# git rev-parse -q --verify 4f3175979e62de3b929bfa54a0db4b87d36257a7^{commit}
4f3175979e62de3b929bfa54a0db4b87d36257a7
already have revision, skipping fetch
# git checkout -q -f -B kisskb 4f3175979e62de3b929bfa54a0db4b87d36257a7
# git clean -qxdf
# < git log -1
# commit 4f3175979e62de3b929bfa54a0db4b87d36257a7
# Author: Nathan Lynch <nathanl@linux.ibm.com>
# Date:   Thu Aug 10 22:37:55 2023 -0500
# 
#     powerpc/rtas_flash: allow user copy to flash block cache objects
#     
#     With hardened usercopy enabled (CONFIG_HARDENED_USERCOPY=y), using the
#     /proc/powerpc/rtas/firmware_update interface to prepare a system
#     firmware update yields a BUG():
#     
#       kernel BUG at mm/usercopy.c:102!
#       Oops: Exception in kernel mode, sig: 5 [#1]
#       LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
#       Modules linked in:
#       CPU: 0 PID: 2232 Comm: dd Not tainted 6.5.0-rc3+ #2
#       Hardware name: IBM,8408-E8E POWER8E (raw) 0x4b0201 0xf000004 of:IBM,FW860.50 (SV860_146) hv:phyp pSeries
#       NIP:  c0000000005991d0 LR: c0000000005991cc CTR: 0000000000000000
#       REGS: c0000000148c76a0 TRAP: 0700   Not tainted  (6.5.0-rc3+)
#       MSR:  8000000000029033 <SF,EE,ME,IR,DR,RI,LE>  CR: 24002242  XER: 0000000c
#       CFAR: c0000000001fbd34 IRQMASK: 0
#       [ ... GPRs omitted ... ]
#       NIP usercopy_abort+0xa0/0xb0
#       LR  usercopy_abort+0x9c/0xb0
#       Call Trace:
#         usercopy_abort+0x9c/0xb0 (unreliable)
#         __check_heap_object+0x1b4/0x1d0
#         __check_object_size+0x2d0/0x380
#         rtas_flash_write+0xe4/0x250
#         proc_reg_write+0xfc/0x160
#         vfs_write+0xfc/0x4e0
#         ksys_write+0x90/0x160
#         system_call_exception+0x178/0x320
#         system_call_common+0x160/0x2c4
#     
#     The blocks of the firmware image are copied directly from user memory
#     to objects allocated from flash_block_cache, so flash_block_cache must
#     be created using kmem_cache_create_usercopy() to mark it safe for user
#     access.
#     
#     Fixes: 6d07d1cd300f ("usercopy: Restrict non-usercopy caches to size 0")
#     Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
#     Reviewed-by: Kees Cook <keescook@chromium.org>
#     [mpe: Trim and indent oops]
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://msgid.link/20230810-rtas-flash-vs-hardened-usercopy-v2-1-dcf63793a938@linux.ibm.com
# < /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 4f3175979e62de3b929bfa54a0db4b87d36257a7
# make -s -j 32 ARCH=powerpc O=/kisskb/build/powerpc-fixes_52xx_tqm5200_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  52xx/tqm5200_defconfig
# < make -s -j 32 ARCH=powerpc O=/kisskb/build/powerpc-fixes_52xx_tqm5200_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  help
# make -s -j 32 ARCH=powerpc O=/kisskb/build/powerpc-fixes_52xx_tqm5200_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  olddefconfig
# make -s -j 32 ARCH=powerpc O=/kisskb/build/powerpc-fixes_52xx_tqm5200_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_52xx_tqm5200_defconfig_powerpc-gcc5
# Build took: 0:01:00.136006