diff options
author | Petr Mladek <pmladek@suse.com> | 2023-11-02 15:04:59 +0300 |
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committer | Petr Mladek <pmladek@suse.com> | 2023-11-02 15:04:59 +0300 |
commit | 2966bd3698451a2172a57e7e97eebb4adbfc48a2 (patch) | |
tree | c598605616f88cd1b9ad15e14872a962265d8f7f /kernel/printk/printk.c | |
parent | 86098bcddeb10ae7975d701c3440d912bd2ebe12 (diff) | |
parent | 98a0465531a5982dd897fd81222a5d3465999951 (diff) | |
download | linux-2966bd3698451a2172a57e7e97eebb4adbfc48a2.tar.xz |
Merge branch 'rework/nbcon-base' into for-linus
Diffstat (limited to 'kernel/printk/printk.c')
-rw-r--r-- | kernel/printk/printk.c | 122 |
1 files changed, 73 insertions, 49 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 95689eccf0fb..be95a6851164 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -102,12 +102,6 @@ DEFINE_STATIC_SRCU(console_srcu); */ int __read_mostly suppress_printk; -/* - * During panic, heavy printk by other CPUs can delay the - * panic and risk deadlock on console resources. - */ -static int __read_mostly suppress_panic_printk; - #ifdef CONFIG_LOCKDEP static struct lockdep_map console_lock_dep_map = { .name = "console_lock" @@ -445,6 +439,12 @@ static int console_msg_format = MSG_FORMAT_DEFAULT; static DEFINE_MUTEX(syslog_lock); #ifdef CONFIG_PRINTK +/* + * During panic, heavy printk by other CPUs can delay the + * panic and risk deadlock on console resources. + */ +static int __read_mostly suppress_panic_printk; + DECLARE_WAIT_QUEUE_HEAD(log_wait); /* All 3 protected by @syslog_lock. */ /* the next printk record to read by syslog(READ) or /proc/kmsg */ @@ -494,7 +494,7 @@ _DEFINE_PRINTKRB(printk_rb_static, CONFIG_LOG_BUF_SHIFT - PRB_AVGBITS, static struct printk_ringbuffer printk_rb_dynamic; -static struct printk_ringbuffer *prb = &printk_rb_static; +struct printk_ringbuffer *prb = &printk_rb_static; /* * We cannot access per-CPU data (e.g. per-CPU flush irq_work) before @@ -698,9 +698,6 @@ out: return len; } -static bool printk_get_next_message(struct printk_message *pmsg, u64 seq, - bool is_extended, bool may_supress); - /* /dev/kmsg - userspace message inject/listen interface */ struct devkmsg_user { atomic64_t seq; @@ -2348,22 +2345,6 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre static u64 syslog_seq; -static size_t record_print_text(const struct printk_record *r, - bool syslog, bool time) -{ - return 0; -} -static ssize_t info_print_ext_header(char *buf, size_t size, - struct printk_info *info) -{ - return 0; -} -static ssize_t msg_print_ext_body(char *buf, size_t size, - char *text, size_t text_len, - struct dev_printk_info *dev_info) { return 0; } -static void console_lock_spinning_enable(void) { } -static int console_lock_spinning_disable_and_check(int cookie) { return 0; } -static bool suppress_message_printing(int level) { return false; } static bool pr_flush(int timeout_ms, bool reset_on_progress) { return true; } static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progress) { return true; } @@ -2717,6 +2698,8 @@ static void __console_unlock(void) up_console_sem(); } +#ifdef CONFIG_PRINTK + /* * Prepend the message in @pmsg->pbufs->outbuf with a "dropped message". This * is achieved by shifting the existing message over and inserting the dropped @@ -2731,8 +2714,7 @@ static void __console_unlock(void) * * If @pmsg->pbufs->outbuf is modified, @pmsg->outbuf_len is updated. */ -#ifdef CONFIG_PRINTK -static void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped) +void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped) { struct printk_buffers *pbufs = pmsg->pbufs; const size_t scratchbuf_sz = sizeof(pbufs->scratchbuf); @@ -2763,9 +2745,6 @@ static void console_prepend_dropped(struct printk_message *pmsg, unsigned long d memcpy(outbuf, scratchbuf, len); pmsg->outbuf_len += len; } -#else -#define console_prepend_dropped(pmsg, dropped) -#endif /* CONFIG_PRINTK */ /* * Read and format the specified record (or a later record if the specified @@ -2786,8 +2765,8 @@ static void console_prepend_dropped(struct printk_message *pmsg, unsigned long d * of @pmsg are valid. (See the documentation of struct printk_message * for information about the @pmsg fields.) */ -static bool printk_get_next_message(struct printk_message *pmsg, u64 seq, - bool is_extended, bool