diff options
| -rw-r--r-- | arch/powerpc/lib/feature-fixups.c | 79 |
1 files changed, 65 insertions, 14 deletions
diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c index 973d547ef01..174c1eba9ac 100644 --- a/arch/powerpc/lib/feature-fixups.c +++ b/arch/powerpc/lib/feature-fixups.c @@ -26,24 +26,66 @@ struct fixup_entry { long alt_end_off; }; -static void patch_feature_section(unsigned long value, struct fixup_entry *fcur) +static unsigned int *calc_addr(struct fixup_entry *fcur, long offset) { - unsigned int *pstart, *pend, *p; + /* + * 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; + return 0; - pstart = ((unsigned int *)fcur) + (fcur->start_off / 4); - pend = ((unsigned int *)fcur) + (fcur->end_off / 4); + src = alt_start; + dest = start; - for (p = pstart; p < pend; p++) { - *p = PPC_NOP_INSTR; - asm volatile ("dcbst 0, %0" : : "r" (p)); + for (; src < alt_end; src++, dest++) { + if (patch_alt_instruction(src, dest, alt_start, alt_end)) + return 1; } - asm volatile ("sync" : : : "memory"); - for (p = pstart; p < pend; p++) - asm volatile ("icbi 0,%0" : : "r" (p)); - asm volatile ("sync; isync" : : : "memory"); + + 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) @@ -53,6 +95,15 @@ void do_feature_fixups(unsigned long value, void *fixup_start, void *fixup_end) fcur = fixup_start; fend = fixup_end; - for (; fcur < fend; fcur++) - patch_feature_section(value, fcur); + 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)); + } + } } |