In order to simplify the use of CPU counter values it is beneficial to
have monotonic increasing values within the range of the CPU counter
ticks data type, e.g. 32-bit unsigned integer. This eases the use of
CPU counter timestamps in external tools which do not know the details
of the CPU counter hardware. The CPU counter is the fastest way to get
a time on an RTEMS system.
Such a CPU counter may be also used as the timecounter. Use it on SPARC
for this purpose to simplify the clock drivers.
Update #3456.
This is needed for building rtems correctly with Clang.
Note that this change does not mean rtems can build correctly with
mainline clang. However the change allows building rtems with a
Clang toolchain that has a rtems frontend similar that of GCC's
builtin rtems specs.
The APIC timer is calibrated by running the i8254 PIT for a fraction of a
second (determined by PIT_CALIBRATE_DIVIDER) and counting how many times the
APIC counter has ticked. The calibration can be run multiple times (determined
by APIC_TIMER_NUM_CALIBRATIONS) and averaged out.
Updates #2898.
The genmcf548x partly uses is own implementation of the interrupt
extension API for libbsd support.
This patch is a part of the BSP source reorganization.
Update #3285.
Remove _CPU_ISR_install_raw_handler() and _CPU_ISR_install_vector()
functions. Applications can install an exception handler via the fatal
error handler to handle synchronous exceptions.
Handle interrupt exceptions via _RISCV_Interrupt_dispatch() which must
be provided by the BSP.
Update #3433.
Current state:
- Basic context initialization and switching code.
- Stubbed console (empty functions).
- Mostly functional linker script (may need tweaks if we ever want to move
away from the large code model (see: CPU_CFLAGS).
- Fully functional boot, by using FreeBSD's bootloader to load RTEMS's ELF for
UEFI-awareness.
In short, the current state with this commit lets us boot, go through the system
initialization functions, and then call user application's Init task too.
Updates #2898.
Statically initialize the interrupt stack area
(_Configuration_Interrupt_stack_area_begin,
_Configuration_Interrupt_stack_area_end, and
_Configuration_Interrupt_stack_size) via <rtems/confdefs.h>. Place the
interrupt stack area in a special section ".rtemsstack.interrupt". Let
BSPs define the optimal placement of this section in their linker
command files (e.g. in a fast on-chip memory).
This change makes makes the CPU_HAS_SOFTWARE_INTERRUPT_STACK and
CPU_HAS_HARDWARE_INTERRUPT_STACK CPU port defines superfluous, since the
low level initialization code has all information available via global
symbols.
This change makes the CPU_ALLOCATE_INTERRUPT_STACK CPU port define
superfluous, since the interrupt stacks are allocated by confdefs.h for
all architectures. There is no need for BSP-specific linker command
file magic (except the section placement), see previous ARM linker
command file as a bad example.
Remove _CPU_Install_interrupt_stack(). Initialize the hardware
interrupt stack in _CPU_Initialize() if necessary (e.g.
m68k_install_interrupt_stack()).
The optional _CPU_Interrupt_stack_setup() is still useful to customize
the registration of the interrupt stack area in the per-CPU information.
The initialization stack can reuse the interrupt stack, since
* interrupts are disabled during the sequential system initialization,
and
* the boot_card() function does not return.
This stack resuse saves memory.
Changes per architecture:
arm:
* Mostly replace the linker symbol based configuration of stacks with
the standard <rtems/confdefs.h> configuration via
CONFIGURE_INTERRUPT_STACK_SIZE. The size of the FIQ, ABT and UND
mode stack is still defined via linker symbols. These modes are
rarely used in applications and the default values provided by the
BSP should be sufficient in most cases.
* Remove the bsp_processor_count linker symbol hack used for the SMP
support. This is possible since the interrupt stack area is now
allocated by the linker and not allocated from the heap. This makes
some configure.ac stuff obsolete. Remove the now superfluous BSP
variants altcycv_devkit_smp and realview_pbx_a9_qemu_smp.
bfin:
* Remove unused magic linker command file allocation of initialization
stack. Maybe a previous linker command file copy and paste problem?
In the start.S the initialization stack is set to a hard coded value.
lm32, m32c, mips, nios2, riscv, sh, v850:
* Remove magic linker command file allocation of initialization stack.
Reuse interrupt stack for initialization stack.
m68k:
* Remove magic linker command file allocation of initialization stack.
Reuse interrupt stack for initialization stack.
powerpc:
* Remove magic linker command file allocation of initialization stack.
Reuse interrupt stack for initialization stack.
* Used dedicated memory region (REGION_RTEMSSTACK) for the interrupt
stack on BSPs using the shared linkcmds.base (replacement for
REGION_RWEXTRA).
sparc:
* Remove the hard coded initialization stack. Use the interrupt stack
for the initialization stack on the boot processor. This saves
16KiB of RAM.
Update #3459.
Use the standard ARMv7-M systick module for the ARMv7-M CPU counter
instead of DWT counter since the DWT counter is affected by power saving
states.
Use an inline function for _CPU_Counter_difference() for all ARM BSPs.
Update #3456.
Add rtems_counter_frequency() API function. Use it to initialize the
counter value converter via the new system initialization step
(RTEMS_SYSINIT_CPU_COUNTER). This decouples the counter implementation
and the counter converter. It avoids an unnecessary pull in of the
64-bit integer division from libgcc.
Update #3456.
The last installed tool in RTEMS repository is the install-if-change
script. It is not used to build/install BSPs. This script does the
same as the standard "install" program with an additional feature to
install variants via the -V command line option.
This script is used by the standard Makefile support:
c/src/make/host.cfg.in:INSTALL_CHANGE=$(PROJECT_BIN)/install-if-change
The INSTALL_CHANGE is used by:
c/src/make/host.cfg.in:ifndef INSTALL_CHANGE
c/src/make/host.cfg.in:INSTALL_CHANGE=$(PROJECT_BIN)/install-if-change
c/src/make/host.cfg.in:INSTALL_VARIANT=$(INSTALL_CHANGE) -V
"$(LIB_VARIANT)"
Remove the support for variant installation and instead use the standard
"install" program. This breaks application Makefiles using the standard
Makefile support of RTEMS.
Close#3455.
All tools should be removed from the RTEMS source repository at some
point in time. Tools with a BSD-style license will be moved to the
RTEMS tools repository. Unfortunately, this tool has no license
information.
Remove all uses of this tool from the code base. Users of HEX files
should consider to use ELF instead.
Close#3379.
All tools should be removed from the RTEMS source repository at some
point in time. Tools with a BSD-style license will be moved to the RTEMS
tools repository. Unfortunately, the shgen tool is GPL licensed.
Remove all uses of this tool from the code base. Replace generated files
with stub functions. If users of this BSP still exist, they can
reimplement the functionality using a BSD-style license.
Close#3443.
