cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

trace_kdb.c (3624B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * kdb helper for dumping the ftrace buffer
      4 *
      5 * Copyright (C) 2010 Jason Wessel <jason.wessel@windriver.com>
      6 *
      7 * ftrace_dump_buf based on ftrace_dump:
      8 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
      9 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
     10 *
     11 */
     12#include <linux/init.h>
     13#include <linux/kgdb.h>
     14#include <linux/kdb.h>
     15#include <linux/ftrace.h>
     16
     17#include "trace.h"
     18#include "trace_output.h"
     19
     20static struct trace_iterator iter;
     21static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS];
     22
     23static void ftrace_dump_buf(int skip_entries, long cpu_file)
     24{
     25	struct trace_array *tr;
     26	unsigned int old_userobj;
     27	int cnt = 0, cpu;
     28
     29	tr = iter.tr;
     30
     31	old_userobj = tr->trace_flags;
     32
     33	/* don't look at user memory in panic mode */
     34	tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
     35
     36	kdb_printf("Dumping ftrace buffer:\n");
     37	if (skip_entries)
     38		kdb_printf("(skipping %d entries)\n", skip_entries);
     39
     40	trace_iterator_reset(&iter);
     41	iter.iter_flags |= TRACE_FILE_LAT_FMT;
     42
     43	if (cpu_file == RING_BUFFER_ALL_CPUS) {
     44		for_each_tracing_cpu(cpu) {
     45			iter.buffer_iter[cpu] =
     46			ring_buffer_read_prepare(iter.array_buffer->buffer,
     47						 cpu, GFP_ATOMIC);
     48			ring_buffer_read_start(iter.buffer_iter[cpu]);
     49			tracing_iter_reset(&iter, cpu);
     50		}
     51	} else {
     52		iter.cpu_file = cpu_file;
     53		iter.buffer_iter[cpu_file] =
     54			ring_buffer_read_prepare(iter.array_buffer->buffer,
     55						 cpu_file, GFP_ATOMIC);
     56		ring_buffer_read_start(iter.buffer_iter[cpu_file]);
     57		tracing_iter_reset(&iter, cpu_file);
     58	}
     59
     60	while (trace_find_next_entry_inc(&iter)) {
     61		if (!cnt)
     62			kdb_printf("---------------------------------\n");
     63		cnt++;
     64
     65		if (!skip_entries) {
     66			print_trace_line(&iter);
     67			trace_printk_seq(&iter.seq);
     68		} else {
     69			skip_entries--;
     70		}
     71
     72		if (KDB_FLAG(CMD_INTERRUPT))
     73			goto out;
     74	}
     75
     76	if (!cnt)
     77		kdb_printf("   (ftrace buffer empty)\n");
     78	else
     79		kdb_printf("---------------------------------\n");
     80
     81out:
     82	tr->trace_flags = old_userobj;
     83
     84	for_each_tracing_cpu(cpu) {
     85		if (iter.buffer_iter[cpu]) {
     86			ring_buffer_read_finish(iter.buffer_iter[cpu]);
     87			iter.buffer_iter[cpu] = NULL;
     88		}
     89	}
     90}
     91
     92/*
     93 * kdb_ftdump - Dump the ftrace log buffer
     94 */
     95static int kdb_ftdump(int argc, const char **argv)
     96{
     97	int skip_entries = 0;
     98	long cpu_file;
     99	char *cp;
    100	int cnt;
    101	int cpu;
    102
    103	if (argc > 2)
    104		return KDB_ARGCOUNT;
    105
    106	if (argc) {
    107		skip_entries = simple_strtol(argv[1], &cp, 0);
    108		if (*cp)
    109			skip_entries = 0;
    110	}
    111
    112	if (argc == 2) {
    113		cpu_file = simple_strtol(argv[2], &cp, 0);
    114		if (*cp || cpu_file >= NR_CPUS || cpu_file < 0 ||
    115		    !cpu_online(cpu_file))
    116			return KDB_BADINT;
    117	} else {
    118		cpu_file = RING_BUFFER_ALL_CPUS;
    119	}
    120
    121	kdb_trap_printk++;
    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
    145	kdb_trap_printk--;
    146
    147	return 0;
    148}
    149
    150static kdbtab_t ftdump_cmd = {
    151	.name = "ftdump",
    152	.func = kdb_ftdump,
    153	.usage = "[skip_#entries] [cpu]",
    154	.help = "Dump ftrace log; -skip dumps last #entries",
    155	.flags = KDB_ENABLE_ALWAYS_SAFE,
    156};
    157
    158static __init int kdb_ftrace_register(void)
    159{
    160	kdb_register(&ftdump_cmd);
    161	return 0;
    162}
    163
    164late_initcall(kdb_ftrace_register);