diff options
Diffstat (limited to 'kernel/printk/printk.c')
-rw-r--r-- | kernel/printk/printk.c | 307 |
1 files changed, 191 insertions, 116 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 13e839d..02d6b6d 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -45,6 +45,7 @@ #include <linux/poll.h> #include <linux/irq_work.h> #include <linux/utsname.h> +#include <linux/ctype.h> #include <asm/uaccess.h> @@ -56,14 +57,11 @@ int console_printk[4] = { CONSOLE_LOGLEVEL_DEFAULT, /* console_loglevel */ - DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */ + MESSAGE_LOGLEVEL_DEFAULT, /* default_message_loglevel */ CONSOLE_LOGLEVEL_MIN, /* minimum_console_loglevel */ CONSOLE_LOGLEVEL_DEFAULT, /* default_console_loglevel */ }; -/* Deferred messaged from sched code are marked by this special level */ -#define SCHED_MESSAGE_LOGLEVEL -2 - /* * Low level drivers may need that to know if they can schedule in * their unblank() callback or not. So let's export it. @@ -113,9 +111,9 @@ static int __down_trylock_console_sem(unsigned long ip) * This is used for debugging the mess that is the VT code by * keeping track if we have the console semaphore held. It's * definitely not the perfect debug tool (we don't know if _WE_ - * hold it are racing, but it helps tracking those weird code - * path in the console code where we end up in places I want - * locked without the console sempahore held + * hold it and are racing, but it helps tracking those weird code + * paths in the console code where we end up in places I want + * locked without the console sempahore held). */ static int console_locked, console_suspended; @@ -146,8 +144,8 @@ static int console_may_schedule; * the overall length of the record. * * The heads to the first and last entry in the buffer, as well as the - * sequence numbers of these both entries are maintained when messages - * are stored.. + * sequence numbers of these entries are maintained when messages are + * stored. * * If the heads indicate available messages, the length in the header * tells the start next message. A length == 0 for the next message @@ -257,7 +255,7 @@ static u64 clear_seq; static u32 clear_idx; #define PREFIX_MAX 32 -#define LOG_LINE_MAX 1024 - PREFIX_MAX +#define LOG_LINE_MAX (1024 - PREFIX_MAX) /* record buffer */ #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) @@ -270,6 +268,18 @@ static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); static char *log_buf = __log_buf; static u32 log_buf_len = __LOG_BUF_LEN; +/* Return log buffer address */ +char *log_buf_addr_get(void) +{ + return log_buf; +} + +/* Return log buffer size */ +u32 log_buf_len_get(void) +{ + return log_buf_len; +} + /* human readable text of the record */ static char *log_text(const struct printk_log *msg) { @@ -344,7 +354,7 @@ static int log_make_free_space(u32 msg_size) while (log_first_seq < log_next_seq) { if (logbuf_has_space(msg_size, false)) return 0; - /* drop old messages until we have enough continuous space */ + /* drop old messages until we have enough contiguous space */ log_first_idx = log_next(log_first_idx); log_first_seq++; } @@ -453,11 +463,7 @@ static int log_store(int facility, int level, return msg->text_len; } -#ifdef CONFIG_SECURITY_DMESG_RESTRICT -int dmesg_restrict = 1; -#else -int dmesg_restrict; -#endif +int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT); static int syslog_action_restricted(int type) { @@ -471,7 +477,7 @@ static int syslog_action_restricted(int type) type != SYSLOG_ACTION_SIZE_BUFFER; } -static int check_syslog_permissions(int type, bool from_file) +int check_syslog_permissions(int type, bool from_file) { /* * If this is from /proc/kmsg and we've already opened it, then we've @@ -509,14 +515,13 @@ struct devkmsg_user { char buf[8192]; }; -static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv, - unsigned long count, loff_t pos) +static ssize_t devkmsg_write(struct kiocb *iocb, struct iov_iter *from) { char *buf, *line; int i; int level = default_message_loglevel; int facility = 1; /* LOG_USER */ - size_t len = iov_length(iv, count); + size_t len = iocb->ki_nbytes; ssize_t ret = len; if (len > LOG_LINE_MAX) @@ -525,13 +530,10 @@ static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv, if (buf == NULL) return -ENOMEM; - line = buf; - for (i = 0; i < count; i++) { - if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len)) { - ret = -EFAULT; - goto out; - } - line += iv[i].iov_len; + buf[len] = '\0'; + if (copy_from_iter(buf, len, from) != len) { + kfree(buf); + return -EFAULT; } /* @@ -557,10 +559,8 @@ static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv, line = endp; } } - line[len] = '\0'; printk_emit(facility, level, NULL, 0, "%s", line); -out: kfree(buf); return ret; } @@ -792,7 +792,7 @@ static int devkmsg_release(struct inode *inode, struct file *file) const struct file_operations kmsg_fops = { .open = devkmsg_open, .read = devkmsg_read, - .aio_write = devkmsg_writev, + .write_iter = devkmsg_write, .llseek = devkmsg_llseek, .poll = devkmsg_poll, .release = devkmsg_release, @@ -828,34 +828,80 @@ void log_buf_kexec_setup(void) /* requested log_buf_len from kernel cmdline */ static unsigned long __initdata new_log_buf_len; -/* save requested log_buf_len since it's too early to process it */ -static int __init log_buf_len_setup(char *str) +/* we practice scaling the ring buffer by powers of 2 */ +static void __init log_buf_len_update(unsigned size) { - unsigned size = memparse(str, &str); - if (size) size = roundup_pow_of_two(size); if (size > log_buf_len) new_log_buf_len = size; +} + +/* save requested log_buf_len since it's too early to process it */ +static int __init log_buf_len_setup(char *str) +{ + unsigned size = memparse(str, &str); + + log_buf_len_update(size); return 0; } early_param("log_buf_len", log_buf_len_setup); +#ifdef CONFIG_SMP +#define __LOG_CPU_MAX_BUF_LEN (1 << CONFIG_LOG_CPU_MAX_BUF_SHIFT) + +static void __init log_buf_add_cpu(void) +{ + unsigned int cpu_extra; + + /* + * archs should set up cpu_possible_bits properly with + * set_cpu_possible() after setup_arch() but just in + * case lets ensure this is valid. + */ + if (num_possible_cpus() == 1) + return; + + cpu_extra = (num_possible_cpus() - 1) * __LOG_CPU_MAX_BUF_LEN; + + /* by default this will only continue through for large > 64 CPUs */ + if (cpu_extra <= __LOG_BUF_LEN / 2) + return; + + pr_info("log_buf_len individual max cpu contribution: %d bytes\n", + __LOG_CPU_MAX_BUF_LEN); + pr_info("log_buf_len total cpu_extra contributions: %d bytes\n", + cpu_extra); + pr_info("log_buf_len min size: %d bytes\n", __LOG_BUF_LEN); + + log_buf_len_update(cpu_extra + __LOG_BUF_LEN); +} +#else /* !CONFIG_SMP */ +static inline void log_buf_add_cpu(void) {} +#endif /* CONFIG_SMP */ + void __init setup_log_buf(int early) { unsigned long flags; char *new_log_buf; int free; + if (log_buf != __log_buf) + return; + + if (!early && !new_log_buf_len) + log_buf_add_cpu(); + if (!new_log_buf_len) return; if (early) { new_log_buf = - memblock_virt_alloc(new_log_buf_len, PAGE_SIZE); + memblock_virt_alloc(new_log_buf_len, LOG_ALIGN); } else { - new_log_buf = memblock_virt_alloc_nopanic(new_log_buf_len, 0); + new_log_buf = memblock_virt_alloc_nopanic(new_log_buf_len, + LOG_ALIGN); } if (unlikely(!new_log_buf)) { @@ -872,7 +918,7 @@ void __init setup_log_buf(int early) memcpy(log_buf, __log_buf, __LOG_BUF_LEN); raw_spin_unlock_irqrestore(&logbuf_lock, flags); - pr_info("log_buf_len: %d\n", log_buf_len); + pr_info("log_buf_len: %d bytes\n", log_buf_len); pr_info("early log buf free: %d(%d%%)\n", free, (free * 100) / __LOG_BUF_LEN); } @@ -881,7 +927,7 @@ static bool __read_mostly ignore_loglevel; static int __init ignore_loglevel_setup(char *str) { - ignore_loglevel = 1; + ignore_loglevel = true; pr_info("debug: ignoring loglevel setting.