Home Forums Software discussion Linux Kernel Current kernel FTBFS

  • This topic has 1 reply, 1 voice, and was last updated 5 years ago by Anonymous.
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  • #593
    Anonymous
    Inactive

    With aarch64-gnu-linux-gcc version 6 or later, you can’t use -fPIC and -mcmodel=large at the same time.
    I found I needed this patch to be able to build the kernel. This is essentially 6ffe9923f2350c19b95a2c9ebf1b4f5f275986f2 from upstream git.

    diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
    index 10a4fd489da0..181786d646d3 100644
    --- a/arch/arm64/Kconfig
    +++ b/arch/arm64/Kconfig
    @@ -360,17 +360,13 @@ config ARM64_ERRATUM_845719
     
     config ARM64_ERRATUM_843419
            bool "Cortex-A53: 843419: A load or store might access an incorrect address"
    -       depends on MODULES
            default y
    +       select ARM64_MODULE_CMODEL_LARGE if MODULES
            help
    -         This option builds kernel modules using the large memory model in
    -         order to avoid the use of the ADRP instruction, which can cause
    -         a subsequent memory access to use an incorrect address on Cortex-A53
    -         parts up to r0p4.
    -
    -         Note that the kernel itself must be linked with a version of ld
    -         which fixes potentially affected ADRP instructions through the
    -         use of veneers.
    +         This option links the kernel with '--fix-cortex-a53-843419' and
    +         builds modules using the large memory model in order to avoid the use
    +         of the ADRP instruction, which can cause a subsequent memory access
    +         to use an incorrect address on Cortex-A53 parts up to r0p4.
     
              If unsure, say Y.
     
    diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
    index cf65c159575e..9033ff7e95e2 100644
    --- a/arch/arm64/Makefile
    +++ b/arch/arm64/Makefile
    @@ -15,6 +15,15 @@ CPPFLAGS_vmlinux.lds = -DTEXT_OFFSET=$(TEXT_OFFSET)
     OBJCOPYFLAGS   :=-O binary -R .note -R .note.gnu.build-id -R .comment -S
     GZFLAGS                :=-9
     
    +ifeq ($(CONFIG_ARM64_ERRATUM_843419),y)
    +ld-843419-workaround := $(call ld-option, --fix-cortex-a53-843419)
    +  ifeq ($(ld-843419-workaround),)
    +$(warning ld does not support --fix-cortex-a53-843419; kernel may be susceptible to erratum)
    +  else
    +LDFLAGS_vmlinux        += --fix-cortex-a53-843419
    +  endif
    +endif
    +
     KBUILD_DEFCONFIG := defconfig
     
     # Check for binutils support for specific extensions
    @@ -42,9 +51,6 @@ endif
     
     CHECKFLAGS     += -D__aarch64__
     
    -ifeq ($(CONFIG_ARM64_ERRATUM_843419), y)
    -KBUILD_CFLAGS_MODULE   += -mcmodel=large
    -endif
     
     # Default value
     head-y         := arch/arm64/kernel/head.o
    
    #594
    Anonymous
    Inactive

    The alternative is probably to build without modules. The instructions for installing the kernel forget to install the modules anyway.

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