Re: [PATCH v6 1/3] x86/syscall: Mark exit[_group] syscall handlers __noreturn

[Josh Poimboeuf <jpoimboe@kernel.org>]

On Thu, Jun 27, 2024 at 09:26:34AM +0200, Borislav Petkov wrote:
> On Tue, Jun 25, 2024 at 11:02:00PM -0700, Josh Poimboeuf wrote:
> > The direct-call syscall dispatch function doesn't know that the exit()
> > and exit_group() syscall handlers don't return, so the call sites aren't
> > optimized accordingly.
> > 
> > Fix that by marking the exit syscall declarations __noreturn.
> > 
> > Fixes the following warnings:
> > 
> >   vmlinux.o: warning: objtool: x64_sys_call+0x2804: __x64_sys_exit() is missing a __noreturn annotation
> >   vmlinux.o: warning: objtool: ia32_sys_call+0x29b6: __ia32_sys_exit_group() is missing a __noreturn annotation
> > 
> > Fixes: 7390db8aea0d ("x86/bhi: Add support for clearing branch history at syscall entry")
> > Reported-by: "Paul E. McKenney" <paulmck@kernel.org>
> > Closes: https://lkml.kernel.org/lkml/6dba9b32-db2c-4e6d-9500-7a08852f17a3@paulmck-laptop
> 
> This here talks about
> 
> 1e3ad78334a6 ("x86/syscall: Don't force use of indirect calls for system calls")
> 
> being the culprit.
> 
> But Fixes points to something unrelated...?

Ah yeah, it should be

Fixes: 1e3ad78334a6 ("x86/syscall: Don't force use of indirect calls for system calls")

-- 
Josh