From 326814784b4528257165e289ec654435a87db122 Mon Sep 17 00:00:00 2001
From: Rahix <rahix@rahix.de>
Date: Sat, 24 Aug 2019 00:32:40 +0200
Subject: [PATCH] fix(serial): Perform serial prints in a critical section
Sometimes during initialization, one `log_msg()` intercepts another one,
leading to a whole lot of weird issues in other modules (like I2C). I
suspect this to be memory corruption of some kind. The issues can be
fixed by performing serial prints in a critical section, thus ensuring
atomicity of prints. Note that this does not mean log messages will not
interleave.
The CDC-ACM and BLE-Serial writes cannot be put into a critical section
and are thus a point where this code can still fail. For now, however,
this fix ensures the race-conditions during startup, where USB and BLE
are not yet running, don't happen anymore.
Signed-off-by: Rahix <rahix@rahix.de>
---
epicardium/modules/serial.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/epicardium/modules/serial.c b/epicardium/modules/serial.c
index a7392056..b7be0594 100644
--- a/epicardium/modules/serial.c
+++ b/epicardium/modules/serial.c
@@ -27,7 +27,21 @@ static QueueHandle_t read_queue;
*/
void epic_uart_write_str(const char *str, intptr_t length)
{
+ uint32_t basepri = __get_BASEPRI();
+ if (xPortIsInsideInterrupt()) {
+ taskENTER_CRITICAL_FROM_ISR();
+ } else {
+ taskENTER_CRITICAL();
+ }
+
UART_Write(ConsoleUart, (uint8_t *)str, length);
+
+ if (xPortIsInsideInterrupt()) {
+ taskEXIT_CRITICAL_FROM_ISR(basepri);
+ } else {
+ taskEXIT_CRITICAL();
+ }
+
cdcacm_write((uint8_t *)str, length);
ble_uart_write((uint8_t *)str, length);
}
--
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