| /* |
| * Kernel Probes (KProbes) |
| * |
| * 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 IBM Corp. 2002, 2006 |
| * |
| * s390 port, used ppc64 as template. Mike Grundy <grundym@us.ibm.com> |
| */ |
| |
| #include <linux/kprobes.h> |
| #include <linux/ptrace.h> |
| #include <linux/preempt.h> |
| #include <linux/stop_machine.h> |
| #include <linux/kdebug.h> |
| #include <linux/uaccess.h> |
| #include <linux/extable.h> |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <linux/hardirq.h> |
| #include <linux/ftrace.h> |
| #include <asm/cacheflush.h> |
| #include <asm/sections.h> |
| #include <asm/uaccess.h> |
| #include <asm/dis.h> |
| |
| DEFINE_PER_CPU(struct kprobe *, current_kprobe); |
| DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); |
| |
| struct kretprobe_blackpoint kretprobe_blacklist[] = { }; |
| |
| DEFINE_INSN_CACHE_OPS(dmainsn); |
| |
| static void *alloc_dmainsn_page(void) |
| { |
| return (void *)__get_free_page(GFP_KERNEL | GFP_DMA); |
| } |
| |
| static void free_dmainsn_page(void *page) |
| { |
| free_page((unsigned long)page); |
| } |
| |
| struct kprobe_insn_cache kprobe_dmainsn_slots = { |
| .mutex = __MUTEX_INITIALIZER(kprobe_dmainsn_slots.mutex), |
| .alloc = alloc_dmainsn_page, |
| .free = free_dmainsn_page, |
| .pages = LIST_HEAD_INIT(kprobe_dmainsn_slots.pages), |
| .insn_size = MAX_INSN_SIZE, |
| }; |
| |
| static void copy_instruction(struct kprobe *p) |
| { |
| unsigned long ip = (unsigned long) p->addr; |
| s64 disp, new_disp; |
| u64 addr, new_addr; |
| |
| if (ftrace_location(ip) == ip) { |
| /* |
| * If kprobes patches the instruction that is morphed by |
| * ftrace make sure that kprobes always sees the branch |
| * "jg .+24" that skips the mcount block or the "brcl 0,0" |
| * in case of hotpatch. |
| */ |
| ftrace_generate_nop_insn((struct ftrace_insn *)p->ainsn.insn); |
| p->ainsn.is_ftrace_insn = 1; |
| } else |
| memcpy(p->ainsn.insn, p->addr, insn_length(*p->addr >> 8)); |
| p->opcode = p->ainsn.insn[0]; |
| if (!probe_is_insn_relative_long(p->ainsn.insn)) |
| return; |
| /* |
| * For pc-relative instructions in RIL-b or RIL-c format patch the |
| * RI2 displacement field. We have already made sure that the insn |
| * slot for the patched instruction is within the same 2GB area |
| * as the original instruction (either kernel image or module area). |
| * Therefore the new displacement will always fit. |
| */ |
| disp = *(s32 *)&p->ainsn.insn[1]; |
| addr = (u64)(unsigned long)p->addr; |
| new_addr = (u64)(unsigned long)p->ainsn.insn; |
| new_disp = ((addr + (disp * 2)) - new_addr) / 2; |
| *(s32 *)&p->ainsn.insn[1] = new_disp; |
| } |
| NOKPROBE_SYMBOL(copy_instruction); |
| |
| static inline int is_kernel_addr(void *addr) |
| { |
| return addr < (void *)_end; |
| } |
| |
| static int s390_get_insn_slot(struct kprobe *p) |
| { |
| /* |
| * Get an insn slot that is within the same 2GB area like the original |
| * instruction. That way instructions with a 32bit signed displacement |
| * field can be patched and executed within the insn slot. |
| */ |
| p->ainsn.insn = NULL; |
| if (is_kernel_addr(p->addr)) |
| p->ainsn.insn = get_dmainsn_slot(); |
| else if (is_module_addr(p->addr)) |
| p->ainsn.insn = get_insn_slot(); |
| return p->ainsn.insn ? 0 : -ENOMEM; |
| } |
| NOKPROBE_SYMBOL(s390_get_insn_slot); |
| |
| static void s390_free_insn_slot(struct kprobe *p) |
| { |
| if (!p->ainsn.insn) |
| return; |
| if (is_kernel_addr(p->addr)) |
| free_dmainsn_slot(p->ainsn.insn, 0); |
| else |
| free_insn_slot(p->ainsn.insn, 0); |
| p->ainsn.insn = NULL; |
| } |
| NOKPROBE_SYMBOL(s390_free_insn_slot); |
