[Precise SRU] Fix oops in arch_trigger_all_cpu_backtrace

[Stefan Bader]

Although there is one of the hooks that looks not completely right,
this is the upstream version (without the unnecessary declaration
in smp.h) which seemed to cause no issues. I was not able to see
any impact either. From previous tests of a kernel with this patch
it was said to resolve the issue.

This was added in 3.5 so it is only required for 3.2.

-Stefan

---

>From 1e78425a8ddace467b9f4ef33a87ad81d476a319 Mon Sep 17 00:00:00 2001
From: Ben Guthro <ben at guthro.net>
Date: Sat, 21 Apr 2012 00:11:04 +0800
Subject: [PATCH] xen: implement apic ipi interface

Map native ipi vector to xen vector.
Implement apic ipi interface with xen_send_IPI_one.

Tested-by: Steven Noonan <steven at uplinklabs.net>
Signed-off-by: Ben Guthro <ben at guthro.net>
Signed-off-by: Lin Ming <mlin at ss.pku.edu.cn>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>

BugLink: http://bugs.launchpad.net/bugs/1168350

(backported from f447d56d36af18c5104ff29dcb1327c0c0ac3634 upstream)
[v2: Drop physflat_send_IPI_allbutself declaration from xen/smp.h]

Signed-off-by: Stefan Bader <stefan.bader at canonical.com>
---
 arch/x86/xen/enlighten.c |    9 ++++++
 arch/x86/xen/smp.c       |   81 +++++++++++++++++++++++++++++++++++++++++++---
 arch/x86/xen/smp.h       |   11 +++++++
 3 files changed, 97 insertions(+), 4 deletions(-)
 create mode 100644 arch/x86/xen/smp.h

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index bb03ff0..b284aa3 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -69,6 +69,7 @@
 
 #include "xen-ops.h"
 #include "mmu.h"
+#include "smp.h"
 #include "multicalls.h"
 
 EXPORT_SYMBOL_GPL(hypercall_page);
@@ -821,6 +822,14 @@ static void set_xen_basic_apic_ops(void)
 	apic->safe_wait_icr_idle = xen_safe_apic_wait_icr_idle;
 	apic->set_apic_id = xen_set_apic_id;
 	apic->get_apic_id = xen_get_apic_id;
+
+#ifdef CONFIG_SMP
+	apic->send_IPI_allbutself = xen_send_IPI_allbutself;
+	apic->send_IPI_mask_allbutself = xen_send_IPI_mask_allbutself;
+	apic->send_IPI_mask = xen_send_IPI_mask;
+	apic->send_IPI_all = xen_send_IPI_all;
+	apic->send_IPI_self = xen_send_IPI_self;
+#endif
 }
 
 #endif
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 9a23fff..36a143f 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -467,8 +467,8 @@ static void xen_smp_send_reschedule(int cpu)
 	xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
 }
 
-static void xen_send_IPI_mask(const struct cpumask *mask,
-			      enum ipi_vector vector)
+static void __xen_send_IPI_mask(const struct cpumask *mask,
+			      int vector)
 {
 	unsigned cpu;
 
@@ -480,7 +480,7 @@ static void xen_smp_send_call_function_ipi(const struct cpumask *mask)
 {
 	int cpu;
 
-	xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);
+	__xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);
 
 	/* Make sure other vcpus get a chance to run if they need to. */
 	for_each_cpu(cpu, mask) {
@@ -493,10 +493,83 @@ static void xen_smp_send_call_function_ipi(const struct cpumask *mask)
 
 static void xen_smp_send_call_function_single_ipi(int cpu)
 {
-	xen_send_IPI_mask(cpumask_of(cpu),
+	__xen_send_IPI_mask(cpumask_of(cpu),
 			  XEN_CALL_FUNCTION_SINGLE_VECTOR);
 }
 
+static inline int xen_map_vector(int vector)
+{
+	int xen_vector;
+
+	switch (vector) {
+	case RESCHEDULE_VECTOR:
+		xen_vector = XEN_RESCHEDULE_VECTOR;
+		break;
+	case CALL_FUNCTION_VECTOR:
+		xen_vector = XEN_CALL_FUNCTION_VECTOR;
+		break;
+	case CALL_FUNCTION_SINGLE_VECTOR:
+		xen_vector = XEN_CALL_FUNCTION_SINGLE_VECTOR;
+		break;
+	default:
+		xen_vector = -1;
+		printk(KERN_ERR "xen: vector 0x%x is not implemented\n",
+			vector);
+	}
+
+	return xen_vector;
+}
+
+void xen_send_IPI_mask(const struct cpumask *mask,
+			      int vector)
+{
+	int xen_vector = xen_map_vector(vector);
+
+	if (xen_vector >= 0)
+		__xen_send_IPI_mask(mask, xen_vector);
+}
+
+void xen_send_IPI_all(int vector)
+{
+	int xen_vector = xen_map_vector(vector);
+
+	if (xen_vector >= 0)
+		__xen_send_IPI_mask(cpu_online_mask, xen_vector);
+}
+
+void xen_send_IPI_self(int vector)
+{
+	int xen_vector = xen_map_vector(vector);
+
+	if (xen_vector >= 0)
+		xen_send_IPI_one(smp_processor_id(), xen_vector);
+}
+
+void xen_send_IPI_mask_allbutself(const struct cpumask *mask,
+				int vector)
+{
+	unsigned cpu;
+	unsigned int this_cpu = smp_processor_id();
+
+	if (!(num_online_cpus() > 1))
+		return;
+
+	for_each_cpu_and(cpu, mask, cpu_online_mask) {
+		if (this_cpu == cpu)
+			continue;
+
+		xen_smp_send_call_function_single_ipi(cpu);
+	}
+}
+
+void xen_send_IPI_allbutself(int vector)
+{
+	int xen_vector = xen_map_vector(vector);
+
+	if (xen_vector >= 0)
+		xen_send_IPI_mask_allbutself(cpu_online_mask, xen_vector);
+}
+
 static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id)
 {
 	irq_enter();
diff --git a/arch/x86/xen/smp.h b/arch/x86/xen/smp.h
new file mode 100644
index 0000000..c7c2d89
--- /dev/null
+++ b/arch/x86/xen/smp.h
@@ -0,0 +1,11 @@
+#ifndef _XEN_SMP_H
+
+extern void xen_send_IPI_mask(const struct cpumask *mask,
+			      int vector);
+extern void xen_send_IPI_mask_allbutself(const struct cpumask *mask,
+				int vector);
+extern void xen_send_IPI_allbutself(int vector);
+extern void xen_send_IPI_all(int vector);
+extern void xen_send_IPI_self(int vector);
+
+#endif
-- 
1.7.9.5