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Fix serial putchar newline deadlock #306

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Merged
Ivan-Velickovic merged 1 commit into from
Jan 30, 2025
Merged

Fix serial putchar newline deadlock #306

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7 changes: 3 additions & 4 deletions util/putchar_serial.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,8 +17,7 @@ static uint32_t local_tail;
/* Ensure to call serial_putchar_init during initialisation. Multiplexes output based on \n or when buffer is full. */
void _sddf_putchar(char character)
{
if (serial_queue_full(tx_queue_handle, local_tail) ||
(character == '\n' && serial_queue_full(tx_queue_handle, local_tail + 1))) {
if (serial_queue_full(tx_queue_handle, local_tail) || serial_queue_full(tx_queue_handle, local_tail + 1)) {
return;
}

Expand All @@ -28,7 +27,8 @@ void _sddf_putchar(char character)
serial_enqueue_local(tx_queue_handle, &local_tail, character);

/* Make changes visible to virtualiser if character is flush or if queue is now filled */
if (serial_queue_full(tx_queue_handle, local_tail) || character == FLUSH_CHAR) {
if (serial_queue_full(tx_queue_handle, local_tail) || serial_queue_full(tx_queue_handle, local_tail + 1)
|| character == FLUSH_CHAR) {
serial_update_shared_tail(tx_queue_handle, local_tail);
microkit_notify(tx_ch);
}
Expand All @@ -41,7 +41,6 @@ void sddf_putchar_unbuffered(char character)
}

serial_enqueue_local(tx_queue_handle, &local_tail, character);

serial_update_shared_tail(tx_queue_handle, local_tail);
microkit_notify(tx_ch);
}
Expand Down