[PATCH v2 1/2] printk: Add function to return log buffer address and size

@@ -10,6 +10,9 @@
 extern const char linux_banner[];
 extern const char linux_proc_banner[];
 
+extern void *get_log_buf_addr(void);
+extern u32 get_log_buf_len(void);
+
 static inline int printk_get_level(const char *buffer)
 {
 	if (buffer[0] == KERN_SOH_ASCII && buffer[1]) {

@@ -270,6 +270,18 @@ static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
 static char *log_buf = __log_buf;
 static u32 log_buf_len = __LOG_BUF_LEN;
 
+/* Return log buffer address */
+void *get_log_buf_addr(void)
+{
+	return log_buf;
+}
+
+/* Return log buffer size */
+u32 get_log_buf_len(void)
+{
+	return log_buf_len;
+}
+
 /* human readable text of the record */
 static char *log_text(const struct printk_log *msg)
 {

@@ -147,6 +147,8 @@ struct opal_sg_list {
 #define OPAL_SET_PARAM				90
 #define OPAL_DUMP_RESEND			91
 #define OPAL_DUMP_INFO2				94
+#define OPAL_REGISTER_DUMP_REGION		101
+#define OPAL_UNREGISTER_DUMP_REGION		102
 
 #ifndef __ASSEMBLY__
 

@@ -860,6 +862,8 @@ int64_t opal_get_param(uint64_t token, uint32_t param_id, uint64_t buffer,
 int64_t opal_set_param(uint64_t token, uint32_t param_id, uint64_t buffer,
 		uint64_t length);
 int64_t opal_sensor_read(uint32_t sensor_hndl, int token, __be32 *sensor_data);
+int64_t opal_register_dump_region(uint32_t id, uint64_t start, uint64_t end);
+int64_t opal_unregister_dump_region(uint32_t id);
 
 /* Internal functions */
 extern int early_init_dt_scan_opal(unsigned long node, const char *uname,

@@ -899,6 +903,8 @@ extern int opal_elog_init(void);
 extern void opal_platform_dump_init(void);
 extern void opal_sys_param_init(void);
 extern void opal_msglog_init(void);
+extern void opal_dump_region_init(void);
+extern void opal_dump_kexec_callback(void);
 
 extern int opal_machine_check(struct pt_regs *regs);
 extern bool opal_mce_check_early_recovery(struct pt_regs *regs);

@@ -912,6 +918,15 @@ struct opal_sg_list *opal_vmalloc_to_sg_list(void *vmalloc_addr,
 					     unsigned long vmalloc_size);
 void opal_free_sg_list(struct opal_sg_list *sg);
 
+/*
+ * Dump regions ids
+ *   0x01 - 0x7F : OPAL
+ *   0x80 - 0xFF : Kernel
+ */
+#define DUMP_REGION_HOST_START		0x80
+#define DUMP_REGION_LOG_BUF		0x80
+#define DUMP_REGION_HOST_END		0xFF
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __OPAL_H */

@@ -1,7 +1,7 @@
 obj-y			+= setup.o opal-wrappers.o opal.o opal-async.o
 obj-y			+= opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
 obj-y			+= rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o
-obj-y			+= opal-msglog.o
+obj-y			+= opal-msglog.o opal-dump-region.o
 
 obj-$(CONFIG_SMP)	+= smp.o subcore.o subcore-asm.o
 obj-$(CONFIG_PCI)	+= pci.o pci-p5ioc2.o pci-ioda.o

@@ -0,0 +1,64 @@
+/*
+ * PowerNV OPAL dump memory region interface
+ *
+ * Copyright 2014 IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/pagemap.h>
+#include <linux/printk.h>
+#include <asm/opal.h>
+
+/*
+ * Pass kernel address range (start, size) that will be included in
+ * system dump (collected by service processor whenever system crashes).
+ *
+ * @id		: Memory region ID (see opal.h)
+ * @addr	: Start address
+ * @size	: size in bytes
+ */
+static int add_dump_region_entry(uint32_t id, void *addr, uint64_t size)
+{
+	__be32 be_id = cpu_to_be32(id);
+	__be64 be_addr = cpu_to_be64(__pa(addr));
+	__be64 be_size = cpu_to_be64(size);
+
+	return opal_register_dump_region(be_id, be_addr, be_size);
+}
+
+static int remove_dump_region_entry(uint32_t id)
+{
+	__be32 be_id = cpu_to_be32(id);
+
+	return opal_unregister_dump_region(be_id);
+}
+
+/* This gets called just before kexec */
+void opal_dump_kexec_callback(void)
+{
+	int rc;
+
+	rc = remove_dump_region_entry(DUMP_REGION_LOG_BUF);
+	if (rc)
+		pr_warn("DUMP: Failed to unregister kernel log buffer. "
+			"rc = %d\n", rc);
+}
+
+void __init opal_dump_region_init(void)
+{
+	void *addr;
+	uint64_t size;
+	int rc;
+
+	/* Register kernel log buffer */
+	addr = get_log_buf_addr();
+	size = get_log_buf_len();
+	rc = add_dump_region_entry(DUMP_REGION_LOG_BUF, addr, size);
+	if (rc)
+		pr_warn("DUMP: Failed to register kernel log buffer. "
+			"rc = %d\n", rc);
+}

@@ -146,3 +146,5 @@ OPAL_CALL(opal_sync_host_reboot,		OPAL_SYNC_HOST_REBOOT);
 OPAL_CALL(opal_sensor_read,			OPAL_SENSOR_READ);
 OPAL_CALL(opal_get_param,			OPAL_GET_PARAM);
 OPAL_CALL(opal_set_param,			OPAL_SET_PARAM);
+OPAL_CALL(opal_register_dump_region,		OPAL_REGISTER_DUMP_REGION);
+OPAL_CALL(opal_unregister_dump_region,		OPAL_UNREGISTER_DUMP_REGION);

@@ -616,6 +616,8 @@ static int __init opal_init(void)
 	/* Create "opal" kobject under /sys/firmware */
 	rc = opal_sysfs_init();
 	if (rc == 0) {
+		/* Setup dump region interface */
+		opal_dump_region_init();
 		/* Setup error log interface */
 		rc = opal_elog_init();
 		/* Setup code update interface */

@@ -184,6 +184,9 @@ static void pnv_shutdown(void)
 	 * DMA'ing ops are complete (such as dump retrieval).
 	 */
 	opal_shutdown();
+
+	/* Unregister memory dump region */
+	opal_dump_kexec_callback();
 }
 
 #ifdef CONFIG_KEXEC