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authorIsaku Yamahata <yamahata@valinux.co.jp>2009-03-04 15:05:39 +0300
committerTony Luck <tony.luck@intel.com>2009-03-26 20:50:32 +0300
commit496203b15b7249599712525c2b6aafe231b4628d (patch)
treeee8c5dbe02b820ac208fe6f3b7982a49a502cc28 /arch/ia64/xen
parent94752a794ddfdef65289a16627faefa7e2e62d58 (diff)
downloadlinux-496203b15b7249599712525c2b6aafe231b4628d.tar.xz
ia64/pv_ops/xen: paravirtualize read/write ar.itc and ar.itm
paravirtualize ar.itc and ar.itm in order to support save/restore. Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64/xen')
-rw-r--r--arch/ia64/xen/xen_pv_ops.c80
1 files changed, 79 insertions, 1 deletions
diff --git a/arch/ia64/xen/xen_pv_ops.c b/arch/ia64/xen/xen_pv_ops.c
index fe72308321b6..d91336114344 100644
--- a/arch/ia64/xen/xen_pv_ops.c
+++ b/arch/ia64/xen/xen_pv_ops.c
@@ -183,6 +183,75 @@ struct pv_fsys_data xen_fsys_data __initdata = {
* intrinsics hooks.
*/
+static void
+xen_set_itm_with_offset(unsigned long val)
+{
+ /* ia64_cpu_local_tick() calls this with interrupt enabled. */
+ /* WARN_ON(!irqs_disabled()); */
+ xen_set_itm(val - XEN_MAPPEDREGS->itc_offset);
+}
+
+static unsigned long
+xen_get_itm_with_offset(void)
+{
+ /* unused at this moment */
+ printk(KERN_DEBUG "%s is called.\n", __func__);
+
+ WARN_ON(!irqs_disabled());
+ return ia64_native_getreg(_IA64_REG_CR_ITM) +
+ XEN_MAPPEDREGS->itc_offset;
+}
+
+/* ia64_set_itc() is only called by
+ * cpu_init() with ia64_set_itc(0) and ia64_sync_itc().
+ * So XEN_MAPPEDRESG->itc_offset cal be considered as almost constant.
+ */
+static void
+xen_set_itc(unsigned long val)
+{
+ unsigned long mitc;
+
+ WARN_ON(!irqs_disabled());
+ mitc = ia64_native_getreg(_IA64_REG_AR_ITC);
+ XEN_MAPPEDREGS->itc_offset = val - mitc;
+ XEN_MAPPEDREGS->itc_last = val;
+}
+
+static unsigned long
+xen_get_itc(void)
+{
+ unsigned long res;
+ unsigned long itc_offset;
+ unsigned long itc_last;
+ unsigned long ret_itc_last;
+
+ itc_offset = XEN_MAPPEDREGS->itc_offset;
+ do {
+ itc_last = XEN_MAPPEDREGS->itc_last;
+ res = ia64_native_getreg(_IA64_REG_AR_ITC);
+ res += itc_offset;
+ if (itc_last >= res)
+ res = itc_last + 1;
+ ret_itc_last = cmpxchg(&XEN_MAPPEDREGS->itc_last,
+ itc_last, res);
+ } while (unlikely(ret_itc_last != itc_last));
+ return res;
+
+#if 0
+ /* ia64_itc_udelay() calls ia64_get_itc() with interrupt enabled.
+ Should it be paravirtualized instead? */
+ WARN_ON(!irqs_disabled());
+ itc_offset = XEN_MAPPEDREGS->itc_offset;
+ itc_last = XEN_MAPPEDREGS->itc_last;
+ res = ia64_native_getreg(_IA64_REG_AR_ITC);
+ res += itc_offset;
+ if (itc_last >= res)
+ res = itc_last + 1;
+ XEN_MAPPEDREGS->itc_last = res;
+ return res;
+#endif
+}
+
static void xen_setreg(int regnum, unsigned long val)
{
switch (regnum) {
@@ -194,11 +263,14 @@ static void xen_setreg(int regnum, unsigned long val)
xen_set_eflag(val);
break;
#endif
+ case _IA64_REG_AR_ITC:
+ xen_set_itc(val);
+ break;
case _IA64_REG_CR_TPR:
xen_set_tpr(val);
break;
case _IA64_REG_CR_ITM:
- xen_set_itm(val);
+ xen_set_itm_with_offset(val);
break;
case _IA64_REG_CR_EOI:
xen_eoi(val);
@@ -222,6 +294,12 @@ static unsigned long xen_getreg(int regnum)
res = xen_get_eflag();
break;
#endif
+ case _IA64_REG_AR_ITC:
+ res = xen_get_itc();
+ break;
+ case _IA64_REG_CR_ITM:
+ res = xen_get_itm_with_offset();
+ break;
case _IA64_REG_CR_IVR:
res = xen_get_ivr();
break;