// SPDX-License-Identifier: GPL-2.0-or-later /* * Kernel Probes (KProbes) * arch/ia64/kernel/kprobes.c * * Copyright (C) IBM Corporation, 2002, 2004 * Copyright (C) Intel Corporation, 2005 * * 2005-Apr Rusty Lynch and Anil S Keshavamurthy * adapted from i386 */ #include #include #include #include #include #include #include #include #include #include DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}}; enum instruction_type {A, I, M, F, B, L, X, u}; static enum instruction_type bundle_encoding[32][3] = { [0x00] = { M, I, I }, [0x01] = { M, I, I }, [0x02] = { M, I, I }, [0x03] = { M, I, I }, [0x04] = { M, L, X }, [0x05] = { M, L, X }, [0x06] = { u, u, u }, [0x07] = { u, u, u }, [0x08] = { M, M, I }, [0x09] = { M, M, I }, [0x0A] = { M, M, I }, [0x0B] = { M, M, I }, [0x0C] = { M, F, I }, [0x0D] = { M, F, I }, [0x0E] = { M, M, F }, [0x0F] = { M, M, F }, [0x10] = { M, I, B }, [0x11] = { M, I, B }, [0x12] = { M, B, B }, [0x13] = { M, B, B }, [0x14] = { u, u, u }, [0x15] = { u, u, u }, [0x16] = { B, B, B }, [0x17] = { B, B, B }, [0x18] = { M, M, B }, [0x19] = { M, M, B }, [0x1A] = { u, u, u }, [0x1B] = { u, u, u }, [0x1C] = { M, F, B }, [0x1D] = { M, F, B }, [0x1E] = { u, u, u }, [0x1F] = { u, u, u }, }; /* Insert a long branch code */ static void __kprobes set_brl_inst(void *from, void *to) { s64 rel = ((s64) to - (s64) from) >> 4; bundle_t *brl; brl = (bundle_t *) ((u64) from & ~0xf); brl->quad0.template = 0x05; /* [MLX](stop) */ brl->quad0.slot0 = NOP_M_INST; /* nop.m 0x0 */ brl->quad0.slot1_p0 = ((rel >> 20) & 0x7fffffffff) << 2; brl->quad1.slot1_p1 = (((rel >> 20) & 0x7fffffffff) << 2) >> (64 - 46); /* brl.cond.sptk.many.clr rel<<4 (qp=0) */ brl->quad1.slot2 = BRL_INST(rel >> 59, rel & 0xfffff); } /* * In this function we check to see if the instruction * is IP relative instruction and update the kprobe * inst flag accordingly */ static void __kprobes 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; p->ainsn.slot = slot; /* Check for Break instruction * Bits 37:40 Major opcode to be zero * Bits 27:32 X6 to be zero * Bits 32:35 X3 to be zero */ if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) { /* is a break instruction */ p->ainsn.inst_flag |= INST_FLAG_BREAK_INST; return; } 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 * (qp) cmpx.crel.ctype p1,p2=r2,r3 * on which we are inserting kprobe is cmp instruction * with ctype as unc. */ static uint __kprobes 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)) { /* Integer 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)) { /* Integer 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 check to see if the instruction * on which we are inserting kprobe is supported. * Returns qp value if supported * Returns -EINVAL if unsupported */ static int __kprobes unsupported_inst(uint template, uint slot, uint major_opcode, unsigned long kprobe_inst, unsigned long addr) { int qp; qp = kprobe_inst & 0x3f; if (is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst)) { if (slot == 1 && qp) { printk(KERN_WARNING "Kprobes on cmp unc " "instruction on slot 1 at <0x%lx> " "is not supported\n", addr); return -EINVAL; } qp = 0; } else if (bundle_encoding[template][slot] == I) { if (major_opcode == 0) { /* * 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; } } else if ((major_opcode == 5) && !(kprobe_inst & (0xFUl << 33)) && (kprobe_inst & (0x1UL << 12))) { /* test bit instructions, tbit,tnat,tf * bit 33-36 to be equal to 0 * bit 12 to be equal to 1 */ if (slot == 1 && qp) { printk(KERN_WARNING "Kprobes on test bit " "instruction on slot at <0x%lx> " "is not supported\n", addr); return -EINVAL; } qp = 0; } } else if (bundle_encoding[template][slot] == B) { if (major_opcode == 7) { /* IP-Relative Predict major code is 7 */ printk(KERN_WARNING "Kprobes on IP-Relative" "Predict is not supported\n"); return -EINVAL; } else if (major_opcode == 2) { /* Indirect Predict, major code is 2 * bit 27-32 to be equal to 10 or 11 */ int x6=(kprobe_inst >> 27) & 0x3F; if ((x6 == 0x10) || (x6 == 0x11)) { printk(KERN_WARNING "Kprobes on " "Indirect Predict is not supported\n"); return -EINVAL; } } } /* kernel does not use float instruction, here for safety kprobe * will judge whether it is fcmp/flass/float approximation instruction */ else if (unlikely(bundle_encoding[template][slot] == F)) { if ((major_opcode == 4 || major_opcode == 5) && (kprobe_inst & (0x1 << 12))) { /* fcmp/fclass unc instruction */ if (slot == 1 && qp) { printk(KERN_WARNING "Kprobes on fcmp/fclass " "instruction on slot at <0x%lx> " "is not supported\n", addr); return -EINVAL; } qp = 0; } if ((major_opcode == 0 || major_opcode == 1) && (kprobe_inst & (0x1UL << 33))) { /* float Approximation instruction */ if (slot == 1 && qp) { printk(KERN_WARNING "Kprobes on float Approx " "instr at <0x%lx> is not supported\n", addr); return -EINVAL; } qp = 0; } } return qp; } /* * In this function we override the bundle with * the break instruction at the given slot. */ static void __kprobes prepare_break_inst(uint template, uint slot, uint major_opcode, unsigned long kprobe_inst, struct kprobe *p, int qp) { unsigned long break_inst = BREAK_INST; bundle_t *bundle = &p->opcode.bundle; /* * Copy the original kprobe_inst qualifying predicate(qp) * to the break instruction */ break_inst |= qp; 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 void __kprobes 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; } } /* Returns non-zero if the addr is in the Interrupt Vector Table */ static int __kprobes in_ivt_functions(unsigned long addr) { return (addr >= (unsigned long)__start_ivt_text && addr < (unsigned long)__end_ivt_text); } static int __kprobes 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; } if (in_ivt_functions(addr)) { printk(KERN_WARNING "Kprobes can't be inserted inside " "IVT functions at 0x%lx\n", addr); return -EINVAL; } return 0; } static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) { unsigned int i; i = atomic_add_return(1, &kcb->prev_kprobe_index); kcb->prev_kprobe[i-1].kp = kprobe_running(); kcb->prev_kprobe[i-1].status = kcb->kprobe_status; } static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) { unsigned int i; i = atomic_read(&kcb->prev_kprobe_index); __this_cpu_write(current_kprobe, kcb->prev_kprobe[i-1].kp); kcb->kprobe_status = kcb->prev_kprobe[i-1].status; atomic_sub(1, &kcb->prev_kprobe_index); } static void __kprobes set_current_kprobe(struct kprobe *p, struct kprobe_ctlblk *kcb) { __this_cpu_write(current_kprobe, p); } void __kretprobe_trampoline(void) { } int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) { regs->cr_iip = __kretprobe_trampoline_handler(regs, NULL); /* * By returning a non-zero value, we are telling * kprobe_handler() that we don't want the post_handler * to run (and have re-enabled preemption) */ return 1; } void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs) { ri->ret_addr = (kprobe_opcode_t *)regs->b0; ri->fp = NULL; /* Replace the return addr with trampoline addr */ regs->b0 = (unsigned long)dereference_function_descriptor(__kretprobe_trampoline); } /* Check the instruction in the slot is break */ static int __kprobes __is_ia64_break_inst(bundle_t *bundle, uint slot) { unsigned int major_opcode; unsigned int template = bundle->quad0.template; unsigned long kprobe_inst; /* 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 probe instruction at given slot*/ get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode); /* For break instruction, * Bits 37:40 Major opcode to be zero * Bits 27:32 X6 to be zero * Bits 32:35 X3 to be zero */ if (major_opcode || ((kprobe_inst >> 27) & 0x1FF)) { /* Not a break instruction */ return 0; } /* Is a break instruction */ return 1; } /* * In this function, we check whether the target bundle modifies IP or * it triggers an exception. If so, it cannot be boostable. */ static int __kprobes can_boost(bundle_t *bundle, uint slot, unsigned long bundle_addr) { unsigned int template = bundle->quad0.template; do { if (search_exception_tables(bundle_addr + slot) || __is_ia64_break_inst(bundle, slot)) return 