| |
| int arch_prepare_kprobe(struct kprobe *p) |
| { |
| if ((unsigned long) p->addr & 0x01) |
| return -EINVAL; |
| /* Make sure the probe isn't going on a difficult instruction */ |
| if (probe_is_prohibited_opcode(p->addr)) |
| return -EINVAL; |
| if (s390_get_insn_slot(p)) |
| return -ENOMEM; |
| copy_instruction(p); |
| return 0; |
| } |
| NOKPROBE_SYMBOL(arch_prepare_kprobe); |
| |
| int arch_check_ftrace_location(struct kprobe *p) |
| { |
| return 0; |
| } |
| |
| struct swap_insn_args { |
| struct kprobe *p; |
| unsigned int arm_kprobe : 1; |
| }; |
| |
| static int swap_instruction(void *data) |
| { |
| struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
| unsigned long status = kcb->kprobe_status; |
| struct swap_insn_args *args = data; |
| struct ftrace_insn new_insn, *insn; |
| struct kprobe *p = args->p; |
| size_t len; |
| |
| new_insn.opc = args->arm_kprobe ? BREAKPOINT_INSTRUCTION : p->opcode; |
| len = sizeof(new_insn.opc); |
| if (!p->ainsn.is_ftrace_insn) |
| goto skip_ftrace; |
| len = sizeof(new_insn); |
| insn = (struct ftrace_insn *) p->addr; |
| if (args->arm_kprobe) { |
| if (is_ftrace_nop(insn)) |
| new_insn.disp = KPROBE_ON_FTRACE_NOP; |
| else |
| new_insn.disp = KPROBE_ON_FTRACE_CALL; |
| } else { |
| ftrace_generate_call_insn(&new_insn, (unsigned long)p->addr); |
| if (insn->disp == KPROBE_ON_FTRACE_NOP) |
| ftrace_generate_nop_insn(&new_insn); |
| } |
| skip_ftrace: |
| kcb->kprobe_status = KPROBE_SWAP_INST; |
| s390_kernel_write(p->addr, &new_insn, len); |
| kcb->kprobe_status = status; |
| return 0; |
| } |
| NOKPROBE_SYMBOL(swap_instruction); |
| |
| void arch_arm_kprobe(struct kprobe *p) |
| { |
| struct swap_insn_args args = {.p = p, .arm_kprobe = 1}; |
| |
| stop_machine(swap_instruction, &args, NULL); |
| } |
| NOKPROBE_SYMBOL(arch_arm_kprobe); |
| |
| void arch_disarm_kprobe(struct kprobe *p) |
| { |
| struct swap_insn_args args = {.p = p, .arm_kprobe = 0}; |
| |
| stop_machine(swap_instruction, &args, NULL); |
| } |
| NOKPROBE_SYMBOL(arch_disarm_kprobe); |
| |
| void arch_remove_kprobe(struct kprobe *p) |
| { |
| s390_free_insn_slot(p); |
| } |
| NOKPROBE_SYMBOL(arch_remove_kprobe); |
| |
| static void enable_singlestep(struct kprobe_ctlblk *kcb, |
| struct pt_regs *regs, |
| unsigned long ip) |
| { |
| struct per_regs per_kprobe; |
| |
| /* Set up the PER control registers %cr9-%cr11 */ |
| per_kprobe.control = PER_EVENT_IFETCH; |
| per_kprobe.start = ip; |
| per_kprobe.end = ip; |
| |
| /* Save control regs and psw mask */ |
| __ctl_store(kcb->kprobe_saved_ctl, 9, 11); |
| kcb->kprobe_saved_imask = regs->psw.mask & |
| (PSW_MASK_PER | PSW_MASK_IO | PSW_MASK_EXT); |
| |
| /* Set PER control regs, turns on single step for the given address */ |
| __ctl_load(per_kprobe, 9, 11); |
| regs->psw.mask |= PSW_MASK_PER; |
| regs->psw.mask &= ~(PSW_MASK_IO | PSW_MASK_EXT); |
| regs->psw.addr = ip; |
| } |
| NOKPROBE_SYMBOL(enable_singlestep); |
| |
| static void disable_singlestep(struct kprobe_ctlblk *kcb, |
| struct pt_regs *regs, |
| unsigned long ip) |
| { |
| /* Restore control regs and psw mask, set new psw address */ |
| __ctl_load(kcb->kprobe_saved_ctl, 9, 11); |
| regs->psw.mask &= ~PSW_MASK_PER; |
| regs->psw.mask |= kcb->kprobe_saved_imask; |
| regs->psw.addr = ip; |
| } |
| NOKPROBE_SYMBOL(disable_singlestep); |
| |
| /* |
| * Activate a kprobe by storing its pointer to current_kprobe. The |
| * previous kprobe is stored in kcb->prev_kprobe. A stack of up to |
| * two kprobes can be active, see KPROBE_REENTER. |
| */ |
| static void push_kprobe(struct kprobe_ctlblk *kcb, struct kprobe *p) |
