# git rev-parse -q --verify f801360e700f3f7a4c89b889696e91972f137351^{commit}
# git fetch -q -n -f git://gitlab.ozlabs.ibm.com/mirror/linux-npiggin.git kerkins
# git rev-parse -q --verify f801360e700f3f7a4c89b889696e91972f137351^{commit}
f801360e700f3f7a4c89b889696e91972f137351
# git checkout -q -f -B kisskb f801360e700f3f7a4c89b889696e91972f137351
# git clean -qxdf
# < git log -1
# commit f801360e700f3f7a4c89b889696e91972f137351
# Author: Nicholas Piggin <npiggin@gmail.com>
# Date:   Fri Sep 13 22:07:01 2019 +1000
# 
#     powerpc/64s: system call support for scv/rfscv instructions
#     
#     Add support for the scv instruction on POWER9 and later CPUs.
#     
#     For now this implements the zeroth scv vector 'scv 0', as identical
#     to 'sc' system calls, with the exception that lr is not preserved, and
#     it is 64-bit only. There may yet be changes made to this ABI, so it's
#     for testing only.
#     
#     rfscv is implemented to return from scv type system calls. It can not
#     be used to return from sc system calls because those are defined to
#     preserve lr.
#     
#     In a comparison of getpid syscall, the test program had scv taking
#     about 3 more cycles in user mode (92 vs 89 for sc), due to lr handling.
#     Total cycles taken for a getpid system call on POWER9 are improved from
#     436 to 345 (26.3% faster), mostly due to reducing mtmsr and mtspr.
# < /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 f801360e700f3f7a4c89b889696e91972f137351
# < make -s -j 10 ARCH=powerpc O=/kisskb/build/npiggin_holly_defconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  holly_defconfig
# < make -s -j 10 ARCH=powerpc O=/kisskb/build/npiggin_holly_defconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  help
# make -s -j 10 ARCH=powerpc O=/kisskb/build/npiggin_holly_defconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  olddefconfig
# make -s -j 10 ARCH=powerpc O=/kisskb/build/npiggin_holly_defconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  
/kisskb/src/fs/proc/inode.c: In function 'proc_reg_open':
/kisskb/src/include/linux/list.h:72:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c:338:21: note: 'pdeo' was declared here
/kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl':
/kisskb/src/kernel/printk/printk.c:204:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/ext4/extents.c: In function 'ext4_convert_unwritten_io_end_vec':
/kisskb/src/fs/ext4/extents.c:5009:23: warning: 'ret' 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:247:18: warning: 'i' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/tty/serial/8250/8250_core.c:227:19: note: 'i' was declared here
/kisskb/src/fs/io_uring.c: In function '__io_sqe_files_update.isra.81':
/kisskb/src/fs/io_uring.c:5819:13: warning: 'err' may be used uninitialized in this function [-Wuninitialized]
INFO: Uncompressed kernel (size 0x557630) overlaps the address of the wrapper(0x400000)
INFO: Fixing the link_address of wrapper to (0x600000)
Completed OK
# rm -rf /kisskb/build/npiggin_holly_defconfig_powerpc-gcc4.6
# Build took: 0:01:17.063491