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ARC: build: Better way to detect ISA compatible toolchain

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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>
This commit is contained in:
Vineet Gupta 2016-02-25 22:04:38 +05:30
parent 7cab91b87d
commit 20d780374c
2 changed files with 14 additions and 6 deletions
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14
arch/arc/Makefile
View file

@ -22,6 +22,20 @@ cflags-y += -fno-common -pipe -fno-builtin -D__linux__
cflags-$(CONFIG_ISA_ARCOMPACT) += -mA7
cflags-$(CONFIG_ISA_ARCV2) += -mcpu=archs
is_700 = $(shell $(CC) -dM -E - < /dev/null | grep -q "ARC700" && echo 1 || echo 0)
ifdef CONFIG_ISA_ARCOMPACT
ifeq ($(is_700), 0)
$(error Toolchain not configured for ARCompact builds)
endif
endif
ifdef CONFIG_ISA_ARCV2
ifeq ($(is_700), 1)
$(error Toolchain not configured for ARCv2 builds)
endif
endif
ifdef CONFIG_ARC_CURR_IN_REG
# For a global register defintion, make sure it gets passed to every file
# We had a customer reported bug where some code built in kernel was NOT using

6
arch/arc/include/asm/arcregs.h
View file

@ -381,12 +381,6 @@ static inline int is_isa_arcompact(void)
return IS_ENABLED(CONFIG_ISA_ARCOMPACT);
}
#if defined(CONFIG_ISA_ARCOMPACT) && !defined(_CPU_DEFAULT_A7)
#error "Toolchain not configured for ARCompact builds"
#elif defined(CONFIG_ISA_ARCV2) && !defined(_CPU_DEFAULT_HS)
#error "Toolchain not configured for ARCv2 builds"
#endif
#endif /* __ASEMBLY__ */
#endif /* _ASM_ARC_ARCREGS_H */