Merge remote-tracking branch 'ia64/next'

Conflicts:
	init/Kconfig

6 files changed, 60 insertions, 9 deletions

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 3279646120e3..5fb10644d9ed 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -40,6 +40,7 @@ config IA64
 	select ARCH_THREAD_INFO_ALLOCATOR
 	select ARCH_CLOCKSOURCE_DATA
 	select GENERIC_TIME_VSYSCALL_OLD
+	select SYSCTL_ARCH_UNALIGN_NO_WARN
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_RELA
 	default y
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index f5596db0cf58..245231126c97 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -1210,7 +1210,16 @@ static int efi_pstore_write(enum pstore_type_id type,
 	u64 storage_space, remaining_space, max_variable_size;
 	efi_status_t status = EFI_NOT_FOUND;
 
-	spin_lock(&efivars->lock);
+	if (pstore_cannot_block_path(reason)) {
+		/*
+		 * If the lock is taken by another cpu in non-blocking path,
+		 * this driver returns without entering firmware to avoid
+		 * hanging up.
+		 */
+		if (!spin_trylock(&efivars->lock))
+			return -EBUSY;
+	} else
+		spin_lock(&efivars->lock);
 
 	/*
 	 * Check if there is a space enough to log.
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 5ea2e77ff023..86d1038b5a12 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -96,6 +96,27 @@ static const char *get_reason_str(enum kmsg_dump_reason reason)
 	}
 }
 
+bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
+{
+	/*
+	 * In case of NMI path, pstore shouldn't be blocked
+	 * regardless of reason.
+	 */
+	if (in_nmi())
+		return true;
+
+	switch (reason) {
+	/* In panic case, other cpus are stopped by smp_send_stop(). */
+	case KMSG_DUMP_PANIC:
+	/* Emergency restart shouldn't be blocked by spin lock. */
+	case KMSG_DUMP_EMERG:
+		return true;
+	default:
+		return false;
+	}
+}
+EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
+
 /*
  * callback from kmsg_dump. (s2,l2) has the most recently
  * written bytes, older bytes are in (s1,l1). Save as much
@@ -114,10 +135,12 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 
 	why = get_reason_str(reason);
 
-	if (in_nmi()) {
-		is_locked = spin_trylock(&psinfo->buf_lock);
-		if (!is_locked)
-			pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
+	if (pstore_cannot_block_path(reason)) {
+		is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
+		if (!is_locked) {
+			pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
+				       , in_nmi() ? "NMI" : why);
+		}
 	} else
 		spin_lock_irqsave(&psinfo->buf_lock, flags);
 	oopscount++;
@@ -143,9 +166,9 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 		total += hsize + len;
 		part++;
 	}
-	if (in_nmi()) {
+	if (pstore_cannot_block_path(reason)) {
 		if (is_locked)
-			spin_unlock(&psinfo->buf_lock);
+			spin_unlock_irqrestore(&psinfo->buf_lock, flags);
 	} else
 		spin_unlock_irqrestore(&psinfo->buf_lock, flags);
 }
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index 1788909d9a99..75d01760c911 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -68,12 +68,18 @@ struct pstore_info {
 
 #ifdef CONFIG_PSTORE
 extern int pstore_register(struct pstore_info *);
+extern bool pstore_cannot_block_path(enum kmsg_dump_reason reason);
 #else
 static inline int
 pstore_register(struct pstore_info *psi)
 {
 	return -ENODEV;
 }
+static inline bool
+pstore_cannot_block_path(enum kmsg_dump_reason reason)
+{
+	return false;
+}
 #endif
 
 #endif /*_LINUX_PSTORE_H*/
diff --git a/init/Kconfig b/init/Kconfig
index 01180da49add..cab5a6c0506d 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1240,6 +1240,13 @@ config SYSCTL_ARCH_UNALIGN_ALLOW
 	  the unaligned access emulation.
 	  see arch/parisc/kernel/unaligned.c for reference
 
+config SYSCTL_ARCH_UNALIGN_NO_WARN
+	bool
+	help
+	  Enable support for /proc/sys/kernel/ignore-unaligned-usertrap
+	  Allows arch to define/use @no_unaligned_warning to possibly warn
+	  about unaligned access emulation going on under the hood.
+
 config KALLSYMS
 	 bool "Load all symbols for debugging/ksymoops" if EXPERT
 	 default y
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 878b4c41cfb7..9f7a6c51376f 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -164,10 +164,13 @@ extern int unaligned_enabled;
 #endif
 
 #ifdef CONFIG_IA64
-extern int no_unaligned_warning;
 extern int unaligned_dump_stack;
 #endif
 
+#ifdef CONFIG_SYSCTL_ARCH_UNALIGN_NO_WARN
+extern int no_unaligned_warning;
+#endif
+
 #ifdef CONFIG_PROC_SYSCTL
 static int proc_do_cad_pid(struct ctl_table *table, int write,
 		  void __user *buffer, size_t *lenp, loff_t *ppos);
@@ -916,7 +919,7 @@ static struct ctl_table kern_table[] = {
 		.proc_handler	= proc_doulongvec_minmax,
 	},
 #endif
-#ifdef CONFIG_IA64
+#ifdef CONFIG_SYSCTL_ARCH_UNALIGN_NO_WARN
 	{
 		.procname	= "ignore-unaligned-usertrap",
 		.data		= &no_unaligned_warning,
@@ -924,6 +927,8 @@ static struct ctl_table kern_table[] = {
 	 	.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
+#endif
+#ifdef CONFIG_IA64
 	{
 		.procname	= "unaligned-dump-stack",
 		.data		= &unaligned_dump_stack,