Before:
The cache won't be disabled when XIP on psram. But during flash
erasing/programming, read data will be courrupt.
When XIP in psram is enabled, the image is not mapped to the cache so
usually there will be no flash access. The only way to read from flash
is via the driver or use mmap. The driver has protection during erasing,
while th mmap region not.
Now:
Mmap APIs provide a flag to make mmap->unmap region mutually exclusive
to flash erase/programming when XIP from psram. SPI Flash write APIs
will benefit from this. When the flag is used, no concurrent access to
mapped region will happen while writing; otherwise the cache will be
disable to avoid data corruption.
Most ESP-IDF APIs calls mmap with this flag. As for users calling
mmap-like APIs directly, they can choose whether to enable this by a
flag.
Closes https://github.com/espressif/esp-idf/issues/14897
Add a test app that verifies PLACE_IN_SECTION, _SECTION_ATTR_SYMBOL_DECL_GENERIC,
_SECTION_START and _SECTION_END macros work correctly on Linux.
The test places 5 uint32_t values into a custom .test_data_table section from
two separate translation units, then iterates the section at runtime to verify
the correct count and content of all entries.
Includes:
- Custom linker script (ld/test_section.ld)
- Build-test-rules entry (linux only)
- pytest host_test marker
Add PLACE_IN_SECTION, _SECTION_ATTR_IMPL_GENERIC, _SECTION_ATTR_SYMBOL_DECL_GENERIC,
_SECTION_START and _SECTION_END macros that emit real section attributes on every
platform (embedded ELF, Linux ELF, macOS Mach-O).
Unlike _SECTION_ATTR_IMPL which is a no-op on Linux, these macros work uniformly
across all targets, enabling link-time arrays for error-code tables, init-function
arrays, and similar patterns.
Also moves _COUNTER_STRINGIFY definition before its first use.
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.
