Hi Nicholas, 2017-07-26 21:46 GMT+09:00 Nicholas Piggin <npiggin@xxxxxxxxx>: > The .data and .bss sections were modified in the generic linker script to > pull in sections named .data.<C identifier>, which are generated by gcc with > -ffunction-sections and -fdata-sections options. > > The problem with this pattern is it can also match section names that Linux > defines explicitly, e.g., .data.unlikely. This can cause Linux sections to > get moved into the wrong place. > > The way to avoid this is to use ".." separators for explicit section names > (the dot character is valid in a section name but not a C identifier). > However currently there are sections which don't follow this rule, so for > now just disable the wild card by default. > > Example: http://marc.info/?l=linux-arm-kernel&m=150106824024221&w=2 > > Cc: <stable@xxxxxxxxxxxxxxx> # 4.9 > Fixes: b67067f1176df ("kbuild: allow archs to select link dead code/data elimination") > Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx> > --- > include/asm-generic/vmlinux.lds.h | 38 ++++++++++++++++++++++++++------------ > 1 file changed, 26 insertions(+), 12 deletions(-) > > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index da0be9a8d1de..9623d78f8494 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -60,6 +60,22 @@ > #define ALIGN_FUNCTION() . = ALIGN(8) > > /* > + * LD_DEAD_CODE_DATA_ELIMINATION option enables -fdata-sections, which > + * generates .data.identifier sections, which need to be pulled in with > + * .data. We don't want to pull in .data..other sections, which Linux > + * has defined. Same for text and bss. > + */ > +#ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION > +#define TEXT_MAIN .text .text.[0-9a-zA-Z_]* > +#define DATA_MAIN .data .data.[0-9a-zA-Z_]* > +#define BSS_MAIN .bss .bss.[0-9a-zA-Z_]* > +#else > +#define TEXT_MAIN .text > +#define DATA_MAIN .data > +#define BSS_MAIN .bss > +#endif >From the git-log, I think you are planning to rename .data.unlikely -> .data..unlikey then the problem will be fixed. ("git grep data.unlikely" gave me only 7 instances.) Why is this patch necessary? You are trying to migrate some architectures to DCDE, so this #ifdef does not solve the problem, I think. -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
