arch/powerpc/lib/feature-fixups.c - arm/linux-arm-legacy - Git at Google

 /*
  *  Copyright (C) 2001 Ben. Herrenschmidt (benh@kernel.crashing.org)
  *
  *  Modifications for ppc64:
  *      Copyright (C) 2003 Dave Engebretsen <engebret@us.ibm.com>
  *
  *  Copyright 2008 Michael Ellerman, IBM Corporation.
  *
  *  This program is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU General Public License
  *  as published by the Free Software Foundation; either version
  *  2 of the License, or (at your option) any later version.
  */

 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/init.h>
 #include <asm/cputable.h>
 #include <asm/code-patching.h>
 #include <asm/page.h>
 #include <asm/sections.h>


 struct fixup_entry {
 	unsigned long	mask;
 	unsigned long	value;
 	long		start_off;
 	long		end_off;
 	long		alt_start_off;
 	long		alt_end_off;
 };

 static unsigned int *calc_addr(struct fixup_entry *fcur, long offset)
 {
 	/*
 	 * We store the offset to the code as a negative offset from
 	 * the start of the alt_entry, to support the VDSO. This
 	 * routine converts that back into an actual address.
 	 */
 	return (unsigned int *)((unsigned long)fcur + offset);
 }

 static int patch_alt_instruction(unsigned int *src, unsigned int *dest,
 				 unsigned int *alt_start, unsigned int *alt_end)
 {
 	unsigned int instr;

 	instr = *src;

 	if (instr_is_relative_branch(*src)) {
 		unsigned int *target = (unsigned int *)branch_target(src);

 		/* Branch within the section doesn't need translating */
 		if (target < alt_start || target >= alt_end) {
 			instr = translate_branch(dest, src);
 			if (!instr)
 				return 1;
 		}
 	}

 	patch_instruction(dest, instr);

 	return 0;
 }

 static int patch_feature_section(unsigned long value, struct fixup_entry *fcur)
 {
 	unsigned int *start, *end, *alt_start, *alt_end, *src, *dest;

 	start = calc_addr(fcur, fcur->start_off);
 	end = calc_addr(fcur, fcur->end_off);
 	alt_start = calc_addr(fcur, fcur->alt_start_off);
 	alt_end = calc_addr(fcur, fcur->alt_end_off);

 	if ((alt_end - alt_start) > (end - start))
 		return 1;

 	if ((value & fcur->mask) == fcur->value)
 		return 0;

 	src = alt_start;
 	dest = start;

 	for (; src < alt_end; src++, dest++) {
 		if (patch_alt_instruction(src, dest, alt_start, alt_end))
 			return 1;
 	}

 	for (; dest < end; dest++)
 		patch_instruction(dest, PPC_INST_NOP);

 	return 0;
 }

 void do_feature_fixups(unsigned long value, void *fixup_start, void *fixup_end)
 {
 	struct fixup_entry *fcur, *fend;

 	fcur = fixup_start;
 	fend = fixup_end;

 	for (; fcur < fend; fcur++) {
 		if (patch_feature_section(value, fcur)) {
 			WARN_ON(1);
 			printk("Unable to patch feature section at %p - %p" \
 				" with %p - %p\n",
 				calc_addr(fcur, fcur->start_off),
 				calc_addr(fcur, fcur->end_off),
 				calc_addr(fcur, fcur->alt_start_off),
 				calc_addr(fcur, fcur->alt_end_off));
 		}
 	}
 }

 void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end)
 {
 	long *start, *end;
 	unsigned int *dest;

 	if (!(value & CPU_FTR_LWSYNC))
 		return ;

 	start = fixup_start;
 	end = fixup_end;

 	for (; start < end; start++) {
 		dest = (void *)start + *start;
 		patch_instruction(dest, PPC_INST_LWSYNC);
 	}
 }

 void do_final_fixups(void)
 {
 #if defined(CONFIG_PPC64) && defined(CONFIG_RELOCATABLE)
 	int *src, *dest;
 	unsigned long length;

 	if (PHYSICAL_START == 0)
 		return;

 	src = (int *)(KERNELBASE + PHYSICAL_START);
 	dest = (int *)KERNELBASE;
 	length = (__end_interrupts - _stext) / sizeof(int);

 	while (length--) {
 		patch_instruction(dest, *src);
 		src++;
 		dest++;
 	}
 #endif
 }

