diff options
Diffstat (limited to 'arch/x86/kernel/kprobes_64.c')
| -rw-r--r-- | arch/x86/kernel/kprobes_64.c | 749 |
1 files changed, 0 insertions, 749 deletions
diff --git a/arch/x86/kernel/kprobes_64.c b/arch/x86/kernel/kprobes_64.c deleted file mode 100644 index 5df19a9f9239..000000000000 --- a/arch/x86/kernel/kprobes_64.c +++ /dev/null @@ -1,749 +0,0 @@ -/* - * 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 (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-Oct Jim Keniston <kenistoj@us.ibm.com> and Prasanna S Panchamukhi - * <prasanna@in.ibm.com> adapted for x86_64 - * 2005-Mar Roland McGrath <roland@redhat.com> - * Fixed to handle %rip-relative addressing mode correctly. - * 2005-May Rusty Lynch <rusty.lynch@intel.com> - * Added function return probes functionality - */ - -#include <linux/kprobes.h> -#include <linux/ptrace.h> -#include <linux/string.h> -#include <linux/slab.h> -#include <linux/preempt.h> -#include <linux/module.h> -#include <linux/kdebug.h> - -#include <asm/pgtable.h> -#include <asm/uaccess.h> -#include <asm/alternative.h> - -void jprobe_return_end(void); -static void __kprobes arch_copy_kprobe(struct kprobe *p); - -DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; -DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); - -struct kretprobe_blackpoint kretprobe_blacklist[] = { - {"__switch_to", }, /* This function switches only current task, but - doesn't switch kernel stack.*/ - {NULL, NULL} /* Terminator */ -}; -const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist); - -/* - * returns non-zero if opcode modifies the interrupt flag. - */ -static int __kprobes is_IF_modifier(kprobe_opcode_t *insn) -{ - switch (*insn) { - case 0xfa: /* cli */ - case 0xfb: /* sti */ - case 0xcf: /* iret/iretd */ - case 0x9d: /* popf/popfd */ - return 1; - } - - if (*insn >= 0x40 && *insn <= 0x4f && *++insn == 0xcf) - return 1; - return 0; -} - -int __kprobes arch_prepare_kprobe(struct kprobe *p) -{ - /* insn: must be on special executable page on x86_64. */ - p->ainsn.insn = get_insn_slot(); - if (!p->ainsn.insn) { - return -ENOMEM; - } - arch_copy_kprobe(p); - return 0; -} - -/* - * Determine if the instruction uses the %rip-relative addressing mode. - * If it does, return the address of the 32-bit displacement word. - * If not, return null. - */ -static s32 __kprobes *is_riprel(u8 *insn) -{ -#define W(row,b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,ba,bb,bc,bd,be,bf) \ - (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \ - (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \ - (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \ - (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \ - << (row % 64)) - static const u64 onebyte_has_modrm[256 / 64] = { - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ - /* ------------------------------- */ - W(0x00, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 00 */ - W(0x10, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 10 */ - W(0x20, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 20 */ - W(0x30, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0), /* 30 */ - W(0x40, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 40 */ - W(0x50, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 50 */ - W(0x60, 0,0,1,1,0,0,0,0,0,1,0,1,0,0,0,0)| /* 60 */ - W(0x70, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 70 */ - W(0x80, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 80 */ - W(0x90, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 90 */ - W(0xa0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* a0 */ - W(0xb0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* b0 */ - W(0xc0, 1,1,0,0,1,1,1,1,0,0,0,0,0,0,0,0)| /* c0 */ - W(0xd0, 1,1,1,1,0,0,0,0,1,1,1,1,1,1,1,1)| /* d0 */ - W(0xe0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* e0 */ - W(0xf0, 0,0,0,0,0,0,1,1,0,0,0,0,0,0,1,1) /* f0 */ - /* ------------------------------- */ - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ - }; - static const u64 twobyte_has_modrm[256 / 64] = { - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ - /* ------------------------------- */ - W(0x00, 1,1,1,1,0,0,0,0,0,0,0,0,0,1,0,1)| /* 0f */ - W(0x10, 1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0)| /* 1f */ - W(0x20, 1,1,1,1,1,0,1,0,1,1,1,1,1,1,1,1)| /* 