On 2/5/20 10:19 AM, Yu-cheng Yu wrote:
> +# Check assembler Shadow Stack suppot
^ support
> +ifdef CONFIG_X86_INTEL_SHADOW_STACK_USER
> + ifeq ($(call as-instr, saveprevssp, y),)
> + $(error CONFIG_X86_INTEL_SHADOW_STACK_USER not supported by the assembler)
> + endif
> +endif
Is this *just* looking for instruction support in the assembler?
We usually just .byte them, like this for pkeys:
asm volatile(".byte 0x0f,0x01,0xee\n\t"
: "=a" (pkru), "=d" (edx)
: "c" (ecx));
That way everybody with old toolchains can still build the kernel (and
run/test code with your config option on, btw...).
