[PATCH] ia64: change ia64_switch_mode_{phys,virt}() to preserve bsp/sp

Change ia64_switch_mode_phys() and ia64_switch_mode_virt() to preserve
the virtual sp/bsp and update the call-sites accordingly.  This avoids
problems with the init_task pointer which lives in region 5 now.
Signed-off-by: David Mosberger <davidm@hpl.hp.com>

arch/ia64/kernel/efi_stub.S

@@ -44,7 +44,7 @@
 
 GLOBAL_ENTRY(efi_call_phys)
 	.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8)
-	alloc loc1=ar.pfs,8,5,7,0
+	alloc loc1=ar.pfs,8,7,7,0
 	ld8 r2=[in0],8			// load EFI function's entry point
 	mov loc0=rp
 	.body
@@ -70,9 +70,13 @@ GLOBAL_ENTRY(efi_call_phys)
 	mov out3=in4
 	mov out5=in6
 	mov out6=in7
+	mov loc5=r19
+	mov loc6=r20
 	br.call.sptk.many rp=b6		// call the EFI function
 .ret1:	mov ar.rsc=0			// put RSE in enforced lazy, LE mode
 	mov r16=loc3
+	mov r19=loc5
+	mov r20=loc6
 	br.call.sptk.many rp=ia64_switch_mode_virt // return to virtual mode
 .ret2:	mov ar.rsc=loc4			// restore RSE configuration
 	mov ar.pfs=loc1

arch/ia64/kernel/head.S

@@ -706,6 +706,9 @@ END(__ia64_init_fpu)
  *
  * Inputs:
  *	r16 = new psr to establish
+ * Output:
+ *	r19 = old virtual address of ar.bsp
+ *	r20 = old virtual address of sp
  *
  * Note: RSE must already be in enforced lazy mode
  */
@@ -724,12 +727,13 @@ GLOBAL_ENTRY(ia64_switch_mode_phys)
 	mov cr.ipsr=r16			// set new PSR
 	add r3=1f-ia64_switch_mode_phys,r15
 
-	mov r17=ar.bsp
+	mov r19=ar.bsp
+	mov r20=sp
 	mov r14=rp			// get return address into a general register
 	;;
 
 	// going to physical mode, use tpa to translate virt->phys
-	tpa r17=r17
+	tpa r17=r19
 	tpa r3=r3
 	tpa sp=sp
 	tpa r14=r14
@@ -752,6 +756,8 @@ END(ia64_switch_mode_phys)
  *
  * Inputs:
  *	r16 = new psr to establish
+ *	r19 = new bspstore to establish
+ *	r20 = new sp to establish
  *
  * Note: RSE must already be in enforced lazy mode
  */
@@ -770,7 +776,6 @@ GLOBAL_ENTRY(ia64_switch_mode_virt)
 	mov cr.ipsr=r16			// set new PSR
 	add r3=1f-ia64_switch_mode_virt,r15
 
-	mov r17=ar.bsp
 	mov r14=rp			// get return address into a general register
 	;;
 
@@ -781,15 +786,14 @@ GLOBAL_ENTRY(ia64_switch_mode_virt)
 	movl r18=KERNEL_START
 	dep r3=0,r3,KERNEL_TR_PAGE_SHIFT,64-KERNEL_TR_PAGE_SHIFT
 	dep r14=0,r14,KERNEL_TR_PAGE_SHIFT,64-KERNEL_TR_PAGE_SHIFT
-	dep r17=-1,r17,61,3
-	dep sp=-1,sp,61,3
+	mov sp=r20
 	;;
 	or r3=r3,r18
 	or r14=r14,r18
 	;;
 
 	mov r18=ar.rnat			// save ar.rnat
-	mov ar.bspstore=r17		// this steps on ar.rnat
+	mov ar.bspstore=r19		// this steps on ar.rnat
 	mov cr.iip=r3
 	mov cr.ifs=r0
 	;;

arch/ia64/kernel/pal.S

@@ -176,10 +176,14 @@ GLOBAL_ENTRY(ia64_pal_call_phys_static)
 	andcm r16=loc3,r16		// removes bits to clear from psr
 	br.call.sptk.many rp=ia64_switch_mode_phys
 .ret1:	mov rp = r8			// install return address (physical)
+	mov loc5 = r19
+	mov loc6 = r20
 	br.cond.sptk.many b7
 1:
 	mov ar.rsc=0			// put RSE in enforced lazy, LE mode
 	mov r16=loc3			// r16= original psr
+	mov r19=loc5
+	mov r20=loc6
 	br.call.sptk.many rp=ia64_switch_mode_virt // return to virtual mode
 .ret2:
 	mov psr.l = loc3		// restore init PSR
@@ -201,7 +205,7 @@ END(ia64_pal_call_phys_static)
  */
 GLOBAL_ENTRY(ia64_pal_call_phys_stacked)
 	.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(5)
-	alloc	loc1 = ar.pfs,5,5,86,0
+	alloc	loc1 = ar.pfs,5,7,4,0
 	movl	loc2 = pal_entry_point
 1:	{
 	  mov r28  = in0		// copy procedure index
@@ -230,10 +234,14 @@ GLOBAL_ENTRY(ia64_pal_call_phys_stacked)
 	andcm r16=loc3,r16		// removes bits to clear from psr
 	br.call.sptk.many rp=ia64_switch_mode_phys
 .ret6:
+	mov loc5 = r19
+	mov loc6 = r20
 	br.call.sptk.many rp=b7		// now make the call
 .ret7:
 	mov ar.rsc=0			// put RSE in enforced lazy, LE mode
 	mov r16=loc3			// r16= original psr
+	mov r19=loc5
+	mov r20=loc6
 	br.call.sptk.many rp=ia64_switch_mode_virt	// return to virtual mode
 
 .ret8:	mov psr.l  = loc3		// restore init PSR