https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117312
--- Comment #2 from H. Peter Anvin <hpa at zytor dot com> --- I did state that the current kernel ABI doesn't *currently* use the red zone. However, in the future, FRED exception handling *would* allow the kernel to use the red zone. There isn't really a good alternative to being able to use "call" from inside inline assembly. In the case of the Linux kernel this comes up mainly due to the alternatives patching mechanism; it also gets used when invoking assembly routines with special constraints or calling conventions. This can be part of a bigger assembly sequence, so even if we did have the ability to call a function with an arbitrary calling convention it wouldn't necessarily solve the problem.
