On Tue, Mar 2, 2021 at 9:28 PM Helge Deller <deller@xxxxxx> wrote:
> * Helge Deller <deller@xxxxxx>:
> > On 3/2/21 7:07 PM, Nick Desaulniers wrote:
> > > + Arnd
> > >
> > > On Tue, Mar 2, 2021 at 10:03 AM Helge Deller <deller@xxxxxx> wrote:
> > > >
> > > >
> From: Helge Deller <deller@xxxxxx>
> Date: Tue, 2 Mar 2021 21:07:07 +0100
> Subject: [PATCH] parisc: Enable -mlong-calls gcc option with
> CONFIG_COMPILE_TEST
>
> The kernel test robot reported multiple linkage problems like this:
>
> hppa64-linux-ld: init/main.o(.init.text+0x56c): cannot reach printk
> init/main.o: in function `unknown_bootoption':
> (.init.text+0x56c): relocation truncated to fit: R_PARISC_PCREL22F against
> symbol `printk' defined in .text.unlikely section in kernel/printk/printk.o
>
> There are two ways to solve it:
> a) Enable the -mlong-call compiler option (CONFIG_MLONGCALLS),
> b) Add long branch stub support in 64-bit linker.
>
> While b) is the long-term solution, this patch works around the issue by
> automatically enabling the CONFIG_MLONGCALLS option when
> CONFIG_COMPILE_TEST is set, which indicates that a non-production kernel
> (e.g. 0-day kernel) is built.
>
> Signed-off-by: Helge Deller <deller@xxxxxx>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Fixes: 00e35f2b0e8a ("parisc: Enable -mlong-calls gcc option by default when !CONFIG_MODULES")
> Cc: stable@xxxxxxxxxxxxxxx # v5.6+
>
> diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
> index 4e53ac46e857..afc3b8d03572 100644
> --- a/arch/parisc/Kconfig
> +++ b/arch/parisc/Kconfig
> @@ -203,9 +203,12 @@ config PREFETCH
> def_bool y
> depends on PA8X00 || PA7200
>
> +config PARISC_HUGE_KERNEL
> + def_bool y if !MODULES || UBSAN || FTRACE || COMPILE_TEST
> +
> config MLONGCALLS
> - def_bool y if !MODULES || UBSAN || FTRACE
> - bool "Enable the -mlong-calls compiler option for big kernels" if MODULES && !UBSAN && !FTRACE
> + def_bool y if PARISC_HUGE_KERNEL
> + bool "Enable the -mlong-calls compiler option for big kernels" if !PARISC_HUGE_KERNEL
> depends on PA8X00
> help
> If you configure the kernel to include many drivers built-in instead
Looks good to me, we should probably do something similar on arm with
CONFIG_{ARM,ARM64}_MODULE_PLTS, though that only affects loadable
modules, as the linker would insert its own trampolines during the final
link when branch relocations are out of range.
Arnd
