1 files changed, 601 insertions, 0 deletions

diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
new file mode 100644
index 000000000000..5978823d5c63
--- /dev/null
+++ b/arch/ia64/kernel/kprobes.c
@@ -0,0 +1,601 @@
+/*
+ *  Kernel Probes (KProbes)
+ *  arch/ia64/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
+ * Copyright (C) Intel Corporation, 2005
+ *
+ * 2005-Apr     Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
+ *              <anil.s.keshavamurthy@intel.com> adapted from i386
+ */
+
+#include <linux/config.h>
+#include <linux/kprobes.h>
+#include <linux/ptrace.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/preempt.h>
+#include <linux/moduleloader.h>
+
+#include <asm/pgtable.h>
+#include <asm/kdebug.h>
+
+extern void jprobe_inst_return(void);
+
+/* kprobe_status settings */
+#define KPROBE_HIT_ACTIVE       0x00000001
+#define KPROBE_HIT_SS           0x00000002
+
+static struct kprobe *current_kprobe, *kprobe_prev;
+static unsigned long kprobe_status, kprobe_status_prev;
+static struct pt_regs jprobe_saved_regs;
+
+enum instruction_type {A, I, M, F, B, L, X, u};
+static enum instruction_type bundle_encoding[32][3] = {
+  { M, I, I },                          /* 00 */
+  { M, I, I },                          /* 01 */
+  { M, I, I },                          /* 02 */
+  { M, I, I },                          /* 03 */
+  { M, L, X },                          /* 04 */
+  { M, L, X },                          /* 05 */
+  { u, u, u },                          /* 06 */
+  { u, u, u },                          /* 07 */
+  { M, M, I },                          /* 08 */
+  { M, M, I },                          /* 09 */
+  { M, M, I },                          /* 0A */
+  { M, M, I },                          /* 0B */
+  { M, F, I },                          /* 0C */
+  { M, F, I },                          /* 0D */
+  { M, M, F },                          /* 0E */
+  { M, M, F },                          /* 0F */
+  { M, I, B },                          /* 10 */
+  { M, I, B },                          /* 11 */
+  { M, B, B },                          /* 12 */
+  { M, B, B },                          /* 13 */
+  { u, u, u },                          /* 14 */
+  { u, u, u },                          /* 15 */
+  { B, B, B },                          /* 16 */
+  { B, B, B },                          /* 17 */
+  { M, M, B },                          /* 18 */
+  { M, M, B },                          /* 19 */
+  { u, u, u },                          /* 1A */
+  { u, u, u },                          /* 1B */
+  { M, F, B },                          /* 1C */
+  { M, F, B },                          /* 1D */
+  { u, u, u },                          /* 1E */
+  { u, u, u },                          /* 1F */
+};
+
+/*
+ * In this function we check to see if the instruction
+ * is IP relative instruction and update the kprobe
+ * inst flag accordingly
+ */
+static void update_kprobe_inst_flag(uint template, uint  slot, uint major_opcode,
+        unsigned long kprobe_inst, struct kprobe *p)
+{
+        p->ainsn.inst_flag = 0;
+        p->ainsn.target_br_reg = 0;
+
+        if (bundle_encoding[template][slot] == B) {
+                switch (major_opcode) {
+                  case INDIRECT_CALL_OPCODE:
+                        p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
+                        p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
+                        break;
+                  case IP_RELATIVE_PREDICT_OPCODE:
+                  case IP_RELATIVE_BRANCH_OPCODE:
+                        p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
+                        break;
+                  case IP_RELATIVE_CALL_OPCODE:
+                        p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
+                        p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
+                        p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
+                        break;
+                }
+        } else if (bundle_encoding[template][slot] == X) {
+                switch (major_opcode) {
+                  case LONG_CALL_OPCODE:
+                        p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
+                        p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
+                  break;
+                }
+        }
+        return;
+}
+
+/*
+ * In this function we check to see if the instruction
+ * on which we are inserting kprobe is supported.