 #ifdef CONFIG_FTR_FIXUP_SELFTEST

 #define check(x)	\
 	if (!(x)) printk("feature-fixups: test failed at line %d\n", __LINE__);

 /* This must be after the text it fixes up, vmlinux.lds.S enforces that atm */
 static struct fixup_entry fixup;

 static long calc_offset(struct fixup_entry *entry, unsigned int *p)
 {
 	return (unsigned long)p - (unsigned long)entry;
 }

 void test_basic_patching(void)
 {
 	extern unsigned int ftr_fixup_test1;
 	extern unsigned int end_ftr_fixup_test1;
 	extern unsigned int ftr_fixup_test1_orig;
 	extern unsigned int ftr_fixup_test1_expected;
 	int size = &end_ftr_fixup_test1 - &ftr_fixup_test1;

 	fixup.value = fixup.mask = 8;
 	fixup.start_off = calc_offset(&fixup, &ftr_fixup_test1 + 1);
 	fixup.end_off = calc_offset(&fixup, &ftr_fixup_test1 + 2);
 	fixup.alt_start_off = fixup.alt_end_off = 0;

 	/* Sanity check */
 	check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0);

 	/* Check we don't patch if the value matches */
 	patch_feature_section(8, &fixup);
 	check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0);

 	/* Check we do patch if the value doesn't match */
 	patch_feature_section(0, &fixup);
 	check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_expected, size) == 0);

 	/* Check we do patch if the mask doesn't match */
 	memcpy(&ftr_fixup_test1, &ftr_fixup_test1_orig, size);
 	check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0);
 	patch_feature_section(~8, &fixup);
 	check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_expected, size) == 0);
 }

 static void test_alternative_patching(void)
 {
 	extern unsigned int ftr_fixup_test2;
 	extern unsigned int end_ftr_fixup_test2;
 	extern unsigned int ftr_fixup_test2_orig;
 	extern unsigned int ftr_fixup_test2_alt;
 	extern unsigned int ftr_fixup_test2_expected;
 	int size = &end_ftr_fixup_test2 - &ftr_fixup_test2;

 	fixup.value = fixup.mask = 0xF;
 	fixup.start_off = calc_offset(&fixup, &ftr_fixup_test2 + 1);
 	fixup.end_off = calc_offset(&fixup, &ftr_fixup_test2 + 2);
 	fixup.alt_start_off = calc_offset(&fixup, &ftr_fixup_test2_alt);
 	fixup.alt_end_off = calc_offset(&fixup, &ftr_fixup_test2_alt + 1);

 	/* Sanity check */
 	check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_orig, size) == 0);

 	/* Check we don't patch if the value matches */
 	patch_feature_section(0xF, &fixup);
 	check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_orig, size) == 0);

 	/* Check we do patch if the value doesn't match */
 	patch_feature_section(0, &fixup);
 	check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_expected, size) == 0);

 	/* Check we do patch if the mask doesn't match */
 	memcpy(&ftr_fixup_test2, &ftr_fixup_test2_orig, size);
 	check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_orig, size) == 0);
 	patch_feature_section(~0xF, &fixup);
 	check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_expected, size) == 0);
 }

 static void test_alternative_case_too_big(void)
 {
 	extern unsigned int ftr_fixup_test3;
 	extern unsigned int end_ftr_fixup_test3;
 	extern unsigned int ftr_fixup_test3_orig;
 	extern unsigned int ftr_fixup_test3_alt;
 	int size = &end_ftr_fixup_test3 - &ftr_fixup_test3;

 	fixup.value = fixup.mask = 0xC;
 	fixup.start_off = calc_offset(&fixup, &ftr_fixup_test3 + 1);
 	fixup.end_off = calc_offset(&fixup, &ftr_fixup_test3 + 2);
 	fixup.alt_start_off = calc_offset(&fixup, &ftr_fixup_test3_alt);
 	fixup.alt_end_off = calc_offset(&fixup, &ftr_fixup_test3_alt + 2);

 	/* Sanity check */
 	check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0);

 	/* Expect nothing to be patched, and the error returned to us */
 	check(patch_feature_section(0xF, &fixup) == 1);
 	check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0);
 	check(patch_feature_section(0, &fixup) == 1);
 	check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0);
 	check(patch_feature_section(~0xF, &fixup) == 1);
 	check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0);
 }

 static void test_alternative_case_too_small(void)
 {
 	extern unsigned int ftr_fixup_test4;
 	extern unsigned int end_ftr_fixup_test4;
 	extern unsigned int ftr_fixup_test4_orig;
 	extern unsigned int ftr_fixup_test4_alt;
 	extern unsigned int ftr_fixup_test4_expected;
 	int size = &end_ftr_fixup_test4 - &ftr_fixup_test4;
 	unsigned long flag;

