On Wed, Nov 6, 2024 at 5:23 PM Jakub Jelinek <ja...@redhat.com> wrote: > > On Wed, Nov 06, 2024 at 05:05:54PM +0100, Uros Bizjak wrote: > > Please see [1]: > > > > /* > > * This output constraint should be used for any inline asm which has a > > "call" > > * instruction. Otherwise the asm may be inserted before the frame pointer > > * gets set up by the containing function. If you forget to do this, > > objtool > > * may print a "call without frame pointer save/setup" warning. > > */ > > register unsigned long current_stack_pointer asm(_ASM_SP); > > #define ASM_CALL_CONSTRAINT "+r" (current_stack_pointer) > > > > Perhaps HPA can say some more? > > So workaround about issues in some kernel tool? > Not sure if gcc needs to provide workaround for that. > Just do the call in a separate .subsection or add some magic labels around > it that the tool can check and disable the warning. Perhaps just a label > at the start of the call insn with some special prefix followed by %= > that the tool can use to find out calls coming from inline asm vs. calls > from C code.
Maybe even prefix the call with "cs;" prefix. Uros.
