[PATCH 4.4 21/38] ELF/MIPS build fix

Greg Kroah-Hartman
2021-02-08T15:31:21Z

From: Ralf Baechle <ralf@linux-mips.org>

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@linux-mips.org
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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/