In order to turn longjmp context-switch safe, it's necessary
to disable interrupts before modifying windowbase and windowstart.
Otherwise, after a context switch, windowstart and windowbase
would be different, leading to a wrongly set windowstart bit due to
longjmp writing it based on the windowbase before the context switch.
This corrupts the registers at the next window overflow reaching
that wrongly set bit.
*Background:*
This PR is related to an issue first observed on ESP-IDF
https://github.com/espressif/esp-idf/issues/5229 and it was, then,
checked on NuttX using a test application.
*The test application:*
To check if the problem affects ESP32, ESP32-S2 and ESP32-S3 on
NuttX, it was created an application based on:
https://en.cppreference.com/w/c/program/longjmp
The application creates 16 tasks (`#define NUMBER_OF_TASKS 16`)
that implements the following daemon:
```
static int setjmp_longjmp_daemon(int argc, char *argv[])
{
for (int i = 0; i < NUMBER_OF_TASKS * 2; i++)
{
jmp_buf env;
volatile int count = 0;
if (setjmp(env) != UINT16_MAX)
{
foo(&env, ++count);
}
}
sem_post(&g_sem);
return EXIT_SUCCESS;
}
```
The main function also initializes a semaphore to avoid application
exiting before tasks return successfully:
```
sem_init(&g_sem, 0, -NUMBER_OF_TASKS);
```
Finally, the round-robin interval was lowered to 1ms to raise the
chances of the longjmp being interrupted by a context switch
(`CONFIG_RR_INTERVAL=1).
This setup was able to reproduce the problem prior to this patch
being applied.
- Add ioctl method to enable allocating the apb buffer.
- Add RX methods to set data width, sample rate, channels and
for receiving data from the I2S peripheral.
- Update the i2schar defconfig to enable the I2S receiver.
- Add nxlooper defconfig to enable testing the RX interface.
- Add specific bindings on ESP32-S2 bringup to enable nxlooper
to work without the need of any specific codec.
Add initial support for the I2S peripheral on ESP32S2.
Add I2S character driver and generic I2S audio driver.
Include i2schar defconfig for ESP32-S2-Saola-1 board.
since the related code was removed by:
commit 4d5a964f29
Author: Jiuzhu Dong <dongjiuzhu1@xiaomi.com>
Date: Tue Feb 23 18:04:13 2021 +0800
net: unify socket into file descriptor
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
