On Wed, 25 Nov 2015 05:33:44 +0100,
Andi Kleen wrote:
>
>
> Hi Takashi,
>
> On Tue, Nov 24, 2015 at 05:33:36PM +0100, Takashi Iwai wrote:
> > LD vmlinux
> > arch/x86/kernel/cpu/perf_event_intel_rapl.c:66:20: error: rapl_domain_names causes a section type conflict with __setup_str_set_reset_devices
> > static const char *rapl_domain_names[NR_RAPL_DOMAINS] __initconst = {
> > ^
> > init/main.c:159:19: note: ‘__setup_str_set_reset_devices’ was declared here
> > __setup("reset_devices", set_reset_devices);
> >
> > Hmm... I see no direct relation, but OK, let's try to get rid of
> > __initconst. Now it hits lots of other errors like:
>
> I hit the same issue, will send a patch. The other symbol is typically some
> random correct symbol because gcc detects the conflict on a pair of symbols.
>
> The problem is that placing const correctly is too difficult, the correct line
> would be
>
> static const char *const rapl_domain_names[NR_RAPL_DOMAINS] __initconst = {
Ah, so I should have ignored the relation with __setup_* but
concentrate on the line. LTO goes much deeper than a human being can
look through :)
Yes, such an error is often overseen. A quick grep shows the
following:
arch/arc/plat-axs10x/axs10x.c:463:static const char *axs101_compat[] __initconst = {
arch/arc/plat-axs10x/axs10x.c:477:static const char *axs103_compat[] __initconst = {
arch/arc/plat-sim/platform.c:22:static const char *simulation_compat[] __initconst = {
arch/arm/mach-imx/mach-imx6ul.c:87:static const char *imx6ul_dt_compat[] __initconst = {
arch/arm/mach-shmobile/setup-r8a7793.c:22:static const char *r8a7793_boards_compat_dt[] __initconst = {
arch/x86/kernel/cpu/perf_event_intel_rapl.c:66:static const char *rapl_domain_names[NR_RAPL_DOMAINS] __initconst = {
drivers/clk/pistachio/clk.h:40:#define PNAME(x) static const char *x[] __initconst
> > `__sw_hweight32' referenced in section `.text' of /tmp/ccUCMU7n.ltrans13.ltrans.o: defined in discarded section `.text' of lib/built-in.o (symbol from plugin)
> > `__sw_hweight32' referenced in section `.text' of /tmp/ccUCMU7n.ltrans13.ltrans.o: defined in discarded section `.text' of lib/built-in.o (symbol from plugin)
> > `__sw_hweight32' referenced in section `.text' of /tmp/ccUCMU7n.ltrans13.ltrans.o: defined in discarded section `.text' of lib/built-in.o (symbol from plugin)
> > `__sw_hweight32' referenced in section `.text' of /tmp/ccUCMU7n.ltrans13.ltrans.o: defined in discarded section `.text' of lib/built-in.o (symbol from plugin)
>
> This needs
>
> https://git.kernel.org/cgit/linux/kernel/git/ak/linux-misc.git/commit/?h=lto-4.0&id=d826425f7a9d935d521989bd0a871b76fb4c59e2
OK, noted.
> > /tmp/ccUCMU7n.ltrans21.ltrans.o: In function `do_exit':
> > <artificial>:(.text+0xfc0): undefined reference to `sys_futex'
> > /tmp/ccUCMU7n.ltrans22.ltrans.o: In function `_do_fork':
> > <artificial>:(.text+0x39f7): undefined reference to `ret_from_fork'
> > <artificial>:(.text+0x4428): undefined reference to `ret_from_kernel_thread'
>
>
> That's new, but can be fixed by adding __visible or asmlinkage to these symbols
> I guess it's from the recent entry* restructuring.
>
> I'll do an updated tree later.
>
> Everything that's called from assembler in C needs to be marked like this. It's
> fairly mechanic.
OK, thanks for the information!
Takashi
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