2f */ - W(0x30, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 3f */ - W(0x40, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 4f */ - W(0x50, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 5f */ - W(0x60, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 6f */ - W(0x70, 1,1,1,1,1,1,1,0,0,0,0,0,1,1,1,1), /* 7f */ - W(0x80, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 8f */ - W(0x90, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 9f */ - W(0xa0, 0,0,0,1,1,1,1,1,0,0,0,1,1,1,1,1)| /* af */ - W(0xb0, 1,1,1,1,1,1,1,1,0,0,1,1,1,1,1,1), /* bf */ - W(0xc0, 1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0)| /* cf */ - W(0xd0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* df */ - W(0xe0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* ef */ - W(0xf0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0) /* ff */ - /* ------------------------------- */ - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ - }; -#undef W - int need_modrm; - - /* Skip legacy instruction prefixes. */ - while (1) { - switch (*insn) { - case 0x66: - case 0x67: - case 0x2e: - case 0x3e: - case 0x26: - case 0x64: - case 0x65: - case 0x36: - case 0xf0: - case 0xf3: - case 0xf2: - ++insn; - continue; - } - break; - } - - /* Skip REX instruction prefix. */ - if ((*insn & 0xf0) == 0x40) - ++insn; - - if (*insn == 0x0f) { /* Two-byte opcode. */ - ++insn; - need_modrm = test_bit(*insn, twobyte_has_modrm); - } else { /* One-byte opcode. */ - need_modrm = test_bit(*insn, onebyte_has_modrm); - } - - if (need_modrm) { - u8 modrm = *++insn; - if ((modrm & 0xc7) == 0x05) { /* %rip+disp32 addressing mode */ - /* Displacement follows ModRM byte. */ - return (s32 *) ++insn; - } - } - - /* No %rip-relative addressing mode here. */ - return NULL; -} - -static void __kprobes arch_copy_kprobe(struct kprobe *p) -{ - s32 *ripdisp; - memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE); - ripdisp = is_riprel(p->ainsn.insn); - if (ripdisp) { - /* - * The copied instruction uses the %rip-relative - * addressing mode. Adjust the displacement for the - * difference between the original location of this - * instruction and the location of the copy that will - * actually be run. The tricky bit here is making sure - * that the sign extension happens correctly in this - * calculation, since we need a signed 32-bit result to - * be sign-extended to 64 bits when it's added to the - * %rip value and yield the same 64-bit result that the - * sign-extension of the original signed 32-bit - * displacement would have given. - */ - s64 disp = (u8 *) p->addr + *ripdisp - (u8 *) p->ainsn.insn; - BUG_ON((s64) (s32) disp != disp); /* Sanity check. */ - *ripdisp = disp; - } - p->opcode = *p->addr; -} - -void __kprobes arch_arm_kprobe(struct kprobe *p) -{ - text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1); -} - -void __kprobes arch_disarm_kprobe(struct kprobe *p) -{ - text_poke(p->addr, &p->opcode, 1); -} - -void __kprobes arch_remove_kprobe(struct kprobe *p) -{ - mutex_lock(&kprobe_mutex); - free_insn_slot(p->ainsn.insn, 0); - mutex_unlock(&kprobe_mutex); -} - -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.old_rflags = kcb->kprobe_old_rflags; - kcb->prev_kprobe.saved_rflags = kcb->kprobe_saved_rflags; -} - -static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) -{ - __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp; - kcb->kprobe_status = kcb->prev_kprobe.status; - kcb->kprobe_old_rflags = kcb->prev_kprobe.old_rflags; - kcb->kprobe_saved_rflags = kcb->prev_kprobe.saved_rflags; -} - -static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, - struct kprobe_ctlblk *kcb) -{ - __get_cpu_var(current_kprobe) = p; - kcb->kprobe_saved_rflags = kcb->kprobe_old_rflags - = (regs->eflags & (TF_MASK | IF_MASK)); - if (is_IF_modifier(p->ainsn.insn)) - kcb->kprobe_saved_rflags &= ~IF_MASK; -} - -static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) -{ - regs->eflags |= TF_MASK; - regs->eflags &= ~IF_MASK; - /*single step inline if the instruction is an int3*/ - if (p->opcode == BREAKPOINT_INSTRUCTION) - regs->rip = (unsigned long)p->addr; - else - regs->rip = (unsigned long)p->ainsn.insn; -} - -/* Called with kretprobe_lock held */ -void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, - struct pt_regs *regs) -{ - unsigned long *sara = (unsigned long *)regs->rsp; - - ri->ret_addr = (kprobe_opcode_t *) *sara; - /* Replace the return addr with trampoline addr */ - *sara = (unsigned long) &kretprobe_trampoline; -} - -int __kprobes kprobe_handler(struct pt_regs *regs) -{ - struct kprobe *p; - int ret = 0; - kprobe_opcode_t *addr = (kprobe_opcode_t *)(regs->rip - sizeof(kprobe_opcode_t)); - struct kprobe_ctlblk *kcb; - - /* - * 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 == BREAKPOINT_INSTRUCTION) { - regs->eflags &= ~TF_MASK; - regs->eflags |= kcb->kprobe_saved_rflags; - goto no_kprobe; - } else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) { - /* TODO: Provide re-entrancy from - * post_kprobes_handler() and avoid exception - * stack corruption while single-stepping on - * the instruction of the new probe. - */ - arch_disarm_kprobe(p); - regs->rip = (unsigned long)p->addr; - reset_current_kprobe(); - ret = 1; - } else { - /* We have reentered the kprobe_handler(), since - * another probe was hit while within the - * handler. We here save the original kprobe - * variables and just single step on 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_INSTRUCTION) { - /* The breakpoint instruction was removed by - * another cpu right after we hit, no further - * handling of this interrupt is appropriate - */ - regs->rip = (unsigned long)addr; - ret = 1; - goto no_kprobe; - } - p = __get_cpu_var(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_INSTRUCTION) { - /* - * 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. - * Back up over the (now missing) int3 and run - * the original instruction. - */ - regs->rip = (unsigned long)addr; - 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; -} - -/* - * For function-return probes, init_kprobes() establishes a probepoint - * here. When a retprobed function returns, this probe is hit and - * trampoline_probe_handler() runs, calling the kretprobe's handler. - */ - void kretprobe_trampoline_holder(void) - { - asm volatile ( ".global kretprobe_trampoline\n" - "kretprobe_trampoline: \n" - "nop\n"); - } - -/* - * Called when we hit the probe point at kretprobe_trampoline - */ -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 *node, *tmp; - unsigned long flags, orig_ret_address = 0; - unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline; - - INIT_HLIST_HEAD(&empty_rp); - spin_lock_irqsave(&kretprobe_lock, flags); - head = kretprobe_inst_table_head(current); - - /* - * 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 then 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, node, 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); - regs->rip = orig_ret_address; - - reset_current_kprobe(); - spin_unlock_irqrestore(&kretprobe_lock, flags); - preempt_enable_no_resched(); - - hlist_for_each_entry_safe(ri, node, 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; -} - -/* - * Called after single-stepping. p->addr is the address of the - * instruction whose first byte has been replaced by the "int 3" - * 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. - * - * This function prepares to return from the post-single-step - * interrupt. We have to fix up the stack as follows: - * - * 0) Except in the case of absolute or indirect jump or call instructions, - * the new rip is relative to the copied instruction. We need to make - * it relative to the original instruction. - * - * 1) If the single-stepped instruction was pushfl, then the TF and IF - * flags are set in the just-pushed eflags, and may need to be cleared. - * - * 2) If the single-stepped instruction was a call, the return address - * that is atop the stack is the address following the copied instruction. - * We need to make it the address following the original instruction. - */ -static void __kprobes resume_execution(struct kprobe *p, - struct pt_regs *regs, struct kprobe_ctlblk *kcb) -{ - unsigned long *tos = (unsigned long *)regs->rsp; - unsigned long copy_rip = (unsigned long)p->ainsn.insn; - unsigned long orig_rip = (unsigned long)p->addr; - kprobe_opcode_t *insn = p->ainsn.insn; - - /*skip the REX prefix*/ - if (*insn >= 0x40 && *insn <= 0x4f) - insn++; - - regs->eflags &= ~TF_MASK; - switch (*insn) { - case 0x9c: /* pushfl */ - *tos &= ~(TF_MASK | IF_MASK); - *tos |= kcb->kprobe_old_rflags; - break; - case 