| { |
| kcb->prev_kprobe.kp = __this_cpu_read(current_kprobe); |
| kcb->prev_kprobe.status = kcb->kprobe_status; |
| __this_cpu_write(current_kprobe, p); |
| } |
| NOKPROBE_SYMBOL(push_kprobe); |
| |
| /* |
| * Deactivate a kprobe by backing up to the previous state. If the |
| * current state is KPROBE_REENTER prev_kprobe.kp will be non-NULL, |
| * for any other state prev_kprobe.kp will be NULL. |
| */ |
| static void pop_kprobe(struct kprobe_ctlblk *kcb) |
| { |
| __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp); |
| kcb->kprobe_status = kcb->prev_kprobe.status; |
| } |
| NOKPROBE_SYMBOL(pop_kprobe); |
| |
| void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs) |
| { |
| ri->ret_addr = (kprobe_opcode_t *) regs->gprs[14]; |
| |
| /* Replace the return addr with trampoline addr */ |
| regs->gprs[14] = (unsigned long) &kretprobe_trampoline; |
| } |
| NOKPROBE_SYMBOL(arch_prepare_kretprobe); |
| |
| static void kprobe_reenter_check(struct kprobe_ctlblk *kcb, struct kprobe *p) |
| { |
| switch (kcb->kprobe_status) { |
| case KPROBE_HIT_SSDONE: |
| case KPROBE_HIT_ACTIVE: |
| kprobes_inc_nmissed_count(p); |
| break; |
| case KPROBE_HIT_SS: |
| case KPROBE_REENTER: |
| default: |
| /* |
| * A kprobe on the code path to single step an instruction |
| * is a BUG. The code path resides in the .kprobes.text |
| * section and is executed with interrupts disabled. |
| */ |
| printk(KERN_EMERG "Invalid kprobe detected at %p.\n", p->addr); |
| dump_kprobe(p); |
| BUG(); |
| } |
| } |
| NOKPROBE_SYMBOL(kprobe_reenter_check); |
| |
| static int kprobe_handler(struct pt_regs *regs) |
| { |
| struct kprobe_ctlblk *kcb; |
| struct kprobe *p; |
| |
| /* |
| * We want to disable preemption for the entire duration of kprobe |
| * processing. That includes the calls to the pre/post handlers |
| * and single stepping the kprobe instruction. |
| */ |
| preempt_disable(); |
| kcb = get_kprobe_ctlblk(); |
| p = get_kprobe((void *)(regs->psw.addr - 2)); |
| |
| if (p) { |
| if (kprobe_running()) { |
| /* |
| * We have hit a kprobe while another is still |
| * active. This can happen in the pre and post |
| * handler. Single step the instruction of the |
| * new probe but do not call any handler function |
| * of this secondary kprobe. |
| * push_kprobe and pop_kprobe saves and restores |
| * the currently active kprobe. |
| */ |
| kprobe_reenter_check(kcb, p); |
| push_kprobe(kcb, p); |
| kcb->kprobe_status = KPROBE_REENTER; |
| } else { |
| /* |
| * If we have no pre-handler or it returned 0, we |
| * continue with single stepping. If we have a |
| * pre-handler and it returned non-zero, it prepped |
| * for calling the break_handler below on re-entry |
| * for jprobe processing, so get out doing nothing |
| * more here. |
| */ |
| push_kprobe(kcb, p); |
| kcb->kprobe_status = KPROBE_HIT_ACTIVE; |
| if (p->pre_handler && p->pre_handler(p, regs)) |
| return 1; |
| kcb->kprobe_status = KPROBE_HIT_SS; |
| } |
| enable_singlestep(kcb, regs, (unsigned long) p->ainsn.insn); |
| return 1; |
| } else if (kprobe_running()) { |
| p = __this_cpu_read(current_kprobe); |
| if (p->break_handler && p->break_handler(p, regs)) { |
| /* |
| * Continuation after the jprobe completed and |
| * caused the jprobe_return trap. The jprobe |
| * break_handler "returns" to the original |
| * function that still has the kprobe breakpoint |
| * installed. We continue with single stepping. |
| */ |
| kcb->kprobe_status = KPROBE_HIT_SS; |
| enable_singlestep(kcb, regs, |
| (unsigned long) p->ainsn.insn); |
| return 1; |
| } /* else: |
| * No kprobe at this address and the current kprobe |
