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arm64: switch to the IRQ stack during ISR execution

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Avoid executing ISRs using the thread stack as it might not be sized
for that. Plus, we do have IRQ stacks already set up for us.

The non-nested IRQ context is still (and has to be) saved on the thread
stack as the thread could be preempted.

The irq_offload case is never nested and always invoked with the
sched_lock held so it can be simplified a bit.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
This commit is contained in:
Nicolas Pitre 2022-02-09 16:54:37 -05:00 • committed by Anas Nashif
commit 34d425fbe5
2 changed files with 24 additions and 7 deletions
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12
arch/arm64/core/isr_wrapper.S
View file

@ -38,6 +38,14 @@ SECTION_FUNC(TEXT, _isr_wrapper)
add w1, w1, #1 add w1, w1, #1
str w1, [x0, #___cpu_t_nested_OFFSET] str w1, [x0, #___cpu_t_nested_OFFSET]
/* If not nested: switch to IRQ stack and save current sp on it. */
cmp w1, #1
bne 1f
ldr x1, [x0, #___cpu_t_irq_stack_OFFSET]
mov x2, sp
mov sp, x1
str x2, [sp, #-16]!
1:
#ifdef CONFIG_SCHED_THREAD_USAGE #ifdef CONFIG_SCHED_THREAD_USAGE
bl z_sched_usage_stop bl z_sched_usage_stop
#endif #endif
@ -107,6 +115,10 @@ spurious_continue:
str w1, [x0, #___cpu_t_nested_OFFSET] str w1, [x0, #___cpu_t_nested_OFFSET]
bne exit bne exit
/* No more nested: retrieve the task's stack. */
ldr x0, [sp]
mov sp, x0
/* /*
* z_arch_get_next_switch_handle() is returning: * z_arch_get_next_switch_handle() is returning:
* *

19
arch/arm64/core/switch.S
View file

@ -147,19 +147,24 @@ SECTION_FUNC(TEXT, z_arm64_sync_exc)
beq offload beq offload
b inv b inv
offload: offload:
/* ++_current_cpu->nested to be checked by arch_is_in_isr() */ /* _current_cpu->nested=1, to be checked by arch_is_in_isr() */
get_cpu x0 get_cpu x0
ldr w1, [x0, #___cpu_t_nested_OFFSET] mov w1, #1
add w1, w1, #1
str w1, [x0, #___cpu_t_nested_OFFSET] str w1, [x0, #___cpu_t_nested_OFFSET]
/* switch to IRQ stack and save current sp on it. */
ldr x1, [x0, #___cpu_t_irq_stack_OFFSET]
mov x2, sp
mov sp, x1
str x2, [sp, #-16]!
bl z_irq_do_offload bl z_irq_do_offload
/* --_current_cpu->nested */ /* _current_cpu->nested=0 */
get_cpu x0 get_cpu x0
ldr w1, [x0, #___cpu_t_nested_OFFSET] str wzr, [x0, #___cpu_t_nested_OFFSET]
sub w1, w1, #1 /* restore original stack pointer. */
str w1, [x0, #___cpu_t_nested_OFFSET] ldr x1, [sp]
mov sp, x1
b z_arm64_exit_exc b z_arm64_exit_exc
#endif #endif
b inv b inv