linux/arch/arc
Vineet Gupta 20d780374c ARC: build: Better way to detect ISA compatible toolchain
ARC architecture has 2 instruction sets: ARCompact/ARCv2.
While same gcc supports compiling for either (using appropriate toggles),
we can't use the same toolchain to build kernel because libgcc needs
to be unique and the toolchian (uClibc based) is not multilibed.

uClibc toolchain is convenient since it allows all userspace and
kernel to be built with a single install for an ISA.

This however means 2 gnu installs (with same triplet prefix) are needed
for building for 2 ISA and need to be in PATH.
As developers we keep switching the builds, but would occassionally fail
to update the PATH leading to usage of wrong tools. And this would only
show up at the end of kernel build when linking incompatible libgcc.

So the initial solution was to have gcc define a special preprocessor macro
DEFAULT_CPU_xxx which is unique for default toolchain configuration.
Claudiu proposed using grep for an existing preprocessor macro which is
again uniquely defined per ISA.

Cc: Michal Marek <mmarek@suse.cz>
Suggested-by: Claudiu Zissulescu <claziss@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2016-03-12 11:58:30 +05:30
..
boot ARC: [plat-sim] unbork non default CONFIG_LINUX_LINK_BASE 2015-12-17 11:06:43 +05:30
configs ARC: [*defconfig] No need to specify CONFIG_CROSS_COMPILE 2016-03-11 14:59:55 +05:30
include ARC: build: Better way to detect ISA compatible toolchain 2016-03-12 11:58:30 +05:30
kernel ARC: Fix misspellings in comments. 2016-03-11 14:59:53 +05:30
lib ARCv2: lib: memcpy: use local symbols 2015-11-03 17:33:00 +05:30
mm ARC: Fix misspellings in comments. 2016-03-11 14:59:53 +05:30
oprofile
plat-axs10x ARCv2: smp: [plat-*]: No need to explicitly call mcip_init_smp() 2015-10-28 16:13:41 +05:30
plat-sim ARC: remove extraneous header include 2015-11-14 13:11:38 +05:30
plat-tb10x
Kbuild
Kconfig ARCv2: Allow enabling PAE40 w/o HIGHMEM 2016-03-12 10:48:14 +05:30
Kconfig.debug ARC: With earlycon in use, retire EARLY_PRINTK 2015-05-11 11:20:21 +05:30
Makefile ARC: build: Better way to detect ISA compatible toolchain 2016-03-12 11:58:30 +05:30