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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /kernel/trace/trace_kdb.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'kernel/trace/trace_kdb.c')
-rw-r--r--kernel/trace/trace_kdb.c164
1 files changed, 164 insertions, 0 deletions
diff --git a/kernel/trace/trace_kdb.c b/kernel/trace/trace_kdb.c
new file mode 100644
index 000000000..59857a1ee
--- /dev/null
+++ b/kernel/trace/trace_kdb.c
@@ -0,0 +1,164 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kdb helper for dumping the ftrace buffer
+ *
+ * Copyright (C) 2010 Jason Wessel <jason.wessel@windriver.com>
+ *
+ * ftrace_dump_buf based on ftrace_dump:
+ * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
+ *
+ */
+#include <linux/init.h>
+#include <linux/kgdb.h>
+#include <linux/kdb.h>
+#include <linux/ftrace.h>
+
+#include "trace.h"
+#include "trace_output.h"
+
+static struct trace_iterator iter;
+static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS];
+
+static void ftrace_dump_buf(int skip_entries, long cpu_file)
+{
+ struct trace_array *tr;
+ unsigned int old_userobj;
+ int cnt = 0, cpu;
+
+ tr = iter.tr;
+
+ old_userobj = tr->trace_flags;
+
+ /* don't look at user memory in panic mode */
+ tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
+
+ kdb_printf("Dumping ftrace buffer:\n");
+ if (skip_entries)
+ kdb_printf("(skipping %d entries)\n", skip_entries);
+
+ trace_iterator_reset(&iter);
+ iter.iter_flags |= TRACE_FILE_LAT_FMT;
+
+ if (cpu_file == RING_BUFFER_ALL_CPUS) {
+ for_each_tracing_cpu(cpu) {
+ iter.buffer_iter[cpu] =
+ ring_buffer_read_prepare(iter.array_buffer->buffer,
+ cpu, GFP_ATOMIC);
+ ring_buffer_read_start(iter.buffer_iter[cpu]);
+ tracing_iter_reset(&iter, cpu);
+ }
+ } else {
+ iter.cpu_file = cpu_file;
+ iter.buffer_iter[cpu_file] =
+ ring_buffer_read_prepare(iter.array_buffer->buffer,
+ cpu_file, GFP_ATOMIC);
+ ring_buffer_read_start(iter.buffer_iter[cpu_file]);
+ tracing_iter_reset(&iter, cpu_file);
+ }
+
+ while (trace_find_next_entry_inc(&iter)) {
+ if (!cnt)
+ kdb_printf("---------------------------------\n");
+ cnt++;
+
+ if (!skip_entries) {
+ print_trace_line(&iter);
+ trace_printk_seq(&iter.seq);
+ } else {
+ skip_entries--;
+ }
+
+ if (KDB_FLAG(CMD_INTERRUPT))
+ goto out;
+ }
+
+ if (!cnt)
+ kdb_printf(" (ftrace buffer empty)\n");
+ else
+ kdb_printf("---------------------------------\n");
+
+out:
+ tr->trace_flags = old_userobj;
+
+ for_each_tracing_cpu(cpu) {
+ if (iter.buffer_iter[cpu]) {
+ ring_buffer_read_finish(iter.buffer_iter[cpu]);
+ iter.buffer_iter[cpu] = NULL;
+ }
+ }
+}
+
+/*
+ * kdb_ftdump - Dump the ftrace log buffer
+ */
+static int kdb_ftdump(int argc, const char **argv)
+{
+ int skip_entries = 0;
+ long cpu_file;
+ char *cp;
+ int cnt;
+ int cpu;
+
+ if (argc > 2)
+ return KDB_ARGCOUNT;
+
+ if (argc) {
+ skip_entries = simple_strtol(argv[1], &cp, 0);
+ if (*cp)
+ skip_entries = 0;
+ }
+
+ if (argc == 2) {
+ cpu_file = simple_strtol(argv[2], &cp, 0);
+ if (*cp || cpu_file >= NR_CPUS || cpu_file < 0 ||
+ !cpu_online(cpu_file))
+ return KDB_BADINT;
+ } else {
+ cpu_file = RING_BUFFER_ALL_CPUS;
+ }
+
+ kdb_trap_printk++;
+
+ trace_init_global_iter(&iter);
+ iter.buffer_iter = buffer_iter;
+
+ for_each_tracing_cpu(cpu) {
+ atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
+ }
+
+ /* A negative skip_entries means skip all but the last entries */
+ if (skip_entries < 0) {
+ if (cpu_file == RING_BUFFER_ALL_CPUS)
+ cnt = trace_total_entries(NULL);
+ else
+ cnt = trace_total_entries_cpu(NULL, cpu_file);
+ skip_entries = max(cnt + skip_entries, 0);
+ }
+
+ ftrace_dump_buf(skip_entries, cpu_file);
+
+ for_each_tracing_cpu(cpu) {
+ atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
+ }
+
+ kdb_trap_printk--;
+
+ return 0;
+}
+
+static kdbtab_t ftdump_cmd = {
+ .name = "ftdump",
+ .func = kdb_ftdump,
+ .usage = "[skip_#entries] [cpu]",
+ .help = "Dump ftrace log; -skip dumps last #entries",
+ .flags = KDB_ENABLE_ALWAYS_SAFE,
+};
+
+static __init int kdb_ftrace_register(void)
+{
+ kdb_register(&ftdump_cmd);
+ return 0;
+}
+
+late_initcall(kdb_ftrace_register);