Michal Suchánek <msucha...@suse.de> writes:
> On Sat, 31 Aug 2019 02:48:26 +0800
> kbuild test robot <l...@intel.com> wrote:
>
>> Hi Nicholas,
>>
>> I love your patch! Yet something to improve:
>>
>> [auto build test ERROR on linus/master]
>> [cannot apply to v5.3-rc6 next-20190830]
>> [if your patch is applied to the wrong git tree, please drop us a note to
>> help improve the system]
>>
>> url:
>> https://github.com/0day-ci/linux/commits/Nicholas-Piggin/powerpc-64-syscalls-in-C/20190828-064221
>> config: powerpc64-defconfig (attached as .config)
>> compiler: powerpc64-linux-gcc (GCC) 7.4.0
>> reproduce:
>> wget
>> https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
>> ~/bin/make.cross
>> chmod +x ~/bin/make.cross
>> # save the attached .config to linux build tree
>> GCC_VERSION=7.4.0 make.cross ARCH=powerpc64
>>
>> If you fix the issue, kindly add following tag
>> Reported-by: kbuild test robot <l...@intel.com>
>>
>> All errors (new ones prefixed by >>):
>>
>> powerpc64-linux-ld: warning: orphan section `.gnu.hash' from `linker
>> stubs' being placed in section `.gnu.hash'.
>> arch/powerpc/kernel/syscall_64.o: In function `.system_call_exception':
>> >> syscall_64.c:(.text+0x180): undefined reference to `.tabort_syscall'
>
> Interestingly it builds and boots for me. Is this something about
> dotted vs dotless symbols depending on some config options?
It's the big endian build that fails, which is ELFv1, and the linker is
saying it can't find a function called `.tabort_syscall` - which is
understandable because there isn't one. There's a text address called
`tabort_syscall` but it has no function descriptor so you can't call it
normally from C.
> I see there is _GLOBAL(ret_from_fork) just below so maybe we need
> _GLOBAL(tabort_syscall) instead of .globl tabort_syscall as well.
Yes, on ELFv1 the _GLOBAL macros creates a function descriptor for you.
This fixes it for me:
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 82bcb9a68172..8f2735da205d 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -170,8 +170,7 @@ _ASM_NOKPROBE_SYMBOL(system_call_common);
b .Lsyscall_restore_regs_cont
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
- .globl tabort_syscall
-tabort_syscall:
+_GLOBAL(tabort_syscall)
/* Firstly we need to enable TM in the kernel */
mfmsr r10
li r9, 1
cheers
