Re: [PATCH v2 1/4] x86: verify function type (and maybe attribute) in switch_stack_and_jump()

[Wei Liu <wl@xxxxxxx>]

On Tue, Dec 15, 2020 at 05:11:41PM +0100, Jan Beulich wrote:
> It is imperative that the functions passed here are taking no arguments,
> return no values, and don't return in the first place. While the type
> can be checked uniformly, the attribute check is limited to gcc 9 and
> newer (no clang support for this so far afaict).
> 
> Note that I didn't want to have the "true" fallback "implementation" of
> __builtin_has_attribute(..., __noreturn__) generally available, as
> "true" may not be a suitable fallback in other cases.
> 
> Note further that the noreturn addition to startup_cpu_idle_loop()'s
> declaration requires adding unreachable() to Arm's
> switch_stack_and_jump(), or else the build would break. I suppose this
> should have been there already.
> 
> For vmx_asm_do_vmentry() along with adding the attribute, also restrict
> its scope.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> Reviewed-by: Juergen Gross <jgross@xxxxxxxx>

Reviewed-by: Wei Liu <wl@xxxxxxx>