[PATCH 0/2] Revert to 32-bit 3.15-style vvar and vdso stripping

From: Andy Lutomirski
Date: Thu Jul 10 2014 - 21:13:28 EST


The fancy ideas of aggressively stripping the vdso and placing the
vvar data after the vdso have been considerably more painful than I
hoped. This reverts to using objcopy -S to strip the vdso (thus
eliminating the whole fake section mechanism and all of its
attendent build-time fragility, I hope) and places the vvar data
before the vdso.

The latter is a bit messy: ELF wasn't really designed to have
symbols at negative virtual addresses. I think I got all the
bitness issues and cross-compilation stuff right, but I'm not
well-equipped to test that. The kbuild robot hasn't complained yet,
though.

I don't know whether this is 3.16 material. I'm not aware of an
actual problem at this point, but the current state of affairs is
quite fragile.

Applies on top of tip/x86/urgent as of a few minutes ago.


Andy Lutomirski (2):
x86,vdso: Move the vvar area before the vdso text
x86,vdso: Get rid of the fake section mechanism

arch/x86/include/asm/vdso.h | 18 +--
arch/x86/vdso/Makefile | 16 ++-
arch/x86/vdso/vdso-fakesections.c | 21 ----
arch/x86/vdso/vdso-layout.lds.S | 44 ++++----
arch/x86/vdso/vdso2c.c | 128 ++++++++++++++++-----
arch/x86/vdso/vdso2c.h | 227 +++++++-------------------------------
arch/x86/vdso/vma.c | 20 ++--
7 files changed, 188 insertions(+), 286 deletions(-)
delete mode 100644 arch/x86/vdso/vdso-fakesections.c

--
1.9.3

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