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164 lines
3.5 KiB
164 lines
3.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* kdb helper for dumping the ftrace buffer |
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* |
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* Copyright (C) 2010 Jason Wessel <[email protected]> |
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* |
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* ftrace_dump_buf based on ftrace_dump: |
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* Copyright (C) 2007-2008 Steven Rostedt <[email protected]> |
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* Copyright (C) 2008 Ingo Molnar <[email protected]> |
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* |
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*/ |
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#include <linux/init.h> |
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#include <linux/kgdb.h> |
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#include <linux/kdb.h> |
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#include <linux/ftrace.h> |
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#include "trace.h" |
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#include "trace_output.h" |
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static struct trace_iterator iter; |
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static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS]; |
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static void ftrace_dump_buf(int skip_entries, long cpu_file) |
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{ |
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struct trace_array *tr; |
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unsigned int old_userobj; |
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int cnt = 0, cpu; |
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tr = iter.tr; |
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old_userobj = tr->trace_flags; |
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/* don't look at user memory in panic mode */ |
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tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ; |
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kdb_printf("Dumping ftrace buffer:\n"); |
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if (skip_entries) |
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kdb_printf("(skipping %d entries)\n", skip_entries); |
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trace_iterator_reset(&iter); |
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iter.iter_flags |= TRACE_FILE_LAT_FMT; |
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if (cpu_file == RING_BUFFER_ALL_CPUS) { |
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for_each_tracing_cpu(cpu) { |
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iter.buffer_iter[cpu] = |
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ring_buffer_read_prepare(iter.array_buffer->buffer, |
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cpu, GFP_ATOMIC); |
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ring_buffer_read_start(iter.buffer_iter[cpu]); |
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tracing_iter_reset(&iter, cpu); |
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} |
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} else { |
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iter.cpu_file = cpu_file; |
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iter.buffer_iter[cpu_file] = |
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ring_buffer_read_prepare(iter.array_buffer->buffer, |
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cpu_file, GFP_ATOMIC); |
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ring_buffer_read_start(iter.buffer_iter[cpu_file]); |
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tracing_iter_reset(&iter, cpu_file); |
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} |
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while (trace_find_next_entry_inc(&iter)) { |
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if (!cnt) |
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kdb_printf("---------------------------------\n"); |
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cnt++; |
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if (!skip_entries) { |
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print_trace_line(&iter); |
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trace_printk_seq(&iter.seq); |
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} else { |
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skip_entries--; |
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} |
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if (KDB_FLAG(CMD_INTERRUPT)) |
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goto out; |
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} |
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if (!cnt) |
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kdb_printf(" (ftrace buffer empty)\n"); |
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else |
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kdb_printf("---------------------------------\n"); |
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out: |
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tr->trace_flags = old_userobj; |
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for_each_tracing_cpu(cpu) { |
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if (iter.buffer_iter[cpu]) { |
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ring_buffer_read_finish(iter.buffer_iter[cpu]); |
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iter.buffer_iter[cpu] = NULL; |
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} |
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} |
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} |
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/* |
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* kdb_ftdump - Dump the ftrace log buffer |
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*/ |
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static int kdb_ftdump(int argc, const char **argv) |
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{ |
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int skip_entries = 0; |
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long cpu_file; |
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char *cp; |
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int cnt; |
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int cpu; |
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if (argc > 2) |
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return KDB_ARGCOUNT; |
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if (argc) { |
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skip_entries = simple_strtol(argv[1], &cp, 0); |
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if (*cp) |
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skip_entries = 0; |
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} |
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if (argc == 2) { |
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cpu_file = simple_strtol(argv[2], &cp, 0); |
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if (*cp || cpu_file >= NR_CPUS || cpu_file < 0 || |
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!cpu_online(cpu_file)) |
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return KDB_BADINT; |
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} else { |
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cpu_file = RING_BUFFER_ALL_CPUS; |
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} |
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kdb_trap_printk++; |
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trace_init_global_iter(&iter); |
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iter.buffer_iter = buffer_iter; |
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for_each_tracing_cpu(cpu) { |
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atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled); |
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} |
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/* A negative skip_entries means skip all but the last entries */ |
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if (skip_entries < 0) { |
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if (cpu_file == RING_BUFFER_ALL_CPUS) |
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cnt = trace_total_entries(NULL); |
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else |
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cnt = trace_total_entries_cpu(NULL, cpu_file); |
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skip_entries = max(cnt + skip_entries, 0); |
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} |
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ftrace_dump_buf(skip_entries, cpu_file); |
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for_each_tracing_cpu(cpu) { |
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atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled); |
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} |
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kdb_trap_printk--; |
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return 0; |
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} |
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static kdbtab_t ftdump_cmd = { |
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.name = "ftdump", |
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.func = kdb_ftdump, |
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.usage = "[skip_#entries] [cpu]", |
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.help = "Dump ftrace log; -skip dumps last #entries", |
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.flags = KDB_ENABLE_ALWAYS_SAFE, |
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}; |
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static __init int kdb_ftrace_register(void) |
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{ |
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kdb_register(&ftdump_cmd); |
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return 0; |
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} |
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late_initcall(kdb_ftrace_register);
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