powerpc/code-patching: Use test_trampoline for prefixed patch test

Use the dedicated test_trampoline function for testing prefixed
patching like other tests and remove the hand coded assembly stuff.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a450ef3f8653f75e1bd9aaf7a3889d379752f33b.1638446239.git.christophe.leroy@csgroup.eu

arch/powerpc/lib/Makefile

@@ -19,7 +19,7 @@ CFLAGS_code-patching.o += -DDISABLE_BRANCH_PROFILING
 CFLAGS_feature-fixups.o += -DDISABLE_BRANCH_PROFILING
 endif
 
-obj-y += alloc.o code-patching.o feature-fixups.o pmem.o test_code-patching.o
+obj-y += alloc.o code-patching.o feature-fixups.o pmem.o
 
 ifndef CONFIG_KASAN
 obj-y	+=	string.o memcmp_$(BITS).o

arch/powerpc/lib/code-patching.c

@@ -399,7 +399,7 @@ static int __init instr_is_branch_to_addr(const u32 *instr, unsigned long addr)
 
 static void __init test_trampoline(void)
 {
-	asm ("nop;\n");
+	asm ("nop;nop;\n");
 }
 
 #define check(x)	do {	\
@@ -708,25 +708,19 @@ static void __init test_translate_branch(void)
 	vfree(buf);
 }
 
-#ifdef CONFIG_PPC64
 static void __init test_prefixed_patching(void)
 {
-	extern unsigned int code_patching_test1[];
-	extern unsigned int code_patching_test1_expected[];
-	extern unsigned int end_code_patching_test1[];
+	u32 *iptr = (u32 *)ppc_function_entry(test_trampoline);
+	u32 expected[2] = {OP_PREFIX << 26, 0};
+	ppc_inst_t inst = ppc_inst_prefix(OP_PREFIX << 26, 0);
 
-	__patch_instruction(code_patching_test1,
-			    ppc_inst_prefix(OP_PREFIX << 26, 0x00000000),
-			    code_patching_test1);
+	if (!IS_ENABLED(CONFIG_PPC64))
+		return;
+
+	patch_instruction(iptr, inst);
 
-	check(!memcmp(code_patching_test1,
-		      code_patching_test1_expected,
-		      sizeof(unsigned int) *
-		      (end_code_patching_test1 - code_patching_test1)));
+	check(!memcmp(iptr, expected, sizeof(expected)));
 }
-#else
-static inline void test_prefixed_patching(void) {}
-#endif
 
 static int __init test_code_patching(void)
 {

arch/powerpc/lib/test_code-patching.S

-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Copyright (C) 2020 IBM Corporation
- */
-#include <asm/ppc-opcode.h>
-
-	.text
-
-#define globl(x)		\
-	.globl x;	\
-x:
-
-globl(code_patching_test1)
-	nop
-	nop
-globl(end_code_patching_test1)
-
-globl(code_patching_test1_expected)
-	.long OP_PREFIX << 26
-	.long 0x0000000