fs: pstore: import vangogh-r-oss support to get last_kmsg

drivers/power/reset/msm-poweroff.c

@@ -490,7 +490,7 @@ static void msm_restart_prepare(const char *cmd)
 		pr_info("Forcing a warm reset of the system\n");
 
 	/* Hard reset the PMIC unless memory contents must be maintained. */
-	if (force_warm_reboot || need_warm_reset)
+	if (force_warm_reboot || need_warm_reset || in_panic)
 		qpnp_pon_system_pwr_off(PON_POWER_OFF_WARM_RESET);
 	else
 		qpnp_pon_system_pwr_off(PON_POWER_OFF_HARD_RESET);

fs/pstore/Kconfig

@@ -153,3 +153,11 @@ config PSTORE_RAM
 	  "ramoops.ko".
 
 	  For more information, see Documentation/admin-guide/ramoops.rst.
+
+config PSTORE_LAST_KMSG
+	bool "export /proc/last_kmsg"
+	default y
+	depends on PSTORE
+	help
+	  When the option is enabled, pstore will export a proc filesystem
+	  interface /proc/last_kmsg.

fs/pstore/inode.c

@@ -2,6 +2,7 @@
  * Persistent Storage - ramfs parts.
  *
  * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
+ * Copyright (C) 2021 XiaoMi, Inc.
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License version 2 as
@@ -36,6 +37,9 @@
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/uaccess.h>
+#ifdef CONFIG_PSTORE_LAST_KMSG
+#include <linux/proc_fs.h>
+#endif
 
 #include "internal.h"
 
@@ -297,6 +301,25 @@ bool pstore_is_mounted(void)
 	return pstore_sb != NULL;
 }
 
+#ifdef CONFIG_PSTORE_LAST_KMSG
+
+static char *console_buffer;
+static ssize_t console_bufsize;
+
+static ssize_t last_kmsg_read(struct file *file, char __user *buf,
+                              size_t len, loff_t *offset)
+{
+	return simple_read_from_buffer(buf, len, offset,
+                                       console_buffer, console_bufsize);
+}
+
+static const struct file_operations last_kmsg_fops = {
+    .owner          = THIS_MODULE,
+    .read           = last_kmsg_read,
+    .llseek         = default_llseek,
+};
+#endif
+
 /*
  * Make a regular file in the root directory of our file system.
  * Load it up with "size" bytes of data from "buf".
@@ -403,6 +426,13 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
 	list_add(&private->list, &allpstore);
 	spin_unlock_irqrestore(&allpstore_lock, flags);
 
+#ifdef CONFIG_PSTORE_LAST_KMSG
+	if (record->type == PSTORE_TYPE_CONSOLE) {
+		console_buffer = private->record->buf;
+		console_bufsize = size;
+	}
+#endif
+
 	return 0;
 
 fail_private:
@@ -488,6 +518,9 @@ static struct file_system_type pstore_fs_type = {
 int __init pstore_init_fs(void)
 {
 	int err;
+#ifdef CONFIG_PSTORE_LAST_KMSG
+	struct proc_dir_entry *last_kmsg_entry = NULL;
+#endif
 
 	/* Create a convenient mount point for people to access pstore */
 	err = sysfs_create_mount_point(fs_kobj, "pstore");
@@ -498,6 +531,14 @@ int __init pstore_init_fs(void)
 	if (err < 0)
 		sysfs_remove_mount_point(fs_kobj, "pstore");
 
+#ifdef CONFIG_PSTORE_LAST_KMSG
+	last_kmsg_entry = proc_create_data("last_kmsg", S_IFREG | S_IRUGO,
+                                       NULL, &last_kmsg_fops, NULL);
+	if (!last_kmsg_entry) {
+		pr_err("Failed to create last_kmsg\n");
+		goto out;
+    }
+#endif
 out:
 	return err;
 }

fs/pstore/ram.c

@@ -2,6 +2,7 @@
  * RAM Oops/Panic logger
  *
  * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
+ * Copyright (C) 2021 XiaoMi, Inc.
  * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
  *
  * This program is free software; you can redistribute it and/or
@@ -35,6 +36,7 @@
 #include <linux/pstore_ram.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
+#include <linux/memblock.h>
 
 #define RAMOOPS_KERNMSG_HDR "===="
 #define MIN_MEM_SIZE 4096UL
@@ -967,6 +969,49 @@ static void __init ramoops_register_dummy(void)
 	}
 }
 
+static struct ramoops_platform_data ramoops_data;
+
+static struct platform_device ramoops_dev  = {
+	.name = "ramoops",
+	.dev = {
+		.platform_data = &ramoops_data,
+	},
+};
+
+static int __init ramoops_memreserve(char *p)
+{
+	unsigned long size;
+
+	if (!p)
+		return 1;
+
+	size = memparse(p, &p) & PAGE_MASK;
+	ramoops_data.mem_size = size;
+	ramoops_data.mem_address = 0xB0000000;
+	ramoops_data.console_size = size / 2;
+	ramoops_data.pmsg_size = size / 2;
+	ramoops_data.dump_oops = 1;
+
+	pr_info("msm_reserve_ramoops_memory addr=%llx,size=%lx\n",
+		ramoops_data.mem_address, ramoops_data.mem_size);
+	pr_info("msm_reserve_ramoops_memory record_size=%lx,ftrace_size=%lx\n",
+		ramoops_data.record_size, ramoops_data.ftrace_size);
+
+	memblock_reserve(ramoops_data.mem_address, ramoops_data.mem_size);
+
+	return 0;
+}
+early_param("ramoops_memreserve", ramoops_memreserve);
+
+static int __init msm_register_ramoops_device(void)
+{
+	pr_info("msm_register_ramoops_device\n");
+	if (platform_device_register(&ramoops_dev))
+		pr_info("Unable to register ramoops platform device\n");
+	return 0;
+}
+core_initcall(msm_register_ramoops_device);
+
 static int __init ramoops_init(void)
 {
 	int ret;