Re: [PATCH v2 14/40] bsd-user/arm/target_arch_cpu.h: Use force_sig_fault for EXCP_UDEF

[Richard Henderson]

On 1/25/22 12:29, Warner Losh wrote:
> +        case EXCP_NOCP:
> +        case EXCP_INVSTATE:
> +            /*
> +             * See arm/arm/undefined.c undefinedinstruction();
> +             *
> +             * A number of details aren't emulated (they likely don't matter):
> +             * o Misaligned PC generates ILL_ILLADR

As I mentioned, misaligned pc will not come here for qemu.
In the Arm ARM, see aarch32/functions/registers/BXWritePC:

// For branches to an unaligned PC counter in A32 state, the processor takes 
the branch
// and does one of:
// * Forces the address to be aligned
// * Leaves the PC unaligned, meaning the target generates a PC Alignment fault.

The hardware will either refuse to allow bit 1 to be set when bit 0 is clear, OR it will 
generate a PREFETCH_DATA_ABORT for Alignment.

QEMU will do the latter.


Otherwise,
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~