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| author |   Michael Ellerman <mpe@ellerman.id.au> | 2019-08-20 17:23:19 +1000 |
|---|---|---|
| committer |   Will Deacon <will@kernel.org> | 2019-08-20 10:01:18 +0100 |
| commit | 117acf5c29dd89e4c86761c365b9724dba0d9763 (patch) | |
| tree | 3d0d685d497e197c818e59f4e9c83fd37814d2e3 /arch/powerpc/Makefile | |
| parent | arm64: unexport set_memory_x and set_memory_nx (diff) | |
| download | linux-dev-117acf5c29dd89e4c86761c365b9724dba0d9763.tar.xz linux-dev-117acf5c29dd89e4c86761c365b9724dba0d9763.zip | |
powerpc/Makefile: Always pass --synthetic to nm if supported
Back in 2004 we added logic to arch/ppc64/Makefile to pass
the --synthetic option to nm, if it was supported by nm.
Then in 2005 when arch/ppc64 and arch/ppc were merged, the logic to
add --synthetic was moved inside an #ifdef CONFIG_PPC64 block within
arch/powerpc/Makefile, and has remained there since.
That was fine, though crufty, until recently when a change to
init/Kconfig added a config time check that uses $(NM). On powerpc
that leads to an infinite loop because Kconfig uses $(NM) to calculate
some values, then the powerpc Makefile changes $(NM), which Kconfig
notices and restarts.
The original commit that added --synthetic simply said:
On new toolchains we need to use nm --synthetic or we miss code
symbols.
And the nm man page says that the --synthetic option causes nm to:
Include synthetic symbols in the output. These are special symbols
created by the linker for various purposes.
So it seems safe to always pass --synthetic if nm supports it, ie. on
32-bit and 64-bit, it just means 32-bit kernels might have more
symbols reported (and in practice I see no extra symbols). Making it
unconditional avoids the #ifdef CONFIG_PPC64, which in turn avoids the
infinite loop.
Debugged-by: Peter Collingbourne <pcc@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/powerpc/Makefile')
| -rw-r--r-- | arch/powerpc/Makefile | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index c345b79414a9..403f7e193833 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -39,13 +39,11 @@ endif uname := $(shell uname -m) KBUILD_DEFCONFIG := $(if $(filter ppc%,$(uname)),$(uname),ppc64)_defconfig -ifdef CONFIG_PPC64 new_nm := $(shell if $(NM) --help 2>&1 | grep -- '--synthetic' > /dev/null; then echo y; else echo n; fi) ifeq ($(new_nm),y) NM := $(NM) --synthetic endif -endif # BITS is used as extension for files which are available in a 32 bit # and a 64 bit version to simplify shared Makefiles. |