| * has no break handler (no jprobe!). The kernel just |
| * exploded, let the standard trap handler pick up the |
| * pieces. |
| */ |
| } /* else: |
| * No kprobe at this address and no active kprobe. The trap has |
| * not been caused by a kprobe breakpoint. The race of breakpoint |
| * vs. kprobe remove does not exist because on s390 as we use |
| * stop_machine to arm/disarm the breakpoints. |
| */ |
| preempt_enable_no_resched(); |
| return 0; |
| } |
| NOKPROBE_SYMBOL(kprobe_handler); |
| |
| /* |
| * Function return probe trampoline: |
| * - init_kprobes() establishes a probepoint here |
| * - When the probed function returns, this probe |
| * causes the handlers to fire |
| */ |
| static void __used kretprobe_trampoline_holder(void) |
| { |
| asm volatile(".global kretprobe_trampoline\n" |
| "kretprobe_trampoline: bcr 0,0\n"); |
| } |
| |
| /* |
| * Called when the probe at kretprobe trampoline is hit |
| */ |
| static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) |
| { |
| struct kretprobe_instance *ri; |
| struct hlist_head *head, empty_rp; |
| struct hlist_node *tmp; |
| unsigned long flags, orig_ret_address; |
| unsigned long trampoline_address; |
| kprobe_opcode_t *correct_ret_addr; |
| |
| INIT_HLIST_HEAD(&empty_rp); |
| kretprobe_hash_lock(current, &head, &flags); |
| |
| /* |
| * It is possible to have multiple instances associated with a given |
| * task either because an multiple functions in the call path |
| * have a return probe installed on them, and/or more than one return |
| * return probe was registered for a target function. |
| * |
| * We can handle this because: |
| * - instances are always inserted at the head of the list |
| * - when multiple return probes are registered for the same |
| * function, the first instance's ret_addr will point to the |
| * real return address, and all the rest will point to |
| * kretprobe_trampoline |
| */ |
| ri = NULL; |
| orig_ret_address = 0; |
| correct_ret_addr = NULL; |
| trampoline_address = (unsigned long) &kretprobe_trampoline; |
| hlist_for_each_entry_safe(ri, tmp, head, hlist) { |
| if (ri->task != current) |
| /* another task is sharing our hash bucket */ |
| continue; |
| |
| orig_ret_address = (unsigned long) ri->ret_addr; |
| |
| if (orig_ret_address != trampoline_address) |
| /* |
| * This is the real return address. Any other |
| * instances associated with this task are for |
| * other calls deeper on the call stack |
| */ |
| break; |
| } |
| |
| kretprobe_assert(ri, orig_ret_address, trampoline_address); |
| |
| correct_ret_addr = ri->ret_addr; |
| hlist_for_each_entry_safe(ri, tmp, head, hlist) { |
| if (ri->task != current) |
| /* another task is sharing our hash bucket */ |
| continue; |
| |
| orig_ret_address = (unsigned long) ri->ret_addr; |
| |
| if (ri->rp && ri->rp->handler) { |
| ri->ret_addr = correct_ret_addr; |
| ri->rp->handler(ri, regs); |
| } |
| |
| recycle_rp_inst(ri, &empty_rp); |
| |
| if (orig_ret_address != trampoline_address) |
| /* |
| * This is the real return address. Any other |
| * instances associated with this task are for |
| * other calls deeper on the call stack |
| */ |
| break; |
| } |
| |
| regs->psw.addr = orig_ret_address; |
| |
| pop_kprobe(get_kprobe_ctlblk()); |
| kretprobe_hash_unlock(current, &flags); |
| preempt_enable_no_resched(); |
| |
| hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { |
| hlist_del(&ri->hlist); |
| kfree(ri); |
| } |
| /* |
| * 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; |
| } |
| NOKPROBE_SYMBOL(trampoline_probe_handler); |
| |
| /* |
| * 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) |