+ * Returns 0 if supported
+ * Returns -EINVAL if unsupported
+ */
+static int unsupported_inst(uint template, uint  slot, uint major_opcode,
+        unsigned long kprobe_inst, struct kprobe *p)
+{
+        unsigned long addr = (unsigned long)p->addr;
+
+        if (bundle_encoding[template][slot] == I) {
+                switch (major_opcode) {
+                        case 0x0: //I_UNIT_MISC_OPCODE:
+                        /*
+                         * Check for Integer speculation instruction
+                         * - Bit 33-35 to be equal to 0x1
+                         */
+                        if (((kprobe_inst >> 33) & 0x7) == 1) {
+                                printk(KERN_WARNING
+                                        "Kprobes on speculation inst at <0x%lx> not supported\n",
+                                        addr);
+                                return -EINVAL;
+                        }
+
+                        /*
+                         * IP relative mov instruction
+                         *  - Bit 27-35 to be equal to 0x30
+                         */
+                        if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
+                                printk(KERN_WARNING
+                                        "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
+                                        addr);
+                                return -EINVAL;
+
+                        }
+                }
+        }
+        return 0;
+}
+
+
+/*
+ * In this function we check to see if the instruction
+ * (qp) cmpx.crel.ctype p1,p2=r2,r3
+ * on which we are inserting kprobe is cmp instruction
+ * with ctype as unc.
+ */
+static uint is_cmp_ctype_unc_inst(uint template, uint slot, uint major_opcode,
+unsigned long kprobe_inst)
+{
+        cmp_inst_t cmp_inst;
+        uint ctype_unc = 0;
+
+        if (!((bundle_encoding[template][slot] == I) ||
+                (bundle_encoding[template][slot] == M)))
+                goto out;
+
+        if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
+                (major_opcode == 0xE)))
+                goto out;
+
+        cmp_inst.l = kprobe_inst;
+        if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
+                /* Integere compare - Register Register (A6 type)*/
+                if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
+                                &&(cmp_inst.f.c == 1))
+                        ctype_unc = 1;
+        } else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
+                /* Integere compare - Immediate Register (A8 type)*/
+                if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
+                        ctype_unc = 1;
+        }
+out:
+        return ctype_unc;
+}
+
+/*
+ * In this function we override the bundle with
+ * the break instruction at the given slot.
+ */
+static void prepare_break_inst(uint template, uint  slot, uint major_opcode,
+        unsigned long kprobe_inst, struct kprobe *p)
+{
+        unsigned long break_inst = BREAK_INST;
+        bundle_t *bundle = &p->ainsn.insn.bundle;
+
+        /*
+         * Copy the original kprobe_inst qualifying predicate(qp)
+         * to the break instruction iff !is_cmp_ctype_unc_inst
+         * because for cmp instruction with ctype equal to unc,
+         * which is a special instruction always needs to be
+         * executed regradless of qp
+         */
+        if (!is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst))
+                break_inst |= (0x3f & kprobe_inst);
+
+        switch (slot) {
+          case 0:
+                bundle->quad0.slot0 = break_inst;
+                break;
+          case 1:
+                bundle->quad0.slot1_p0 = break_inst;
+                bundle->quad1.slot1_p1 = break_inst >> (64-46);
+                break;
+          case 2:
+                bundle->quad1.slot2 = break_inst;
+                break;
+        }
+
+        /*
+         * Update the instruction flag, so that we can
+         * emulate the instruction properly after we
+         * single step on original instruction
+         */
+        update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
+}
+
+static inline void get_kprobe_inst(bundle_t *bundle, uint slot,
+                unsigned long *kprobe_inst, uint *major_opcode)
+{
+        unsigned long kprobe_inst_p0, kprobe_inst_p1;
+        unsigned int template;
+
+        template = bundle->quad0.template;
+
+        switch (slot) {
+          case 0:
+                *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
+                *kprobe_inst = bundle->quad0.slot0;
+                break;
+          case 1:
+                *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
+                kprobe_inst_p0 = bundle->quad0.slot1_p0;
+                kprobe_inst_p1 = bundle->quad1.slot1_p1;
+                *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
+                break;
+          case 2:
+                *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
+                *kprobe_inst = bundle->quad1.slot2;
+                break;
+        }
+}
+
+static int valid_kprobe_addr(int template, int slot, unsigned long addr)
+{
+        if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
+                printk(KERN_WARNING "Attempting to insert unaligned kprobe at 0x%lx\n",
+                                addr);
+                return -EINVAL;
+        }
+        return 0;
+}
+
+static inline void save_previous_kprobe(void)
+{
+        kprobe_prev = current_kprobe;
+        kprobe_status_prev = kprobe_status;
+}
+
+static inline void restore_previous_kprobe(void)
+{
+        current_kprobe = kprobe_prev;
+        kprobe_status = kprobe_status_prev;
+}
+
+static inline void set_current_kprobe(struct kprobe *p)
+{
+        current_kprobe = p;
+}
+
+int arch_prepare_kprobe(struct kprobe *p)
+{
+        unsigned long addr = (unsigned long) p->addr;
+        unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
