jump label: x86 support

[pandora-kernel.git] / arch / x86 / kernel / jump_label.c

diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
new file mode 100644 (file)
index 0000000..961b6b3
--- /dev/null
+++ b/arch/x86/kernel/jump_label.c
@@ -0,0 +1,50 @@
+/*
+ * jump label x86 support
+ *
+ * Copyright (C) 2009 Jason Baron <jbaron@redhat.com>
+ *
+ */
+#include <linux/jump_label.h>
+#include <linux/memory.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/jhash.h>
+#include <linux/cpu.h>
+#include <asm/kprobes.h>
+#include <asm/alternative.h>
+
+#ifdef HAVE_JUMP_LABEL
+
+union jump_code_union {
+       char code[JUMP_LABEL_NOP_SIZE];
+       struct {
+               char jump;
+               int offset;
+       } __attribute__((packed));
+};
+
+void arch_jump_label_transform(struct jump_entry *entry,
+                              enum jump_label_type type)
+{
+       union jump_code_union code;
+
+       if (type == JUMP_LABEL_ENABLE) {
+               code.jump = 0xe9;
+               code.offset = entry->target -
+                               (entry->code + JUMP_LABEL_NOP_SIZE);
+       } else
+               memcpy(&code, ideal_nop5, JUMP_LABEL_NOP_SIZE);
+       get_online_cpus();
+       mutex_lock(&text_mutex);
+       text_poke_smp((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE);
+       mutex_unlock(&text_mutex);
+       put_online_cpus();
+}
+
+void arch_jump_label_text_poke_early(jump_label_t addr)
+{
+       text_poke_early((void *)addr, ideal_nop5, JUMP_LABEL_NOP_SIZE);
+}
+
+#endif