diff options
Diffstat (limited to 'arch/tile/kernel/kprobes.c')
-rw-r--r-- | arch/tile/kernel/kprobes.c | 527 |
1 files changed, 0 insertions, 527 deletions
diff --git a/arch/tile/kernel/kprobes.c b/arch/tile/kernel/kprobes.c deleted file mode 100644 index c68694bb1ad2..000000000000 --- a/arch/tile/kernel/kprobes.c +++ /dev/null @@ -1,527 +0,0 @@ -/* - * arch/tile/kernel/kprobes.c - * Kprobes on TILE-Gx - * - * Some portions copied from the MIPS version. - * - * Copyright (C) IBM Corporation, 2002, 2004 - * Copyright 2006 Sony Corp. - * Copyright 2010 Cavium Networks - * - * Copyright 2012 Tilera Corporation. All Rights Reserved. - * - * 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, version 2. - * - * 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, GOOD TITLE or - * NON INFRINGEMENT. See the GNU General Public License for - * more details. - */ - -#include <linux/kprobes.h> -#include <linux/kdebug.h> -#include <linux/module.h> -#include <linux/slab.h> -#include <linux/uaccess.h> -#include <asm/cacheflush.h> - -#include <arch/opcode.h> - -DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; -DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); - -tile_bundle_bits breakpoint_insn = TILEGX_BPT_BUNDLE; -tile_bundle_bits breakpoint2_insn = TILEGX_BPT_BUNDLE | DIE_SSTEPBP; - -/* - * Check whether instruction is branch or jump, or if executing it - * has different results depending on where it is executed (e.g. lnk). - */ -static int __kprobes insn_has_control(kprobe_opcode_t insn) -{ - if (get_Mode(insn) != 0) { /* Y-format bundle */ - if (get_Opcode_Y1(insn) != RRR_1_OPCODE_Y1 || - get_RRROpcodeExtension_Y1(insn) != UNARY_RRR_1_OPCODE_Y1) - return 0; - - switch (get_UnaryOpcodeExtension_Y1(insn)) { - case JALRP_UNARY_OPCODE_Y1: - case JALR_UNARY_OPCODE_Y1: - case JRP_UNARY_OPCODE_Y1: - case JR_UNARY_OPCODE_Y1: - case LNK_UNARY_OPCODE_Y1: - return 1; - default: - return 0; - } - } - - switch (get_Opcode_X1(insn)) { - case BRANCH_OPCODE_X1: /* branch instructions */ - case JUMP_OPCODE_X1: /* jump instructions: j and jal */ - return 1; - - case RRR_0_OPCODE_X1: /* other jump instructions */ - if (get_RRROpcodeExtension_X1(insn) != UNARY_RRR_0_OPCODE_X1) - return 0; - switch (get_UnaryOpcodeExtension_X1(insn)) { - case JALRP_UNARY_OPCODE_X1: - case JALR_UNARY_OPCODE_X1: - case JRP_UNARY_OPCODE_X1: - case JR_UNARY_OPCODE_X1: - case LNK_UNARY_OPCODE_X1: - return 1; - default: - return 0; - } - default: - return 0; - } -} - -int __kprobes arch_prepare_kprobe(struct kprobe *p) -{ - unsigned long addr = (unsigned long)p->addr; - - if (addr & (sizeof(kprobe_opcode_t) - 1)) - return -EINVAL; - - if (insn_has_control(*p->addr)) { - pr_notice("Kprobes for control instructions are not supported\n"); - return -EINVAL; - } - - /* insn: must be on special executable page on tile. */ - p->ainsn.insn = get_insn_slot(); - if (!p->ainsn.insn) - return -ENOMEM; - - /* - * In the kprobe->ainsn.insn[] array we store the original - * instruction at index zero and a break trap instruction at - * index one. - */ - memcpy(&p->ainsn.insn[0], p->addr, sizeof(kprobe_opcode_t)); - p->ainsn.insn[1] = breakpoint2_insn; - p->opcode = *p->addr; - - return 0; -} - -void __kprobes arch_arm_kprobe(struct kprobe *p) -{ - unsigned long addr_wr; - - /* Operate on writable kernel text mapping. */ - addr_wr = ktext_writable_addr(p->addr); - - if (probe_kernel_write((void *)addr_wr, &breakpoint_insn, - sizeof(breakpoint_insn))) - pr_err("%s: failed to enable kprobe\n", __func__); - - smp_wmb(); - flush_insn_slot(p); -} - -void __kprobes arch_disarm_kprobe(struct kprobe *kp) -{ - unsigned long addr_wr; - - /* Operate