On Fri, Mar 17, 2023 at 01:05:46PM -0300, Guilherme G. Piccoli wrote: > Annotate the function prototype and definition as noreturn to prevent > objtool warnings like: > > vmlinux.o: warning: objtool: hyperv_init+0x55c: unreachable instruction > > Also, as per Josh's suggestion, add it to the global_noreturns list. > As a comparison, an objdump output without the annotation: > > [...] > 1b63: mov $0x1,%esi > 1b68: xor %edi,%edi > 1b6a: callq ffffffff8102f680 <hv_ghcb_terminate> > 1b6f: jmpq ffffffff82f217ec <hyperv_init+0x9c> # unreachable > 1b74: cmpq $0xffffffffffffffff,-0x702a24(%rip) > [...] > > Now, after adding the __noreturn to the function prototype: > > [...] > 17df: callq ffffffff8102f6d0 <hv_ghcb_negotiate_protocol> > 17e4: test %al,%al > 17e6: je ffffffff82f21bb9 <hyperv_init+0x469> > [...] <many insns> > 1bb9: mov $0x1,%esi > 1bbe: xor %edi,%edi > 1bc0: callq ffffffff8102f680 <hv_ghcb_terminate> > 1bc5: nopw %cs:0x0(%rax,%rax,1) # end of function > > Reported-by: Arnd Bergmann <arnd@xxxxxxxx> > Link: https://lore.kernel.org/r/9698eff1-9680-4f0a-94de-590eaa923e94@xxxxxxxxxxxxxxxx/ > Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> > Cc: Michael Kelley <mikelley@xxxxxxxxxxxxx> > Signed-off-by: Guilherme G. Piccoli <gpiccoli@xxxxxxxxxx> Looks good to me. I've got some other noreturn fixes pending, so I can add this patch to the pile unless somebody else wants to take it. -- Josh
