knacky
March 25, 2019, 10:31pm
1
Hello, target optimization seems to be missing after defconfig for the following:
CONFIG_TARGET_ipq806x=y
Used to show in menuconfig Advanced configuration options > Target Options as:
Now shows in menuconfig Advanced configuration options > Target Options as:
I performed these steps:
git pull
./scripts/feeds update -a && ./scripts/feeds install -a
make clean with the following changes: Target System (Qualcomm Atheros IPQ806X) and Target Profile (Netgear Nighthawk X4S R7800)
make defconfig
make menuconfig
-mcpu and -mfpu are seemingly no longer defined for this target. Is this intended?
1 Like
I think the best answer to this question is: "They moved" (together with -mfloat=hard, which you never saw before, but it was necessary).
committed 08:15PM - 25 Mar 19 UTC
Set the toolchain's ARM CPU and FPU architectures by utilizing' gcc's
--with-cpu… / --with-fpu configure options that: "Specify which cpu
variant the compiler should generate code for by default. cpu will
be used as the default value of the -mcpu= switch."
This will resolve the following kernel compilation failures under
gcc 8.x on ARM because the kernel wants to set (possibly conflicting)
optimization flags.
.../ccyVnmrs.s:204: Error: selected processor does not support `dmb ish' in ARM mode
.../ccyVnmrs.s:215: Error: architectural extension `mp' is not allowed for the current base architecture
.../ccyVnmrs.s:216: Error: selected processor does not support `pldw [r4]' in ARM mode
Because this is a big change, the .config and toolchain need to be
refreshed (as in removed and regenerated).
Reported-by: Ansuel Smith <ansuelsmth@gmail.com>
Reported-by: Daniel Engberg <daniel.engberg.lists@pyret.net> [#1203]
Signed-off-by: Boris Krasnovskiy <borkra@gmail.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com> [extended commit message,
removed now-deprecated CPU_CFLAGS, changed author to gmail address]
The idea is that cpu=cortex-a15 and fpu=neon-vfpv4 settings are now the built-in "defaults" as far as gcc for the IPQ806X is concerned. So they don't need to be specified specifically.
BIG EDIT: In case this gets overlooked from the commit: "Because this is a big change, the .config and toolchain need to be refreshed (as in removed and regenerated).". The existing toolchain needs to be refreshed!
To check this, run:
staging_dir/toolchain-arm_cortex-a15+neon-vfpv4_gcc-7.4.0_musl_eabi/bin/arm-openwrt-linux-gcc --help=target -Q
and look for -mcpu=, -mfpu=, ...
On the "old/deprecated toolchains" this will look like:
./staging_dir/toolchain-arm_cortex-a15+neon-vfpv4_gcc-7.4.0_musl_eabi/bin/arm-openwrt-linux-gcc -Q --help=target
arm-openwrt-linux-gcc: warning: environment variable 'STAGING_DIR' not defined
The following options are target specific:
-mabi= aapcs-linux
-mabort-on-noreturn [disabled]
-mandroid [disabled]
-mapcs [disabled]
-mapcs-frame [disabled]
-mapcs-reentrant [disabled]
-mapcs-stack-check [disabled]
-march= armv2
-marm [enabled]
-masm-syntax-unified [disabled]
-mbig-endian [disabled]
-mbionic [disabled]
-mcallee-super-interworking [disabled]
-mcaller-super-interworking [disabled]
-mcmse [disabled]
-mcpu= [default]
-mfix-cortex-m3-ldrd [disabled]
-mflip-thumb [disabled]
-mfloat-abi= hard
-mfp16-format= none
-mfpu= vfp
-mglibc [disabled]
-mhard-float
-mlittle-endian [enabled]
-mlong-calls [disabled]
-mmusl [enabled]
-mneon-for-64bits [disabled]
-mpic-data-is-text-relative [enabled]
-mpic-register=
-mpoke-function-name [disabled]
-mprint-tune-info [disabled]
-mpure-code [disabled]
-mrestrict-it [disabled]
-msched-prolog [enabled]
-msingle-pic-base [disabled]
-mslow-flash-data [disabled]
-msoft-float
-mstructure-size-boundary= 8
-mthumb [disabled]
-mthumb-interwork [disabled]
-mtls-dialect= gnu
-mtp= soft
-mtpcs-frame [disabled]
-mtpcs-leaf-frame [disabled]
-mtune= [default]
-muclibc [disabled]
-munaligned-access [disabled]
-mvectorize-with-neon-double [disabled]
-mvectorize-with-neon-quad [enabled]
-mword-relocations [disabled]
on the newly generated one (this is from gcc 8.3, but it's close enough):
The following options are target specific:
-mabi= aapcs-linux
-mabort-on-noreturn [disabled]
-mandroid [disabled]
-mapcs [disabled]
-mapcs-frame [disabled]
-mapcs-reentrant [disabled]
-mapcs-stack-check [disabled]
-march= armv7ve+simd
-marm [enabled]
-masm-syntax-unified [disabled]
-mbe32 [enabled]
-mbe8 [disabled]
-mbig-endian [disabled]
-mbionic [disabled]
-mbranch-cost= -1
-mcallee-super-interworking [disabled]
-mcaller-super-interworking [disabled]
-mcmse [disabled]
-mcpu= cortex-a15
-mfix-cortex-m3-ldrd [disabled]
-mflip-thumb [disabled]
-mfloat-abi= hard
-mfp16-format= none
-mfpu= neon-vfpv4
-mglibc [disabled]
-mhard-float
-mlittle-endian [enabled]
-mlong-calls [disabled]
-mmusl [enabled]
-mneon-for-64bits [disabled]
-mpic-data-is-text-relative [enabled]
-mpic-register=
-mpoke-function-name [disabled]
-mprint-tune-info [disabled]
-mpure-code [disabled]
-mrestrict-it [disabled]
-msched-prolog [enabled]
-msingle-pic-base [disabled]
-mslow-flash-data [disabled]
-msoft-float
-mstructure-size-boundary= 8
-mthumb [disabled]
-mthumb-interwork [disabled]
-mtls-dialect= gnu
-mtp= cp15
-mtpcs-frame [disabled]
-mtpcs-leaf-frame [disabled]
-mtune=
-muclibc [disabled]
-munaligned-access [enabled]
-mvectorize-with-neon-double [disabled]
-mvectorize-with-neon-quad [enabled]
-mword-relocations [disabled]
2 Likes
knacky
March 26, 2019, 12:02am
3
Thank you chunkeey for the detailed explanation! I frequently review the project git in shortlog format for recent commits, but did not drill down into this particular one since I was (mistakenly) under the impression it was GCC 8-specific, while I use the default GCC 7 compiler.
I will do a fresh clone so next compile will have a correctly built toolchain.
tmomas
April 5, 2019, 12:11am
4
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