The SPARC ABI is a bit special with respect to the floating point context.
The complete floating point context is volatile. Thus, from an ABI point
of view nothing needs to be saved and restored during a context switch.
Instead the floating point context must be saved and restored during
interrupt processing. Historically, the deferred floating point switch was
used for SPARC and the complete floating point context is saved and
restored during a context switch to the new floating point unit owner.
This is a bit dangerous since post-switch actions (e.g. signal handlers)
and context switch extensions may silently corrupt the floating point
context.
The floating point unit is disabled for interrupt handlers. Thus, in case
an interrupt handler uses the floating point unit then this will result in a
trap (INTERNAL_ERROR_ILLEGAL_USE_OF_FLOATING_POINT_UNIT).
In uniprocessor configurations, a lazy floating point context switch is
used. In case an active floating point thread is interrupted (PSR[EF] == 1)
and a thread dispatch is carried out, then this thread is registered as the
floating point owner. When a floating point owner is present during a
context switch, the floating point unit is disabled for the heir thread
(PSR[EF] == 0). The floating point disabled trap checks that the use of the
floating point unit is allowed and saves/restores the floating point context
on demand.
Update #3077.
The loop that checks if the current address is already mapped uses
the same local variable for the chanin node as the newly allocated
chain node so the allocated chain node gets over written.
Added a new local variable for the loop that checks the address
Updates #2859.
Rename NGMP to GR740 and add configs for UT699, UT700, and GR712RC
The UT699 requires -mcpu=leon as it does not support the CAS instruction
provided by -mcpu=leon3. It also requires -mfix-ut699 for errata fixes.
UT700 and GR712RC requires the -mfix-ut700 and -mfix-gr712rc flags that
have been recently added to GCC's master and 7-branch.
Remove -msoft-float from the leon3 config to make the more common case
of using the FPU the default.
Update #3057.
This patch adds NOP instructions to prevent instruction sequences
that are sensitive to the LEON3FT B2BST errata. See GRLIB-TN-0009:
"LEON3FT Stale Cache Entry After Store with Data Tag Parity Error"
for more information.
The sequences are only modified if __FIX_LEON3FT_B2BST is defined.
The patch works in conjunction with the -mfix-ut700, -mfix-gr712rc,
and -mfix-ut699 GCC flags that prevents the sensitive sequences from
being generated.
Update #3057.
Added a mmap file handler to struct _rtems_filesystem_file_handlers_r.
Updated each file handler object to support the default mmap handler.
Updated mmap() to call the mmap handler for MAP_SHARED.
Added a mmap file handler for shm
Added support for MAP_ANON in mmap().
Updates #2859
The EDF SMP scheduler supports simple thread processor affinities
(see #3059) with a small run-time overhead. The current default SMP
scheduler lacks support for thread processor affinities at all. The EDF
SMP scheduler offers a good feature set for most applications. So, use
it by default. Run-time libraries like libgomp, MTAPI, work stealing
schedulers, language interpreters (e.g. Erlang virtual machine),
maintainence of per-processor data (e.g. Universal Memory Allocator
(UMA)), etc. use a one-to-one thread processor affinity for example.
Update #3063.