on writable kernel text mapping. */ - addr_wr = ktext_writable_addr(kp->addr); - - if (probe_kernel_write((void *)addr_wr, &kp->opcode, - sizeof(kp->opcode))) - pr_err("%s: failed to enable kprobe\n", __func__); - - smp_wmb(); - flush_insn_slot(kp); -} - -void __kprobes arch_remove_kprobe(struct kprobe *p) -{ - if (p->ainsn.insn) { - free_insn_slot(p->ainsn.insn, 0); - p->ainsn.insn = NULL; - } -} - -static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) -{ - kcb->prev_kprobe.kp = kprobe_running(); - kcb->prev_kprobe.status = kcb->kprobe_status; - kcb->prev_kprobe.saved_pc = kcb->kprobe_saved_pc; -} - -static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) -{ - __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp); - kcb->kprobe_status = kcb->prev_kprobe.status; - kcb->kprobe_saved_pc = kcb->prev_kprobe.saved_pc; -} - -static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, - struct kprobe_ctlblk *kcb) -{ - __this_cpu_write(current_kprobe, p); - kcb->kprobe_saved_pc = regs->pc; -} - -static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) -{ - /* Single step inline if the instruction is a break. */ - if (p->opcode == breakpoint_insn || - p->opcode == breakpoint2_insn) - regs->pc = (unsigned long)p->addr; - else - regs->pc = (unsigned long)&p->ainsn.insn[0]; -} - -static int __kprobes kprobe_handler(struct pt_regs *regs) -{ - struct kprobe *p; - int ret = 0; - kprobe_opcode_t *addr; - struct kprobe_ctlblk *kcb; - - addr = (kprobe_opcode_t *)regs->pc; - - /* - * We don't want to be preempted for the entire - * duration of kprobe processing. - */ - preempt_disable(); - kcb = get_kprobe_ctlblk(); - - /* Check we're not actually recursing. */ - if (kprobe_running()) { - p = get_kprobe(addr); - if (p) { - if (kcb->kprobe_status == KPROBE_HIT_SS && - p->ainsn.insn[0] == breakpoint_insn) { - goto no_kprobe; - } - /* - * We have reentered the 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, regs, kcb); - kprobes_inc_nmissed_count(p); - prepare_singlestep(p, regs); - kcb->kprobe_status = KPROBE_REENTER; - return 1; - } else { - if (*addr != breakpoint_insn) { - /* - * 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; - } - p = __this_cpu_read(current_kprobe); - if (p->break_handler && p->break_handler(p, regs)) - goto ss_probe; - } - goto no_kprobe; - } - - p = get_kprobe(addr); - if (!p) { - if (*addr != breakpoint_insn) { - /* - * 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; - } - - set_current_kprobe(p, regs, kcb); - kcb->kprobe_status = KPROBE_HIT_ACTIVE; - - 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); - kcb->kprobe_status = KPROBE_HIT_SS; - return 1; - -no_kprobe: - preempt_enable_no_resched(); - return ret; -} - -/* - * Called after single-stepping. p->addr is the address of the - * instruction that has been replaced by the breakpoint. 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. - * - * This function prepares to return from the post-single-step - * breakpoint trap. - */ -static void __kprobes resume_execution(struct kprobe *p, - struct pt_regs *regs, - struct kprobe_ctlblk *kcb) -{ - unsigned long orig_pc = kcb->kprobe_saved_pc; - regs->pc = orig_pc + 8; -} - -static inline int post_kprobe_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, kcb); - - /* 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; -} - -static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr) -{ - struct kprobe *cur = kprobe_running(); - struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - - if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) - return 1; - - if (kcb->kprobe_status & KPROBE_HIT_SS) { - /* - * We are here because the