 	/* Check a high-bit flag */
 	flag = 1UL << ((sizeof(unsigned long) - 1) * 8);
 	fixup.value = fixup.mask = flag;
 	fixup.start_off = calc_offset(&fixup, &ftr_fixup_test4 + 1);
 	fixup.end_off = calc_offset(&fixup, &ftr_fixup_test4 + 5);
 	fixup.alt_start_off = calc_offset(&fixup, &ftr_fixup_test4_alt);
 	fixup.alt_end_off = calc_offset(&fixup, &ftr_fixup_test4_alt + 2);

 	/* Sanity check */
 	check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_orig, size) == 0);

 	/* Check we don't patch if the value matches */
 	patch_feature_section(flag, &fixup);
 	check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_orig, size) == 0);

 	/* Check we do patch if the value doesn't match */
 	patch_feature_section(0, &fixup);
 	check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_expected, size) == 0);

 	/* Check we do patch if the mask doesn't match */
 	memcpy(&ftr_fixup_test4, &ftr_fixup_test4_orig, size);
 	check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_orig, size) == 0);
 	patch_feature_section(~flag, &fixup);
 	check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_expected, size) == 0);
 }

 static void test_alternative_case_with_branch(void)
 {
 	extern unsigned int ftr_fixup_test5;
 	extern unsigned int end_ftr_fixup_test5;
 	extern unsigned int ftr_fixup_test5_expected;
 	int size = &end_ftr_fixup_test5 - &ftr_fixup_test5;

 	check(memcmp(&ftr_fixup_test5, &ftr_fixup_test5_expected, size) == 0);
 }

 static void test_alternative_case_with_external_branch(void)
 {
 	extern unsigned int ftr_fixup_test6;
 	extern unsigned int end_ftr_fixup_test6;
 	extern unsigned int ftr_fixup_test6_expected;
 	int size = &end_ftr_fixup_test6 - &ftr_fixup_test6;

 	check(memcmp(&ftr_fixup_test6, &ftr_fixup_test6_expected, size) == 0);
 }

 static void test_cpu_macros(void)
 {
 	extern u8 ftr_fixup_test_FTR_macros;
 	extern u8 ftr_fixup_test_FTR_macros_expected;
 	unsigned long size = &ftr_fixup_test_FTR_macros_expected -
 			     &ftr_fixup_test_FTR_macros;

 	/* The fixups have already been done for us during boot */
 	check(memcmp(&ftr_fixup_test_FTR_macros,
 		     &ftr_fixup_test_FTR_macros_expected, size) == 0);
 }

 static void test_fw_macros(void)
 {
 #ifdef CONFIG_PPC64
 	extern u8 ftr_fixup_test_FW_FTR_macros;
 	extern u8 ftr_fixup_test_FW_FTR_macros_expected;
 	unsigned long size = &ftr_fixup_test_FW_FTR_macros_expected -
 			     &ftr_fixup_test_FW_FTR_macros;

 	/* The fixups have already been done for us during boot */
 	check(memcmp(&ftr_fixup_test_FW_FTR_macros,
 		     &ftr_fixup_test_FW_FTR_macros_expected, size) == 0);
 #endif
 }

 static void test_lwsync_macros(void)
 {
 	extern u8 lwsync_fixup_test;
 	extern u8 end_lwsync_fixup_test;
 	extern u8 lwsync_fixup_test_expected_LWSYNC;
 	extern u8 lwsync_fixup_test_expected_SYNC;
 	unsigned long size = &end_lwsync_fixup_test -
 			     &lwsync_fixup_test;

 	/* The fixups have already been done for us during boot */
 	if (cur_cpu_spec->cpu_features & CPU_FTR_LWSYNC) {
 		check(memcmp(&lwsync_fixup_test,
 			     &lwsync_fixup_test_expected_LWSYNC, size) == 0);
 	} else {
 		check(memcmp(&lwsync_fixup_test,
 			     &lwsync_fixup_test_expected_SYNC, size) == 0);
 	}
 }

 static int __init test_feature_fixups(void)
 {
 	printk(KERN_DEBUG "Running feature fixup self-tests ...\n");

 	test_basic_patching();
 	test_alternative_patching();
 	test_alternative_case_too_big();
 	test_alternative_case_too_small();
 	test_alternative_case_with_branch();
 	test_alternative_case_with_external_branch();
 	test_cpu_macros();
 	test_fw_macros();
 	test_lwsync_macros();

 	return 0;
 }
 late_initcall(test_feature_fixups);