+        unsigned long kprobe_inst=0;
+        unsigned int slot = addr & 0xf, template, major_opcode = 0;
+        bundle_t *bundle = &p->ainsn.insn.bundle;
+
+        memcpy(&p->opcode.bundle, kprobe_addr, sizeof(bundle_t));
+        memcpy(&p->ainsn.insn.bundle, kprobe_addr, sizeof(bundle_t));
+
+        template = bundle->quad0.template;
+
+        if(valid_kprobe_addr(template, slot, addr))
+                return -EINVAL;
+
+        /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
+        if (slot == 1 && bundle_encoding[template][1] == L)
+                slot++;
+
+        /* Get kprobe_inst and major_opcode from the bundle */
+        get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
+
+        if (unsupported_inst(template, slot, major_opcode, kprobe_inst, p))
+                        return -EINVAL;
+
+        prepare_break_inst(template, slot, major_opcode, kprobe_inst, p);
+
+        return 0;
+}
+
+void arch_arm_kprobe(struct kprobe *p)
+{
+        unsigned long addr = (unsigned long)p->addr;
+        unsigned long arm_addr = addr & ~0xFULL;
+
+        memcpy((char *)arm_addr, &p->ainsn.insn.bundle, sizeof(bundle_t));
+        flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
+}
+
+void arch_disarm_kprobe(struct kprobe *p)
+{
+        unsigned long addr = (unsigned long)p->addr;
+        unsigned long arm_addr = addr & ~0xFULL;
+
+        /* p->opcode contains the original unaltered bundle */
+        memcpy((char *) arm_addr, (char *) &p->opcode.bundle, sizeof(bundle_t));
+        flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
+}
+
+void arch_remove_kprobe(struct kprobe *p)
+{
+}
+
+/*
+ * We are resuming execution after a single step fault, so the pt_regs
+ * structure reflects the register state after we executed the instruction
+ * located in the kprobe (p->ainsn.insn.bundle).  We still need to adjust
+ * the ip to point back to the original stack address. To set the IP address
+ * to original stack address, handle the case where we need to fixup the
+ * relative IP address and/or fixup branch register.
+ */
+static void resume_execution(struct kprobe *p, struct pt_regs *regs)
+{
+        unsigned long bundle_addr = ((unsigned long) (&p->opcode.bundle)) & ~0xFULL;
+        unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
+        unsigned long template;
+        int slot = ((unsigned long)p->addr & 0xf);
+
+        template = p->opcode.bundle.quad0.template;
+
+        if (slot == 1 && bundle_encoding[template][1] == L)
+                slot = 2;
+
+        if (p->ainsn.inst_flag) {
+
+                if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
+                        /* Fix relative IP address */
+                        regs->cr_iip = (regs->cr_iip - bundle_addr) + resume_addr;
+                }
+
+                if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
+                /*
+                 * Fix target branch register, software convention is
+                 * to use either b0 or b6 or b7, so just checking
+                 * only those registers
+                 */
+                        switch (p->ainsn.target_br_reg) {
+                        case 0:
+                                if ((regs->b0 == bundle_addr) ||
+                                        (regs->b0 == bundle_addr + 0x10)) {
+                                        regs->b0 = (regs->b0 - bundle_addr) +
+                                                resume_addr;
+                                }
+                                break;
+                        case 6:
+                                if ((regs->b6 == bundle_addr) ||
+                                        (regs->b6 == bundle_addr + 0x10)) {
+                                        regs->b6 = (regs->b6 - bundle_addr) +
+                                                resume_addr;
+                                }
+                                break;
+                        case 7:
+                                if ((regs->b7 == bundle_addr) ||
+                                        (regs->b7 == bundle_addr + 0x10)) {
+                                        regs->b7 = (regs->b7 - bundle_addr) +
+                                                resume_addr;
+                                }
+                                break;
+                        } /* end switch */
+                }
+                goto turn_ss_off;
+        }
+
+        if (slot == 2) {
+                if (regs->cr_iip == bundle_addr + 0x10) {
+                        regs->cr_iip = resume_addr + 0x10;
+                }
+        } else {
+                if (regs->cr_iip == bundle_addr) {
+                        regs->cr_iip = resume_addr;
+                }
+        }
+
+turn_ss_off:
+        /* Turn off Single Step bit */
+        ia64_psr(regs)->ss = 0;
+}
+
+static void prepare_ss(struct kprobe *p, struct pt_regs *regs)
+{
+        unsigned long bundle_addr = (unsigned long) &p->opcode.bundle;
+        unsigned long slot = (unsigned long)p->addr & 0xf;
+
+        /* Update instruction pointer (IIP) and slot number (IPSR.ri) */
+        regs->cr_iip = bundle_addr & ~0xFULL;
+
+        if (slot > 2)
+                slot = 0;
+
+        ia64_psr(regs)->ri = slot;
+
+        /* turn on single stepping */
+        ia64_psr(regs)->ss = 1;
+}
+
+static int pre_kprobes_handler(struct die_args *args)
+{
+        struct kprobe *p;
+        int ret = 0;
+        struct pt_regs *regs = args->regs;
+        kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
+
+        preempt_disable();
+
+        /* Handle recursion cases */
+        if (kprobe_running()) {
+                p = get_kprobe(addr);
+                if (p) {
+                        if (kprobe_status == KPROBE_HIT_SS) {
+                                unlock_kprobes();
+                                goto no_kprobe;
+                        }
+                        /* We have reentered the pre_kprobe_handler(), since
+                         * another probe was hit while within the handler.
