Newer picolibc versions require some additional symbols defined in the
linker script to correctly manage alignment constraints on thread
local storage.
Signed-off-by: Keith Packard <keithp@keithp.com>
Fixes this error with binutils 2.37:
```
/usr/lib/gcc/arm-none-eabi/11.2.0/../../../../arm-none-eabi/bin/ld:cortexm_base.ld:217: warning: memory region `bkup' not declared
/usr/lib/gcc/arm-none-eabi/11.2.0/../../../../arm-none-eabi/bin/ld:cortexm_base.ld:217: syntax error
```
The global core/ldscripts/xfa.ld doesn't match our cortexm_base.ld.
This commit directly adds the two XFA lines to cortexm_base.ld.
In addition to that, a dummy (empty) xfa.ld is added, which the linker will pick
instead of core/ldscripts/xfa.ld, effectingly not using it.
Allocate and initialize a thread-local block for each thread at the
top of the stack.
Set the tls base when switching to a new thread.
Add tdata/tbss linker instructions to cortex_m and risc-v scripts.
Signed-off-by: Keith Packard <keithp@keithp.com>
---
v2:
Squash fixes
v3:
Replace tabs with spaces
v4:
Add tbss to fe310 linker script
Many MCUs contain some Backup or Low Power SRAM that is retained'even
in the deepest sleep modes.
In such sleep modes the MCU is essentually turned off with only the RTC
still running.
It can be woken by a GPIO or a RTC alarm. When this happens, a reset is
triggered and the normal startup routine is invoked.
This adds bss & data section for this memory in the linker script.
This allows for structures to be placed in it e.g.:
e.g.:
static uint8_t persistent_buffer[64] __attribute__((section(".backup.bss")));
static uint32_t persistent_counter __attribute__((section(".backup.data"))) = 1234;
If the .noinit section starts at the beginning of the RAM,
a bootloader that is unaware of it will clear it.
Instead, move it behind the .bss section, hoping that a bootloader
will always use less .bss memory than RIOT proper.
Make it possible to specify a section of RAM that is not touched by
the init routing so data can be kept across resets.
This should behave the same as on atmega & lpc2387.
Allow defining a specific rom length to use for linking the firmware,
_fw_rom_length, instead of the default configuration to use the whole rom from
_rom_offset to the end.
* Add cortexm_common/Makefile.include FW_ROM_SIZE configuration
* Add an assertion that _fw_rom_length still respects _rom_length
The required space for the hardfault handler is defined by
HARDFAULT_HANDLER_REQUIRED_STACK_SPACE, which is given in bytes,
this length is added to &_sram to find a lower limit on the amount of
stack space that the hard fault handler can work with. The _sram
variable, was mistakenly defined as a uint32_t, which makes &_sram into
a uint32_t*, which through pointer addition, made the required space 4
times as big as it was supposed to. By changing the type of _sram to
uint8_t, the required stack space is correctly computed.
The symptom was that the hardfault handler always reported that the
stack pointer had been corrupted and it was impossible to get any useful
information from the crash text.