 #endif /* CONFIG_FTR_FIXUP_SELFTEST */
	/*
	* Copyright (C) 2001 Ben. Herrenschmidt (benh@kernel.crashing.org)
	*
	* Modifications for ppc64:
	* Copyright (C) 2003 Dave Engebretsen <engebret@us.ibm.com>
	*
	* Copyright 2008 Michael Ellerman, IBM Corporation.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*/

	#include <linux/types.h>
	#include <linux/kernel.h>
	#include <linux/string.h>
	#include <linux/init.h>
	#include <asm/cputable.h>
	#include <asm/code-patching.h>
	#include <asm/page.h>
	#include <asm/sections.h>


	struct fixup_entry {
	unsigned long mask;
	unsigned long value;
	long start_off;
	long end_off;
	long alt_start_off;
	long alt_end_off;
	};

	static unsigned int calc_addr(struct fixup_entry fcur, long offset)
	{
	/*
	* We store the offset to the code as a negative offset from
	* the start of the alt_entry, to support the VDSO. This
	* routine converts that back into an actual address.
	*/
	return (unsigned int *)((unsigned long)fcur + offset);
	}

	static int patch_alt_instruction(unsigned int src, unsigned int dest,
	unsigned int alt_start, unsigned int alt_end)
	{
	unsigned int instr;

	instr = *src;

	if (instr_is_relative_branch(*src)) {
	unsigned int target = (unsigned int )branch_target(src);

	/* Branch within the section doesn't need translating */
	if (target < alt_start \|\| target >= alt_end) {
	instr = translate_branch(dest, src);
	if (!instr)
	return 1;
	}
	}

	patch_instruction(dest, instr);

	return 0;
	}

	static int patch_feature_section(unsigned long value, struct fixup_entry *fcur)
	{
	unsigned int start, end, alt_start, alt_end, src, dest;

	start = calc_addr(fcur, fcur->start_off);
	end = calc_addr(fcur, fcur->end_off);
	alt_start = calc_addr(fcur, fcur->alt_start_off);
	alt_end = calc_addr(fcur, fcur->alt_end_off);

	if ((alt_end - alt_start) > (end - start))
	return 1;

	if ((value & fcur->mask) == fcur->value)
	return 0;

	src = alt_start;
	dest = start;

	for (; src < alt_end; src++, dest++) {
	if (patch_alt_instruction(src, dest, alt_start, alt_end))
	return 1;
	}

	for (; dest < end; dest++)
	patch_instruction(dest, PPC_INST_NOP);

	return 0;
	}

	void do_feature_fixups(unsigned long value, void fixup_start, void fixup_end)
	{
	struct fixup_entry fcur, fend;

	fcur = fixup_start;
	fend = fixup_end;

	for (; fcur < fend; fcur++) {
	if (patch_feature_section(value, fcur)) {
	WARN_ON(1);
	printk("Unable to patch feature section at %p - %p" \
	" with %p - %p\n",
	calc_addr(fcur, fcur->start_off),
	calc_addr(fcur, fcur->end_off),
	calc_addr(fcur, fcur->alt_start_off),
	calc_addr(fcur, fcur->alt_end_off));
	}
	}
	}

	void do_lwsync_fixups(unsigned long value, void fixup_start, void fixup_end)
	{
	long start, end;
	unsigned int *dest;

	if (!(value & CPU_FTR_LWSYNC))
	return ;

	start = fixup_start;
	end = fixup_end;

	for (; start < end; start++) {
	dest = (void )start + start;
	patch_instruction(dest, PPC_INST_LWSYNC);
	}
	}

	void do_final_fixups(void)
	{
	#if defined(CONFIG_PPC64) && defined(CONFIG_RELOCATABLE)
	int src, dest;
	unsigned long length;

	if (PHYSICAL_START == 0)
	return;

	src = (int *)(KERNELBASE + PHYSICAL_START);
	dest = (int *)KERNELBASE;
	length = (__end_interrupts - _stext) / sizeof(int);

	while (length--) {
	patch_instruction(dest, *src);
	src++;
	dest++;
	}
	#endif
	}