instruction being single - * stepped caused a page fault. We reset the current - * kprobe and the ip points back to the probe address - * and allow the page fault handler to continue as a - * normal page fault. - */ - resume_execution(cur, regs, kcb); - reset_current_kprobe(); - preempt_enable_no_resched(); - } - return 0; -} - -/* - * Wrapper routine 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; - - switch (val) { - case DIE_BREAK: - if (kprobe_handler(args->regs)) - ret = NOTIFY_STOP; - break; - case DIE_SSTEPBP: - if (post_kprobe_handler(args->regs)) - ret = NOTIFY_STOP; - break; - case DIE_PAGE_FAULT: - /* kprobe_running() needs smp_processor_id(). */ - preempt_disable(); - - if (kprobe_running() - && kprobe_fault_handler(args->regs, args->trapnr)) - ret = NOTIFY_STOP; - preempt_enable(); - 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); - struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - - kcb->jprobe_saved_regs = *regs; - kcb->jprobe_saved_sp = regs->sp; - - memcpy(kcb->jprobes_stack, (void *)kcb->jprobe_saved_sp, - MIN_JPROBES_STACK_SIZE(kcb->jprobe_saved_sp)); - - regs->pc = (unsigned long)(jp->entry); - - return 1; -} - -/* Defined in the inline asm below. */ -void jprobe_return_end(void); - -void __kprobes jprobe_return(void) -{ - asm volatile( - "bpt\n\t" - ".globl jprobe_return_end\n" - "jprobe_return_end:\n"); -} - -int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) -{ - struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - - if (regs->pc >= (unsigned long)jprobe_return && - regs->pc <= (unsigned long)jprobe_return_end) { - *regs = kcb->jprobe_saved_regs; - memcpy((void *)kcb->jprobe_saved_sp, kcb->jprobes_stack, - MIN_JPROBES_STACK_SIZE(kcb->jprobe_saved_sp)); - preempt_enable_no_resched(); - - return 1; - } - return 0; -} - -/* - * 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( - "nop\n\t" - ".global kretprobe_trampoline\n" - "kretprobe_trampoline:\n\t" - "nop\n\t" - : : : "memory"); -} - -void kretprobe_trampoline(void); - -void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, - struct pt_regs *regs) -{ - ri->ret_addr = (kprobe_opcode_t *) regs->lr; - - /* Replace the return addr with trampoline addr */ - regs->lr = (unsigned long)kretprobe_trampoline; -} - -/* - * Called when the probe at kretprobe trampoline is hit. - */ -static int __kprobes trampoline_probe_handler(struct kprobe *p, - struct pt_regs *regs) -{ - struct kretprobe_instance *ri = NULL; - struct hlist_head *head, empty_rp; - struct hlist_node *tmp; - unsigned long flags, orig_ret_address = 0; - unsigned long trampoline_address = (unsigned long)kretprobe_trampoline; - - 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 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 - */ - hlist_for_each_entry_safe(ri, tmp, head, hlist) { - if (ri->task != current) - /* another task is sharing our hash bucket */ - continue; - - if (ri->rp && ri->rp->handler) - ri->rp->handler(ri, regs); - - orig_ret_address = (unsigned long)ri->ret_addr; - 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; - } - } - - kretprobe_assert(ri, orig_ret_address, trampoline_address); - instruction_pointer(regs) = orig_ret_address; - - reset_current_kprobe(); - 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; -} - -int __kprobes arch_trampoline_kprobe(struct kprobe *p) -{ - if (p->addr == (kprobe_opcode_t *)kretprobe_trampoline) - return 1; - - return 0; -} - -static struct kprobe trampoline_p = { - .addr = (kprobe_opcode_t *)kretprobe_trampoline, - .pre_handler = trampoline_probe_handler -}; - -int __init arch_init_kprobes(void) -{ - register_kprobe(&trampoline_p); - return 0; -} |