diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2023-09-16 21:26:06 +0206 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2023-09-18 17:03:45 +0200 |
| commit | 06653d57ff283be627a2c769139d73ecc487810f (patch) | |
| tree | 75bf0fc325ba6723dbc506c035b3cfd31624bc79 /include/linux/console.h | |
| parent | ad56ebd1d79b216dc147474fac89a11daf6b10df (diff) | |
printk: nbcon: Add emit function and callback function for atomic printing
Implement an emit function for nbcon consoles to output printk
messages. It utilizes the lockless printk_get_next_message() and
console_prepend_dropped() functions to retrieve/build the output
message. The emit function includes the required safety points to
check for handover/takeover and calls a new write_atomic callback
of the console driver to output the message. It also includes
proper handling for updating the nbcon console sequence number.
A new nbcon_write_context struct is introduced. This is provided
to the write_atomic callback and includes only the information
necessary for performing atomic writes.
Co-developed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Thomas Gleixner (Intel) <tglx@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20230916192007.608398-8-john.ogness@linutronix.de
Diffstat (limited to 'include/linux/console.h')
| -rw-r--r-- | include/linux/console.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/include/linux/console.h b/include/linux/console.h index 20cd486b76ad..14563dcb34b1 100644 --- a/include/linux/console.h +++ b/include/linux/console.h @@ -242,6 +242,7 @@ struct printk_buffers; * be used only with NBCON_PRIO_PANIC @prio. It * might cause a system freeze when the console * is used later. + * @backlog: Ringbuffer has pending records * @pbufs: Pointer to the text buffer for this context * @seq: The sequence number to print for this context */ @@ -252,12 +253,29 @@ struct nbcon_context { enum nbcon_prio prio; unsigned int allow_unsafe_takeover : 1; + /* members set by emit */ + unsigned int backlog : 1; + /* members set by acquire */ struct printk_buffers *pbufs; u64 seq; }; /** + * struct nbcon_write_context - Context handed to the nbcon write callbacks + * @ctxt: The core console context + * @outbuf: Pointer to the text buffer for output + * @len: Length to write + * @unsafe_takeover: If a hostile takeover in an unsafe state has occurred + */ +struct nbcon_write_context { + struct nbcon_context __private ctxt; + char *outbuf; + unsigned int len; + bool unsafe_takeover; +}; + +/** * struct console - The console descriptor structure * @name: The name of the console driver * @write: Write callback to output messages (Optional) @@ -277,6 +295,7 @@ struct nbcon_context { * @data: Driver private data * @node: hlist node for the console list * + * @write_atomic: Write callback for atomic context * @nbcon_state: State for nbcon consoles * @nbcon_seq: Sequence number of the next record for nbcon to print * @pbufs: Pointer to nbcon private buffer @@ -301,6 +320,8 @@ struct console { struct hlist_node node; /* nbcon console specific members */ + bool (*write_atomic)(struct console *con, + struct nbcon_write_context *wctxt); atomic_t __private nbcon_state; atomic_long_t __private nbcon_seq; struct printk_buffers *pbufs; |