Hi Dan,
FYI, the error/warning still remains.
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 368094df48e680fa51cedb68537408cfa64b788e
commit: ec6347bb43395cb92126788a1a5b25302543f815 x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()
date: 8 months ago
config: x86_64-randconfig-r025-20210610 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ec6347bb43395cb92126788a1a5b25302543f815
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout ec6347bb43395cb92126788a1a5b25302543f815
# save the attached .config to linux build tree
make W=1 ARCH=x86_64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
>> arch/x86/lib/copy_mc.c:30:1: warning: no previous prototype for 'copy_mc_fragile_handle_tail' [-Wmissing-prototypes]
30 | copy_mc_fragile_handle_tail(char *to, char *from, unsigned len)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
vim +/copy_mc_fragile_handle_tail +30 arch/x86/lib/copy_mc.c
24
25 /*
26 * Similar to copy_user_handle_tail, probe for the write fault point, or
27 * source exception point.
28 */
29 __visible notrace unsigned long
> 30 copy_mc_fragile_handle_tail(char *to, char *from, unsigned len)
31 {
32 for (; len; --len, to++, from++)
33 if (copy_mc_fragile(to, from, 1))
34 break;
35 return len;
36 }
37 #else
38 /*
39 * No point in doing careful copying, or consulting a static key when
40 * there is no #MC handler in the CONFIG_X86_MCE=n case.
41 */
42 void enable_copy_mc_fragile(void)
43 {
44 }
45 #define copy_mc_fragile_enabled (0)
46 #endif
47
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
On Wed, Jun 9, 2021 at 3:43 PM kernel test robot <[email protected]> wrote:
>
> Hi Dan,
>
> FYI, the error/warning still remains.
>
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head: 368094df48e680fa51cedb68537408cfa64b788e
> commit: ec6347bb43395cb92126788a1a5b25302543f815 x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()
> date: 8 months ago
> config: x86_64-randconfig-r025-20210610 (attached as .config)
> compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
> reproduce (this is a W=1 build):
> # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ec6347bb43395cb92126788a1a5b25302543f815
> git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> git fetch --no-tags linus master
> git checkout ec6347bb43395cb92126788a1a5b25302543f815
> # save the attached .config to linux build tree
> make W=1 ARCH=x86_64
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <[email protected]>
>
> All warnings (new ones prefixed by >>):
>
> >> arch/x86/lib/copy_mc.c:30:1: warning: no previous prototype for 'copy_mc_fragile_handle_tail' [-Wmissing-prototypes]
> 30 | copy_mc_fragile_handle_tail(char *to, char *from, unsigned len)
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~
This routine is only ever called from ASM code, so the fact that there
is no C declaration is expected.
For W=1 builds we could do something like this:
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index bad4dee4f0e4..b87f40cbc3d5 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -44,6 +44,7 @@ obj-$(CONFIG_SMP) += msr-smp.o cache-smp.o
lib-y := delay.o misc.o cmdline.o cpu.o
lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o
lib-y += memcpy_$(BITS).o
+CFLAGS_copy_mc.o = -Wno-strict-prototypes
lib-$(CONFIG_ARCH_HAS_COPY_MC) += copy_mc.o copy_mc_64.o
lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o insn-eval.o
lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
...but I don't like it nor adding a dummy declaration.
> This routine is only ever called from ASM code, so the fact that there
> is no C declaration is expected.
Does the asm code really need to call back into C?
Could you just have the asm code do "jmp .L_read_trailing_bytes" (might need to only do that if %ecx is non-zero)?
-Tony
On Wed, Jun 9, 2021 at 4:55 PM Luck, Tony <[email protected]> wrote:
>
> > This routine is only ever called from ASM code, so the fact that there
> > is no C declaration is expected.
>
> Does the asm code really need to call back into C?
>
> Could you just have the asm code do "jmp .L_read_trailing_bytes" (might need to only do that if %ecx is non-zero)?
I could... it turns out when Peter did this:
3693ca81151e x86/uaccess: Move copy_user_handle_tail() into asm
...he did not also go fixup my cargo culting. I'll take a look...