\n"); return 0; @@ -947,11 +993,7 @@ static inline void boot_delay_msec(int level) } #endif -#if defined(CONFIG_PRINTK_TIME) -static bool printk_time = 1; -#else -static bool printk_time; -#endif +static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME); module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); static size_t print_time(u64 ts, char *buf) @@ -1214,7 +1256,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear) int do_syslog(int type, char __user *buf, int len, bool from_file) { bool clear = false; - static int saved_console_loglevel = -1; + static int saved_console_loglevel = LOGLEVEL_DEFAULT; int error; error = check_syslog_permissions(type, from_file); @@ -1271,15 +1313,15 @@ int do_syslog(int type, char __user *buf, int len, bool from_file) break; /* Disable logging to console */ case SYSLOG_ACTION_CONSOLE_OFF: - if (saved_console_loglevel == -1) + if (saved_console_loglevel == LOGLEVEL_DEFAULT) saved_console_loglevel = console_loglevel; console_loglevel = minimum_console_loglevel; break; /* Enable logging to console */ case SYSLOG_ACTION_CONSOLE_ON: - if (saved_console_loglevel != -1) { + if (saved_console_loglevel != LOGLEVEL_DEFAULT) { console_loglevel = saved_console_loglevel; - saved_console_loglevel = -1; + saved_console_loglevel = LOGLEVEL_DEFAULT; } break; /* Set level of messages printed to console */ @@ -1291,7 +1333,7 @@ int do_syslog(int type, char __user *buf, int len, bool from_file) len = minimum_console_loglevel; console_loglevel = len; /* Implicitly re-enable logging to console */ - saved_console_loglevel = -1; + saved_console_loglevel = LOGLEVEL_DEFAULT; error = 0; break; /* Number of chars in the log buffer */ @@ -1310,7 +1352,7 @@ int do_syslog(int type, char __user *buf, int len, bool from_file) * for pending data, not the size; return the count of * records, not the length. */ - error = log_next_idx - syslog_idx; + error = log_next_seq - syslog_seq; } else { u64 seq = syslog_seq; u32 idx = syslog_idx; @@ -1416,10 +1458,9 @@ static int have_callable_console(void) /* * Can we actually use the console at this time on this cpu? * - * Console drivers may assume that per-cpu resources have - * been allocated. So unless they're explicitly marked as - * being able to cope (CON_ANYTIME) don't call them until - * this CPU is officially up. + * Console drivers may assume that per-cpu resources have been allocated. So + * unless they're explicitly marked as being able to cope (CON_ANYTIME) don't + * call them until this CPU is officially up. */ static inline int can_use_console(unsigned int cpu) { @@ -1432,8 +1473,10 @@ static inline int can_use_console(unsigned int cpu) * console_lock held, and 'console_locked' set) if it * is successful, false otherwise. */ -static int console_trylock_for_printk(unsigned int cpu) +static int console_trylock_for_printk(void) { + unsigned int cpu = smp_processor_id(); + if (!console_trylock()) return 0; /* @@ -1476,7 +1519,7 @@ static struct cont { struct task_struct *owner; /* task of first print*/ u64 ts_nsec; /* time of first print */ u8 level; /* log level of first message */ - u8 facility; /* log level of first message */ + u8 facility; /* log facility of first message */ enum log_flags flags; /* prefix, newline flags */ bool flushed:1; /* buffer sealed and committed */ } cont; @@ -1581,10 +1624,10 @@ asmlinkage int vprintk_emit(int facility, int level, int printed_len = 0; bool in_sched = false; /* cpu currently holding logbuf_lock in this function */ - static volatile unsigned int logbuf_cpu = UINT_MAX; + static unsigned int logbuf_cpu = UINT_MAX; - if (level == SCHED_MESSAGE_LOGLEVEL) { - level = -1; + if (level == LOGLEVEL_SCHED) { + level = LOGLEVEL_DEFAULT; in_sched = true; } @@ -1608,7 +1651,8 @@ asmlinkage int vprintk_emit(int facility, int level, */ if (!oops_in_progress && !lockdep_recursing(current)) { recursion_bug = 1; - goto out_restore_irqs; + local_irq_restore(flags); + return 0; } zap_locks(); } @@ -1617,27 +1661,22 @@ asmlinkage int vprintk_emit(int facility, int level, raw_spin_lock(&logbuf_lock); logbuf_cpu = this_cpu; - if (recursion_bug) { + if (unlikely(recursion_bug)) { static const char recursion_msg[] = "BUG: recent printk recursion!"; recursion_bug = 0; - text_len = strlen(recursion_msg); /* emit KERN_CRIT message */ printed_len += log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0, - NULL, 