This patch implements interrupt initialization and the basic
exception/interrupt handling flow on RISC-V.
init_interrupt() needs to be invoked during CPU initialization to
set up the trap vector and enable the interrupt.
RISC-V exception and interrupt handling includes:
- Saving and restoring CPU registers around traps
- Implementing handlers for:
- Supervisor software interrupt
- Supervisor timer interrupt
- Halting the CPU for all other interrupts and exceptions
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TODOs:
1. add support for registering interrupt handlers via request_irq() and
further adoption of the common IRQ framework.
2. add support for external interrupt.
Tracked-On: #8813
Signed-off-by: Haicheng Li <haicheng.li@intel.com>
Co-developed-by: Shiqing Gao <shiqing.gao@intel.com>
Signed-off-by: Shiqing Gao <shiqing.gao@intel.com>
Reviewed-by: Yifan Liu <yifan1.liu@intel.com>
Acked-by: Wang, Yu1 <yu1.wang@intel.com>
