# git rev-parse -q --verify 4ff753feab021242144818b9a3ba011238218145^{commit}
4ff753feab021242144818b9a3ba011238218145
already have revision, skipping fetch
# git checkout -q -f -B kisskb 4ff753feab021242144818b9a3ba011238218145
# git clean -qxdf
# < git log -1
# commit 4ff753feab021242144818b9a3ba011238218145
# Author: Ganesh Goudar <ganeshgr@linux.ibm.com>
# Date:   Fri Jul 24 12:09:46 2020 +0530
# 
#     powerpc/pseries: Avoid using addr_to_pfn in real mode
#     
#     When an UE or memory error exception is encountered the MCE handler
#     tries to find the pfn using addr_to_pfn() which takes effective
#     address as an argument, later pfn is used to poison the page where
#     memory error occurred, recent rework in this area made addr_to_pfn
#     to run in real mode, which can be fatal as it may try to access
#     memory outside RMO region.
#     
#     Have two helper functions to separate things to be done in real mode
#     and virtual mode without changing any functionality. This also fixes
#     the following error as the use of addr_to_pfn is now moved to virtual
#     mode.
#     
#     Without this change following kernel crash is seen on hitting UE.
#     
#     [  485.128036] Oops: Kernel access of bad area, sig: 11 [#1]
#     [  485.128040] LE SMP NR_CPUS=2048 NUMA pSeries
#     [  485.128047] Modules linked in:
#     [  485.128067] CPU: 15 PID: 6536 Comm: insmod Kdump: loaded Tainted: G OE 5.7.0 #22
#     [  485.128074] NIP:  c00000000009b24c LR: c0000000000398d8 CTR: c000000000cd57c0
#     [  485.128078] REGS: c000000003f1f970 TRAP: 0300   Tainted: G OE (5.7.0)
#     [  485.128082] MSR:  8000000000001003 <SF,ME,RI,LE>  CR: 28008284  XER: 00000001
#     [  485.128088] CFAR: c00000000009b190 DAR: c0000001fab00000 DSISR: 40000000 IRQMASK: 1
#     [  485.128088] GPR00: 0000000000000001 c000000003f1fbf0 c000000001634300 0000b0fa01000000
#     [  485.128088] GPR04: d000000002220000 0000000000000000 00000000fab00000 0000000000000022
#     [  485.128088] GPR08: c0000001fab00000 0000000000000000 c0000001fab00000 c000000003f1fc14
#     [  485.128088] GPR12: 0000000000000008 c000000003ff5880 d000000002100008 0000000000000000
#     [  485.128088] GPR16: 000000000000ff20 000000000000fff1 000000000000fff2 d0000000021a1100
#     [  485.128088] GPR20: d000000002200000 c00000015c893c50 c000000000d49b28 c00000015c893c50
#     [  485.128088] GPR24: d0000000021a0d08 c0000000014e5da8 d0000000021a0818 000000000000000a
#     [  485.128088] GPR28: 0000000000000008 000000000000000a c0000000017e2970 000000000000000a
#     [  485.128125] NIP [c00000000009b24c] __find_linux_pte+0x11c/0x310
#     [  485.128130] LR [c0000000000398d8] addr_to_pfn+0x138/0x170
#     [  485.128133] Call Trace:
#     [  485.128135] Instruction dump:
#     [  485.128138] 3929ffff 7d4a3378 7c883c36 7d2907b4 794a1564 7d294038 794af082 3900ffff
#     [  485.128144] 79291f24 790af00e 78e70020 7d095214 <7c69502a> 2fa30000 419e011c 70690040
#     [  485.128152] ---[ end trace d34b27e29ae0e340 ]---
#     
#     Fixes: 9ca766f9891d ("powerpc/64s/pseries: machine check convert to use common event code")
#     Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20200724063946.21378-1-ganeshgr@linux.ibm.com
# < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version
# < git log --format=%s --max-count=1 4ff753feab021242144818b9a3ba011238218145
# < make -s -j 40 ARCH=powerpc O=/kisskb/build/powerpc-fixes_85xx_tqm8548_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-  85xx/tqm8548_defconfig
# make -s -j 40 ARCH=powerpc O=/kisskb/build/powerpc-fixes_85xx_tqm8548_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-  
INFO: Uncompressed kernel (size 0x552abc) overlaps the address of the wrapper(0x400000)
INFO: Fixing the link_address of wrapper to (0x600000)
INFO: Uncompressed kernel (size 0x542358) overlaps the address of the wrapper(0x400000)
INFO: Fixing the link_address of wrapper to (0x600000)
Image Name:   Linux-5.9.0-rc2-g4ff753feab02
Created:      Fri Oct 23 19:47:30 2020
Image Type:   PowerPC Linux Kernel Image (gzip compressed)
Data Size:    2741890 Bytes = 2677.63 KiB = 2.61 MiB
Load Address: 00600000
Entry Point:  006002a4
Image Name:   Linux-5.9.0-rc2-g4ff753feab02
Created:      Fri Oct 23 19:47:30 2020
Image Type:   PowerPC Linux Kernel Image (gzip compressed)
Data Size:    2711048 Bytes = 2647.51 KiB = 2.59 MiB
Load Address: 00000000
Entry Point:  00000000
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_85xx_tqm8548_defconfig_powerpc-gcc4.9
# Build took: 0:00:26.386113