# 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/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 7e1ed4da4a16e035a76001461fbd75c453b73206
# < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_85xx_ksi8560_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  85xx/ksi8560_defconfig
# make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_85xx_ksi8560_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
INFO: Uncompressed kernel (size 0x4bd0a0) overlaps the address of the wrapper(0x400000)
INFO: Fixing the link_address of wrapper to (0x500000)
INFO: Uncompressed kernel (size 0x4ac9e0) overlaps the address of the wrapper(0x400000)
INFO: Fixing the link_address of wrapper to (0x500000)
Image Name:   Linux-5.0.0-rc2-g7e1ed4da4a16
Created:      Wed Feb  6 01:45:56 2019
Image Type:   PowerPC Linux Kernel Image (gzip compressed)
Data Size:    2450804 Bytes = 2393.36 KiB = 2.34 MiB
Load Address: 00000000
Entry Point:  00000000
Image Name:   Linux-5.0.0-rc2-g7e1ed4da4a16
Created:      Wed Feb  6 01:45:56 2019
Image Type:   PowerPC Linux Kernel Image (gzip compressed)
Data Size:    2480677 Bytes = 2422.54 KiB = 2.37 MiB
Load Address: 00500000
Entry Point:  00500314
Completed OK
# rm -rf /kisskb/build/powerpc-next_85xx_ksi8560_defconfig_powerpc-gcc5
# Build took: 0:00:35.520488