[Xen-changelog] [xen-unstable] IA64: Rationalize VMM mode alignment checking

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
# Date 1228272234 -32400
# Node ID 54e5d15af567012bb7e88b0ccb3bad9a7f0168a5
# Parent  b3265ff6c61332dbb43660df43e5b0508b684ec7
IA64: Rationalize VMM mode alignment checking

This is the xen port of ia64 linux chageset of
b704882e70d87d7f56db5ff17e2253f3fa90e4f3

    [IA64] Rationalize kernel mode alignment checking

    Itanium processors can handle some misaligned data accesses. They
    also provide a mode where all such accesses are forced to trap. The
    kernel was schizophrenic about use of this mode:

    * Base kernel code ran in permissive mode where the only traps
      generated were from those cases that the h/w could not handle.
    * Interrupt, syscall and trap code ran in strict mode where all
      unaligned accesses caused traps to the 0x5a00 unaligned reference
      vector.

    Use strict alignment checking throughout the kernel, but make
    sure that we continue to let user mode use more relaxed mode
    as the default.

    Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>

Signed-off-by: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
---
 xen/arch/ia64/linux-xen/head.S |    5 +++++
 1 files changed, 5 insertions(+)

diff -r b3265ff6c613 -r 54e5d15af567 xen/arch/ia64/linux-xen/head.S
--- a/xen/arch/ia64/linux-xen/head.S    Wed Nov 26 10:23:49 2008 +0900
+++ b/xen/arch/ia64/linux-xen/head.S    Wed Dec 03 11:43:54 2008 +0900
@@ -267,8 +267,13 @@ start_ap:
        /*
         * Switch into virtual mode:
         */
+#ifdef XEN
+               movl 
r16=(IA64_PSR_IT|IA64_PSR_IC|IA64_PSR_DT|IA64_PSR_RT|IA64_PSR_DFH|IA64_PSR_BN \
+                 |IA64_PSR_DI|IA64_PSR_AC)
+#else
        movl 
r16=(IA64_PSR_IT|IA64_PSR_IC|IA64_PSR_DT|IA64_PSR_RT|IA64_PSR_DFH|IA64_PSR_BN \
                  |IA64_PSR_DI)
+#endif
        ;;
        mov cr.ipsr=r16
        movl r17=1f

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