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 000000000000..6caf9e8d8080
--- /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;
+}