# 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 # 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 # [mpe: Drop one remaining use of __nostackprotector, reported by snowpatch] # Signed-off-by: Michael Ellerman # 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 48 ARCH=powerpc O=/kisskb/build/powerpc-next_83xx_mpc832x_mds_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- 83xx/mpc832x_mds_defconfig # < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_83xx_mpc832x_mds_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- help # make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_83xx_mpc832x_mds_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- olddefconfig # make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_83xx_mpc832x_mds_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- INFO: Uncompressed kernel (size 0x6567f4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0x700000) INFO: Uncompressed kernel (size 0x64610c) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0x700000) Image Name: Linux-5.10.0-rc2-65308-g2d83b0f3 Created: Tue Nov 3 02:55:47 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 2796282 Bytes = 2730.74 KiB = 2.67 MiB Load Address: 00000000 Entry Point: 00000000 Image Name: Linux-5.10.0-rc2-65308-g2d83b0f3 Created: Tue Nov 3 02:55:47 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 2825648 Bytes = 2759.42 KiB = 2.69 MiB Load Address: 00700000 Entry Point: 00700294 Completed OK # rm -rf /kisskb/build/powerpc-next_83xx_mpc832x_mds_defconfig_powerpc-gcc5 # Build took: 0:00:47.535698