	#ifdef CONFIG_FTR_FIXUP_SELFTEST

	#define check(x) \
	if (!(x)) printk("feature-fixups: test failed at line %d\n", __LINE__);

	/* This must be after the text it fixes up, vmlinux.lds.S enforces that atm */
	static struct fixup_entry fixup;

	static long calc_offset(struct fixup_entry entry, unsigned int p)
	{
	return (unsigned long)p - (unsigned long)entry;
	}

	void test_basic_patching(void)
	{
	extern unsigned int ftr_fixup_test1;
	extern unsigned int end_ftr_fixup_test1;
	extern unsigned int ftr_fixup_test1_orig;
	extern unsigned int ftr_fixup_test1_expected;
	int size = &end_ftr_fixup_test1 - &ftr_fixup_test1;

	fixup.value = fixup.mask = 8;
	fixup.start_off = calc_offset(&fixup, &ftr_fixup_test1 + 1);
	fixup.end_off = calc_offset(&fixup, &ftr_fixup_test1 + 2);
	fixup.alt_start_off = fixup.alt_end_off = 0;

	/* Sanity check */
	check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0);

	/* Check we don't patch if the value matches */
	patch_feature_section(8, &fixup);
	check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0);

	/* Check we do patch if the value doesn't match */
	patch_feature_section(0, &fixup);
	check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_expected, size) == 0);

	/* Check we do patch if the mask doesn't match */
	memcpy(&ftr_fixup_test1, &ftr_fixup_test1_orig, size);
	check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0);
	patch_feature_section(~8, &fixup);
	check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_expected, size) == 0);
	}

	static void test_alternative_patching(void)
	{
	extern unsigned int ftr_fixup_test2;
	extern unsigned int end_ftr_fixup_test2;
	extern unsigned int ftr_fixup_test2_orig;
	extern unsigned int ftr_fixup_test2_alt;
	extern unsigned int ftr_fixup_test2_expected;
	int size = &end_ftr_fixup_test2 - &ftr_fixup_test2;

	fixup.value = fixup.mask = 0xF;
	fixup.start_off = calc_offset(&fixup, &ftr_fixup_test2 + 1);
	fixup.end_off = calc_offset(&fixup, &ftr_fixup_test2 + 2);
	fixup.alt_start_off = calc_offset(&fixup, &ftr_fixup_test2_alt);
	fixup.alt_end_off = calc_offset(&fixup, &ftr_fixup_test2_alt + 1);

	/* Sanity check */
	check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_orig, size) == 0);

	/* Check we don't patch if the value matches */
	patch_feature_section(0xF, &fixup);
	check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_orig, size) == 0);

	/* Check we do patch if the value doesn't match */
	patch_feature_section(0, &fixup);
	check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_expected, size) == 0);

	/* Check we do patch if the mask doesn't match */
	memcpy(&ftr_fixup_test2, &ftr_fixup_test2_orig, size);
	check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_orig, size) == 0);
	patch_feature_section(~0xF, &fixup);
	check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_expected, size) == 0);
	}

	static void test_alternative_case_too_big(void)
	{
	extern unsigned int ftr_fixup_test3;
	extern unsigned int end_ftr_fixup_test3;
	extern unsigned int ftr_fixup_test3_orig;
	extern unsigned int ftr_fixup_test3_alt;
	int size = &end_ftr_fixup_test3 - &ftr_fixup_test3;

	fixup.value = fixup.mask = 0xC;
	fixup.start_off = calc_offset(&fixup, &ftr_fixup_test3 + 1);
	fixup.end_off = calc_offset(&fixup, &ftr_fixup_test3 + 2);
	fixup.alt_start_off = calc_offset(&fixup, &ftr_fixup_test3_alt);
	fixup.alt_end_off = calc_offset(&fixup, &ftr_fixup_test3_alt + 2);

	/* Sanity check */
	check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0);

	/* Expect nothing to be patched, and the error returned to us */
	check(patch_feature_section(0xF, &fixup) == 1);
	check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0);
	check(patch_feature_section(0, &fixup) == 1);
	check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0);
	check(patch_feature_section(~0xF, &fixup) == 1);
	check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0);
	}

	static void test_alternative_case_too_small(void)
	{
	extern unsigned int ftr_fixup_test4;
	extern unsigned int end_ftr_fixup_test4;
	extern unsigned int ftr_fixup_test4_orig;
	extern unsigned int ftr_fixup_test4_alt;
	extern unsigned int ftr_fixup_test4_expected;
	int size = &end_ftr_fixup_test4 - &ftr_fixup_test4;
	unsigned long flag;

