From 0b582db5490a1f250ef63337dd46d5c7599dae80 Mon Sep 17 00:00:00 2001
From: Jordan Niethe <jniethe5@gmail.com>
Date: Wed, 6 May 2020 13:40:40 +1000
Subject: [PATCH] powerpc: Make test_translate_branch() independent of
 instruction length

References: jsc#SLE-13847
Patch-mainline: v5.8-rc1
Git-commit: 0b582db5490a1f250ef63337dd46d5c7599dae80

test_translate_branch() uses two pointers to instructions within a
buffer, p and q, to test patch_branch(). The pointer arithmetic done on
them assumes a size of 4. This will not work if the instruction length
changes. Instead do the arithmetic relative to the void * to the buffer.

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/20200506034050.24806-21-jniethe5@gmail.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/lib/code-patching.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index 435fc8e9f45d..d946f7d6bb32 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -572,7 +572,7 @@ static void __init test_branch_bform(void)
 static void __init test_translate_branch(void)
 {
 	unsigned long addr;
-	struct ppc_inst *p, *q;
+	void *p, *q;
 	struct ppc_inst instr;
 	void *buf;
 
@@ -586,7 +586,7 @@ static void __init test_translate_branch(void)
 	addr = (unsigned long)p;
 	patch_branch(p, addr, 0);
 	check(instr_is_branch_to_addr(p, addr));
-	q = p + 1;
+	q = p + 4;
 	translate_branch(&instr, q, p);
 	patch_instruction(q, instr);
 	check(instr_is_branch_to_addr(q, addr));
@@ -642,7 +642,7 @@ static void __init test_translate_branch(void)
 	create_cond_branch(&instr, p, addr, 0);
 	patch_instruction(p, instr);
 	check(instr_is_branch_to_addr(p, addr));
-	q = p + 1;
+	q = buf + 4;
 	translate_branch(&instr, q, p);
 	patch_instruction(q, instr);
 	check(instr_is_branch_to_addr(q, addr));
-- 
2.26.2