From 7fccfcfba04f9cb46438f368755d368f6c57f3a0 Mon Sep 17 00:00:00 2001
From: Jordan Niethe <jniethe5@gmail.com>
Date: Wed, 6 May 2020 13:40:39 +1000
Subject: [PATCH] powerpc/xmon: Move insertion of breakpoint for xol'ing

References: jsc#SLE-13847
Patch-mainline: v5.8-rc1
Git-commit: 7fccfcfba04f9cb46438f368755d368f6c57f3a0

When a new breakpoint is created, the second instruction of that
breakpoint is patched with a trap instruction. This assumes the length
of the instruction is always the same. In preparation for prefixed
instructions, remove this assumption. Insert the trap instruction at the
same time the first instruction is inserted.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-20-jniethe5@gmail.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/xmon/xmon.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index d8b29f6925be..00b24f357c2b 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -878,7 +878,6 @@ static struct bpt *new_breakpoint(unsigned long a)
 		if (!bp->enabled && atomic_read(&bp->ref_count) == 0) {
 			bp->address = a;
 			bp->instr = (void *)(bpt_table + ((bp - bpts) * BPT_WORDS));
-			patch_instruction(bp->instr + 1, ppc_inst(bpinstr));
 			return bp;
 		}
 	}
@@ -910,6 +909,8 @@ static void insert_bpts(void)
 			continue;
 		}
 		patch_instruction(bp->instr, instr);
+		patch_instruction((void *)bp->instr + ppc_inst_len(instr),
+				  ppc_inst(bpinstr));
 		if (bp->enabled & BP_CIABR)
 			continue;
 		if (patch_instruction((struct ppc_inst *)bp->address,
-- 
2.26.2