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UBUNTU: SAUCE: arm: Fix instruction set selection for GCC 11

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BugLink: https://bugs.launchpad.net/bugs/1939308

GCC 11 on ARM now complains like the following when trying to determine if
an arch is supported. Presumably because it enforces the default option
which (in our case) is '--with-float=hard'?
  $ arm-linux-gnueabihf-gcc-11 -march=armv7-a -c -x c /dev/null
  cc1: error: ‘-mfloat-abi=hard’: selected architecture lacks an FPU

Due to that, the kernel build system selects the wrong compiler options
which throws errros like this:
  /tmp/ccrHfZPj.s: Assembler messages:
  /tmp/ccrHfZPj.s:116: Error: selected processor does not support `dmb ish' in ARM mode
  /tmp/ccrHfZPj.s:150: Error: selected processor does not support `isb ' in ARM mode
  /tmp/ccrHfZPj.s:160: Error: selected processor does not support `mrrc p15,1,r4,r5,c14' in ARM mode
  /tmp/ccrHfZPj.s:245: Error: selected processor does not support `dmb ish' in ARM mode
  /tmp/ccrHfZPj.s:503: Error: selected processor does not support `dmb ish' in ARM mode
  /tmp/ccrHfZPj.s:527: Error: selected processor does not support `dmb ish' in ARM mode
  /tmp/ccrHfZPj.s:698: Error: selected processor does not support `dmb ish' in ARM mode
  /tmp/ccrHfZPj.s:731: Error: selected processor does not support `isb ' in ARM mode

Fix that by moving the option '-msoft-float' up before the
'arch-$(CONFIG_CPU_<foo>)' instruction selection macros.

Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
This commit is contained in:
Juerg Haefliger
2021-08-09 17:22:38 +02:00
committed by Paolo Pisati
parent b3a4e9889c
commit 8c31039695
1 changed files with 4 additions and 1 deletions
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arch/arm/Makefile
+4 -1
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@@ -59,6 +59,9 @@ endif
#
KBUILD_CFLAGS += $(call cc-option,-fno-ipa-sra)
# Need -msoft-float for gcc 11 for the below instruction set selection
KBUILD_CFLAGS += -msoft-float
# This selects which instruction set is used.
arch-$(CONFIG_CPU_32v7M) :=-march=armv7-m
arch-$(CONFIG_CPU_32v7) :=-march=armv7-a
@@ -141,7 +144,7 @@ endif
# Need -Uarm for gcc < 3.x
KBUILD_CPPFLAGS +=$(cpp-y)
KBUILD_CFLAGS +=$(CFLAGS_ABI) $(CFLAGS_ISA) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -msoft-float -Uarm
KBUILD_CFLAGS +=$(CFLAGS_ABI) $(CFLAGS_ISA) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,)) -Uarm
KBUILD_AFLAGS +=$(CFLAGS_ABI) $(AFLAGS_ISA) -Wa,$(arch-y) $(tune-y) -include asm/unified.h -msoft-float
CHECKFLAGS += -D__arm__