0; /* exception may occur in this bundle*/ } while ((++slot) < 3); template &= 0x1e; if (template >= 0x10 /* including B unit */ || template == 0x04 /* including X unit */ || template == 0x06) /* undefined */ return 0; return 1; } /* Prepare long jump bundle and disables other boosters if need */ static void __kprobes prepare_booster(struct kprobe *p) { unsigned long addr = (unsigned long)p->addr & ~0xFULL; unsigned int slot = (unsigned long)p->addr & 0xf; struct kprobe *other_kp; if (can_boost(&p->ainsn.insn[0].bundle, slot, addr)) { set_brl_inst(&p->ainsn.insn[1].bundle, (bundle_t *)addr + 1); p->ainsn.inst_flag |= INST_FLAG_BOOSTABLE; } /* disables boosters in previous slots */ for (; addr < (unsigned long)p->addr; addr++) { other_kp = get_kprobe((void *)addr); if (other_kp) other_kp->ainsn.inst_flag &= ~INST_FLAG_BOOSTABLE; } } int __kprobes 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; int qp; bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle; 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); qp = unsupported_inst(template, slot, major_opcode, kprobe_inst, addr); if (qp < 0) return -EINVAL; p->ainsn.insn = get_insn_slot(); if (!p->ainsn.insn) return -ENOMEM; memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t)); memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t)); prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp); prepare_booster(p); return 0; } void __kprobes arch_arm_kprobe(struct kprobe *p) { unsigned long arm_addr; bundle_t *src, *dest; arm_addr = ((unsigned long)p->addr) & ~0xFUL; dest = &((kprobe_opcode_t *)arm_addr)->bundle; src = &p->opcode.bundle; flush_icache_range((unsigned long)p->ainsn.insn, (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t) * MAX_INSN_SIZE); switch (p->ainsn.slot) { case 0: dest->quad0.slot0 = src->quad0.slot0; break; case 1: dest->quad1.slot1_p1 = src->quad1.slot1_p1; break; case 2: dest->quad1.slot2 = src->quad1.slot2; break; } flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t)); } void __kprobes arch_disarm_kprobe(struct kprobe *p) { unsigned long arm_addr; bundle_t *src, *dest; arm_addr = ((unsigned long)p->addr) & ~0xFUL; dest = &((kprobe_opcode_t *)arm_addr)->bundle; /* p->ainsn.insn contains the original unaltered kprobe_opcode_t */ src = &p->ainsn.insn->bundle; switch (p->ainsn.slot) { case 0: dest->quad0.slot0 = src->quad0.slot0; break; case 1: dest->quad1.slot1_p1 = src->quad1.slot1_p1; break; case 2: dest->quad1.slot2 = src->quad1.slot2; break; } flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t)); } void __kprobes arch_remove_kprobe(struct kprobe *p) { if (p->ainsn.insn) { free_insn_slot(p->ainsn.insn, p->ainsn.inst_flag & INST_FLAG_BOOSTABLE); p->ainsn.insn = NULL; } } /* * 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 __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs) { unsigned long bundle_addr = (unsigned long) (&p->ainsn.insn->bundle); unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL; unsigned long template; int slot = ((unsigned long)p->addr & 0xf); template = p->ainsn.insn->bundle.quad0.template; if (slot == 1 && bundle_encoding[template][1] == L) slot = 2; if (p->ainsn.inst_flag & ~INST_FLAG_BOOSTABLE) { 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 __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs) { unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle; unsigned long slot = (unsigned long)p->addr & 0xf; /* single step inline if break instruction */ if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST) regs->cr_iip = (unsigned long)p->addr & ~0xFULL; else 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 __kprobes is_ia64_break_inst(struct pt_regs *regs) { unsigned int slot = ia64_psr(regs)->ri; unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip; bundle_t bundle; memcpy(&bundle, kprobe_addr, sizeof(bundle_t)); return __is_ia64_break_inst(&bundle, slot); } static int __kprobes 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); struct kprobe_ctlblk *kcb; /* * We don't want to be preempted for