1 files changed, 270 insertions, 0 deletions
diff --git a/arch/avr32/kernel/kprobes.c b/arch/avr32/kernel/kprobes.c
new file mode 100644
index 00000000000..6caf9e8d808
--- /dev/null
+++ b/arch/avr32/kernel/kprobes.c
@@ -0,0 +1,270 @@
+/*
+ *  Kernel Probes (KProbes)
+ *
+ * Copyright (C) 2005-2006 Atmel Corporation
+ *
+ * Based on arch/ppc64/kernel/kprobes.c
+ *  Copyright (C) IBM Corporation, 2002, 2004
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kprobes.h>
+#include <linux/ptrace.h>
+
+#include <asm/cacheflush.h>
+#include <asm/kdebug.h>
+#include <asm/ocd.h>
+
+DEFINE_PER_CPU(struct kprobe *, current_kprobe);
+static unsigned long kprobe_status;
+static struct pt_regs jprobe_saved_regs;
+
+int __kprobes arch_prepare_kprobe(struct kprobe *p)
+{
+	int ret = 0;
+
+	if ((unsigned long)p->addr & 0x01) {
+		printk("Attempt to register kprobe at an unaligned address\n");
+		ret = -EINVAL;
+	}
+
+	/* XXX: Might be a good idea to check if p->addr is a valid
+	 * kernel address as well... */
+
+	if (!ret) {
+		pr_debug("copy kprobe at %p\n", p->addr);
+		memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+		p->opcode = *p->addr;
+	}
+
+	return ret;
+}
+
+void __kprobes arch_arm_kprobe(struct kprobe *p)
+{
+	pr_debug("arming kprobe at %p\n", p->addr);
+	*p->addr = BREAKPOINT_INSTRUCTION;
+	flush_icache_range((unsigned long)p->addr,
+			   (unsigned long)p->addr + sizeof(kprobe_opcode_t));
+}
+
+void __kprobes arch_disarm_kprobe(struct kprobe *p)
+{
+	pr_debug("disarming kprobe at %p\n", p->addr);
+	*p->addr = p->opcode;
+	flush_icache_range((unsigned long)p->addr,
+			   (unsigned long)p->addr + sizeof(kprobe_opcode_t));
+}
+
+static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
+{
+	unsigned long dc;
+
+	pr_debug("preparing to singlestep over %p (PC=%08lx)\n",
+		 p->addr, regs->pc);
+
+	BUG_ON(!(sysreg_read(SR) & SYSREG_BIT(SR_D)));
+
+	dc = __mfdr(DBGREG_DC);
+	dc |= DC_SS;
+	__mtdr(DBGREG_DC, dc);
+
+	/*
+	 * We must run the instruction from its original location
+	 * since it may actually reference PC.
+	 *
+	 * TODO: Do the instruction replacement directly in icache.
+	 */
+	*p->addr = p->opcode;
+	flush_icache_range((unsigned long)p->addr,
+			   (unsigned long)p->addr + sizeof(kprobe_opcode_t));
+}
+
+static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
+{
+	unsigned long dc;
+
+	pr_debug("resuming execution at PC=%08lx\n", regs->pc);
+
+	dc = __mfdr(DBGREG_DC);
+	dc &= ~DC_SS;
+	__mtdr(DBGREG_DC, dc);
+
+	*p->addr = BREAKPOINT_INSTRUCTION;
+	flush_icache_range((unsigned long)p->addr,
+			   (unsigned long)p->addr + sizeof(kprobe_opcode_t));
+}
+
+static void __kprobes set_current_kprobe(struct kprobe *p)
+{
+	__get_cpu_var(current_kprobe) = p;
+}
+
+static int __kprobes kprobe_handler(struct pt_regs *regs)
+{
+	struct kprobe *p;
+	void *addr = (void *)regs->pc;
+	int ret = 0;
+
+	pr_debug("kprobe_handler: kprobe_running=%d\n",
+		 kprobe_running());
+
+	/*
+	 * We don't want to be preempted for the entire
+	 * duration of kprobe processing
+	 */
+	preempt_disable();
+
+	/* Check that we're not recursing */
+	if (kprobe_running()) {
+		p = get_kprobe(addr);
+		if (p) {
+			if (kprobe_status == KPROBE_HIT_SS) {
