# git rev-parse -q --verify d9da4b51c27d706592a967c45c8525ed4e19bc6a^{commit}
d9da4b51c27d706592a967c45c8525ed4e19bc6a
already have revision, skipping fetch
# git checkout -q -f -B kisskb d9da4b51c27d706592a967c45c8525ed4e19bc6a
# git clean -qxdf
# < git log -1
# commit d9da4b51c27d706592a967c45c8525ed4e19bc6a
# Author: Michael Ellerman <mpe@ellerman.id.au>
# Date:   Thu Feb 14 15:00:36 2019 +1100
# 
#     powerpc/64s: Fix possible corruption on big endian due to pgd/pud_present()
#     
#     In v4.20 we changed our pgd/pud_present() to check for _PAGE_PRESENT
#     rather than just checking that the value is non-zero, e.g.:
#     
#       static inline int pgd_present(pgd_t pgd)
#       {
#      -       return !pgd_none(pgd);
#      +       return (pgd_raw(pgd) & cpu_to_be64(_PAGE_PRESENT));
#       }
#     
#     Unfortunately this is broken on big endian, as the result of the
#     bitwise && is truncated to int, which is always zero because
#     _PAGE_PRESENT is 0x8000000000000000ul. This means pgd_present() and
#     pud_present() are always false at compile time, and the compiler
#     elides the subsequent code.
#     
#     Remarkably with that bug present we are still able to boot and run
#     with few noticeable effects. However under some work loads we are able
#     to trigger a warning in the ext4 code:
#     
#       WARNING: CPU: 11 PID: 29593 at fs/ext4/inode.c:3927 .ext4_set_page_dirty+0x70/0xb0
#       CPU: 11 PID: 29593 Comm: debugedit Not tainted 4.20.0-rc1 #1
#       ...
#       NIP .ext4_set_page_dirty+0x70/0xb0
#       LR  .set_page_dirty+0xa0/0x150
#       Call Trace:
#        .set_page_dirty+0xa0/0x150
#        .unmap_page_range+0xbf0/0xe10
#        .unmap_vmas+0x84/0x130
#        .unmap_region+0xe8/0x190
#        .__do_munmap+0x2f0/0x510
#        .__vm_munmap+0x80/0x110
#        .__se_sys_munmap+0x14/0x30
#        system_call+0x5c/0x70
#     
#     The fix is simple, we need to convert the result of the bitwise && to
#     an int before returning it.
#     
#     Thanks to Erhard, Jan Kara and Aneesh for help with debugging.
#     
#     Fixes: da7ad366b497 ("powerpc/mm/book3s: Update pmd_present to look at _PAGE_PRESENT bit")
#     Cc: stable@vger.kernel.org # v4.20+
#     Reported-by: Erhard F. <erhard_f@mailbox.org>
#     Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/mips-linux/bin/mips-linux-gcc --version
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/mips-linux/bin/mips-linux-ld --version
# < git log --format=%s --max-count=1 d9da4b51c27d706592a967c45c8525ed4e19bc6a
# < make -s -j 48 ARCH=mips O=/kisskb/build/powerpc-fixes_mips-defconfig_mips CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/mips-linux/bin/mips-linux-  defconfig
# make -s -j 48 ARCH=mips O=/kisskb/build/powerpc-fixes_mips-defconfig_mips CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/mips-linux/bin/mips-linux-  
/kisskb/src/arch/mips/vdso/Makefile:38: MIPS VDSO requires binutils >= 2.25
/kisskb/src/arch/mips/boot/dts/xilfpga/nexys4ddr.dts:109.16-112.8: Warning (i2c_bus_reg): /i2c@10A00000/ad7420@4B: I2C bus unit address format error, expected "4b"
/kisskb/src/arch/mips/vdso/Makefile:38: MIPS VDSO requires binutils >= 2.25
/kisskb/src/kernel/cgroup/cgroup-v1.c: In function 'cgroup1_mount':
/kisskb/src/kernel/cgroup/cgroup-v1.c:1263:20: warning: 'root' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/rcu/srcutree.c: In function 'init_srcu_struct_fields':
/kisskb/src/kernel/rcu/srcutree.c:152:32: warning: 'levelspread[<U6640>]' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/rcu/srcutree.c:100:6: note: 'levelspread[<U6640>]' was declared here
/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/drivers/base/regmap/regmap.c: In function '_regmap_raw_write':
/kisskb/src/drivers/base/regmap/regmap.c:1855:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/base/regmap/regmap.c: In function 'regmap_raw_read':
/kisskb/src/drivers/base/regmap/regmap.c:2594:6: warning: 'ret' 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
/kisskb/src/drivers/i2c/i2c-core-base.c: In function 'i2c_generic_scl_recovery':
/kisskb/src/drivers/i2c/i2c-core-base.c:235:5: 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/arch/mips/vdso/Makefile:38: MIPS VDSO requires binutils >= 2.25
/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]
FIT description: Linux 5.0.0-rc1-gd9da4b51c27d
Created:         Sat Feb 16 21:28:48 2019
 Image 0 (kernel@0)
  Description:  Linux 5.0.0-rc1-gd9da4b51c27d
  Created:      Sat Feb 16 21:28:48 2019
  Type:         Kernel Image
  Compression:  gzip compressed
  Data Size:    4326235 Bytes = 4224.84 KiB = 4.13 MiB
  Architecture: MIPS
  OS:           Linux
  Load Address: 0x80100000
  Entry Point:  0x8080b0d0
  Hash algo:    sha1
  Hash value:   053cc15a5f6de3ae5992e78e10dd71b45401908a
 Image 1 (fdt@boston)
  Description:  img,boston Device Tree
  Created:      Sat Feb 16 21:28:48 2019
  Type:         Flat Device Tree
  Compression:  uncompressed
  Data Size:    3793 Bytes = 3.70 KiB = 0.00 MiB
  Architecture: MIPS
  Hash algo:    sha1
  Hash value:   4799f50d688573234da6e9d7701234d394759ef4
 Image 2 (fdt@ni169445)
  Description:  NI 169445 device tree
  Created:      Sat Feb 16 21:28:48 2019
  Type:         Flat Device Tree
  Compression:  uncompressed
  Data Size:    1871 Bytes = 1.83 KiB = 0.00 MiB
  Architecture: MIPS
  Hash algo:    sha1
  Hash value:   51b89b31605ee62038c8468c429af091dfc75ec7
 Image 3 (fdt@xilfpga)
  Description:  MIPSfpga (xilfpga) Device Tree
  Created:      Sat Feb 16 21:28:48 2019
  Type:         Flat Device Tree
  Compression:  uncompressed
  Data Size:    2708 Bytes = 2.64 KiB = 0.00 MiB
  Architecture: MIPS
  Hash algo:    sha1
  Hash value:   509ce58e44c561d54539e64e9d4b47054e696fc6
 Default Configuration: 'conf@default'
 Configuration 0 (conf@default)
  Description:  Generic Linux kernel
  Kernel:       kernel@0
 Configuration 1 (conf@boston)
  Description:  Boston Linux kernel
  Kernel:       kernel@0
  FDT:          fdt@boston
 Configuration 2 (conf@ni169445)
  Description:  NI 169445 Linux Kernel
  Kernel:       kernel@0
  FDT:          fdt@ni169445
 Configuration 3 (conf@xilfpga)
  Description:  MIPSfpga Linux kernel
  Kernel:       kernel@0
  FDT:          fdt@xilfpga
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_mips-defconfig_mips
# Build took: 0:01:17.570571