From: Ralf Baechle <ralf@xxxxxxxxxxxxxx> commit f43edca7ed08fc02279f2a62015da5cb6aa0ad61 upstream. CONFIG_MIPS32_N32=y but CONFIG_BINFMT_ELF disabled results in the following linker errors: arch/mips/built-in.o: In function `elf_core_dump': binfmt_elfn32.c:(.text+0x23dbc): undefined reference to `elf_core_extra_phdrs' binfmt_elfn32.c:(.text+0x246e4): undefined reference to `elf_core_extra_data_size' binfmt_elfn32.c:(.text+0x248d0): undefined reference to `elf_core_write_extra_phdrs' binfmt_elfn32.c:(.text+0x24ac4): undefined reference to `elf_core_write_extra_data' CONFIG_MIPS32_O32=y but CONFIG_BINFMT_ELF disabled results in the following linker errors: arch/mips/built-in.o: In function `elf_core_dump': binfmt_elfo32.c:(.text+0x28a04): undefined reference to `elf_core_extra_phdrs' binfmt_elfo32.c:(.text+0x29330): undefined reference to `elf_core_extra_data_size' binfmt_elfo32.c:(.text+0x2951c): undefined reference to `elf_core_write_extra_phdrs' binfmt_elfo32.c:(.text+0x29710): undefined reference to `elf_core_write_extra_data' This is because binfmt_elfn32 and binfmt_elfo32 are using symbols from elfcore but for these configurations elfcore will not be built. Fixed by making elfcore selectable by a separate config symbol which unlike the current mechanism can also be used from other directories than kernel/, then having each flavor of ELF that relies on elfcore.o, select it in Kconfig, including CONFIG_MIPS32_N32 and CONFIG_MIPS32_O32 which fixes this issue. Link: http://lkml.kernel.org/r/20160520141705.GA1913@xxxxxxxxxxxxxx Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Reviewed-by: James Hogan <james.hogan@xxxxxxxxxx> Cc: "Maciej W. Rozycki" <macro@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/mips/Kconfig | 1 + fs/Kconfig.binfmt | 8 ++++++++ kernel/Makefile | 4 +--- 3 files changed, 10 insertions(+), 3 deletions(-) --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -2990,6 +2990,7 @@ config MIPS32_N32 config BINFMT_ELF32 bool default y if MIPS32_O32 || MIPS32_N32 + select ELFCORE endmenu --- a/fs/Kconfig.binfmt +++ b/fs/Kconfig.binfmt @@ -1,6 +1,7 @@ config BINFMT_ELF bool "Kernel support for ELF binaries" depends on MMU && (BROKEN || !FRV) + select ELFCORE default y ---help--- ELF (Executable and Linkable Format) is a format for libraries and @@ -26,6 +27,7 @@ config BINFMT_ELF config COMPAT_BINFMT_ELF bool depends on COMPAT && BINFMT_ELF + select ELFCORE config ARCH_BINFMT_ELF_STATE bool @@ -34,6 +36,7 @@ config BINFMT_ELF_FDPIC bool "Kernel support for FDPIC ELF binaries" default y depends on (FRV || BLACKFIN || (SUPERH32 && !MMU) || C6X) + select ELFCORE help ELF FDPIC binaries are based on ELF, but allow the individual load segments of a binary to be located in memory independently of each @@ -43,6 +46,11 @@ config BINFMT_ELF_FDPIC It is also possible to run FDPIC ELF binaries on MMU linux also. +config ELFCORE + bool + help + This option enables kernel/elfcore.o. + config CORE_DUMP_DEFAULT_ELF_HEADERS bool "Write ELF core dumps with partial segments" default y --- a/kernel/Makefile +++ b/kernel/Makefile @@ -77,9 +77,7 @@ obj-$(CONFIG_TASK_DELAY_ACCT) += delayac obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o obj-$(CONFIG_TRACEPOINTS) += tracepoint.o obj-$(CONFIG_LATENCYTOP) += latencytop.o -obj-$(CONFIG_BINFMT_ELF) += elfcore.o -obj-$(CONFIG_COMPAT_BINFMT_ELF) += elfcore.o -obj-$(CONFIG_BINFMT_ELF_FDPIC) += elfcore.o +obj-$(CONFIG_ELFCORE) += elfcore.o obj-$(CONFIG_FUNCTION_TRACER) += trace/ obj-$(CONFIG_TRACING) += trace/ obj-$(CONFIG_TRACE_CLOCK) += trace/
