https://github.com/torvalds/linux
Revision b8083f86e8e9b23ad4d75d334c92b601947dfa91 authored by Jonathan Austin on 04 March 2013, 14:17:36 UTC, committed by Russell King on 06 March 2013, 23:45:42 UTC
Before jumping to (position independent) C-code from the decompressor's
assembler world we set-up the C environment. This setup currently does not
set r9, which for arm-none-uclinux-uclibceabi toolchains is by default
expected to be the PIC offset base register (IE should point to the
beginning of the GOT).

Currently, therefore, in order to build working kernels that use the
decompressor it is necessary to use an arm-linux-gnueabi toolchain, or
similar. uClinux toolchains cause a prefetch abort to occur at the beginning
of the decompress_kernel function.

This patch allows uClinux toolchains to build bootable zImages by forcing
the -mno-single-pic-base option, which ensures that the location of the GOT
is re-derived each time it is required, and r9 becomes free for use as a
general purpose register.

This has a small (4% in instruction terms) advantage over the alternative of
setting r9 to point to the GOT before calling into the C-world.

Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
1 parent 3f7d1fe
History
Tip revision: b8083f86e8e9b23ad4d75d334c92b601947dfa91 authored by Jonathan Austin on 04 March 2013, 14:17:36 UTC
ARM: 7666/1: decompressor: add -mno-single-pic-base for building the decompressor
Tip revision: b8083f8
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basic
coccinelle
dtc
genksyms
kconfig
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rt-tester
selinux
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Kbuild.include -rw-r--r-- 10.1 KB
Lindent -rwxr-xr-x 460 bytes
Makefile -rw-r--r-- 1.4 KB
Makefile.asm-generic -rw-r--r-- 684 bytes
Makefile.build -rw-r--r-- 15.1 KB
Makefile.clean -rw-r--r-- 3.2 KB
Makefile.fwinst -rw-r--r-- 2.0 KB
Makefile.headersinst -rw-r--r-- 4.1 KB
Makefile.help -rw-r--r-- 68 bytes
Makefile.host -rw-r--r-- 6.5 KB
Makefile.lib -rw-r--r-- 13.5 KB
Makefile.modbuiltin -rw-r--r-- 1.8 KB
Makefile.modinst -rw-r--r-- 1.2 KB
Makefile.modpost -rw-r--r-- 5.0 KB
Makefile.modsign -rw-r--r-- 1003 bytes
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cleanfile -rwxr-xr-x 3.4 KB
cleanpatch -rwxr-xr-x 5.0 KB
coccicheck -rwxr-xr-x 3.6 KB
config -rwxr-xr-x 3.6 KB
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decodecode -rwxr-xr-x 1.9 KB
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diffconfig -rwxr-xr-x 3.6 KB
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gcc-version.sh -rw-r--r-- 822 bytes
gcc-x86_32-has-stack-protector.sh -rw-r--r-- 184 bytes
gcc-x86_64-has-stack-protector.sh -rw-r--r-- 200 bytes
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headerdep.pl -rwxr-xr-x 3.5 KB
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kallsyms.c -rw-r--r-- 15.2 KB
kernel-doc -rwxr-xr-x 71.4 KB
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mkversion -rw-r--r-- 74 bytes
module-common.lds -rw-r--r-- 737 bytes
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pnmtologo.c -rw-r--r-- 11.9 KB
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sortextable.c -rw-r--r-- 6.8 KB
sortextable.h -rw-r--r-- 4.9 KB
tags.sh -rwxr-xr-x 9.4 KB
unifdef.c -rw-r--r-- 34.8 KB
ver_linux -rwxr-xr-x 3.1 KB
xz_wrap.sh -rw-r--r-- 562 bytes

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