# git rev-parse -q --verify 2d83b0f30c1483a556c8aa1f7d891006fffcd5e0^{commit}
2d83b0f30c1483a556c8aa1f7d891006fffcd5e0
already have revision, skipping fetch
# git checkout -q -f -B kisskb 2d83b0f30c1483a556c8aa1f7d891006fffcd5e0
# git clean -qxdf
# < git log -1
# commit 2d83b0f30c1483a556c8aa1f7d891006fffcd5e0
# Author: Ard Biesheuvel <ardb@kernel.org>
# Date:   Wed Oct 28 09:04:33 2020 +0100
# 
#     powerpc: Avoid broken GCC __attribute__((optimize))
#     
#     Commit 7053f80d9696 ("powerpc/64: Prevent stack protection in early
#     boot") introduced a couple of uses of __attribute__((optimize)) with
#     function scope, to disable the stack protector in some early boot
#     code.
#     
#     Unfortunately, and this is documented in the GCC man pages [0],
#     overriding function attributes for optimization is broken, and is only
#     supported for debug scenarios, not for production: the problem appears
#     to be that setting GCC -f flags using this method will cause it to
#     forget about some or all other optimization settings that have been
#     applied.
#     
#     So the only safe way to disable the stack protector is to disable it
#     for the entire source file.
#     
#     [0] https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html
#     
#     Fixes: 7053f80d9696 ("powerpc/64: Prevent stack protection in early boot")
#     Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
#     [mpe: Drop one remaining use of __nostackprotector, reported by snowpatch]
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20201028080433.26799-1-ardb@kernel.org
# < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version
# < git log --format=%s --max-count=1 2d83b0f30c1483a556c8aa1f7d891006fffcd5e0
# < make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-next_85xx_ksi8560_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  85xx/ksi8560_defconfig
# make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-next_85xx_ksi8560_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
INFO: Uncompressed kernel (size 0x533928) overlaps the address of the wrapper(0x400000)
INFO: Fixing the link_address of wrapper to (0x600000)
INFO: Uncompressed kernel (size 0x523298) overlaps the address of the wrapper(0x400000)
INFO: Fixing the link_address of wrapper to (0x600000)
Image Name:   Linux-5.10.0-rc2-g2d83b0f30c14
Created:      Tue Nov  3 02:51:12 2020
Image Type:   PowerPC Linux Kernel Image (gzip compressed)
Data Size:    2658712 Bytes = 2596.40 KiB = 2.54 MiB
Load Address: 00000000
Entry Point:  00000000
Image Name:   Linux-5.10.0-rc2-g2d83b0f30c14
Created:      Tue Nov  3 02:51:13 2020
Image Type:   PowerPC Linux Kernel Image (gzip compressed)
Data Size:    2688133 Bytes = 2625.13 KiB = 2.56 MiB
Load Address: 00600000
Entry Point:  00600314
Completed OK
# rm -rf /kisskb/build/powerpc-next_85xx_ksi8560_defconfig_powerpc-gcc5
# Build took: 0:00:26.537562