um: Avoid longjmp/setjmp symbol clashes with libpthread.a

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.fainelli@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

diff --git a/arch/um/Makefile b/arch/um/Makefile
index 0ca46ed..6ca4f66 100644 (file)
--- 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 b766792..3905319 100644 (file)
--- 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 45f547b..c56942e 100644 (file)
--- 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