| /* | 
 |  *  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/kernel.h> | 
 | #include <linux/string.h> | 
 | #include <linux/init.h> | 
 | #include <asm/cputable.h> | 
 | #include <asm/code-patching.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_NOP_INSTR); | 
 |  | 
 | 	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) | 
 | { | 
 | 	unsigned int *start, *end, *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_LWSYNC_INSTR); | 
 | 	} | 
 | } | 
 |  | 
 | #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 void ftr_fixup_test_FTR_macros; | 
 | 	extern void 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 void ftr_fixup_test_FW_FTR_macros; | 
 | 	extern void 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 void lwsync_fixup_test; | 
 | 	extern void end_lwsync_fixup_test; | 
 | 	extern void lwsync_fixup_test_expected_LWSYNC; | 
 | 	extern void 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 */ |