On 05/23/2017 05:32 PM, Florian Fainelli wrote:
> Building a statically linked UML kernel on a Centos 6.9 host resulted in
> the following linking failure (GCC 4.4, glibc-2.12):
>
> /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../lib64/libpthread.a(libpthread.o):
> In function `siglongjmp':
> (.text+0x8490): multiple definition of `longjmp'
> arch/x86/um/built-in.o:/local/users/fainelli/openwrt/trunk/build_dir/target-x86_64_musl/linux-uml/linux-4.4.69/arch/x86/um/setjmp_64.S:44:
> first defined here
> /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../lib64/libpthread.a(libpthread.o):
> In function `sem_open':
> (.text+0x77cd): warning: the use of `mktemp' is dangerous, better use
> `mkstemp'
> collect2: ld returned 1 exit status
> make[4]: *** [vmlinux] Error 1
>
> Adopt a solution similar to the one done for vmap where we define
> longjmp/setjmp to be kernel_longjmp/setjmp. In the process, make sure we
> do rename the functions in arch/x86/um/setjmp_*.S accordingly.
>
> Fixes: a7df4716d195 ("um: link with -lpthread")
> Signed-off-by: Florian Fainelli <f.faine...@gmail.com>
Richard, we are kind of hijacking this thread now that was originally
about statically linking UML, is this particular patch okay?
> ---
> Changes in v2:
> - fix typo introduced on longjmp
>
> arch/um/Makefile | 4 ++++
> arch/x86/um/setjmp_32.S | 16 ++++++++--------
> arch/x86/um/setjmp_64.S | 16 ++++++++--------
> 3 files changed, 20 insertions(+), 16 deletions(-)
>
> diff --git a/arch/um/Makefile b/arch/um/Makefile
> index 0ca46ededfc7..6ca4f66085c1 100644
> --- a/arch/um/Makefile
> +++ b/arch/um/Makefile
> @@ -59,10 +59,14 @@ KBUILD_CPPFLAGS += -I$(srctree)/$(HOST_DIR)/um
> # Same things for in6addr_loopback and mktime - found in libc. For these two
> we
> # only get link-time error, luckily.
> #
> +# -Dlongjmp=kernel_longjmp prevents anything from referencing the
> libpthread.a
> +# embedded copy of longjmp, same thing for setjmp.
> +#
> # These apply to USER_CFLAGS to.
>
> KBUILD_CFLAGS += $(CFLAGS) $(CFLAGS-y) -D__arch_um__ \
> $(ARCH_INCLUDE) $(MODE_INCLUDE) -Dvmap=kernel_vmap \
> + -Dlongjmp=kernel_longjmp -Dsetjmp=kernel_setjmp \
> -Din6addr_loopback=kernel_in6addr_loopback \
> -Din6addr_any=kernel_in6addr_any -Dstrrchr=kernel_strrchr
>
> diff --git a/arch/x86/um/setjmp_32.S b/arch/x86/um/setjmp_32.S
> index b766792c9933..39053192918d 100644
> --- a/arch/x86/um/setjmp_32.S
> +++ b/arch/x86/um/setjmp_32.S
> @@ -16,9 +16,9 @@
>
> .text
> .align 4
> - .globl setjmp
> - .type setjmp, @function
> -setjmp:
> + .globl kernel_setjmp
> + .type kernel_setjmp, @function
> +kernel_setjmp:
> #ifdef _REGPARM
> movl %eax,%edx
> #else
> @@ -35,13 +35,13 @@ setjmp:
> movl %ecx,20(%edx) # Return address
> ret
>
> - .size setjmp,.-setjmp
> + .size kernel_setjmp,.-kernel_setjmp
>
> .text
> .align 4
> - .globl longjmp
> - .type longjmp, @function
> -longjmp:
> + .globl kernel_longjmp
> + .type kernel_longjmp, @function
> +kernel_longjmp:
> #ifdef _REGPARM
> xchgl %eax,%edx
> #else
> @@ -55,4 +55,4 @@ longjmp:
> movl 16(%edx),%edi
> jmp *20(%edx)
>
> - .size longjmp,.-longjmp
> + .size kernel_longjmp,.-kernel_longjmp
> diff --git a/arch/x86/um/setjmp_64.S b/arch/x86/um/setjmp_64.S
> index 45f547b4043e..c56942e1a38c 100644
> --- a/arch/x86/um/setjmp_64.S
> +++ b/arch/x86/um/setjmp_64.S
> @@ -18,9 +18,9 @@
>
> .text
> .align 4
> - .globl setjmp
> - .type setjmp, @function
> -setjmp:
> + .globl kernel_setjmp
> + .type kernel_setjmp, @function
> +kernel_setjmp:
> pop %rsi # Return address, and adjust the stack
> xorl %eax,%eax # Return value
> movq %rbx,(%rdi)
> @@ -34,13 +34,13 @@ setjmp:
> movq %rsi,56(%rdi) # Return address
> ret
>
> - .size setjmp,.-setjmp
> + .size kernel_setjmp,.-kernel_setjmp
>
> .text
> .align 4
> - .globl longjmp
> - .type longjmp, @function
> -longjmp:
> + .globl kernel_longjmp
> + .type kernel_longjmp, @function
> +kernel_longjmp:
> movl %esi,%eax # Return value (int)
> movq (%rdi),%rbx
> movq 8(%rdi),%rsp
> @@ -51,4 +51,4 @@ longjmp:
> movq 48(%rdi),%r15
> jmp *56(%rdi)
>
> - .size longjmp,.-longjmp
> + .size kernel_longjmp,.-kernel_longjmp
>
--
Florian
