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@arndb.de>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/32453a703dfcf0d007b473c9acbf70718222b74b.1681342859.git.jpoimboe@kernel.org
return ES_OK;
}
-void hv_ghcb_terminate(unsigned int set, unsigned int reason)
+void __noreturn hv_ghcb_terminate(unsigned int set, unsigned int reason)
{
u64 val = GHCB_MSR_TERM_REQ;
void hv_ghcb_msr_write(u64 msr, u64 value);
void hv_ghcb_msr_read(u64 msr, u64 *value);
bool hv_ghcb_negotiate_protocol(void);
-void hv_ghcb_terminate(unsigned int set, unsigned int reason);
+void __noreturn hv_ghcb_terminate(unsigned int set, unsigned int reason);
#else
static inline void hv_ghcb_msr_write(u64 msr, u64 value) {}
static inline void hv_ghcb_msr_read(u64 msr, u64 *value) {}
"ex_handler_msr_mce",
"fortify_panic",
"hlt_play_dead",
+ "hv_ghcb_terminate",
"kthread_complete_and_exit",
"kthread_exit",
"kunit_try_catch_throw",