linux/arch/powerpc
Ganesh Goudar 4ff753feab 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: 9ca766f989 ("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
2020-10-22 14:34:45 +11:00
..
boot powerpc: Remove support for PowerPC 601 2020-10-08 21:17:13 +11:00
configs powerpc: switch 85xx defconfigs from legacy ide to libata 2020-10-06 23:22:24 +11:00
crypto powerpc: Replace HTTP links with HTTPS ones 2020-07-22 00:01:23 +10:00
include powerpc/uaccess: Don't use "m<>" constraint with GCC 4.9 2020-10-22 14:26:09 +11:00
kernel powerpc/eeh: Fix eeh_dev_check_failure() for PE#0 2020-10-22 10:38:53 +11:00
kexec powerpc/kexec_file: Enable early kernel OPAL calls 2020-07-29 23:47:55 +10:00
kvm powerpc/64s: handle ISA v3.1 local copy-paste context switches 2020-09-08 22:57:12 +10:00
lib powerpc/sstep: Remove empty if statement checking for invalid form 2020-09-18 20:05:24 +10:00
math-emu
mm powerpc/32s: Setup the early hash table at all time. 2020-10-08 21:17:14 +11:00
net powerpc/ppc-opcode: Consolidate powerpc instructions from bpf_jit.h 2020-07-16 13:12:42 +10:00
oprofile powerpc/oprofile: fix spelling mistake "contex" -> "context" 2020-08-25 01:31:33 +10:00
perf powerpc/hv-gpci: Add sysfs files inside hv-gpci device to show cpumask 2020-10-07 22:34:49 +11:00
platforms powerpc/pseries: Avoid using addr_to_pfn in real mode 2020-10-22 14:34:45 +11:00
purgatory powerpc/kexec_file: Enable early kernel OPAL calls 2020-07-29 23:47:55 +10:00
sysdev powerpc/xive: Make debug routines static 2020-09-18 20:05:25 +10:00
tools powerpc/tools: Remove 90 line limit in checkpatch script 2020-09-08 22:57:11 +10:00
xmon powerpc/watchpoint: Add hw_len wherever missing 2020-09-15 22:13:20 +10:00
Kbuild powerpc/kexec: Move kexec files into a dedicated subdir. 2019-11-21 15:41:34 +11:00
Kconfig powerpc/rtas: Restrict RTAS requests from userspace 2020-10-06 23:22:27 +11:00
Kconfig.debug powerpc: Remove Xilinx PPC405/PPC440 support 2020-05-28 23:24:34 +10:00
Makefile powerpc/32s: Rename head_32.S to head_book3s_32.S 2020-10-08 21:17:14 +11:00
Makefile.postlink powerpc: unrel_branch_check.sh: use nm to find symbol value 2020-09-02 11:00:22 +10:00