# git rev-parse -q --verify 7e1ed4da4a16e035a76001461fbd75c453b73206^{commit}
7e1ed4da4a16e035a76001461fbd75c453b73206
already have revision, skipping fetch
# git checkout -q -f -B kisskb 7e1ed4da4a16e035a76001461fbd75c453b73206
# git clean -qxdf
# < git log -1
# commit 7e1ed4da4a16e035a76001461fbd75c453b73206
# Author: Breno Leitao <leitao@debian.org>
# Date:   Wed Jan 30 10:46:00 2019 -0200
# 
#     powerpc/ptrace: Mitigate potential Spectre v1
#     
#     'regno' is directly controlled by user space, hence leading to a potential
#     exploitation of the Spectre variant 1 vulnerability.
#     
#     On PTRACE_SETREGS and PTRACE_GETREGS requests, user space passes the
#     register number that would be read or written. This register number is
#     called 'regno' which is part of the 'addr' syscall parameter.
#     
#     This 'regno' value is checked against the maximum pt_regs structure size,
#     and then used to dereference it, which matches the initial part of a
#     Spectre v1 (and Spectre v1.1) attack. The dereferenced value, then,
#     is returned to userspace in the GETREGS case.
#     
#     This patch sanitizes 'regno' before using it to dereference pt_reg.
#     
#     Notice that given that speculation windows are large, the policy is
#     to kill the speculation on the first load and not worry if it can be
#     completed with a dependent load/store [1].
#     
#     [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2
#     
#     Signed-off-by: Breno Leitao <leitao@debian.org>
#     Acked-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-gcc --version
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-ld --version
# < git log --format=%s --max-count=1 7e1ed4da4a16e035a76001461fbd75c453b73206
# < make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-next_mpc85xx_basic_defconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  mpc85xx_basic_defconfig
# make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-next_mpc85xx_basic_defconfig_powerpc-gcc4.6 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:186:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c: In function 'proc_reg_open':
/kisskb/src/include/linux/list.h:65:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c:339:21: note: 'pdeo' was declared here
Completed OK
# rm -rf /kisskb/build/powerpc-next_mpc85xx_basic_defconfig_powerpc-gcc4.6
# Build took: 0:00:23.027229