x86/mce: Provide a lockless memory pool to save error records

printk() is not safe to use in MCE context. Add a lockless
memory allocator pool to save error records in MCE context.
Those records will be issued later, in a printk-safe context.
The idea is inspired by the APEI/GHES driver.

We're very conservative and allocate only two pages for it but
since we're going to use those pages throughout the system's
lifetime, we allocate them statically to avoid early boot time
allocation woes.

Signed-off-by: Chen, Gong <gong.chen@linux.intel.com>
[ Rewrite. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/1439396985-12812-3-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/mcheck/mce-internal.h b/arch/x86/kernel/cpu/mcheck/mce-internal.h
index fe32074b865b..ea8b62264c14 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-internal.h
+++ b/arch/x86/kernel/cpu/mcheck/mce-internal.h
@@ -13,6 +13,8 @@ enum severity_level {
 	MCE_PANIC_SEVERITY,
 };
 
+extern struct atomic_notifier_head x86_mce_decoder_chain;
+
 #define ATTR_LEN		16
 #define INITIAL_CHECK_INTERVAL	5 * 60 /* 5 minutes */
 
@@ -24,6 +26,16 @@ struct mce_bank {
 	char			attrname[ATTR_LEN];	/* attribute name */
 };
 
+struct mce_evt_llist {
+	struct llist_node llnode;
+	struct mce mce;
+};
+
+void mce_gen_pool_process(void);
+bool mce_gen_pool_empty(void);
+int mce_gen_pool_add(struct mce *mce);
+int mce_gen_pool_init(void);
+
 extern int (*mce_severity)(struct mce *a, int tolerant, char **msg, bool is_excp);
 struct dentry *mce_get_debugfs_dir(void);