# git rev-parse -q --verify 6830fcf476286380beeac027eaa2718cb574438a^{commit}
6830fcf476286380beeac027eaa2718cb574438a
already have revision, skipping fetch
# git checkout -q -f -B kisskb 6830fcf476286380beeac027eaa2718cb574438a
# git clean -qxdf
# < git log -1
# commit 6830fcf476286380beeac027eaa2718cb574438a
# Author: Nicholas Piggin <npiggin@gmail.com>
# Date:   Tue May 22 09:00:00 2018 +1000
# 
#     powerpc/64s: Add support for a store forwarding barrier at kernel entry/exit
#     
#     commit a048a07d7f4535baa4cbad6bc024f175317ab938 upstream.
#     
#     On some CPUs we can prevent a vulnerability related to store-to-load
#     forwarding by preventing store forwarding between privilege domains,
#     by inserting a barrier in kernel entry and exit paths.
#     
#     This is known to be the case on at least Power7, Power8 and Power9
#     powerpc CPUs.
#     
#     Barriers must be inserted generally before the first load after moving
#     to a higher privilege, and after the last store before moving to a
#     lower privilege, HV and PR privilege transitions must be protected.
#     
#     Barriers are added as patch sections, with all kernel/hypervisor entry
#     points patched, and the exit points to lower privilge levels patched
#     similarly to the RFI flush patching.
#     
#     Firmware advertisement is not implemented yet, so CPU flush types
#     are hard coded.
#     
#     Thanks to Michal Suchánek for bug fixes and review.
#     
#     Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
#     Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
#     Signed-off-by: Michael Neuling <mikey@neuling.org>
#     Signed-off-by: Michal Suchánek <msuchanek@suse.de>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-gcc --version
# < git log --format=%s --max-count=1 6830fcf476286380beeac027eaa2718cb574438a
# < make -s -j 8 ARCH=powerpc O=/kisskb/build/mpe_83xx_mpc837x_mds_defconfig_powerpc CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  83xx/mpc837x_mds_defconfig
# make -s -j 8 ARCH=powerpc O=/kisskb/build/mpe_83xx_mpc837x_mds_defconfig_powerpc CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  
/kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl':
/kisskb/src/kernel/printk/printk.c:183:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/tty/serial/8250/8250_core.c: In function 'univ8250_release_irq':
/kisskb/src/drivers/tty/serial/8250/8250_core.c:251:18: warning: 'i' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/tty/serial/8250/8250_core.c:231:19: note: 'i' was declared here
INFO: Uncompressed kernel (size 0x52c0e0) overlaps the address of the wrapper(0x400000)
INFO: Fixing the link_address of wrapper to (0x600000)
Image Name:   Linux-4.16.10-g6830fcf
Created:      Tue May 22 15:46:16 2018
Image Type:   PowerPC Linux Kernel Image (gzip compressed)
Data Size:    2632562 Bytes = 2570.86 kB = 2.51 MB
Load Address: 00000000
Entry Point:  00000000
Completed OK
# rm -rf /kisskb/build/mpe_83xx_mpc837x_mds_defconfig_powerpc
# Build took: 0:00:49.349922