r9=[temp2],16 // sal_gp
;;
- ld8 r22=[temp1],24 // pal_min_state, virtual. skip prev_task
+ ld8 r22=[temp1],16 // pal_min_state, virtual
ld8 r21=[temp2],16 // prev_IA64_KR_CURRENT
;;
+ ld8 r16=[temp1],16 // prev_IA64_KR_CURRENT_STACK
+ ld8 r20=[temp2],16 // prev_task
+ ;;
ld8 temp3=[temp1],16 // cr.isr
ld8 temp4=[temp2],16 // cr.ifa
;;
@@ -846,6 +852,45 @@
ld8 r8=[temp1] // os_status
ld8 r10=[temp2] // context
+ /* Wire IA64_TR_CURRENT_STACK to the stack that we are resuming to. To
+ * avoid any dependencies on the algorithm in ia64_switch_to(), just
+ * purge any existing CURRENT_STACK mapping and insert the new one.
+ *
+ * r16 contains prev_IA64_KR_CURRENT_STACK, r21 contains
+ * prev_IA64_KR_CURRENT, these values may have been changed by the C
+ * code. Do not use r8, r9, r10, r22, they contain values ready for
+ * the return to SAL.
+ */
+
+ mov r15=IA64_KR(CURRENT_STACK) // physical granule mapped by IA64_TR_CURRENT_STACK
+ ;;
+ shl r15=r15,IA64_GRANULE_SHIFT
+ ;;
+ dep r15=-1,r15,61,3 // virtual granule
+ mov r18=IA64_GRANULE_SHIFT<<2 // for cr.itir.ps
+ ;;
+ ptr.d r15,r18
+ ;;
+ srlz.d
+
+ extr.u r19=r21,61,3 // r21 = prev_IA64_KR_CURRENT
+ shl r20=r16,IA64_GRANULE_SHIFT // r16 = prev_IA64_KR_CURRENT_STACK
+ movl r21=PAGE_KERNEL // page properties
+ ;;
+ mov IA64_KR(CURRENT_STACK)=r16
+ cmp.ne p6,p0=RGN_KERNEL,r19 // new stack is in the kernel region?
+ or r21=r20,r21 // construct PA | page properties
+(p6) br.spnt 1f // the dreaded cpu 0 idle task in region 5:(
+ ;;
+ mov cr.itir=r18
+ mov cr.ifa=r21
+ mov r20=IA64_TR_CURRENT_STACK
+ ;;
+ itr.d dtr[r20]=r21
+ ;;
+ srlz.d
+1:
+
br.sptk b0
//EndStub//////////////////////////////////////////////////////////////////////
@@ -982,6 +1027,7 @@
add temp4=temp4, temp1 // &struct ia64_sal_os_state.os_gp
add r12=temp1, temp3 // kernel stack pointer on MCA/INIT stack
add r13=temp1, r3 // set current to start of MCA/INIT stack
+ add r20=temp1, r3 // physical start of MCA/INIT stack
;;
ld8 r1=[temp4] // OS GP from SAL OS state
;;
@@ -991,7 +1037,35 @@
;;
mov IA64_KR(CURRENT)=r13
- // FIXME: do I need to wire IA64_KR_CURRENT_STACK and IA64_TR_CURRENT_STACK?
+ /* Wire IA64_TR_CURRENT_STACK to the MCA/INIT handler stack. To avoid
+ * any dependencies on the algorithm in ia64_switch_to(), just purge
+ * any existing CURRENT_STACK mapping and insert the new one.
+ */
+
+ mov r16=IA64_KR(CURRENT_STACK) // physical granule mapped by IA64_TR_CURRENT_STACK
+ ;;
+ shl r16=r16,IA64_GRANULE_SHIFT
+ ;;
+ dep r16=-1,r16,61,3 // virtual granule
+ mov r18=IA64_GRANULE_SHIFT<<2 // for cr.itir.ps
+ ;;
+ ptr.d r16,r18
+ ;;
+ srlz.d
+
+ shr.u r16=r20,IA64_GRANULE_SHIFT // r20 = physical start of MCA/INIT stack
+ movl r21=PAGE_KERNEL // page properties
+ ;;
+ mov IA64_KR(CURRENT_STACK)=r16
+ or r21=r20,r21 // construct PA | page properties
+ ;;
+ mov cr.itir=r18
+ mov cr.ifa=r13
+ mov r20=IA64_TR_CURRENT_STACK
+ ;;
+ itr.d dtr[r20]=r21
+ ;;
+ srlz.d
br.sptk b0
diff --git a/include/asm-ia64/mca.h b/include/asm-ia64/mca.h
index 97a28b8..c7d9c9e 100644
--- a/include/asm-ia64/mca.h
+++ b/include/asm-ia64/mca.h
@@ -80,7 +80,12 @@
u64 sal_ra; /* Return address in SAL, physical */
u64 sal_gp; /* GP of the SAL - physical */
pal_min_state_area_t *pal_min_state; /* from R17. physical in asm, virtual in C */
+ /* Previous values of IA64_KR(CURRENT) and IA64_KR(CURRENT_STACK).
+ * Note: if the MCA/INIT recovery code wants to resume to a new context
+ * then it must change these values to reflect the new kernel stack.
+ */
u64 prev_IA64_KR_CURRENT; /* previous value of IA64_KR(CURRENT) */
+ u64 prev_IA64_KR_CURRENT_STACK;
struct task_struct *prev_task; /* previous task, NULL if it is not useful */
/* Some interrupt registers are not saved in minstate, pt_regs or
* switch_stack. Because MCA/INIT can occur when interrupts are