Added storing of FPU regs on context switches when CONFIG_FPU is defined.
On context switches, EXC_RETURN[4] is checked in order to tell which tasks
have used floating point and which have not. The FPU regs are only stored on
task stacks for tasks that use the floating point. Tasks that use floating
point will therefore require roughly an additional 128 bytes of stack space,
and context switches will take about 32 clock cycles longer for each task
involved in the switch that uses FP.
For tasks that don't use floating point, the stack usage actually decreases
by 64 bytes because previously we were reserving stack space for FPU regs
S0-S15 on every context switch for every task, even though we weren't doing
anything with them.
If a task only uses the FPU for a brief window, it can call
task_clear_fp_used() in order to clear the FP used bit so that context
switches using that task will not backup FP regs anymore.
BUG=chrome-os-partner:27971
BRANCH=none
TEST=Tested on glimmer and peppy. Added the following code, which uses the
FPU in both the hooks task and the console task. Note, I tested this for
a handful of registers, notably registers in the group s0-s15 which are
backed up by lazy stacking, and registers in the group s16-s31 which are
backed up manually.
float dummy = 2.0f;
static void hook_fpu(void)
{
union {
float f;
int i;
} tmp;
/* do a dummy FP calculation to set CONTROL.FPCA high. */
dummy = 2.3f*7.8f;
/* read and print FP reg. */
asm volatile("vmov %0, s29" : "=r"(tmp.f));
ccprintf("Hook float 0x%08x\n", tmp.i);
/* write FP reg. */
tmp.i = 0x1234;
asm volatile("vmov s29, %0" : : "r"(tmp.f));
}
DECLARE_HOOK(HOOK_SECOND, hook_fpu, HOOK_PRIO_DEFAULT);
static int command_fpu_test(int argc, char **argv)
{
union {
float f;
int i;
} tmp;
/* do a dummy FP calculation to set CONTROL.FPCA high. */
dummy = 2.7f*7.8f;
/* read and print FP reg. */
asm volatile("vmov %0, s29" : "=r"(tmp.f));
ccprintf("Console float 0x%08x\n", tmp.i);
if (argc == 2) {
char *e;
tmp.i = strtoi(argv[1], &e, 0);
if (*e)
return EC_ERROR_PARAM1;
/* write FP reg. */
asm volatile("vmov s29, %0" : : "r"(tmp.f));
} else {
task_clear_fp_used();
}
return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(fputest, command_fpu_test, "", "", NULL);
When you call fputest 5 from EC console before this CL, then on the next
HOOK_SECOND, the value of register s29 is 5, instead of 0x1234 because
register s29 is not saved on context switches:
Hook float 0x00001234
> fputest 5
Console float 0x00001234
Hook float 0x00000005
When this CL is in use, the register holds the correct value for each task:
Hook float 0x00001234
> fputest 5
Console float 0x00001234
Hook float 0x00001234
> fputest
Console float 0x00000005
Hook float 0x00001234
Change-Id: Ifb1b5cbf1c6fc9193f165f8d69c96443b35bf981
Signed-off-by: Alec Berg <alecaberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/194949
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
With this CL, if CONFIG_FPU is defined (only for Link, ATM), the EC task
switcher will enable CONTROL.FPCA and expect all stack contexts to include
floating point state as well as normal state (an additional 18 words).
To support this, we need to increase the allocated stack space for each
task. The stack sizes are already chosen empirically, so I'm just rounding
them up a bit.
BUG=chrome-os-partner:14766
BRANCH=Link
TEST=manual
There should be no noticeable change. If you run the EC command "taskinfo"
you'll see the increased size each thread's stack, but everything that was
working before should continue to work just fine.
The additional overhead required to load and store another 18 words on each
context switch is not really measurable (I tried).
Change-Id: Ibaca7d7a2565285f049fda6906f32761e83207af
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/34391
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
(Or, if profiling is enabled.)
Also, track the number of task switches if profiling is enabled.
Signed-off-by: Randall Spangler <rspangler@chromium.org>
BUG=chrome-os-partner:9274
TEST=taskinfo
Also test by commenting out CONFIG_TASK_PROFILING in board.h; code
should still compile and run.
Change-Id: Ib3dbce74b6ccfba2bbe18c7309136412c30f364e
Also tracks the distribution of IRQs, so we can see what's triggering
interrupts.
Task profiling is optional, enabled via CONFIG_TASK_PROFILING.
Signed-off-by: Randall Spangler <rspangler@chromium.org>
BUG=chrome-os-partner:7464
TEST=taskinfo
Change-Id: I266f2b49bff9648cda446210d5a302b460fec244
Signed-off-by: Randall Spangler <rspangler@chromium.org>
BUG=chrome-os-partner:8350
TEST=manual
Hack a task function to return. Then see that it prints an error to
the debug console and the EC continues running, instead of seeing a
hard-fault.
Change-Id: Iacd2b83c4d4845bb8e6c61e07c3150df8edc7e49
Preparatory work to introduce a second SoC : 3/5
We split the drivers files which contain SoC specific drivers from the
OS files which only depend the actual CPU core.
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
BUG=None
TEST=run EC firmware on BDS and test a few commands on the console.
Change-Id: I598f8b23e074da9bd6b0e2ce6689c1075fe854f0