+                         * We here save the original kprobes variables and
+                         * just single step on the instruction of the new probe
+                         * without calling any user handlers.
+                         */
+                        save_previous_kprobe();
+                        set_current_kprobe(p);
+                        p->nmissed++;
+                        prepare_ss(p, regs);
+                        kprobe_status = KPROBE_REENTER;
+                        return 1;
+                } else if (args->err == __IA64_BREAK_JPROBE) {
+                        /*
+                         * jprobe instrumented function just completed
+                         */
+                        p = current_kprobe;
+                        if (p->break_handler && p->break_handler(p, regs)) {
+                                goto ss_probe;
+                        }
+                } else {
+                        /* Not our break */
+                        goto no_kprobe;
+                }
+        }
+
+        lock_kprobes();
+        p = get_kprobe(addr);
+        if (!p) {
+                unlock_kprobes();
+                goto no_kprobe;
+        }
+
+        kprobe_status = KPROBE_HIT_ACTIVE;
+        set_current_kprobe(p);
+
+        if (p->pre_handler && p->pre_handler(p, regs))
+                /*
+                 * Our pre-handler is specifically requesting that we just
+                 * do a return.  This is handling the case where the
+                 * pre-handler is really our special jprobe pre-handler.
+                 */
+                return 1;
+
+ss_probe:
+        prepare_ss(p, regs);
+        kprobe_status = KPROBE_HIT_SS;
+        return 1;
+
+no_kprobe:
+        preempt_enable_no_resched();
+        return ret;
+}
+
+static int post_kprobes_handler(struct pt_regs *regs)
+{
+        if (!kprobe_running())
+                return 0;
+
+        if ((kprobe_status != KPROBE_REENTER) && current_kprobe->post_handler) {
+                kprobe_status = KPROBE_HIT_SSDONE;
+                current_kprobe->post_handler(current_kprobe, regs, 0);
+        }
+
+        resume_execution(current_kprobe, regs);
+
+        /*Restore back the original saved kprobes variables and continue. */
+        if (kprobe_status == KPROBE_REENTER) {
+                restore_previous_kprobe();
+                goto out;
+        }
+
+        unlock_kprobes();
+
+out:
+        preempt_enable_no_resched();
+        return 1;
+}
+
+static int kprobes_fault_handler(struct pt_regs *regs, int trapnr)
+{
+        if (!kprobe_running())
+                return 0;
+
+        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);
+                unlock_kprobes();
+                preempt_enable_no_resched();
+        }
+
+        return 0;
+}
+
+int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
+                             void *data)
+{
+        struct die_args *args = (struct die_args *)data;
+        switch(val) {
+        case DIE_BREAK:
+                if (pre_kprobes_handler(args))
+                        return NOTIFY_STOP;
+                break;
+        case DIE_SS:
+                if (post_kprobes_handler(args->regs))
+                        return NOTIFY_STOP;
+                break;
+        case DIE_PAGE_FAULT:
+                if (kprobes_fault_handler(args->regs, args->trapnr))
+                        return NOTIFY_STOP;
+        default:
+                break;
+        }
+        return NOTIFY_DONE;
+}
+
+int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+        struct jprobe *jp = container_of(p, struct jprobe, kp);
+        unsigned long addr = ((struct fnptr *)(jp->entry))->ip;
+
+        /* save architectural state */
+        jprobe_saved_regs = *regs;
+
+        /* after rfi, execute the jprobe instrumented function */
+        regs->cr_iip = addr & ~0xFULL;
+        ia64_psr(regs)->ri = addr & 0xf;
+        regs->r1 = ((struct fnptr *)(jp->entry))->gp;
+
+        /*
+         * fix the return address to our jprobe_inst_return() function
+         * in the jprobes.S file
+         */
+        regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
+
+        return 1;
+}
+
+int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
+{
+        *regs = jprobe_saved_regs;
+        return 1;
+}