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@xxxxxxx>,
Cc: Yutaka Ezaki <yutaka.ezaki@xxxxxxxxxxxxxx>,
Cc: Masaki Kanno <kanno.masaki@xxxxxxxxxxxxxx>,
Cc: Kazuhiro Suzuki <kaz@xxxxxxxxxxxxxx>,
Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>
---
Date: Thu, 13 Sep 2007 15:31:43 +0900
From: Horms <horms@xxxxxxxxxxxx>
Fixes as suggested by SUZUKI Kazuhiro:
- Fix up comment relating to the use of SET_PER_CPU_DATA -
it was describing a previous version of the fix.
- 2.6.18 does perge the DTR for PERCPU data, so there is
no need to guard it with #ifdef XEN, although later
kernels do remove this code
- Dereference what is at offset IA64_DOMAIN_FLAGS_OFFSET
Index: xen-unstable.hg/xen/arch/ia64/linux-xen/mca_asm.S
===================================================================
--- xen-unstable.hg.orig/xen/arch/ia64/linux-xen/mca_asm.S 2007-07-11
12:05:33.000000000 +0900
+++ xen-unstable.hg/xen/arch/ia64/linux-xen/mca_asm.S 2007-07-11
13:13:56.000000000 +0900
@@ -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 +269,16 @@ 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 +292,8 @@ 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];;
@@ -289,18 +304,18 @@ 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
;;
--
--
Horms
H: http://www.vergenet.net/~horms/
W: http://www.valinux.co.jp/en/
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