target/riscv: Add functions for common matching conditions of trigger

According to RISC-V Debug specification version 0.13 [1] (also applied
to version 1.0 [2] but it has not been ratified yet), there are several
common matching conditions before firing a trigger, including the
enabled privilege levels of the trigger.

This commit adds trigger_common_match() to prepare the common matching
conditions for the type 2/3/6 triggers. For now, we just implement
trigger_priv_match() to check if the enabled privilege levels of the
trigger match CPU's current privilege level.

Remove the related code in riscv_cpu_debug_check_breakpoint() and invoke
trigger_common_match() to check the privilege levels of the type 2 and
type 6 triggers for the breakpoints.

This commit also changes the behavior of looping the triggers. In
previous implementation, if we have a type 2 trigger and
env->virt_enabled is true, we directly return false to stop the loop.
Now we keep looping all the triggers until we find a matched trigger.

Only the execution bit and the executed PC should be futher checked in
riscv_cpu_debug_check_breakpoint().

[1]: https://github.com/riscv/riscv-debug-spec/releases/tag/task_group_vote
[2]: https://github.com/riscv/riscv-debug-spec/releases/tag/1.0.0-rc1-asciidoc

Signed-off-by: Alvin Chang <alvinga@andestech.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240626132247.2761286-2-alvinga@andestech.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
1 file changed