[Buildroot] [git commit] arch/arm: add armv8.2a cortex-based cores
Thomas Petazzoni
thomas.petazzoni at bootlin.com
Sun Dec 30 15:09:17 UTC 2018
commit: https://git.buildroot.net/buildroot/commit/?id=56a315f18f47626a98facac71a52e7e8541c5753
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/master
The armv8.2a generation is a cumulative extension to armv8.1a.
Since gcc correctly enables the appropriate extensions based on the core
name, we don't really need to introduce a separate config for armv8.2a,
and we can piggyback on armv8a.
In theory, gcc supports those cores in arm mode. However, configuring
gcc thusly generates a non-working gcc that constantly whines:
cc1: warning: switch -mcpu=cortex-a55 conflicts with -march=armv8.2-a switch
It is to be noted that the -march flag is internal to gcc. It is not
something that Buildroot did set when configuring gcc; Buildroot only
ever sets --with-cpu (not --with-arch).
Additionally, uClibc fails to build entirely (unsure if this is caused
by the above, or if it is a separate issue, though), with:
#### Your compiler does not support TLS and you are trying to build uClibc-ng
#### with NPTL support. Upgrade your binutils and gcc to versions which
#### support TLS for your architecture. Do not contact uClibc-ng maintainers
#### about this problem.
Glibc and musl have not been tested in arm mode, so maybe we could have
a toolchain that eventually works (or at least, pretends to be working),
but we decided it was not worth the effort.
Thus, we restrict those cores to AArch64 mode only.
Signed-off-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
---
arch/Config.in.arm | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/arch/Config.in.arm b/arch/Config.in.arm
index bc1bb26582..e3c64d12ab 100644
--- a/arch/Config.in.arm
+++ b/arch/Config.in.arm
@@ -451,6 +451,28 @@ config BR2_vulcan
select BR2_ARCH_HAS_MMU_OPTIONAL
select BR2_ARCH_NEEDS_GCC_AT_LEAST_7
endif # BR2_ARCH_IS_64
+
+if BR2_ARCH_IS_64
+comment "armv8.2a cores"
+config BR2_cortex_a55
+ bool "cortex-A55"
+ select BR2_ARM_CPU_HAS_FP_ARMV8
+ select BR2_ARM_CPU_ARMV8A
+ select BR2_ARCH_HAS_MMU_OPTIONAL
+ select BR2_ARCH_NEEDS_GCC_AT_LEAST_8
+config BR2_cortex_a75
+ bool "cortex-A75"
+ select BR2_ARM_CPU_HAS_FP_ARMV8
+ select BR2_ARM_CPU_ARMV8A
+ select BR2_ARCH_HAS_MMU_OPTIONAL
+ select BR2_ARCH_NEEDS_GCC_AT_LEAST_8
+config BR2_cortex_a75_a55
+ bool "cortex-A75/A55 big.LITTLE"
+ select BR2_ARM_CPU_HAS_FP_ARMV8
+ select BR2_ARM_CPU_ARMV8A
+ select BR2_ARCH_HAS_MMU_OPTIONAL
+ select BR2_ARCH_NEEDS_GCC_AT_LEAST_8
+endif # BR2_ARCH_IS_64
endchoice
config BR2_ARM_ENABLE_NEON
@@ -796,6 +818,10 @@ config BR2_GCC_TARGET_CPU
default "thunderx2t99" if BR2_thunderx2t99
default "thunderx2t99p1" if BR2_thunderx2t99p1
default "vulcan" if BR2_vulcan
+ # armv8.2a
+ default "cortex-a55" if BR2_cortex_a55
+ default "cortex-a75" if BR2_cortex_a75
+ default "cortex-a75.cortex-a55" if BR2_cortex_a75_a55
config BR2_GCC_TARGET_ABI
default "aapcs-linux" if BR2_arm || BR2_armeb
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