3 Apr
2022
3 Apr
'22
5:14 p.m.
On Sun, Apr 03 2022 at 18:57, Thomas Gleixner wrote:
On Tue, Mar 29 2022 at 17:47, Ammar Faizi wrote:
The asm constraint does not reflect that the asm statement can modify the value of @loops. But the asm statement in delay_loop() does modify the @loops.
Specifiying the wrong constraint may lead to undefined behavior, it may clobber random stuff (e.g. local variable, important temporary value in regs, etc.). This is especially dangerous when the compiler decides to inline the function and since it doesn't know that the value gets modified, it might decide to use it from a register directly without reloading it.
Ignore me, I misread this part of the explanation.
Thanks,
tglx