may_suppress) +bool printk_get_next_message(struct printk_message *pmsg, u64 seq, + bool is_extended, bool may_suppress) { static int panic_console_dropped; @@ -2846,6 +2825,13 @@ out: } /* + * Used as the printk buffers for non-panic, serialized console printing. + * This is for legacy (!CON_NBCON) as well as all boot (CON_BOOT) consoles. + * Its usage requires the console_lock held. + */ +struct printk_buffers printk_shared_pbufs; + +/* * Print one record for the given console. The record printed is whatever * record is the next available record for the given console. * @@ -2862,12 +2848,10 @@ out: */ static bool console_emit_next_record(struct console *con, bool *handover, int cookie) { - static struct printk_buffers pbufs; - bool is_extended = console_srcu_read_flags(con) & CON_EXTENDED; - char *outbuf = &pbufs.outbuf[0]; + char *outbuf = &printk_shared_pbufs.outbuf[0]; struct printk_message pmsg = { - .pbufs = &pbufs, + .pbufs = &printk_shared_pbufs, }; unsigned long flags; @@ -2918,6 +2902,16 @@ skip: return true; } +#else + +static bool console_emit_next_record(struct console *con, bool *handover, int cookie) +{ + *handover = false; + return false; +} + +#endif /* CONFIG_PRINTK */ + /* * Print out all remaining records to all consoles. * @@ -3162,6 +3156,7 @@ void console_flush_on_panic(enum con_flush_mode mode) if (mode == CONSOLE_REPLAY_ALL) { struct console *c; + short flags; int cookie; u64 seq; @@ -3169,11 +3164,17 @@ void console_flush_on_panic(enum con_flush_mode mode) cookie = console_srcu_read_lock(); for_each_console_srcu(c) { - /* - * This is an unsynchronized assignment, but the - * kernel is in "hope and pray" mode anyway. - */ - c->seq = seq; + flags = console_srcu_read_flags(c); + + if (flags & CON_NBCON) { + nbcon_seq_force(c, seq); + } else { + /* + * This is an unsynchronized assignment. On + * panic legacy consoles are only best effort. + */ + c->seq = seq; + } } console_srcu_read_unlock(cookie); } @@ -3325,11 +3326,6 @@ static void try_enable_default_console(struct console *newcon) newcon->flags |= CON_CONSDEV; } -#define con_printk(lvl, con, fmt, ...) \ - printk(lvl pr_fmt("%sconsole [%s%d] " fmt), \ - (con->flags & CON_BOOT) ? "boot" : "", \ - con->name, con->index, ##__VA_ARGS__) - static void console_init_seq(struct console *newcon, bool bootcon_registered) { struct console *con; @@ -3443,6 +3439,15 @@ void register_console(struct console *newcon) goto unlock; } + if (newcon->flags & CON_NBCON) { + /* + * Ensure the nbcon console buffers can be allocated + * before modifying any global data. + */ + if (!nbcon_alloc(newcon)) + goto unlock; + } + /* * See if we want to enable this console driver by default. * @@ -3470,8 +3475,11 @@ void register_console(struct console *newcon) err = try_enable_preferred_console(newcon, false); /* printk() messages are not printed to the Braille console. */ - if (err || newcon->flags & CON_BRL) + if (err || newcon->flags & CON_BRL) { + if (newcon->flags & CON_NBCON) + nbcon_free(newcon); goto unlock; + } /* * If we have a bootconsole, and are switching to a real console, @@ -3487,6 +3495,9 @@ void register_console(struct console *newcon) newcon->dropped = 0; console_init_seq(newcon, bootcon_registered); + if (newcon->flags & CON_NBCON) + nbcon_init(newcon); + /* * Put this console in the list - keep the * preferred driver at the head of the list. @@ -3578,6 +3589,9 @@ static int unregister_console_locked(struct console *console) */ synchronize_srcu(&console_srcu); + if (console->flags & CON_NBCON) + nbcon_free(console); + console_sysfs_notify(); if (console->exit) @@ -3732,6 +3746,7 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre struct console *c; u64 last_diff = 0; u64 printk_seq; + short flags; int cookie; u64 diff; u64 seq; @@ -3762,6 +3777,9 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre for_each_console_srcu(c) { if (con && con != c) continue; + + flags = console_srcu_read_flags(c); + /* * If consoles are not usable, it cannot be expected * that they make forward progress, so only increment @@ -3769,7 +3787,13 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre */ if (!console_is_usable(c)) continue; - printk_seq = c->seq; + + if (flags & CON_NBCON) { + printk_seq = nbcon_seq_read(c); + } else { + printk_seq = c->seq; + } + if (printk_seq < seq) diff += seq - printk_seq; } |