Add Kconfig option SPIRAM_ALLOW_NOINIT_EXTERNAL_MEMORY
When enabled, a new linker script rule (from esp32.extram.noinit.ld)
places any variables in the .ext_ram.noinit section in SPIRAM.
This section is exempted from the startup SPIRAM memory test and is
not zero-initialized or added to the malloc pool, making it usable
for noinit variables that persist across reset.
The EXT_RAM_NOINIT_ATTR macro places variables in this section.
The psram cache bug fix was also being applied to the bootloader binary (for cmake),
which doesnt do any psram access.
Applying this fix would increase the binary size, as much as 300 bytes in worst case scenarios
Workaround libc can be moved to flash thanks to KConfig macros.
However, the following functions: `itoa`, `memcmp`, `memcpy`, `memset`, `strcat`, `strcmp`, and `strlen` are always kept it in IRAM.
Additionally, always enable the partition MD5 check if flash encryption is on in
Release mode. This ensures the partition table ciphertext has not been modified
(CVE-2021-27926).
The exception is pre-V3.1 ESP-IDF bootloaders and partition tables, which
don't have support for the MD5 entry.
Since dd849ffc, _rodata_start label has been moved to a different
linker output section from where the TLS templates (.tdata, .tbss)
are located. Since link-time addresses of thread-local variables are
calculated relative to the section start address, this resulted in
incorrect calculation of THREADPTR/$tp registers.
Fix by introducing new linker label, _flash_rodata_start, which points
to the .flash.rodata output section where TLS variables are located,
and use it when calculating THREADPTR/$tp.
Also remove the hardcoded rodata section alignment for Xtensa targets.
Alignment of rodata can be affected by the user application, which is
the issue dd849ffc was fixing. To accommodate any possible alignment,
save it in a linker label (_flash_rodata_align) and then use when
calculating THREADPTR. Note that this is not required on RISC-V, since
this target doesn't use TPOFF.
It is now possible to have any alignment restriction on rodata in the user
applicaiton. It will not affect the first section which must be aligned
on a 16-byte bound.
Closes https://github.com/espressif/esp-idf/issues/6719
When `DIS_USB_JTAG` eFuse is NOT burned (`False`), it is not possible
to set pins 18 and 19 as GPIOs. This commit solves this by manually
disabling USB JTAG when using pins 18 or 19.
The functions shall use `gpio_hal_iomux_func_sel` instead of
`PIN_FUNC_SELELECT`.
The CPU might prefetch instructions, which means it in some cases
will try to fetch instruction located after the last instruction in
flash.text.
Add dummy bytes to ensure fetching these wont result in an error,
e.g. MMU exceptions
Fixes issue with DPORT init task, this task uses minimum stack size and may not be
enough if stack smashing detection is set to Overall mode.
Also reworks the way we calculate minimum stack to allow for adding multiple
contributing factors.
Closes https://github.com/espressif/esp-idf/issues/6403
