On 08.05.2018 14:19, Robin Murphy wrote: > On 08/05/18 12:32, Stefan Agner wrote: >> Mixing asm and C code is not recommended in a naked function by >> gcc and leads to an error when using clang: >> drivers/bus/arm-cci.c:2107:2: error: non-ASM statement in naked >> function is not supported >> unreachable(); >> ^ >> >> While the function is marked __naked it actually properly return >> in asm. There is no need for the unreachable() call. > > The commit title is a bit out-of-date now (I guess it could just be > something like "remove unnecessary unreachable()" now), but the rest > looks OK to me - even GCC clearly doesn't expect anything beyond the > asm to be reachable anyway since the lack of epilogue includes the > lack of any compiler-generated return. I've checked that GCC 7.2 > generates identical object files before and after, other than (for > obvious reasons) the line numbers generated by WANT_WARN_ON_SLOWPATH > for all the WARN()s appearing later in the file.
Title: Oops, good catch! Will send a v3. Thanks for checking gcc. -- Stefan > > Reviewed-by: Robin Murphy <[email protected]> > >> Suggested-by: Russell King <[email protected]> >> Signed-off-by: Stefan Agner <[email protected]> >> Acked-by: Nicolas Pitre <[email protected]> >> --- >> drivers/bus/arm-cci.c | 2 -- >> 1 file changed, 2 deletions(-) >> >> diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c >> index 443e4c3fd357..b8184a903583 100644 >> --- a/drivers/bus/arm-cci.c >> +++ b/drivers/bus/arm-cci.c >> @@ -371,8 +371,6 @@ asmlinkage void __naked cci_enable_port_for_self(void) >> [sizeof_struct_cpu_port] "i" (sizeof(struct cpu_port)), >> [sizeof_struct_ace_port] "i" (sizeof(struct cci_ace_port)), >> [offsetof_port_phys] "i" (offsetof(struct cci_ace_port, phys)) ); >> - >> - unreachable(); >> } >> /** >>
