VFP code cannot see CPACR write in the same TB

[Hansni Bu]

If FPU is enabled by writing to CPACR, and the code is in the same translation block as the following VFP code, qemu generates "v7M NOCP UsageFault".

This can be reproduced with git HEAD (commit 8fe9f1f891eff4e37f82622b7480ee748bf4af74).

The target binary is attached. The qemu command is:
qemu-system-arm -nographic -monitor null -serial null -semihosting -machine mps2-an505 -cpu cortex-m33 -kernel cpacr_vfp.elf -d in_asm,int,exec,cpu,cpu_reset,unimp,guest_errors,nochain -D log

If the code is changed a little, so that they are not in the same block, VFP code can see the effect of CPACR, or -singlestep of qemu has the same result.

[Hansni Bu (hansni)]

Sorry, it's because a "ISB" is missing after CPACR is changed. Not bug of qemu.