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.
Selecting this option will pass "-Map=$(TOPDIR)$(DELIM)nuttx.map" to ld
when linking NuttX ELF. That file can be useful for verifying
and debugging magic section games, and for seeing which
pieces of code get eliminated with DEBUG_OPT_UNUSED_SECTIONS.
Signed-off-by: chao.an <anchao@xiaomi.com>
Enable this option to optimization the unused input sections with the
linker by compiling with " -ffunction-sections -fdata-sections ", and
linking with " --gc-sections ".
Signed-off-by: chao.an <anchao@xiaomi.com>
## Summary
A lot of linker scripts were listed twice, once for unix, once for windows.
This PR cleans up the logic so they're only listed once.
## Impact
Any opportunity to use a single source of truth and reduce lines of code is a win!
## Testing
CI will test all build
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>
