Messages in this thread | | | From | Arnd Bergmann <> | Date | Thu, 30 Apr 2020 00:46:57 +0200 | Subject | Re: Remaining randconfig objtool warnings, linux-next-20200428 |
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On Wed, Apr 29, 2020 at 8:55 PM Josh Poimboeuf <jpoimboe@redhat.com> wrote: > > On Tue, Apr 28, 2020 at 11:10:44AM -0500, Josh Poimboeuf wrote: > > > ==> build/x86/0xE0F2ACFF_defconfig/log <== > > > kernel/time/posix-stubs.o: warning: objtool: __x64_sys_timer_create()+0x23: sibling call from callable instruction with modified stack frame > > This one is fixed with the following cleanup: > > From: Josh Poimboeuf <jpoimboe@redhat.com> > Subject: [PATCH] linkage: Convert syscall alias macros to C > > There's no need to use inline asm to create ELF alias symbols. > Annotated C function declarations can be used instead. > > This also makes the ordering of the ELF symbol table more logical, with > the real function now always coming before the aliases. This makes it > easier for objtool, objdump and other tools to differentiate them. > > This fixes the following warning: > > kernel/time/posix-stubs.o: warning: objtool: __x64_sys_timer_create()+0x23: sibling call from callable instruction with modified stack frame > > Reported-by: Arnd Bergmann <arnd@arndb.de> > Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> > --- > include/linux/linkage.h | 14 ++++---------- > 1 file changed, 4 insertions(+), 10 deletions(-)
Unfortunately, this patch leads to new warnings when CONFIG_POSIX_TIMERS is disabled:
In file included from /git/arm-soc/kernel/time/posix-stubs.c:9: /git/arm-soc/kernel/time/posix-stubs.c:35:37: error: conflicting types for 'sys_timer_create' 35 | #define SYS_NI(name) SYSCALL_ALIAS(sys_##name, sys_ni_posix_timers) | ^~~~ /git/arm-soc/include/linux/linkage.h:26:63: note: in definition of macro 'SYSCALL_ALIAS' 26 | #define SYSCALL_ALIAS(alias, name) __alias(name) typeof(name) alias | ^~~~~ /git/arm-soc/kernel/time/posix-stubs.c:42:1: note: in expansion of macro 'SYS_NI' 42 | SYS_NI(timer_create); | ^~~~~~ In file included from /git/arm-soc/kernel/time/posix-stubs.c:13: /git/arm-soc/include/linux/syscalls.h:616:17: note: previous declaration of 'sys_timer_create' was here 616 | asmlinkage long sys_timer_create(clockid_t which_clock, | ^~~~~~~~~~~~~~~~
We can probably move those SYS_NI() instances to kernel/sys_ni.c, which does not include the header, but it's still a bit ugly. I'll try that tomorrow unless you come up with a better suggestion first.
Arnd
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