the entire * duration of kprobe processing */ preempt_disable(); kcb = get_kprobe_ctlblk(); /* Handle recursion cases */ if (kprobe_running()) { p = get_kprobe(addr); if (p) { if ((kcb->kprobe_status == KPROBE_HIT_SS) && (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) { ia64_psr(regs)->ss = 0; 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(kcb); set_current_kprobe(p, kcb); kprobes_inc_nmissed_count(p); prepare_ss(p, regs); kcb->kprobe_status = KPROBE_REENTER; return 1; } else if (!is_ia64_break_inst(regs)) { /* The breakpoint instruction was removed by * another cpu right after we hit, no further * handling of this interrupt is appropriate */ ret = 1; goto no_kprobe; } else { /* Not our break */ goto no_kprobe; } } p = get_kprobe(addr); if (!p) { if (!is_ia64_break_inst(regs)) { /* * 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 our break, let kernel handle it */ goto no_kprobe; } set_current_kprobe(p, kcb); kcb->kprobe_status = KPROBE_HIT_ACTIVE; if (p->pre_handler && p->pre_handler(p, regs)) { reset_current_kprobe(); preempt_enable_no_resched(); return 1; } #if !defined(CONFIG_PREEMPTION) if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) { /* Boost up -- we can execute copied instructions directly */ ia64_psr(regs)->ri = p->ainsn.slot; regs->cr_iip = (unsigned long)&p->ainsn.insn->bundle & ~0xFULL; /* turn single stepping off */ ia64_psr(regs)->ss = 0; reset_current_kprobe(); preempt_enable_no_resched(); return 1; } #endif prepare_ss(p, regs); kcb->kprobe_status = KPROBE_HIT_SS; return 1; no_kprobe: preempt_enable_no_resched(); return ret; } static int __kprobes post_kprobes_handler(struct pt_regs *regs) { struct kprobe *cur = kprobe_running(); struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); if (!cur) return 0; if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { kcb->kprobe_status = KPROBE_HIT_SSDONE; cur->post_handler(cur, regs, 0); } resume_execution(cur, regs); /*Restore back the original saved kprobes variables and continue. */ if (kcb->kprobe_status == KPROBE_REENTER) { restore_previous_kprobe(kcb); goto out; } reset_current_kprobe(); out: preempt_enable_no_resched(); return 1; } int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) { struct kprobe *cur = kprobe_running(); struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); switch(kcb->kprobe_status) { case KPROBE_HIT_SS: case KPROBE_REENTER: /* * We are here because the instruction being single * stepped caused a page fault. We reset the current * kprobe and the instruction pointer points back to * the probe address and allow the page fault handler * to continue as a normal page fault. */ regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL; ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf; if (kcb->kprobe_status == KPROBE_REENTER) restore_previous_kprobe(kcb); else reset_current_kprobe(); preempt_enable_no_resched(); break; case KPROBE_HIT_ACTIVE: case KPROBE_HIT_SSDONE: /* * In case the user-specified fault handler returned * zero, try to fix up. */ if (ia64_done_with_exception(regs)) return 1; /* * Let ia64_do_page_fault() fix it. */ break; default: break; } return 0; } 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; if (args->regs && user_mode(args->regs)) return ret; switch(val) { case DIE_BREAK: /* err is break number from ia64_bad_break() */ if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12) || args->err == 0) if (pre_kprobes_handler(args)) ret = NOTIFY_STOP; break; case DIE_FAULT: /* err is vector number from ia64_fault() */ if (args->err == 36) if (post_kprobes_handler(args->regs)) ret = NOTIFY_STOP; break; default: break; } return ret; } static struct kprobe trampoline_p = { .pre_handler = trampoline_probe_handler }; int __init arch_init_kprobes(void) { trampoline_p.addr = dereference_function_descriptor(__kretprobe_trampoline); return register_kprobe(&trampoline_p); } int __kprobes arch_trampoline_kprobe(struct kprobe *p) { if (p->addr == dereference_function_descriptor(__kretprobe_trampoline)) return 1; return 0; }