Merge branch 'ras-core-for-linus' of git://git.kernel.org/pub/scm/lin…

…ux/kernel/git/tip/tip

Pull RAS updates from Thomas Gleixner:
 "The RAS updates for the 4.13 merge window:

   - Cleanup of the MCE injection facility (Borsilav Petkov)

   - Rework of the AMD/SMCA handling (Yazen Ghannam)

   - Enhancements for ACPI/APEI to handle new notitication types (Shiju
     Jose)

   - atomic_t to refcount_t conversion (Elena Reshetova)

   - A few fixes and enhancements all over the place"

* 'ras-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  RAS/CEC: Check the correct variable in the debugfs error handling
  x86/mce: Always save severity in machine_check_poll()
  x86/MCE, xen/mcelog: Make /dev/mcelog registration messages more precise
  x86/mce: Update bootlog description to reflect behavior on AMD
  x86/mce: Don't disable MCA banks when offlining a CPU on AMD
  x86/mce/mce-inject: Preset the MCE injection struct
  x86/mce: Clean up include files
  x86/mce: Get rid of register_mce_write_callback()
  x86/mce: Merge mce_amd_inj into mce-inject
  x86/mce/AMD: Use saved threshold block info in interrupt handler
  x86/mce/AMD: Use msr_stat when clearing MCA_STATUS
  x86/mce/AMD: Carve out SMCA bank configuration
  x86/mce/AMD: Redo error logging from APIC LVT interrupt handlers
  x86/mce: Convert threshold_bank.cpus from atomic_t to refcount_t
  RAS: Make local function parse_ras_param() static
  ACPI/APEI: Handle GSIV and GPIO notification types

Documentation/x86/x86_64/boot-options.txt

@@ -36,7 +36,8 @@ Machine check
 		to broadcast MCEs.
    mce=bootlog
 		Enable logging of machine checks left over from booting.
-		Disabled by default on AMD because some BIOS leave bogus ones.
+		Disabled by default on AMD Fam10h and older because some BIOS
+		leave bogus ones.
 		If your BIOS doesn't do that it's a good idea to enable though
 		to make sure you log even machine check events that result
 		in a reboot. On Intel systems it is enabled by default.

arch/x86/Kconfig

@@ -1085,7 +1085,7 @@ config X86_MCE_THRESHOLD
 	def_bool y
 
 config X86_MCE_INJECT
-	depends on X86_MCE && X86_LOCAL_APIC && X86_MCELOG_LEGACY
+	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
 	tristate "Machine check injector support"
 	---help---
 	  Provide support for injecting machine checks for testing purposes.

arch/x86/Makefile

@@ -257,8 +257,6 @@ drivers-$(CONFIG_PM) += arch/x86/power/
 
 drivers-$(CONFIG_FB) += arch/x86/video/
 
-drivers-$(CONFIG_RAS) += arch/x86/ras/
-
 ####
 # boot loader support. Several targets are kept for legacy purposes
 

arch/x86/include/asm/amd_nb.h

@@ -3,6 +3,7 @@
 
 #include <linux/ioport.h>
 #include <linux/pci.h>
+#include <linux/refcount.h>
 
 struct amd_nb_bus_dev_range {
 	u8 bus;
@@ -55,7 +56,7 @@ struct threshold_bank {
 	struct threshold_block	*blocks;
 
 	/* initialized to the number of CPUs on the node sharing this bank */
-	atomic_t		cpus;
+	refcount_t		cpus;
 };
 
 struct amd_northbridge {

arch/x86/include/asm/mce.h

@@ -285,10 +285,6 @@ int mce_notify_irq(void);
 
 DECLARE_PER_CPU(struct mce, injectm);
 
-extern void register_mce_write_callback(ssize_t (*)(struct file *filp,
-				    const char __user *ubuf,
-				    size_t usize, loff_t *off));
-
 /* Disable CMCI/polling for MCA bank claimed by firmware */
 extern void mce_disable_bank(int bank);
 

arch/x86/include/asm/processor.h

@@ -907,8 +907,13 @@ static inline int mpx_disable_management(void)
 }
 #endif /* CONFIG_X86_INTEL_MPX */
 
+#ifdef CONFIG_CPU_SUP_AMD
 extern u16 amd_get_nb_id(int cpu);
 extern u32 amd_get_nodes_per_socket(void);
+#else
+static inline u16 amd_get_nb_id(int cpu)		{ return 0; }
+static inline u32 amd_get_nodes_per_socket(void)	{ return 0; }
+#endif
 
 static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves)
 {

arch/x86/kernel/cpu/mcheck/dev-mcelog.c

@@ -17,6 +17,8 @@
 
 #include "mce-internal.h"
 
+static BLOCKING_NOTIFIER_HEAD(mce_injector_chain);
+
 static DEFINE_MUTEX(mce_chrdev_read_mutex);
 
 static char mce_helper[128];
@@ -345,24 +347,49 @@ static long mce_chrdev_ioctl(struct file *f, unsigned int cmd,
 	}
 }
 
-static ssize_t (*mce_write)(struct file *filp, const char __user *ubuf,
-			    size_t usize, loff_t *off);
+void mce_register_injector_chain(struct notifier_block *nb)
+{
+	blocking_notifier_chain_register(&mce_injector_chain, nb);
+}
+EXPORT_SYMBOL_GPL(mce_register_injector_chain);
 
-void register_mce_write_callback(ssize_t (*fn)(struct file *filp,
-			     const char __user *ubuf,
-			     size_t usize, loff_t *off))
+void mce_unregister_injector_chain(struct notifier_block *nb)
 {
-	mce_write = fn;
+	blocking_notifier_chain_unregister(&mce_injector_chain, nb);
 }
-EXPORT_SYMBOL_GPL(register_mce_write_callback);
+EXPORT_SYMBOL_GPL(mce_unregister_injector_chain);
 
 static ssize_t mce_chrdev_write(struct file *filp, const char __user *ubuf,
 				size_t usize, loff_t *off)
 {
-	if (mce_write)
-		return mce_write(filp, ubuf, usize, off);
-	else
+	struct mce m;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+	/*
+	 * There are some cases where real MSR reads could slip
+	 * through.
+	 */
+	if (!boot_cpu_has(X86_FEATURE_MCE) || !boot_cpu_has(X86_FEATURE_MCA))
+		return -EIO;
+
+	if ((unsigned long)usize > sizeof(struct mce))
+		usize = sizeof(struct mce);
+	if (copy_from_user(&m, ubuf, usize))
+		return -EFAULT;
+
+	if (m.extcpu >= num_possible_cpus() || !cpu_online(m.extcpu))
 		return -EINVAL;
+
+	/*
+	 * Need to give user space some time to set everything up,
+	 * so do it a jiffie or two later everywhere.
+	 */
+	schedule_timeout(2);
+
+	blocking_notifier_call_chain(&mce_injector_chain, 0, &m);
+
+	return usize;
 }
 
 static const struct file_operations mce_chrdev_ops = {
@@ -388,9 +415,15 @@ static __init int dev_mcelog_init_device(void)
 	/* register character device /dev/mcelog */
 	err = misc_register(&mce_chrdev_device);
 	if (err) {
-		pr_err("Unable to init device /dev/mcelog (rc: %d)\n", err);
+		if (err == -EBUSY)
+			/* Xen dom0 might have registered the device already. */
+			pr_info("Unable to init device /dev/mcelog, already registered");
+		else
+			pr_err("Unable to init device /dev/mcelog (rc: %d)\n", err);
+
 		return err;
 	}
+
 	mce_register_decode_chain(&dev_mcelog_nb);
 	return 0;
 }