add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/kernel/trace/trace_kdb.c
..
..
@@ -17,22 +17,16 @@
17
17
 #include "trace.h"
18
18
 #include "trace_output.h"
19
19
 
20
-static void ftrace_dump_buf(int skip_lines, long cpu_file)
20
+static struct trace_iterator iter;
21
+static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS];
22
+
23
+static void ftrace_dump_buf(int skip_entries, long cpu_file)
21
24
 {
22
-	/* use static because iter can be a bit big for the stack */
23
-	static struct trace_iterator iter;
24
-	static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS];
25
25
 	struct trace_array *tr;
26
26
 	unsigned int old_userobj;
27
27
 	int cnt = 0, cpu;
28
28
 
29
-	trace_init_global_iter(&iter);
30
-	iter.buffer_iter = buffer_iter;
31
29
 	tr = iter.tr;
32
-
33
-	for_each_tracing_cpu(cpu) {
34
-		atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
35
-	}
36
30
 
37
31
 	old_userobj = tr->trace_flags;
38
32
 
..
..
@@ -40,6 +34,8 @@
40
34
 	tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
41
35
 
42
36
 	kdb_printf("Dumping ftrace buffer:\n");
37
+	if (skip_entries)
38
+		kdb_printf("(skipping %d entries)\n", skip_entries);
43
39
 
44
40
 	trace_iterator_reset(&iter);
45
41
 	iter.iter_flags |= TRACE_FILE_LAT_FMT;
..
..
@@ -47,7 +43,7 @@
47
43
 	if (cpu_file == RING_BUFFER_ALL_CPUS) {
48
44
 		for_each_tracing_cpu(cpu) {
49
45
 			iter.buffer_iter[cpu] =
50
-			ring_buffer_read_prepare(iter.trace_buffer->buffer,
46
+			ring_buffer_read_prepare(iter.array_buffer->buffer,
51
47
 						 cpu, GFP_ATOMIC);
52
48
 			ring_buffer_read_start(iter.buffer_iter[cpu]);
53
49
 			tracing_iter_reset(&iter, cpu);
..
..
@@ -55,7 +51,7 @@
55
51
 	} else {
56
52
 		iter.cpu_file = cpu_file;
57
53
 		iter.buffer_iter[cpu_file] =
58
-			ring_buffer_read_prepare(iter.trace_buffer->buffer,
54
+			ring_buffer_read_prepare(iter.array_buffer->buffer,
59
55
 						 cpu_file, GFP_ATOMIC);
60
56
 		ring_buffer_read_start(iter.buffer_iter[cpu_file]);
61
57
 		tracing_iter_reset(&iter, cpu_file);
..
..
@@ -66,11 +62,11 @@
66
62
 			kdb_printf("---------------------------------\n");
67
63
 		cnt++;
68
64
 
69
-		if (!skip_lines) {
65
+		if (!skip_entries) {
70
66
 			print_trace_line(&iter);
71
67
 			trace_printk_seq(&iter.seq);
72
68
 		} else {
73
-			skip_lines--;
69
+			skip_entries--;
74
70
 		}
75
71
 
76
72
 		if (KDB_FLAG(CMD_INTERRUPT))
..
..
@@ -86,10 +82,6 @@
86
82
 	tr->trace_flags = old_userobj;
87
83
 
88
84
 	for_each_tracing_cpu(cpu) {
89
-		atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
90
-	}
91
-
92
-	for_each_tracing_cpu(cpu) {
93
85
 		if (iter.buffer_iter[cpu]) {
94
86
 			ring_buffer_read_finish(iter.buffer_iter[cpu]);
95
87
 			iter.buffer_iter[cpu] = NULL;
..
..
@@ -102,17 +94,19 @@
102
94
  */
103
95
 static int kdb_ftdump(int argc, const char **argv)
104
96
 {
105
-	int skip_lines = 0;
97
+	int skip_entries = 0;
106
98
 	long cpu_file;
107
99
 	char *cp;
100
+	int cnt;
101
+	int cpu;
108
102
 
109
103
 	if (argc > 2)
110
104
 		return KDB_ARGCOUNT;
111
105
 
112
106
 	if (argc) {
113
-		skip_lines = simple_strtol(argv[1], &cp, 0);
107
+		skip_entries = simple_strtol(argv[1], &cp, 0);
114
108
 		if (*cp)
115
-			skip_lines = 0;
109
+			skip_entries = 0;
116
110
 	}
117
111
 
118
112
 	if (argc == 2) {
..
..
@@ -125,7 +119,29 @@
125
119
 	}
126
120
 
127
121
 	kdb_trap_printk++;
128
-	ftrace_dump_buf(skip_lines, cpu_file);
122
+
123
+	trace_init_global_iter(&iter);
124
+	iter.buffer_iter = buffer_iter;
125
+
126
+	for_each_tracing_cpu(cpu) {
127
+		atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
128
+	}
129
+
130
+	/* A negative skip_entries means skip all but the last entries */
131
+	if (skip_entries < 0) {
132
+		if (cpu_file == RING_BUFFER_ALL_CPUS)
133
+			cnt = trace_total_entries(NULL);
134
+		else
135
+			cnt = trace_total_entries_cpu(NULL, cpu_file);
136
+		skip_entries = max(cnt + skip_entries, 0);
137
+	}
138
+
139
+	ftrace_dump_buf(skip_entries, cpu_file);
140
+
141
+	for_each_tracing_cpu(cpu) {
142
+		atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
143
+	}
144
+
129
145
 	kdb_trap_printk--;
130
146
 
131
147
 	return 0;
..
..
@@ -133,8 +149,9 @@
133
149
 
134
150
 static __init int kdb_ftrace_register(void)
135
151
 {
136
-	kdb_register_flags("ftdump", kdb_ftdump, "[skip_#lines] [cpu]",
137
-			    "Dump ftrace log", 0, KDB_ENABLE_ALWAYS_SAFE);
152
+	kdb_register_flags("ftdump", kdb_ftdump, "[skip_#entries] [cpu]",
153
+			    "Dump ftrace log; -skip dumps last #entries", 0,
154
+			    KDB_ENABLE_ALWAYS_SAFE);
138
155
 	return 0;
139
156
 }
140
157