+				printk("FIXME: kprobe hit while single-stepping!\n");
+				goto no_kprobe;
+			}
+
+			printk("FIXME: kprobe hit while handling another kprobe\n");
+			goto no_kprobe;
+		} else {
+			p = kprobe_running();
+			if (p->break_handler && p->break_handler(p, regs))
+				goto ss_probe;
+		}
+		/* If it's not ours, can't be delete race, (we hold lock). */
+		goto no_kprobe;
+	}
+
+	p = get_kprobe(addr);
+	if (!p)
+		goto no_kprobe;
+
+	kprobe_status = KPROBE_HIT_ACTIVE;
+	set_current_kprobe(p);
+	if (p->pre_handler && p->pre_handler(p, regs))
+		/* handler has already set things up, so skip ss setup */
+		return 1;
+
+ss_probe:
+	prepare_singlestep(p, regs);
+	kprobe_status = KPROBE_HIT_SS;
+	return 1;
+
+no_kprobe:
+	return ret;
+}
+
+static int __kprobes post_kprobe_handler(struct pt_regs *regs)
+{
+	struct kprobe *cur = kprobe_running();
+
+	pr_debug("post_kprobe_handler, cur=%p\n", cur);
+
+	if (!cur)
+		return 0;
+
+	if (cur->post_handler) {
+		kprobe_status = KPROBE_HIT_SSDONE;
+		cur->post_handler(cur, regs, 0);
+	}
+
+	resume_execution(cur, regs);
+	reset_current_kprobe();
+	preempt_enable_no_resched();
+
+	return 1;
+}
+
+static int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+{
+	struct kprobe *cur = kprobe_running();
+
+	pr_debug("kprobe_fault_handler: trapnr=%d\n", trapnr);
+
+	if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
+		return 1;
+
+	if (kprobe_status & KPROBE_HIT_SS) {
+		resume_execution(cur, regs);
+		preempt_enable_no_resched();
+	}
+	return 0;
+}
+
+/*
+ * Wrapper routine to for handling exceptions.
+ */
+int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
+				       unsigned long val, void *data)
+{
+	struct die_args *args = (struct die_args *)data;
+	int ret = NOTIFY_DONE;
+
+	pr_debug("kprobe_exceptions_notify: val=%lu, data=%p\n",
+		 val, data);
+
+	switch (val) {
+	case DIE_BREAKPOINT:
+		if (kprobe_handler(args->regs))
+			ret = NOTIFY_STOP;
+		break;
+	case DIE_SSTEP:
+		if (post_kprobe_handler(args->regs))
+			ret = NOTIFY_STOP;
+		break;
+	case DIE_FAULT:
+		if (kprobe_running()
+		    && kprobe_fault_handler(args->regs, args->trapnr))
+			ret = NOTIFY_STOP;
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+	struct jprobe *jp = container_of(p, struct jprobe, kp);
+
+	memcpy(&jprobe_saved_regs, regs, sizeof(struct pt_regs));
+
+	/*
+	 * TODO: We should probably save some of the stack here as
+	 * well, since gcc may pass arguments on the stack for certain
+	 * functions (lots of arguments, large aggregates, varargs)
+	 */
+
+	/* setup return addr to the jprobe handler routine */
+	regs->pc = (unsigned long)jp->entry;
+	return 1;
+}
+
+void __kprobes jprobe_return(void)
+{
+	asm volatile("breakpoint" ::: "memory");
+}
+
+int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
+{
+	/*
+	 * FIXME - we should ideally be validating that we got here 'cos
+	 * of the "trap" in jprobe_return() above, before restoring the
+	 * saved regs...
+	 */
+	memcpy(regs, &jprobe_saved_regs, sizeof(struct pt_regs));
+	return 1;
+}
+
+int __init arch_init_kprobes(void)
+{
+	printk("KPROBES: Enabling monitor mode (MM|DBE)...\n");
+	__mtdr(DBGREG_DC, DC_MM | DC_DBE);
+
+	/* TODO: Register kretprobe trampoline */
+	return 0;
+}