Re: [PATCH v3 16/27] linux-user/nios2: Properly emulate EXCP_TRAP

[Richard Henderson]

On 9/27/21 9:23 AM, Peter Maydell wrote:
> Loading the insn and fishing out the imm5 field is about 2
> lines of code, isn't it?
> It's how we handle similar cases for other targets.

And we actively get it wrong, e.g. mips.
So I have patches to move that code *out* of linux-user.

We have macros in target/nios2/ to do the field decode, and not in linux-user/.

> I think I prefer that over putting
> linux-user specific fields and handling into the target/nios2
> code.

Would you prefer a generic-y named field like error_code, which we include in 
other targets?

> The kernel also defines:
>   * trap 31 ("breakpoint"), which should wind PC back by 4 and
>     send a SIGTRAP/TRAP_BRKPT
>   * trap 30 ("KGDB breakpoint"), which we should treat the same
>     as the "default" case since we should be acting like "kernel
>     with CONFIG_KGDB not defined"

Dang it, how did I miss those?


r~