kernel-ark/arch
Lee Nicks 9e3699ea7b [PATCH] ppc: prevent GCC 4 from generating AltiVec instructions in kernel
Depending on how GCC is built, GCC 4 may generate altivec instructions without
user explicitly requesting vector operations in the code.  Although this is a
performance booster for user applications, it is a problem for kernel.

This patch explicitly instruct GCC to NOT generate altivec instructions while
building the kernel.

Here are some test cases I ran.

(1) build gcc 4.0.1 with '--with-cpu=7450 --enable-altivec
    --enable-cxx-flags=-mcpu=7450', and use this gcc to build kernel WITHOUT
    this kernel patch.  Kernel fail to boot up on a 7450 board because of
    altivec instructions in kernel.

(2) build gcc 4.0.1 with "--with-cpu=7450 --enable-altivec
    --enable-cxx-flags=-mcpu=7450", and use this gcc to build kernel WITH this
    kernel patch.  Kernel boot up on a 7450 board without any problem.

(3) build gcc 4.0.1 with "--with-cpu=750 --enable-cxx-flags=-mcpu=750",
    and use this gcc to build kernel with or without this kernel patch.
    Kernel boot up on a 7450 board without any problem.

This patch should also work with GCC 3 or even earlier GCC 2.95.3.

Signed-off-by: Lee Nicks <allinux@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-29 13:55:19 +10:00
..
alpha [PATCH] alpha: fix kernel alignment traps 2005-10-02 14:32:49 -07:00
arm [ARM] fix sharp zaurus c-3000 compile failure without CONFIG_FB_PXA 2005-10-24 22:30:10 +01:00
arm26
cris [NETFILTER]: Fix OOPSes on machines with discontiguous cpu numbering. 2005-10-13 14:41:23 -07:00
frv
h8300
i386 [PATCH] typo fix in last cpufreq powernow patch 2005-10-21 17:08:30 -07:00
ia64 [PATCH] swiotlb: make sure initial DMA allocations really are in DMA memory 2005-10-19 23:11:33 -07:00
m32r [PATCH] m32r: Fix smp.c for preempt kernel 2005-10-14 17:10:12 -07:00
m68k
m68knommu
mips [PATCH] mips: fix build error in TANBAC TB0226 2005-10-14 17:10:11 -07:00
parisc
powerpc powerpc: Merge xmon 2005-10-28 22:53:37 +10:00
ppc [PATCH] ppc: prevent GCC 4 from generating AltiVec instructions in kernel 2005-10-29 13:55:19 +10:00
ppc64 [PATCH] ppc: prevent GCC 4 from generating AltiVec instructions in kernel 2005-10-29 13:55:19 +10:00
s390 [PATCH] s390 signal annotations 2005-09-29 08:46:27 -07:00
sh [NETFILTER]: Fix OOPSes on machines with discontiguous cpu numbering. 2005-10-13 14:41:23 -07:00
sh64
sparc [SPARC32]: Revert IOMAP change eb98129eec 2005-10-10 21:02:26 -07:00
sparc64 [SPARC64]: Fix powering off on SMP. 2005-10-14 15:26:08 -07:00
um [PATCH] uml: fix compile failure for TT mode 2005-10-24 08:59:25 -07:00
v850
x86_64 [PATCH] x86_64: Allocate cpu local data for all possible CPUs 2005-10-10 16:33:25 -07:00
xtensa