Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 290 insertions, 0 deletions

diff --git a/arch/ppc64/kernel/kprobes.c b/arch/ppc64/kernel/kprobes.c
new file mode 100644
index 000000000000..103daaf73573
--- /dev/null
+++ b/arch/ppc64/kernel/kprobes.c
@@ -0,0 +1,290 @@
+/*
+ *  Kernel Probes (KProbes)
+ *  arch/ppc64/kernel/kprobes.c
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2002, 2004
+ *
+ * 2002-Oct     Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
+ *              Probes initial implementation ( includes contributions from
+ *              Rusty Russell).
+ * 2004-July    Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
+ *              interface to access function arguments.
+ * 2004-Nov     Ananth N Mavinakayanahalli <ananth@in.ibm.com> kprobes port
+ *              for PPC64
+ */
+
+#include <linux/config.h>
+#include <linux/kprobes.h>
+#include <linux/ptrace.h>
+#include <linux/spinlock.h>
+#include <linux/preempt.h>
+#include <asm/kdebug.h>
+#include <asm/sstep.h>
+
+/* kprobe_status settings */
+#define KPROBE_HIT_ACTIVE       0x00000001
+#define KPROBE_HIT_SS           0x00000002
+
+static struct kprobe *current_kprobe;
+static unsigned long kprobe_status, kprobe_saved_msr;
+static struct pt_regs jprobe_saved_regs;
+
+int arch_prepare_kprobe(struct kprobe *p)
+{
+        kprobe_opcode_t insn = *p->addr;
+
+        if (IS_MTMSRD(insn) || IS_RFID(insn))
+                /* cannot put bp on RFID/MTMSRD */
+                return 1;
+        return 0;
+}
+
+void arch_copy_kprobe(struct kprobe *p)
+{
+        memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+}
+
+void arch_remove_kprobe(struct kprobe *p)
+{
+}
+
+static inline void disarm_kprobe(struct kprobe *p, struct pt_regs *regs)
+{
+        *p->addr = p->opcode;
+        regs->nip = (unsigned long)p->addr;
+}
+
+static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
+{
+        regs->msr |= MSR_SE;
+        /*single step inline if it a breakpoint instruction*/
+        if (p->opcode == BREAKPOINT_INSTRUCTION)
+                regs->nip = (unsigned long)p->addr;
+        else
+                regs->nip = (unsigned long)&p->ainsn.insn;
+}
+
+static inline int kprobe_handler(struct pt_regs *regs)
+{
+        struct kprobe *p;
+        int ret = 0;
+        unsigned int *addr = (unsigned int *)regs->nip;
+
+        /* Check we're not actually recursing */
+        if (kprobe_running()) {
+                /* We *are* holding lock here, so this is safe.
+                   Disarm the probe we just hit, and ignore it. */
+                p = get_kprobe(addr);
+                if (p) {
+                        if (kprobe_status == KPROBE_HIT_SS) {
+                                regs->msr &= ~MSR_SE;
+                                regs->msr |= kprobe_saved_msr;
+                                unlock_kprobes();
+                                goto no_kprobe;
+                        }
+                        disarm_kprobe(p, regs);
+                        ret = 1;
+                } else {
+                        p = current_kprobe;
+                        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;
+        }
+
+        lock_kprobes();
+        p = get_kprobe(addr);
+        if (!p) {
+                unlock_kprobes();
+                if (*addr != BREAKPOINT_INSTRUCTION) {
+                        /*
+                         * PowerPC has multiple variants of the "trap"
+                         * instruction. If the current instruction is a
+                         * trap variant, it could belong to someone else
+                         */
+                        kprobe_opcode_t cur_insn = *addr;
+                        if (IS_TW(cur_insn) || IS_TD(cur_insn) ||
+                                        IS_TWI(cur_insn) || IS_TDI(cur_insn))
+                                goto no_kprobe;
+                        /*
+                         * The breakpoint instruction was removed right
+                         * after we hit it.  Another cpu has removed
+                         * either a probepoint or a debugger breakpoint
+                         * at this address.  In either case, no further
+                         * handling of this interrupt is appropriate.