0, recursion_msg, text_len); + NULL, 0, recursion_msg, + strlen(recursion_msg)); } /* * The printf needs to come first; we need the syslog * prefix which might be passed-in as a parameter. */ - if (in_sched) - text_len = scnprintf(text, sizeof(textbuf), - KERN_WARNING "[sched_delayed] "); - - text_len += vscnprintf(text + text_len, - sizeof(textbuf) - text_len, fmt, args); + text_len = vscnprintf(text, sizeof(textbuf), fmt, args); /* mark and strip a trailing newline */ if (text_len && text[text_len-1] == '\n') { @@ -1653,8 +1692,9 @@ asmlinkage int vprintk_emit(int facility, int level, const char *end_of_header = printk_skip_level(text); switch (kern_level) { case '0' ... '7': - if (level == -1) + if (level == LOGLEVEL_DEFAULT) level = kern_level - '0'; + /* fallthrough */ case 'd': /* KERN_DEFAULT */ lflags |= LOG_PREFIX; } @@ -1668,7 +1708,7 @@ asmlinkage int vprintk_emit(int facility, int level, } } - if (level == -1) + if (level == LOGLEVEL_DEFAULT) level = default_message_loglevel; if (dict) @@ -1716,28 +1756,37 @@ asmlinkage int vprintk_emit(int facility, int level, logbuf_cpu = UINT_MAX; raw_spin_unlock(&logbuf_lock); + lockdep_on(); + local_irq_restore(flags); /* If called from the scheduler, we can not call up(). */ if (!in_sched) { + lockdep_off(); + /* + * Disable preemption to avoid being preempted while holding + * console_sem which would prevent anyone from printing to + * console + */ + preempt_disable(); + /* * Try to acquire and then immediately release the console * semaphore. The release will print out buffers and wake up * /dev/kmsg and syslog() users. */ - if (console_trylock_for_printk(this_cpu)) + if (console_trylock_for_printk()) console_unlock(); + preempt_enable(); + lockdep_on(); } - lockdep_on(); -out_restore_irqs: - local_irq_restore(flags); return printed_len; } EXPORT_SYMBOL(vprintk_emit); asmlinkage int vprintk(const char *fmt, va_list args) { - return vprintk_emit(0, -1, NULL, 0, fmt, args); + return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args); } EXPORT_SYMBOL(vprintk); @@ -1756,6 +1805,30 @@ asmlinkage int printk_emit(int facility, int level, } EXPORT_SYMBOL(printk_emit); +int vprintk_default(const char *fmt, va_list args) +{ + int r; + +#ifdef CONFIG_KGDB_KDB + if (unlikely(kdb_trap_printk)) { + r = vkdb_printf(fmt, args); + return r; + } +#endif + r = vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args); + + return r; +} +EXPORT_SYMBOL_GPL(vprintk_default); + +/* + * This allows printk to be diverted to another function per cpu. + * This is useful for calling printk functions from within NMI + * without worrying about race conditions that can lock up the + * box. + */ +DEFINE_PER_CPU(printk_func_t, printk_func) = vprintk_default; + /** * printk - print a kernel message * @fmt: format string @@ -1779,19 +1852,21 @@ EXPORT_SYMBOL(printk_emit); */ asmlinkage __visible int printk(const char *fmt, ...) { + printk_func_t vprintk_func; va_list args; int r; -#ifdef CONFIG_KGDB_KDB - if (unlikely(kdb_trap_printk)) { - va_start(args, fmt); - r = vkdb_printf(fmt, args); - va_end(args); - return r; - } -#endif va_start(args, fmt); - r = vprintk_emit(0, -1, NULL, 0, fmt, args); + + /* + * If a caller overrides the per_cpu printk_func, then it needs + * to disable preemption when calling printk(). Otherwise + * the printk_func should be set to the default. No need to + * disable preemption here. + */ + vprintk_func = this_cpu_read(printk_func); + r = vprintk_func(fmt, args); + va_end(args); return r; @@ -1802,7 +1877,7 @@ EXPORT_SYMBOL(printk); #define LOG_LINE_MAX 0 #define PREFIX_MAX 0 -#define LOG_LINE_MAX 0 + static u64 syslog_seq; static u32 syslog_idx; static u64 console_seq; @@ -1825,28 +1900,28 @@ static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev, bool syslog, char *buf, size_t size) { return 0; } static size_t cont_print_text(char *text, size_t size) { return 0; } +/* Still needs to be defined for users */ +DEFINE_PER_CPU(printk_func_t, printk_func); + #endif /* CONFIG_PRINTK */ #ifdef