return 1;
}
-/*
- * Call the specified console driver, asking it to write out the specified
- * text and length. If @dropped_text is non-NULL and any records have been
- * dropped, a dropped message will be written out first.
- */
-static void call_console_driver(struct console *con, const char *text, size_t len,
- char *dropped_text)
-{
- size_t dropped_len;
-
- if (con->dropped && dropped_text) {
- dropped_len = snprintf(dropped_text, DROPPED_TEXT_MAX,
- "** %lu printk messages dropped **\n",
- con->dropped);
- con->dropped = 0;
- con->write(con, dropped_text, dropped_len);
- }
-
- con->write(con, text, len);
-}
-
/*
* Recursion is tracked separately on each CPU. If NMIs are supported, an
* additional NMI context per CPU is also separately tracked. Until per-CPU
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 void call_console_driver(struct console *con, const char *text, size_t len,
- char *dropped_text)
-{
-}
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; }
up_console_sem();
}
+/*
+ * Prepend the message in @pmsg->pbufs->outbuf with a "dropped message". This
+ * is achieved by shifting the existing message over and inserting the dropped
+ * message.
+ *
+ * @pmsg is the printk message to prepend.
+ *
+ * @dropped is the dropped count to report in the dropped message.
+ *
+ * If the message text in @pmsg->pbufs->outbuf does not have enough space for
+ * the dropped message, the message text will be sufficiently truncated.
+ *
+ * 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)
+{
+ struct printk_buffers *pbufs = pmsg->pbufs;
+ const size_t scratchbuf_sz = sizeof(pbufs->scratchbuf);
+ const size_t outbuf_sz = sizeof(pbufs->outbuf);
+ char *scratchbuf = &pbufs->scratchbuf[0];
+ char *outbuf = &pbufs->outbuf[0];
+ size_t len;
+
+ len = snprintf(scratchbuf, scratchbuf_sz,
+ "** %lu printk messages dropped **\n", dropped);
+
+ /*
+ * Make sure outbuf is sufficiently large before prepending.
+ * Keep at least the prefix when the message must be truncated.
+ * It is a rather theoretical problem when someone tries to
+ * use a minimalist buffer.
+ */
+ if (WARN_ON_ONCE(len + PREFIX_MAX >= outbuf_sz))
+ return;
+
+ if (pmsg->outbuf_len + len >= outbuf_sz) {
+ /* Truncate the message, but keep it terminated. */
+ pmsg->outbuf_len = outbuf_sz - (len + 1);
+ outbuf[pmsg->outbuf_len] = 0;
+ }
+
+ memmove(outbuf + len, outbuf, pmsg->outbuf_len + 1);
+ 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
* record is not available).
*/
static bool console_emit_next_record(struct console *con, bool *handover, int cookie)
{
- static char dropped_text[DROPPED_TEXT_MAX];
static struct printk_buffers pbufs;
bool is_extended = console_srcu_read_flags(con) & CON_EXTENDED;
goto skip;
}
+ if (con->dropped && !is_extended) {
+ console_prepend_dropped(&pmsg, con->dropped);
+ con->dropped = 0;
+ }
+
/*
* While actively printing out messages, if another printk()
* were to occur on another CPU, it may wait for this one to
printk_safe_enter_irqsave(flags);
console_lock_spinning_enable();
- stop_critical_timings(); /* don't trace print latency */
- call_console_driver(con, outbuf, pmsg.outbuf_len,
- is_extended ? NULL : dropped_text);
+ /* Do not trace print latency. */
+ stop_critical_timings();
+
+ /* Write everything out to the hardware. */
+ con->write(con, outbuf, pmsg.outbuf_len);
+
start_critical_timings();
con->seq = pmsg.seq + 1;