| { |
| struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
| unsigned long ip = regs->psw.addr; |
| int fixup = probe_get_fixup_type(p->ainsn.insn); |
| |
| /* Check if the kprobes location is an enabled ftrace caller */ |
| if (p->ainsn.is_ftrace_insn) { |
| struct ftrace_insn *insn = (struct ftrace_insn *) p->addr; |
| struct ftrace_insn call_insn; |
| |
| ftrace_generate_call_insn(&call_insn, (unsigned long) p->addr); |
| /* |
| * A kprobe on an enabled ftrace call site actually single |
| * stepped an unconditional branch (ftrace nop equivalent). |
| * Now we need to fixup things and pretend that a brasl r0,... |
| * was executed instead. |
| */ |
| if (insn->disp == KPROBE_ON_FTRACE_CALL) { |
| ip += call_insn.disp * 2 - MCOUNT_INSN_SIZE; |
| regs->gprs[0] = (unsigned long)p->addr + sizeof(*insn); |
| } |
| } |
| |
| if (fixup & FIXUP_PSW_NORMAL) |
| ip += (unsigned long) p->addr - (unsigned long) p->ainsn.insn; |
| |
| if (fixup & FIXUP_BRANCH_NOT_TAKEN) { |
| int ilen = insn_length(p->ainsn.insn[0] >> 8); |
| if (ip - (unsigned long) p->ainsn.insn == ilen) |
| ip = (unsigned long) p->addr + ilen; |
| } |
| |
| if (fixup & FIXUP_RETURN_REGISTER) { |
| int reg = (p->ainsn.insn[0] & 0xf0) >> 4; |
| regs->gprs[reg] += (unsigned long) p->addr - |
| (unsigned long) p->ainsn.insn; |
| } |
| |
| disable_singlestep(kcb, regs, ip); |
| } |
| NOKPROBE_SYMBOL(resume_execution); |
| |
| static int post_kprobe_handler(struct pt_regs *regs) |
| { |
| struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
| struct kprobe *p = kprobe_running(); |
| |
| if (!p) |
| return 0; |
| |
| if (kcb->kprobe_status != KPROBE_REENTER && p->post_handler) { |
| kcb->kprobe_status = KPROBE_HIT_SSDONE; |
| p->post_handler(p, regs, 0); |
| } |
| |
| resume_execution(p, regs); |
| pop_kprobe(kcb); |
| preempt_enable_no_resched(); |
| |
| /* |
| * if somebody else is singlestepping across a probe point, psw mask |
| * will have PER set, in which case, continue the remaining processing |
| * of do_single_step, as if this is not a probe hit. |
| */ |
| if (regs->psw.mask & PSW_MASK_PER) |
| return 0; |
| |
| return 1; |
| } |
| NOKPROBE_SYMBOL(post_kprobe_handler); |
| |
| static int kprobe_trap_handler(struct pt_regs *regs, int trapnr) |
| { |
| struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
| struct kprobe *p = kprobe_running(); |
| const struct exception_table_entry *entry; |
| |
| switch(kcb->kprobe_status) { |
| case KPROBE_SWAP_INST: |
| /* We are here because the instruction replacement failed */ |
| return 0; |
| 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 nip points back to the probe address |
| * and allow the page fault handler to continue as a |
| * normal page fault. |
| */ |
| disable_singlestep(kcb, regs, (unsigned long) p->addr); |
| pop_kprobe(kcb); |
| preempt_enable_no_resched(); |
| break; |
| case KPROBE_HIT_ACTIVE: |
| case KPROBE_HIT_SSDONE: |
| /* |
| * We increment the nmissed count for accounting, |
| * we can also use npre/npostfault count for accounting |
| * these specific fault cases. |
| */ |
| kprobes_inc_nmissed_count(p); |
| |
| /* |
| * We come here because instructions in the pre/post |
| * handler caused the page_fault, this could happen |
| * if handler tries to access user space by |
| * copy_from_user(), get_user() etc. Let the |
| * user-specified handler try to fix it first. |
| */ |
| if (p->fault_handler && p->fault_handler(p, regs, trapnr)) |
| return 1; |
| |
| /* |
| * In case the user-specified fault handler returned |
| * zero, try to fix up. |
| */ |
| entry = search_exception_tables(regs->psw.addr); |