+                         */
+                        ret = 1;
+                }
+                /* Not one of ours: let kernel handle it */
+                goto no_kprobe;
+        }
+
+        kprobe_status = KPROBE_HIT_ACTIVE;
+        current_kprobe = p;
+        kprobe_saved_msr = regs->msr;
+        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;
+        /*
+         * This preempt_disable() matches the preempt_enable_no_resched()
+         * in post_kprobe_handler().
+         */
+        preempt_disable();
+        return 1;
+
+no_kprobe:
+        return ret;
+}
+
+/*
+ * Called after single-stepping.  p->addr is the address of the
+ * instruction whose first byte has been replaced by the "breakpoint"
+ * instruction.  To avoid the SMP problems that can occur when we
+ * temporarily put back the original opcode to single-step, we
+ * single-stepped a copy of the instruction.  The address of this
+ * copy is p->ainsn.insn.
+ */
+static void resume_execution(struct kprobe *p, struct pt_regs *regs)
+{
+        int ret;
+
+        regs->nip = (unsigned long)p->addr;
+        ret = emulate_step(regs, p->ainsn.insn[0]);
+        if (ret == 0)
+                regs->nip = (unsigned long)p->addr + 4;
+
+        regs->msr &= ~MSR_SE;
+}
+
+static inline int post_kprobe_handler(struct pt_regs *regs)
+{
+        if (!kprobe_running())
+                return 0;
+
+        if (current_kprobe->post_handler)
+                current_kprobe->post_handler(current_kprobe, regs, 0);
+
+        resume_execution(current_kprobe, regs);
+        regs->msr |= kprobe_saved_msr;
+
+        unlock_kprobes();
+        preempt_enable_no_resched();
+
+        /*
+         * if somebody else is singlestepping across a probe point, msr
+         * will have SE set, in which case, continue the remaining processing
+         * of do_debug, as if this is not a probe hit.
+         */
+        if (regs->msr & MSR_SE)
+                return 0;
+
+        return 1;
+}
+
+/* Interrupts disabled, kprobe_lock held. */
+static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+{
+        if (current_kprobe->fault_handler
+            && current_kprobe->fault_handler(current_kprobe, regs, trapnr))
+                return 1;
+
+        if (kprobe_status & KPROBE_HIT_SS) {
+                resume_execution(current_kprobe, regs);
+                regs->msr |= kprobe_saved_msr;
+
+                unlock_kprobes();
+                preempt_enable_no_resched();
+        }
+        return 0;
+}
+
+/*
+ * Wrapper routine to for handling exceptions.
+ */
+int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
+                             void *data)
+{
+        struct die_args *args = (struct die_args *)data;
+        int ret = NOTIFY_DONE;
+
+        /*
+         * Interrupts are not disabled here.  We need to disable
+         * preemption, because kprobe_running() uses smp_processor_id().
+         */
+        preempt_disable();
+        switch (val) {
+        case DIE_IABR_MATCH:
+        case DIE_DABR_MATCH:
+        case DIE_BPT:
+                if (kprobe_handler(args->regs))
+                        ret = NOTIFY_STOP;
+                break;
+        case DIE_SSTEP:
+                if (post_kprobe_handler(args->regs))
+                        ret = NOTIFY_STOP;
+                break;
+        case DIE_GPF:
+        case DIE_PAGE_FAULT:
+                if (kprobe_running() &&
+                    kprobe_fault_handler(args->regs, args->trapnr))
+                        ret = NOTIFY_STOP;
+                break;
+        default:
+                break;
+        }
+        preempt_enable();
+        return ret;
+}
+
+int 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));
+
+        /* setup return addr to the jprobe handler routine */
+        regs->nip = (unsigned long)(((func_descr_t *)jp->entry)->entry);
+        regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc);
+
+        return 1;
+}
+
+void jprobe_return(void)
+{
+        asm volatile("trap" ::: "memory");
+}
+
+void jprobe_return_end(void)
+{
+};
+
+int 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;
+}