powerpc: Make test_translate_branch() independent of instruction length

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

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index 435fc8e..d946f7d 100644 (file)
--- 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));