ligd 8b8a2610ab armv6/7/8m: use pendsv to handle context switch
This PR support Nested interrupt in armv6/7/8m:

There are two types of nested interrupt model:

Zero latency nested interrupt
Interrupt           Priority            Note
Data abort          Highest
SVC                 0x50
High irq1           0x60             ISR can't access system API
irq_save()          0x70
High irq2           0x80             ISR can't access system API
normal irq3         0xB0
We have already support this mode before this PR

Nested interrupt which interrupt level lower than up_irq_save()
Interrupt           Priority            Note
Data abort          Highest
SVC                 0x70
irq_save()          0x80
High irq1           0x90              ISR can access system API
High irq2           0xA0              ISR can access system API
normal irq3         0xB0
Now, this PR can support this mode

Signed-off-by: ligd <liguiding1@xiaomi.com>
2024-10-18 23:54:11 +08:00
..