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Commit 05d0b088 authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

x86, vdso: Error out if the vdso contains external references 



The vdso is a piece of userspace code which is supposed to be fully
self-contained.  Any external (undefined) reference is an error, and
should be caught at compile time.  This was giving us trouble when
compiling with -Os on gcc 4.5.0, for example (failed inline).

The need to do a buildtime check was pointed out by Andi Kleen.

Reported-by: default avatarAndi Kleen <andi@firstfloor.org>
LKML-Reference: <tip-*@vger.kernel.org>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 7e27d6e7

arch/x86/vdso/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -120,7 +120,8 @@ $(obj)/vdso32-syms.lds: $(vdso32.so-y:%=$(obj)/vdso32-%-syms.lds) FORCE 
quiet_cmd_vdso = VDSO    $@

      cmd_vdso = $(CC) -nostdlib -o $@ \

		       $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \

		       -Wl,-T,$(filter %.lds,$^) $(filter %.o,$^)

		       -Wl,-T,$(filter %.lds,$^) $(filter %.o,$^) && \

		 sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'



VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=sysv)

GCOV_PROFILE := n

arch/x86/vdso/checkundef.sh

0 → 100755
+10 −0
Original line number Diff line number Diff line 
#!/bin/sh

nm="$1"

file="$2"

"$nm" "$file" | grep '^ *U' > /dev/null 2>&1

if [ $? -eq 1 ]; then

    exit 0

else

    echo "$file: undefined symbols found" >&2

    exit 1

fi