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-rw-r--r--arch/powerpc/lib/feature-fixups.c79
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));
+ }
+ }
}