---

yaml
---
r: 17541
b: refs/heads/master
c: 51be560
h: refs/heads/master
i:
  17539: d6aa8e5
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: cc57165874e938ef684d71ba7d36e7088b551489
+refs/heads/master: 51be5606d9ff9eb27ed6514f6172fbd7578a25d6

trunk/drivers/base/cpu.c

@@ -83,6 +83,33 @@ static inline void register_cpu_control(struct cpu *cpu)
 }
 #endif /* CONFIG_HOTPLUG_CPU */
 
+#ifdef CONFIG_KEXEC
+#include <linux/kexec.h>
+
+static ssize_t show_crash_notes(struct sys_device *dev, char *buf)
+{
+	struct cpu *cpu = container_of(dev, struct cpu, sysdev);
+	ssize_t rc;
+	unsigned long long addr;
+	int cpunum;
+
+	cpunum = cpu->sysdev.id;
+
+	/*
+	 * Might be reading other cpu's data based on which cpu read thread
+	 * has been scheduled. But cpu data (memory) is allocated once during
+	 * boot up and this data does not change there after. Hence this
+	 * operation should be safe. No locking required.
+	 */
+	get_cpu();
+	addr = __pa(per_cpu_ptr(crash_notes, cpunum));
+	rc = sprintf(buf, "%Lx\n", addr);
+	put_cpu();
+	return rc;
+}
+static SYSDEV_ATTR(crash_notes, 0400, show_crash_notes, NULL);
+#endif
+
 /*
  * register_cpu - Setup a driverfs device for a CPU.
  * @cpu - Callers can set the cpu->no_control field to 1, to indicate not to
@@ -108,6 +135,11 @@ int __devinit register_cpu(struct cpu *cpu, int num, struct node *root)
 		register_cpu_control(cpu);
 	if (!error)
 		cpu_sys_devices[num] = &cpu->sysdev;
+
+#ifdef CONFIG_KEXEC
+	if (!error)
+		error = sysdev_create_file(&cpu->sysdev, &attr_crash_notes);
+#endif
 	return error;
 }
 

trunk/kernel/ksysfs.c

@@ -51,26 +51,13 @@ static ssize_t uevent_helper_store(struct subsystem *subsys, const char *page, s
 KERNEL_ATTR_RW(uevent_helper);
 #endif
 
-#ifdef CONFIG_KEXEC
-#include <asm/kexec.h>
-
-static ssize_t crash_notes_show(struct subsystem *subsys, char *page)
-{
-	return sprintf(page, "%p\n", (void *)crash_notes);
-}
-KERNEL_ATTR_RO(crash_notes);
-#endif
-
 decl_subsys(kernel, NULL, NULL);
 EXPORT_SYMBOL_GPL(kernel_subsys);
 
 static struct attribute * kernel_attrs[] = {
 #ifdef CONFIG_HOTPLUG
 	&uevent_seqnum_attr.attr,
 	&uevent_helper_attr.attr,
-#endif
-#ifdef CONFIG_KEXEC
-	&crash_notes_attr.attr,
 #endif
 	NULL
 };