| /* |
| * 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(); |
| 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 */ |