# git rev-parse -q --verify 8734b41b3efe0fc6082c1937b0e88556c396dc96^{commit}
8734b41b3efe0fc6082c1937b0e88556c396dc96
already have revision, skipping fetch
# git checkout -q -f -B kisskb 8734b41b3efe0fc6082c1937b0e88556c396dc96
# git clean -qxdf
# < git log -1
# commit 8734b41b3efe0fc6082c1937b0e88556c396dc96
# Author: Russell Currey <ruscur@russell.cc>
# Date:   Tue Nov 23 18:15:20 2021 +1000
# 
#     powerpc/module_64: Fix livepatching for RO modules
#     
#     Livepatching a loaded module involves applying relocations through
#     apply_relocate_add(), which attempts to write to read-only memory when
#     CONFIG_STRICT_MODULE_RWX=y.  Work around this by performing these
#     writes through the text poke area by using patch_instruction().
#     
#     R_PPC_REL24 is the only relocation type generated by the kpatch-build
#     userspace tool or klp-convert kernel tree that I observed applying a
#     relocation to a post-init module.
#     
#     A more comprehensive solution is planned, but using patch_instruction()
#     for R_PPC_REL24 on should serve as a sufficient fix.
#     
#     This does have a performance impact, I observed ~15% overhead in
#     module_load() on POWER8 bare metal with checksum verification off.
#     
#     Fixes: c35717c71e98 ("powerpc: Set ARCH_HAS_STRICT_MODULE_RWX")
#     Cc: stable@vger.kernel.org # v5.14+
#     Reported-by: Joe Lawrence <joe.lawrence@redhat.com>
#     Signed-off-by: Russell Currey <ruscur@russell.cc>
#     Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
#     [mpe: Check return codes from patch_instruction()]
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20211214121248.777249-1-mpe@ellerman.id.au
# < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version
# < git log --format=%s --max-count=1 8734b41b3efe0fc6082c1937b0e88556c396dc96
# < make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64_defconfig+NO_HUGETLB+4K_PAGES_powerpc-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  ppc64_defconfig
# Added to kconfig CONFIG_PPC_64K_PAGES=n
# Added to kconfig CONFIG_PPC_4K_PAGES=y
# Added to kconfig CONFIG_HUGETLBFS=n
# < make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64_defconfig+NO_HUGETLB+4K_PAGES_powerpc-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  help
# make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64_defconfig+NO_HUGETLB+4K_PAGES_powerpc-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  olddefconfig
.config:4506:warning: override: reassigning to symbol PPC_4K_PAGES
# make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64_defconfig+NO_HUGETLB+4K_PAGES_powerpc-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
<stdin>:1559:2: warning: #warning syscall futex_waitv not implemented [-Wcpp]
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_ppc64_defconfig+NO_HUGETLB+4K_PAGES_powerpc-gcc11
# Build took: 0:05:04.807046