debug lk

hc

2024-02-20 e636c8d336489bf3eed5878299e6cc045bbad077

 kernel/fs/pstore/ftrace.c
..
..
@@ -1,14 +1,6 @@
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+// SPDX-License-Identifier: GPL-2.0-only
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 /*
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  * Copyright 2012  Google, Inc.
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- *
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- * This software is licensed under the terms of the GNU General Public
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- * License version 2, as published by the Free Software Foundation, and
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- * may be copied, distributed, and modified under those terms.
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- *
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- * This program is distributed in the hope that it will be useful,
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- * but WITHOUT ANY WARRANTY; without even the implied warranty of
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- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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- * GNU General Public License for more details.
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4
  */
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5
 
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 #include <linux/kernel.h>
..
..
@@ -24,6 +16,7 @@
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 #include <linux/debugfs.h>
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 #include <linux/err.h>
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 #include <linux/cache.h>
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+#include <linux/slab.h>
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20
 #include <asm/barrier.h>
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 #include "internal.h"
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22
 
..
..
@@ -120,27 +113,13 @@
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113
 
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 void pstore_register_ftrace(void)
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 {
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-	struct dentry *file;
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-
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 	if (!psinfo->write)
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 		return;
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 	pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);
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-	if (!pstore_ftrace_dir) {
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-		pr_err("%s: unable to create pstore directory\n", __func__);
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-		return;
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-	}
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120
 
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-	file = debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir,
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-				   NULL, &pstore_knob_fops);
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-	if (!file) {
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-		pr_err("%s: unable to create record_ftrace file\n", __func__);
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-		goto err_file;
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-	}
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-
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-	return;
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-err_file:
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-	debugfs_remove(pstore_ftrace_dir);
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+	debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir, NULL,
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+			    &pstore_knob_fops);
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123
 }
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124
 
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 void pstore_unregister_ftrace(void)
..
..
@@ -148,9 +127,62 @@
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127
 	mutex_lock(&pstore_ftrace_lock);
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128
 	if (pstore_ftrace_enabled) {
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 		unregister_ftrace_function(&pstore_ftrace_ops);
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-		pstore_ftrace_enabled = 0;
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+		pstore_ftrace_enabled = false;
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 	}
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 	mutex_unlock(&pstore_ftrace_lock);
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133
 
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 	debugfs_remove_recursive(pstore_ftrace_dir);
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135
 }
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+
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+ssize_t pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size,
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+				  const char *src_log, size_t src_log_size)
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+{
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+	size_t dest_size, src_size, total, dest_off, src_off;
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+	size_t dest_idx = 0, src_idx = 0, merged_idx = 0;
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+	void *merged_buf;
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+	struct pstore_ftrace_record *drec, *srec, *mrec;
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+	size_t record_size = sizeof(struct pstore_ftrace_record);
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+
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+	dest_off = *dest_log_size % record_size;
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+	dest_size = *dest_log_size - dest_off;
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+
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+	src_off = src_log_size % record_size;
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+	src_size = src_log_size - src_off;
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+
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+	total = dest_size + src_size;
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+	merged_buf = kmalloc(total, GFP_KERNEL);
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+	if (!merged_buf)
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+		return -ENOMEM;
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+
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+	drec = (struct pstore_ftrace_record *)(*dest_log + dest_off);
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+	srec = (struct pstore_ftrace_record *)(src_log + src_off);
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+	mrec = (struct pstore_ftrace_record *)(merged_buf);
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+
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+	while (dest_size > 0 && src_size > 0) {
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+		if (pstore_ftrace_read_timestamp(&drec[dest_idx]) <
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+		    pstore_ftrace_read_timestamp(&srec[src_idx])) {
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+			mrec[merged_idx++] = drec[dest_idx++];
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+			dest_size -= record_size;
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+		} else {
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+			mrec[merged_idx++] = srec[src_idx++];
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+			src_size -= record_size;
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+		}
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+	}
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+
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+	while (dest_size > 0) {
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+		mrec[merged_idx++] = drec[dest_idx++];
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+		dest_size -= record_size;
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+	}
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+
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+	while (src_size > 0) {
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+		mrec[merged_idx++] = srec[src_idx++];
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+		src_size -= record_size;
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+	}
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+
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+	kfree(*dest_log);
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+	*dest_log = merged_buf;
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+	*dest_log_size = total;
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+
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+	return 0;
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+}
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+EXPORT_SYMBOL_GPL(pstore_ftrace_combine_log);