ia64/pv_ops/xen: define xen pv_cpu_ops.

define xen pv_cpu_ops which implementes xen paravirtualized
privileged instructions.

Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/xen/xen_pv_ops.c

@@ -162,6 +162,119 @@ static const struct pv_init_ops xen_init_ops __initdata = {
 	.post_smp_prepare_boot_cpu = xen_post_smp_prepare_boot_cpu,
 };
 
+/***************************************************************************
+ * pv_cpu_ops
+ * intrinsics hooks.
+ */
+
+static void xen_setreg(int regnum, unsigned long val)
+{
+	switch (regnum) {
+	case _IA64_REG_AR_KR0 ... _IA64_REG_AR_KR7:
+		xen_set_kr(regnum - _IA64_REG_AR_KR0, val);
+		break;
+#ifdef CONFIG_IA32_SUPPORT
+	case _IA64_REG_AR_EFLAG:
+		xen_set_eflag(val);
+		break;
+#endif
+	case _IA64_REG_CR_TPR:
+		xen_set_tpr(val);
+		break;
+	case _IA64_REG_CR_ITM:
+		xen_set_itm(val);
+		break;
+	case _IA64_REG_CR_EOI:
+		xen_eoi(val);
+		break;
+	default:
+		ia64_native_setreg_func(regnum, val);
+		break;
+	}
+}
+
+static unsigned long xen_getreg(int regnum)
+{
+	unsigned long res;
+
+	switch (regnum) {
+	case _IA64_REG_PSR:
+		res = xen_get_psr();
+		break;
+#ifdef CONFIG_IA32_SUPPORT
+	case _IA64_REG_AR_EFLAG:
+		res = xen_get_eflag();
+		break;
+#endif
+	case _IA64_REG_CR_IVR:
+		res = xen_get_ivr();
+		break;
+	case _IA64_REG_CR_TPR:
+		res = xen_get_tpr();
+		break;
+	default:
+		res = ia64_native_getreg_func(regnum);
+		break;
+	}
+	return res;
+}
+
+/* turning on interrupts is a bit more complicated.. write to the
+ * memory-mapped virtual psr.i bit first (to avoid race condition),
+ * then if any interrupts were pending, we have to execute a hyperprivop
+ * to ensure the pending interrupt gets delivered; else we're done! */
+static void
+xen_ssm_i(void)
+{
+	int old = xen_get_virtual_psr_i();
+	xen_set_virtual_psr_i(1);
+	barrier();
+	if (!old && xen_get_virtual_pend())
+		xen_hyper_ssm_i();
+}
+
+/* turning off interrupts can be paravirtualized simply by writing
+ * to a memory-mapped virtual psr.i bit (implemented as a 16-bit bool) */
+static void
+xen_rsm_i(void)
+{
+	xen_set_virtual_psr_i(0);
+	barrier();
+}
+
+static unsigned long
+xen_get_psr_i(void)
+{
+	return xen_get_virtual_psr_i() ? IA64_PSR_I : 0;
+}
+
+static void
+xen_intrin_local_irq_restore(unsigned long mask)
+{
+	if (mask & IA64_PSR_I)
+		xen_ssm_i();
+	else
+		xen_rsm_i();
+}
+
+static const struct pv_cpu_ops xen_cpu_ops __initdata = {
+	.fc		= xen_fc,
+	.thash		= xen_thash,
+	.get_cpuid	= xen_get_cpuid,
+	.get_pmd	= xen_get_pmd,
+	.getreg		= xen_getreg,
+	.setreg		= xen_setreg,
+	.ptcga		= xen_ptcga,
+	.get_rr		= xen_get_rr,
+	.set_rr		= xen_set_rr,
+	.set_rr0_to_rr4	= xen_set_rr0_to_rr4,
+	.ssm_i		= xen_ssm_i,
+	.rsm_i		= xen_rsm_i,
+	.get_psr_i	= xen_get_psr_i,
+	.intrin_local_irq_restore
+			= xen_intrin_local_irq_restore,
+};
+
 /***************************************************************************
  * pv_ops initialization
  */
@@ -172,4 +285,5 @@ xen_setup_pv_ops(void)
 	xen_info_init();
 	pv_info = xen_info;
 	pv_init_ops = xen_init_ops;
+	pv_cpu_ops = xen_cpu_ops;
 }