| if (entry) { |
| regs->psw.addr = extable_fixup(entry); |
| return 1; |
| } |
| |
| /* |
| * fixup_exception() could not handle it, |
| * Let do_page_fault() fix it. |
| */ |
| break; |
| default: |
| break; |
| } |
| return 0; |
| } |
| NOKPROBE_SYMBOL(kprobe_trap_handler); |
| |
| int kprobe_fault_handler(struct pt_regs *regs, int trapnr) |
| { |
| int ret; |
| |
| if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT)) |
| local_irq_disable(); |
| ret = kprobe_trap_handler(regs, trapnr); |
| if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT)) |
| local_irq_restore(regs->psw.mask & ~PSW_MASK_PER); |
| return ret; |
| } |
| NOKPROBE_SYMBOL(kprobe_fault_handler); |
| |
| /* |
| * 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; |
| struct pt_regs *regs = args->regs; |
| int ret = NOTIFY_DONE; |
| |
| if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT)) |
| local_irq_disable(); |
| |
| switch (val) { |
| case DIE_BPT: |
| if (kprobe_handler(regs)) |
| ret = NOTIFY_STOP; |
| break; |
| case DIE_SSTEP: |
| if (post_kprobe_handler(regs)) |
| ret = NOTIFY_STOP; |
| break; |
| case DIE_TRAP: |
| if (!preemptible() && kprobe_running() && |
| kprobe_trap_handler(regs, args->trapnr)) |
| ret = NOTIFY_STOP; |
| break; |
| default: |
| break; |
| } |
| |
| if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT)) |
| local_irq_restore(regs->psw.mask & ~PSW_MASK_PER); |
| |
| return ret; |
| } |
| NOKPROBE_SYMBOL(kprobe_exceptions_notify); |
| |
| int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) |
| { |
| struct jprobe *jp = container_of(p, struct jprobe, kp); |
| struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
| unsigned long stack; |
| |
| memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs)); |
| |
| /* setup return addr to the jprobe handler routine */ |
| regs->psw.addr = (unsigned long) jp->entry; |
| regs->psw.mask &= ~(PSW_MASK_IO | PSW_MASK_EXT); |
| |
| /* r15 is the stack pointer */ |
| stack = (unsigned long) regs->gprs[15]; |
| |
| memcpy(kcb->jprobes_stack, (void *) stack, MIN_STACK_SIZE(stack)); |
| |
| /* |
| * jprobes use jprobe_return() which skips the normal return |
| * path of the function, and this messes up the accounting of the |
| * function graph tracer to get messed up. |
| * |
| * Pause function graph tracing while performing the jprobe function. |
| */ |
| pause_graph_tracing(); |
| return 1; |
| } |
| NOKPROBE_SYMBOL(setjmp_pre_handler); |
| |
| void jprobe_return(void) |
| { |
| asm volatile(".word 0x0002"); |
| } |
| NOKPROBE_SYMBOL(jprobe_return); |
| |
| int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) |
| { |
| struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
| unsigned long stack; |
| |
| /* It's OK to start function graph tracing again */ |
| unpause_graph_tracing(); |
| |
| stack = (unsigned long) kcb->jprobe_saved_regs.gprs[15]; |
| |
| /* Put the regs back */ |
| memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs)); |
| /* put the stack back */ |
| memcpy((void *) stack, kcb->jprobes_stack, MIN_STACK_SIZE(stack)); |
| preempt_enable_no_resched(); |
| return 1; |
| } |
| NOKPROBE_SYMBOL(longjmp_break_handler); |
| |
| static struct kprobe trampoline = { |
| .addr = (kprobe_opcode_t *) &kretprobe_trampoline, |
| .pre_handler = trampoline_probe_handler |
| }; |
| |
| int __init arch_init_kprobes(void) |
| { |
| return register_kprobe(&trampoline); |
| } |
| |
| int arch_trampoline_kprobe(struct kprobe *p) |
| { |
| return p->addr == (kprobe_opcode_t *) &kretprobe_trampoline; |
| } |
| NOKPROBE_SYMBOL(arch_trampoline_kprobe); |