CONFIG_EARLY_PRINTK struct console *early_console; -void early_vprintk(const char *fmt, va_list ap) -{ - if (early_console) { - char buf[512]; - int n = vscnprintf(buf, sizeof(buf), fmt, ap); - - early_console->write(early_console, buf, n); - } -} - asmlinkage __visible void early_printk(const char *fmt, ...) { va_list ap; + char buf[512]; + int n; + + if (!early_console) + return; va_start(ap, fmt); - early_vprintk(fmt, ap); + n = vscnprintf(buf, sizeof(buf), fmt, ap); va_end(ap); + + early_console->write(early_console, buf, n); } #endif @@ -1881,11 +1956,12 @@ static int __add_preferred_console(char *name, int idx, char *options, return 0; } /* - * Set up a list of consoles. Called from init/main.c + * Set up a console. Called via do_early_param() in init/main.c + * for each "console=" parameter in the boot command line. */ static int __init console_setup(char *str) { - char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */ + char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for "ttyS" */ char *s, *options, *brl_options = NULL; int idx; @@ -1902,7 +1978,8 @@ static int __init console_setup(char *str) strncpy(buf, str, sizeof(buf) - 1); } buf[sizeof(buf) - 1] = 0; - if ((options = strchr(str, ',')) != NULL) + options = strchr(str, ','); + if (options) *(options++) = 0; #ifdef __sparc__ if (!strcmp(str, "ttya")) @@ -1911,7 +1988,7 @@ static int __init console_setup(char *str) strcpy(buf, "ttyS1"); #endif for (s = buf; *s; s++) - if ((*s >= '0' && *s <= '9') || *s == ',') + if (isdigit(*s) || *s == ',') break; idx = simple_strtoul(s, NULL, 10); *s = 0; @@ -1950,7 +2027,6 @@ int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, cha i++, c++) if (strcmp(c->name, name) == 0 && c->index == idx) { strlcpy(c->name, name_new, sizeof(c->name)); - c->name[sizeof(c->name) - 1] = 0; c->options = options; c->index = idx_new; return i; @@ -1959,12 +2035,12 @@ int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, cha return -1; } -bool console_suspend_enabled = 1; +bool console_suspend_enabled = true; EXPORT_SYMBOL(console_suspend_enabled); static int __init console_suspend_disable(char *str) { - console_suspend_enabled = 0; + console_suspend_enabled = false; return 1; } __setup("no_console_suspend", console_suspend_disable); @@ -2045,8 +2121,8 @@ EXPORT_SYMBOL(console_lock); /** * console_trylock - try to lock the console system for exclusive use. * - * Tried to acquire a lock which guarantees that the caller has - * exclusive access to the console system and the console_drivers list. + * Try to acquire a lock which guarantees that the caller has exclusive + * access to the console system and the console_drivers list. * * returns 1 on success, and 0 on failure to acquire the lock. */ @@ -2570,7 +2646,7 @@ void wake_up_klogd(void) preempt_disable(); if (waitqueue_active(&log_wait)) { this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP); - irq_work_queue(&__get_cpu_var(wake_up_klogd_work)); + irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); } preempt_enable(); } @@ -2582,11 +2658,11 @@ int printk_deferred(const char *fmt, ...) preempt_disable(); va_start(args, fmt); - r = vprintk_emit(0, SCHED_MESSAGE_LOGLEVEL, NULL, 0, fmt, args); + r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args); va_end(args); __this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT); - irq_work_queue(&__get_cpu_var(wake_up_klogd_work)); + irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); preempt_enable(); return r; @@ -2618,14 +2694,13 @@ EXPORT_SYMBOL(__printk_ratelimit); bool printk_timed_ratelimit(unsigned long *caller_jiffies, unsigned int interval_msecs) { - if (*caller_jiffies == 0 - || !time_in_range(jiffies, *caller_jiffies, - *caller_jiffies - + msecs_to_jiffies(interval_msecs))) { - *caller_jiffies = jiffies; - return true; - } - return false; + unsigned long elapsed = jiffies - *caller_jiffies; + + if (*caller_jiffies && elapsed <= msecs_to_jiffies(interval_msecs)) + return false; + + *caller_jiffies = jiffies; + return true; } EXPORT_SYMBOL(printk_timed_ratelimit); |