	/* Check a high-bit flag */
	flag = 1UL << ((sizeof(unsigned long) - 1) * 8);
	fixup.value = fixup.mask = flag;
	fixup.start_off = calc_offset(&fixup, &ftr_fixup_test4 + 1);
	fixup.end_off = calc_offset(&fixup, &ftr_fixup_test4 + 5);
	fixup.alt_start_off = calc_offset(&fixup, &ftr_fixup_test4_alt);
	fixup.alt_end_off = calc_offset(&fixup, &ftr_fixup_test4_alt + 2);

	/* Sanity check */
	check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_orig, size) == 0);

	/* Check we don't patch if the value matches */
	patch_feature_section(flag, &fixup);
	check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_orig, size) == 0);

	/* Check we do patch if the value doesn't match */
	patch_feature_section(0, &fixup);
	check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_expected, size) == 0);

	/* Check we do patch if the mask doesn't match */
	memcpy(&ftr_fixup_test4, &ftr_fixup_test4_orig, size);
	check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_orig, size) == 0);
	patch_feature_section(~flag, &fixup);
	check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_expected, size) == 0);
	}

	static void test_alternative_case_with_branch(void)
	{
	extern unsigned int ftr_fixup_test5;
	extern unsigned int end_ftr_fixup_test5;
	extern unsigned int ftr_fixup_test5_expected;
	int size = &end_ftr_fixup_test5 - &ftr_fixup_test5;

	check(memcmp(&ftr_fixup_test5, &ftr_fixup_test5_expected, size) == 0);
	}

	static void test_alternative_case_with_external_branch(void)
	{
	extern unsigned int ftr_fixup_test6;
	extern unsigned int end_ftr_fixup_test6;
	extern unsigned int ftr_fixup_test6_expected;
	int size = &end_ftr_fixup_test6 - &ftr_fixup_test6;

	check(memcmp(&ftr_fixup_test6, &ftr_fixup_test6_expected, size) == 0);
	}

	static void test_cpu_macros(void)
	{
	extern u8 ftr_fixup_test_FTR_macros;
	extern u8 ftr_fixup_test_FTR_macros_expected;
	unsigned long size = &ftr_fixup_test_FTR_macros_expected -
	&ftr_fixup_test_FTR_macros;

	/* The fixups have already been done for us during boot */
	check(memcmp(&ftr_fixup_test_FTR_macros,
	&ftr_fixup_test_FTR_macros_expected, size) == 0);
	}

	static void test_fw_macros(void)
	{
	#ifdef CONFIG_PPC64
	extern u8 ftr_fixup_test_FW_FTR_macros;
	extern u8 ftr_fixup_test_FW_FTR_macros_expected;
	unsigned long size = &ftr_fixup_test_FW_FTR_macros_expected -
	&ftr_fixup_test_FW_FTR_macros;

	/* The fixups have already been done for us during boot */
	check(memcmp(&ftr_fixup_test_FW_FTR_macros,
	&ftr_fixup_test_FW_FTR_macros_expected, size) == 0);
	#endif
	}

	static void test_lwsync_macros(void)
	{
	extern u8 lwsync_fixup_test;
	extern u8 end_lwsync_fixup_test;
	extern u8 lwsync_fixup_test_expected_LWSYNC;
	extern u8 lwsync_fixup_test_expected_SYNC;
	unsigned long size = &end_lwsync_fixup_test -
	&lwsync_fixup_test;

	/* The fixups have already been done for us during boot */
	if (cur_cpu_spec->cpu_features & CPU_FTR_LWSYNC) {
	check(memcmp(&lwsync_fixup_test,
	&lwsync_fixup_test_expected_LWSYNC, size) == 0);
	} else {
	check(memcmp(&lwsync_fixup_test,
	&lwsync_fixup_test_expected_SYNC, size) == 0);
	}
	}

	static int __init test_feature_fixups(void)
	{
	printk(KERN_DEBUG "Running feature fixup self-tests ...\n");

	test_basic_patching();
	test_alternative_patching();
	test_alternative_case_too_big();
	test_alternative_case_too_small();
	test_alternative_case_with_branch();
	test_alternative_case_with_external_branch();
	test_cpu_macros();
	test_fw_macros();
	test_lwsync_macros();

	return 0;
	}
	late_initcall(test_feature_fixups);

	#endif /* CONFIG_FTR_FIXUP_SELFTEST */