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Diffstat (limited to 'arch/powerpc/lib/feature-fixups.c')
| -rw-r--r-- | arch/powerpc/lib/feature-fixups.c | 351 |
1 files changed, 351 insertions, 0 deletions
diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c new file mode 100644 index 00000000000..4e43702b981 --- /dev/null +++ b/arch/powerpc/lib/feature-fixups.c @@ -0,0 +1,351 @@ +/* + * 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 */ |