diff options
| author | Michael Ellerman <mpe@ellerman.id.au> | 2020-12-18 22:16:18 +1100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-12-21 22:06:26 +1100 |
| commit | 107521e8039688f7a9548f17919dfde670b911c1 (patch) | |
| tree | 6aa264d0a30ae84d32b979fbd2af7a2188ddbe38 /arch/powerpc | |
| parent | 42ed6d56ade21f367f27aa5915cc397510cfdef5 (diff) | |
powerpc/vdso: Don't pass 64-bit ABI cflags to 32-bit VDSO
When building the 32-bit VDSO, we are building 32-bit code as part of
a 64-bit kernel build. That requires us to tweak the cflags to trick
the compiler into building 32-bit code for us. The main way we do that
is by passing -m32, but there are other options that affect code
generation and ABI selection.
In particular when building vgettimeofday.c, we end up passing
-mcall-aixdesc because it's in KBUILD_CFLAGS, which causes the
compiler to generate function descriptors, and dot symbols, eg:
$ nm arch/powerpc/kernel/vdso32/vgettimeofday.o
000005d0 T .__c_kernel_clock_getres
00000024 D __c_kernel_clock_getres
...
We get away with that at the moment because we also use the DOTSYM
macro, and that is also incorrectly prepending a '.' in 32-bit VDSO
code due to a separate bug.
But we shouldn't be generating function descriptors for this file,
there's no 32-bit ABI that includes function descriptors, so the
resulting object file is some frankenstein and it's surprising that it
even links.
So filter out all the ABI-related options we add to CFLAGS for 64-bit
builds, so that they're not used when building 32-bit code. With that
we only see regular text symbols:
$ nm arch/powerpc/kernel/vdso32/vgettimeofday.o michael@alpine1-p1
000005d0 T __c_kernel_clock_getres
00000000 T __c_kernel_clock_gettime
00000200 T __c_kernel_clock_gettime64
00000410 T __c_kernel_gettimeofday
00000650 T __c_kernel_time
Fixes: ab037dd87a2f ("powerpc/vdso: Switch VDSO to generic C implementation.")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201218111619.1206391-2-mpe@ellerman.id.au
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/vdso32/Makefile | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/vdso32/Makefile b/arch/powerpc/kernel/vdso32/Makefile index 6616f4e794d0..9cb6f524854b 100644 --- a/arch/powerpc/kernel/vdso32/Makefile +++ b/arch/powerpc/kernel/vdso32/Makefile @@ -27,7 +27,7 @@ endif CC32FLAGS := ifdef CONFIG_PPC64 CC32FLAGS += -m32 -KBUILD_CFLAGS := $(filter-out -mcmodel=medium,$(KBUILD_CFLAGS)) +KBUILD_CFLAGS := $(filter-out -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc,$(KBUILD_CFLAGS)) endif targets := $(obj-vdso32) vdso32.so.dbg |