From 81a413259a224f0d1783c41a74f18864d4f3d67e Mon Sep 17 00:00:00 2001
From: Balamuruhan S <bala24@linux.ibm.com>
Date: Mon, 30 Mar 2020 13:29:54 +0530
Subject: [PATCH] powerpc/xmon: Use `dcbf` inplace of `dcbi` instruction for
64bit Book3S
References: bsc#1065729
Patch-mainline: v5.9-rc1
Git-commit: 81a413259a224f0d1783c41a74f18864d4f3d67e
Data Cache Block Invalidate (dcbi) instruction implemented back in
PowerPC architecture version 2.03. But as per Power Processor Users Manual
it is obsolete and not supported by POWER8/POWER9 core. Attempt to use of
this illegal instruction results in a hypervisor emulation assistance
interrupt. So, ifdef it out the option `i` in xmon for 64bit Book3S.
0:mon> fi
cpu 0x0: Vector: 700 (Program Check) at [c000000003be74a0]
pc: c000000000102030: cacheflush+0x180/0x1a0
lr: c000000000101f3c: cacheflush+0x8c/0x1a0
sp: c000000003be7730
msr: 8000000000081033
current = 0xc0000000035e5c00
paca = 0xc000000001910000 irqmask: 0x03 irq_happened: 0x01
pid = 1025, comm = bash
Linux version 5.6.0-rc5-g5aa19adac (root@ltc-wspoon6) (gcc version 7.4.0
(Ubuntu 7.4.0-1ubuntu1~18.04.1)) #1 SMP Tue Mar 10 04:38:41 CDT 2020
cpu 0x0: Exception 700 (Program Check) in xmon, returning to main loop
[c000000003be7c50] c00000000084abb0 __handle_sysrq+0xf0/0x2a0
[c000000003be7d00] c00000000084b3c0 write_sysrq_trigger+0xb0/0xe0
[c000000003be7d30] c0000000004d1edc proc_reg_write+0x8c/0x130
[c000000003be7d60] c00000000040dc7c __vfs_write+0x3c/0x70
[c000000003be7d80] c000000000410e70 vfs_write+0xd0/0x210
[c000000003be7dd0] c00000000041126c ksys_write+0xdc/0x130
[c000000003be7e20] c00000000000b9d0 system_call+0x5c/0x68
--- Exception: c01 (System Call) at 00007fffa345e420
SP (7ffff0b08ab0) is in userspace
Signed-off-by: Balamuruhan S <bala24@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200330075954.538773-1-bala24@linux.ibm.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/xmon/xmon.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 8fb1f857c11c..4923347b884b 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1869,7 +1869,7 @@ static void cacheflush(void)
catch_memory_errors = 1;
sync();
- if (cmd != 'i') {
+ if (cmd != 'i' || IS_ENABLED(CONFIG_PPC_BOOK3S_64)) {
for (; nflush > 0; --nflush, adrs += L1_CACHE_BYTES)
cflush((void *) adrs);
} else {
--
2.28.0