x86 vDSO: generate vdso-syms.lds

This patch adds a new way of extracting symbols from the built vDSO image.
This is much simpler and less fragile than using ld -R; it removes the
need to control the DSO layout quite so exactly.  I was clearly unduly
distracted by clever ld uses when I did the original vDSO implementation.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Roland McGrath 2008-01-30 13:30:40 +01:00 committed by Ingo Molnar
parent c1d171a002
commit 5b93049337
2 changed files with 24 additions and 0 deletions

View File

@ -55,6 +55,20 @@ SYSCFLAGS_vdso-syms.o = -r -d
$(obj)/vdso-syms.o: $(src)/vdso.lds $(vobjs) FORCE
$(call if_changed,syscall)
targets += vdso-syms.lds
obj-y += vdso-syms.lds
#
# Match symbols in the DSO that look like VDSO*; produce a file of constants.
#
sed-vdsosym := -e 's/^00*/0/' \
-e 's/^\([0-9a-fA-F]*\) . \(VDSO[a-zA-Z0-9_]*\)$$/\2 = 0x\1;/p'
quiet_cmd_vdsosym = VDSOSYM $@
cmd_vdsosym = $(NM) $< | sed -n $(sed-vdsosym) | LC_ALL=C sort > $@
$(obj)/%-syms.lds: $(obj)/%.so.dbg FORCE
$(call if_changed,vdsosym)
quiet_cmd_vdso_install = INSTALL $@
cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
vdso.so:

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@ -8,6 +8,16 @@
#define VDSO_PRELINK 0xffffffffff700000
/*
* Symbols we define here called VDSO* get their values into vdso-syms.lds
* and become visible to the kernel itself.
*/
VDSO64_PRELINK = VDSO_PRELINK;
#define VEXTERN(x) VDSO64_ ## x = vdso_ ## x;
#include "vextern.h"
#undef VEXTERN
SECTIONS
{
. = VDSO_PRELINK + SIZEOF_HEADERS;