From: Alex Williamson <alex.williamson@hp.com>
Date: Thu, 27 Sep 2007 22:24:02 +0000 (-0600)
Subject: [IA64] Kexec: Fix ia64_do_tlb_purge so that it works with XEN
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~14944
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/success//%22http:/www.example.com/cgi/success/?a=commitdiff_plain;h=fa297137042a2079bff62323522db0b826300c3c;p=xen.git

[IA64] Kexec: Fix ia64_do_tlb_purge so that it works with XEN

Fix ia64_do_tlb_purge, its broken in too many ways

1. Call SET_PER_CPU_DATA before making any calls to GET_THIS_PADDR
   to ensure that per-cpu data is set up correctly.

2. Use the per_cpu variable to derive CURRENT_STACK_OFFSET rather
   than reading it from a kernel register. See 1) for explanation
   of why.

3. In the VHPT pruning code, don't use r25 as ia64_jump_to_sal,
   which branches to ia64_do_tlb_purge expects r25 to be preserved.
   There seems no reason not to use r2 as per the other purges
   done in ia64_do_tlb_purge.  Furthermore use r16 and r18 instead
   of r20 and r24 for consistency reasons.

4. Move __va_ul(vcpu_vhpt_maddr(v)) comment outside of
   #if VHPT_ENABLED as it also applies to code further down that
   is outside the #if

Cc: Tristan Gingold <tgingold@free.fr>,
Cc: Yutaka Ezaki <yutaka.ezaki@jp.fujitsu.com>,
Cc: Masaki Kanno <kanno.masaki@jp.fujitsu.com>,
Cc: Kazuhiro Suzuki <kaz@jp.fujitsu.com>,
Signed-off-by: Simon Horman <horms@verge.net.au>
---

diff --git a/xen/arch/ia64/linux-xen/mca_asm.S b/xen/arch/ia64/linux-xen/mca_asm.S
index b5f95345df..f9d0de33a7 100644
--- a/xen/arch/ia64/linux-xen/mca_asm.S
+++ b/xen/arch/ia64/linux-xen/mca_asm.S
@@ -195,6 +195,10 @@
  */
 
 ia64_do_tlb_purge:
+#ifdef XEN
+	// This needs to be called in order for GET_THIS_PADDR to work
+	SET_PER_CPU_DATA();;
+#endif
 #define O(member)	IA64_CPUINFO_##member##_OFFSET
 
 	GET_THIS_PADDR(r2, cpu_info)	// load phys addr of cpu_info into r2
@@ -263,7 +267,16 @@ ia64_do_tlb_purge:
 	srlz.i
 	;;
 	// 4. Purge DTR for stack.
+#ifdef XEN
+	// Kernel registers are saved in a per_cpu cpu_kr_ia64_t
+	// to allow the kernel registers themselves to be used by domains.
+	GET_THIS_PADDR(r2, cpu_kr);;
+	add r2=IA64_KR_CURRENT_STACK_OFFSET,r2
+	;;
+	ld8 r16=[r2]
+#else
 	mov r16=IA64_KR(CURRENT_STACK)
+#endif
 	;;
 	shl r16=r16,IA64_GRANULE_SHIFT
 	movl r19=PAGE_OFFSET
@@ -277,8 +290,8 @@ ia64_do_tlb_purge:
 	;;
 #ifdef XEN
 	// 5. VHPT
+	// r2 = __va_ul(vcpu_vhpt_maddr(v));
 #if VHPT_ENABLED
-	// r25 = __va_ul(vcpu_vhpt_maddr(v));
 	GET_THIS_PADDR(r2,cpu_kr);;
 	add r2=IA64_KR_CURRENT_OFFSET,r2;;
 	ld8 r2=[r2];;
@@ -296,18 +309,18 @@ ia64_do_tlb_purge:
 	add r2=IA64_VCPU_VHPT_MADDR_OFFSET,r2;;
 	dep r2=0,r2,60,4;;			// virtual to physical
 	ld8 r2=[r2];; 
-	dep r25=-1,r2,60,4;;			// physical to virtual
+	dep r2=-1,r2,60,4;;			// physical to virtual
 	br.sptk		.percpu_vhpt_done
 #endif
 .not_pervcpu_vhpt:
 	GET_THIS_PADDR(r2, vhpt_paddr);; 
 	ld8 r2=[r2];; 
-	dep r25=-1,r2,60,4;;			// physical to virtual
+	dep r2=-1,r2,60,4;;			// physical to virtual
 .percpu_vhpt_done:
-	dep r20=0,r25,0,IA64_GRANULE_SHIFT
-	mov r24=IA64_GRANULE_SHIFT<<2
+	dep r16=0,r2,0,IA64_GRANULE_SHIFT
+	mov r18=IA64_GRANULE_SHIFT<<2
 	;;
-	ptr.d r20,r24
+	ptr.d r16,r18
 	;;
 	srlz.d
 	;;