Commit 891eb3b0 was fixing an issue with PS and EPC1 not being
preserved after the window spill procedure. It did so by saving PS in
a2 and EPC1 in a4. However the a4 register may be a live register of
another window in the call stack, and if it is overwritten and then
spilled to the stack, then the corresponding register value will end
up being corrupted. In practice the problem would show up as an
IllegalInstruction exception, when trying to return from a function
when a0 value was 0x40020.
Fix by using a0 register instead of a4 as scratch. Also fix a comment
about xthal_save_extra_nw, as this function in fact doesn't clobber
a4 or a5 because XCHAL_NCP_NUM_ATMPS is defined as 1.
Closes https://github.com/espressif/esp-idf/issues/5758
CONFIG_FREERTOS_ISR_STACKSIZE was set to 2100 when ELF core dump was
enabled, which resulted in a non-16-byte-aligned interrupt stack
offset. This triggered "is SP corrupted" check in the backtrace,
terminating the backtrace early.
Fix the default value, and make sure that the stack is always aligned,
regardless of the value of CONFIG_FREERTOS_ISR_STACKSIZE.
This MR uses an intermediary function `start_app` to call after system
initialization instead of `app_main`.
In RTOS builds, freertos provides `start_app` and calls `app_main`.
In non-RTOS builds, user provides `start_app` directly.
Changes the startup flow to the ff:
hardware -> core libraries init -> other libraries init -> os
init (optional) -> app_main
- hardware init resides in the port layer, and is the entry point
- core libraries init executes init functions of core components
- other libraries init executes init functions of other components (weak
references)
- after other lib is init, the app_main function is called, however,
an OS can wrap the real call to app_main to init its own stuff, and
*then* call the real app_main
FreeRTOS scheduler uses additional stack space, as in some functions
variables are placed onto the stack instead of registers.
This issue resulted in occasional stack overflows in dport task, when
compiling at -O0 optimization level.
- Increase the configMINIMAL_STACK_SIZE to 1kB.
- Enable the watchpoint at the end of stack in CI startup test for
this optimization level.
This fixes the issue where XTOS_SET_INTLEVEL would lower INTLEVEL from
4 to 3, when eTaskGetState is invoked during the core dump, triggered
from the interrupt watchdog.
Configurable option to use IRAM as byte accessible memory (in single core mode) using
load-store (non-word aligned and non-word size IRAM access specific) exception handlers.
This allows to use IRAM for use-cases where certain performance penalty
(upto 170 cpu cycles per load or store operation) is acceptable. Additional configuration
option has been provided to redirect mbedTLS specific in-out content length buffers to
IRAM (in single core mode), allows to save 20KB per TLS connection.
