On Tue, Oct 17, 2017 at 11:13:36AM +0200, David Brown wrote:
> My solution to this
> particular ordering problem is:
>
> uint32_t status;
> asm volatile ("mrs %0, PRIMASK" : "=r" (status) :: );
> asm volatile ("cpsid i" :: "" (status) :);
>
> foo();
>
> asm volatile ("msr PRIMASK, %0" :: "r" (status) : );
And that only works for you because you have foo() separately compiled.
If it was inlined (say with LTO) its instructions could move anywhere.
That is without changing a character in your source code; your program
simply does not mean what you think it means.
Segher
