240 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright 2023 Red Hat4 */5 6#include "logger.h"7 8#include <asm/current.h>9#include <linux/delay.h>10#include <linux/hardirq.h>11#include <linux/module.h>12#include <linux/printk.h>13#include <linux/sched.h>14 15#include "errors.h"16#include "thread-device.h"17#include "thread-utils.h"18 19int vdo_log_level = VDO_LOG_DEFAULT;20 21int vdo_get_log_level(void)22{23 int log_level_latch = READ_ONCE(vdo_log_level);24 25 if (unlikely(log_level_latch > VDO_LOG_MAX)) {26 log_level_latch = VDO_LOG_DEFAULT;27 WRITE_ONCE(vdo_log_level, log_level_latch);28 }29 return log_level_latch;30}31 32static const char *get_current_interrupt_type(void)33{34 if (in_nmi())35 return "NMI";36 37 if (in_irq())38 return "HI";39 40 if (in_softirq())41 return "SI";42 43 return "INTR";44}45 46/**47 * emit_log_message_to_kernel() - Emit a log message to the kernel at the specified priority.48 *49 * @priority: The priority at which to log the message50 * @fmt: The format string of the message51 */52static void emit_log_message_to_kernel(int priority, const char *fmt, ...)53{54 va_list args;55 struct va_format vaf;56 57 if (priority > vdo_get_log_level())58 return;59 60 va_start(args, fmt);61 vaf.fmt = fmt;62 vaf.va = &args;63 64 switch (priority) {65 case VDO_LOG_EMERG:66 case VDO_LOG_ALERT:67 case VDO_LOG_CRIT:68 pr_crit("%pV", &vaf);69 break;70 case VDO_LOG_ERR:71 pr_err("%pV", &vaf);72 break;73 case VDO_LOG_WARNING:74 pr_warn("%pV", &vaf);75 break;76 case VDO_LOG_NOTICE:77 case VDO_LOG_INFO:78 pr_info("%pV", &vaf);79 break;80 case VDO_LOG_DEBUG:81 pr_debug("%pV", &vaf);82 break;83 default:84 printk(KERN_DEFAULT "%pV", &vaf);85 break;86 }87 88 va_end(args);89}90 91/**92 * emit_log_message() - Emit a log message to the kernel log in a format suited to the current93 * thread context.94 *95 * Context info formats:96 *97 * interrupt: uds[NMI]: blah98 * kvdo thread: kvdo12:foobarQ: blah99 * thread w/device id: kvdo12:myprog: blah100 * other thread: uds: myprog: blah101 *102 * Fields: module name, interrupt level, process name, device ID.103 *104 * @priority: the priority at which to log the message105 * @module: The name of the module doing the logging106 * @prefix: The prefix of the log message107 * @vaf1: The first message format descriptor108 * @vaf2: The second message format descriptor109 */110static void emit_log_message(int priority, const char *module, const char *prefix,111 const struct va_format *vaf1, const struct va_format *vaf2)112{113 int device_instance;114 115 /*116 * In interrupt context, identify the interrupt type and module. Ignore the process/thread117 * since it could be anything.118 */119 if (in_interrupt()) {120 const char *type = get_current_interrupt_type();121 122 emit_log_message_to_kernel(priority, "%s[%s]: %s%pV%pV\n", module, type,123 prefix, vaf1, vaf2);124 return;125 }126 127 /* Not at interrupt level; we have a process we can look at, and might have a device ID. */128 device_instance = vdo_get_thread_device_id();129 if (device_instance >= 0) {130 emit_log_message_to_kernel(priority, "%s%u:%s: %s%pV%pV\n", module,131 device_instance, current->comm, prefix, vaf1,132 vaf2);133 return;134 }135 136 /*137 * If it's a kernel thread and the module name is a prefix of its name, assume it is ours138 * and only identify the thread.139 */140 if (((current->flags & PF_KTHREAD) != 0) &&141 (strncmp(module, current->comm, strlen(module)) == 0)) {142 emit_log_message_to_kernel(priority, "%s: %s%pV%pV\n", current->comm,143 prefix, vaf1, vaf2);144 return;145 }146 147 /* Identify the module and the process. */148 emit_log_message_to_kernel(priority, "%s: %s: %s%pV%pV\n", module, current->comm,149 prefix, vaf1, vaf2);150}151 152/*153 * vdo_log_embedded_message() - Log a message embedded within another message.154 * @priority: the priority at which to log the message155 * @module: the name of the module doing the logging156 * @prefix: optional string prefix to message, may be NULL157 * @fmt1: format of message first part (required)158 * @args1: arguments for message first part (required)159 * @fmt2: format of message second part160 */161void vdo_log_embedded_message(int priority, const char *module, const char *prefix,162 const char *fmt1, va_list args1, const char *fmt2, ...)163{164 va_list args1_copy;165 va_list args2;166 struct va_format vaf1, vaf2;167 168 va_start(args2, fmt2);169 170 if (module == NULL)171 module = VDO_LOGGING_MODULE_NAME;172 173 if (prefix == NULL)174 prefix = "";175 176 /*177 * It is implementation dependent whether va_list is defined as an array type that decays178 * to a pointer when passed as an argument. Copy args1 and args2 with va_copy so that vaf1179 * and vaf2 get proper va_list pointers irrespective of how va_list is defined.180 */181 va_copy(args1_copy, args1);182 vaf1.fmt = fmt1;183 vaf1.va = &args1_copy;184 185 vaf2.fmt = fmt2;186 vaf2.va = &args2;187 188 emit_log_message(priority, module, prefix, &vaf1, &vaf2);189 190 va_end(args1_copy);191 va_end(args2);192}193 194int vdo_vlog_strerror(int priority, int errnum, const char *module, const char *format,195 va_list args)196{197 char errbuf[VDO_MAX_ERROR_MESSAGE_SIZE];198 const char *message = uds_string_error(errnum, errbuf, sizeof(errbuf));199 200 vdo_log_embedded_message(priority, module, NULL, format, args, ": %s (%d)",201 message, errnum);202 return errnum;203}204 205int __vdo_log_strerror(int priority, int errnum, const char *module, const char *format, ...)206{207 va_list args;208 209 va_start(args, format);210 vdo_vlog_strerror(priority, errnum, module, format, args);211 va_end(args);212 return errnum;213}214 215void vdo_log_backtrace(int priority)216{217 if (priority > vdo_get_log_level())218 return;219 220 dump_stack();221}222 223void __vdo_log_message(int priority, const char *module, const char *format, ...)224{225 va_list args;226 227 va_start(args, format);228 vdo_log_embedded_message(priority, module, NULL, format, args, "%s", "");229 va_end(args);230}231 232/*233 * Sleep or delay a few milliseconds in an attempt to allow the log buffers to be flushed lest they234 * be overrun.235 */236void vdo_pause_for_logger(void)237{238 fsleep(4000);239}240