https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96061
Bug ID: 96061
Summary: Please support 'no_caller_saved_registers' attribute
on aarch64 (or maybe on all targets)
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: alex.popov at linux dot com
Target Milestone: ---
This is an enhancement request.
GCC currently supports 'no_caller_saved_registers' attribute only for x86.
Clang supports it for all target architectures.
It would be very useful for Linux kernel, if GCC supported
'no_caller_saved_registers' attribute for at least aarch64. In particular, that
would allow to avoid useless work with caller-saved registers caused by
STACKLEAK GCC plugin instrumentation for the Linux kernel on aarch64.
This kernel patch uses 'no_caller_saved_registers' to fix the described issue
on x86:
https://www.openwall.com/lists/kernel-hardening/2020/06/24/13
(the patch is accepted for the mainline kernel)
That GCC enhancement can be useful for _mcount (gprof) as well.
Thanks!
