Before this change _invalid_pc_placeholder pointed to address of _init
function from crti.o
This made GDB input a bit confusing:
0x40080400 in _init ()
(gdb) bt
#0 0x40080400 in _init ()
#1 0x400e519a in test_instr_fetch_prohibited () at /home/alex/git/esp-idf/tools/test_apps/system/panic/main/test_panic.c:271
#2 0x400d89a7 in app_main () at /home/alex/git/esp-idf/tools/test_apps/system/panic/main/test_app_main.c:116
#3 0x400e5f22 in main_task (args=0x0) at /home/alex/git/esp-idf/components/freertos/app_startup.c:208
#4 0x400895a8 in vPortTaskWrapper (pxCode=0x400e5eb0 <main_task>, pvParameters=0x0) at /home/alex/git/esp-idf/components/freertos/FreeRTOS-Kernel/portable/xtensa/port.c:139
After the change GDB prints output that contains a hint:
_invalid_pc_placeholder () at /home/alex/git/esp-idf/components/xtensa/xtensa_vectors.S:2235
2235 UNREACHABLE_INSTRUCTION_CHECK_PREVIOUS_FRAMES
(gdb) bt
#0 _invalid_pc_placeholder () at /home/alex/git/esp-idf/components/xtensa/xtensa_vectors.S:2235
#1 0x400e519e in test_instr_fetch_prohibited () at /home/alex/git/esp-idf/tools/test_apps/system/panic/main/test_panic.c:271
#2 0x400d89ab in app_main () at /home/alex/git/esp-idf/tools/test_apps/system/panic/main/test_app_main.c:116
#3 0x400e5f26 in main_task (args=0x0) at /home/alex/git/esp-idf/components/freertos/app_startup.c:208
#4 0x400895a8 in vPortTaskWrapper (pxCode=0x400e5eb4 <main_task>, pvParameters=0x0) at /home/alex/git/esp-idf/components/freertos/FreeRTOS-Kernel/portable/xtensa/port.c:139
- As the PMA entry that made some memory regions cacheable was
assigned the highest priority, some intermediate inaccessible
memory regions bypassed protection.
- Added tests for the same
- Verified that even after changing the priority of the PMA entry,
a write operation at SOC_IRAM_LOW + 0x40 (a random RAM cached address)
still needs the same number (29) of CPU cycles.
fix(panic): fixed cache error being reported as illegal instruction
Closes IDF-6398, IDF-5657, IDF-7015, and IDF-6733
See merge request espressif/esp-idf!27430
On riscv chips accessing cache mapped memory regions over the ibus would
result in an illegal instructions exception triggering faster than the cache
error interrupt/exception.
Added a cache error check in the panic handler, if any cache errors are active
the panic handler will now report a cache error, even if the trigger exception
was a illegal instructions.
- add hardware stack guard based on assist-debug module
- enable hardware stack guard by default
- disable hardware stack guard for freertos ci.release test
- refactor rtos_int_enter/rtos_int_exit to change SP register inside them
- fix panic_reason.h header for RISC-V
- update docs to include information about the new feature
- Add support for esp32s2, esp32c3 and esp32c2 for the `memprot`-related tests
- Preliminary support for esp32s3 has also been added,
the test app will be enabled for esp32s3 later when
the memprot-related issues are fixed.
- Override panic handler to dump the violation intr status
- Dump the `memprot` violation registers before calling the
real panic handler
- Handle `Illegal Instruction` exception in case of memprot permission violation
* In esp32c3 with `memprot` enabled, if we try to execute arbitrary code
from RTC_FAST_MEM we get an `Illegal Instruction` exception from the panic
handler rather than a `Memory Protection Fault`.
* This is because the Illegal Instruction interrupt occurs earlier than the
memory protection interrupt due to a higher interrupt latency.