0xc2: /* iret/ret/lret */ - case 0xc3: - case 0xca: - case 0xcb: - case 0xcf: - case 0xea: /* jmp absolute -- ip is correct */ - /* ip is already adjusted, no more changes required */ - goto no_change; - case 0xe8: /* call relative - Fix return addr */ - *tos = orig_rip + (*tos - copy_rip); - break; - case 0xff: - if ((insn[1] & 0x30) == 0x10) { - /* call absolute, indirect */ - /* Fix return addr; ip is correct. */ - *tos = orig_rip + (*tos - copy_rip); - goto no_change; - } else if (((insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */ - ((insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */ - /* ip is correct. */ - goto no_change; - } - default: - break; - } - - regs->rip = orig_rip + (regs->rip - copy_rip); -no_change: - - return; -} - -int __kprobes 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); - regs->eflags |= kcb->kprobe_saved_rflags; - trace_hardirqs_fixup_flags(regs->eflags); - - /* Restore 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(); - - /* - * if somebody else is singlestepping across a probe point, eflags - * will have TF set, in which case, continue the remaining processing - * of do_debug, as if this is not a probe hit. - */ - if (regs->eflags & TF_MASK) - return 0; - - 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(); - const struct exception_table_entry *fixup; - - 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 rip points back to the probe address - * and allow the page fault handler to continue as a - * normal page fault. - */ - regs->rip = (unsigned long)cur->addr; - regs->eflags |= kcb->kprobe_old_rflags; - 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: - /* - * We increment the nmissed count for accounting, - * we can also use npre/npostfault count for accouting - * these specific fault cases. - */ - kprobes_inc_nmissed_count(cur); - - /* - * 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 (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) - return 1; - - /* - * In case the user-specified fault handler returned - * zero, try to fix up. - */ - fixup = search_exception_tables(regs->rip); - if (fixup) { - regs->rip = fixup->fixup; - return 1; - } - - /* - * fixup() could not handle it, - * Let do_page_fault() fix it. - */ - break; - default: - break; - } - 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; - - if (args->regs && user_mode(args->regs)) - return ret; - - switch (val) { - case DIE_INT3: - if (kprobe_handler(args->regs)) - ret = NOTIFY_STOP; - break; - case DIE_DEBUG: - if (post_kprobe_handler(args->regs)) - ret = NOTIFY_STOP; - break; - case DIE_GPF: - /* 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); - unsigned long addr; - struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - - kcb->jprobe_saved_regs = *regs; - kcb->jprobe_saved_rsp = (long *) regs->rsp; - addr = (unsigned long)(kcb->jprobe_saved_rsp); - /* - * As Linus pointed out, gcc assumes that the callee - * owns the argument space and could overwrite it, e.g. - * tailcall optimization. So, to be absolutely safe - * we also save and restore enough stack bytes to cover - * the argument area. - */ - memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr, - MIN_STACK_SIZE(addr)); - regs->eflags &= ~IF_MASK; - trace_hardirqs_off(); - regs->rip = (unsigned long)(jp->entry); - return 1; -} - -void __kprobes jprobe_return(void) -{ - struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - - asm volatile (" xchg %%rbx,%%rsp \n" - " int3 \n" - " .globl jprobe_return_end \n" - " jprobe_return_end: \n" - " nop \n"::"b" - (kcb->jprobe_saved_rsp):"memory"); -} - -int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) -{ - struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - u8 *addr = (u8 *) (regs->rip - 1); - unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_rsp); - struct jprobe *jp = container_of(p, struct jprobe, kp); - - if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) { - if ((unsigned long *)regs->rsp != kcb->jprobe_saved_rsp) { - struct pt_regs *saved_regs = &kcb->jprobe_saved_regs; - printk("current rsp %p does not match saved rsp %p\n", - (long *)regs->rsp, kcb->jprobe_saved_rsp); - printk("Saved registers for jprobe %p\n", jp); - show_registers(saved_regs); - printk("Current registers\n"); - show_registers(regs); - BUG(); - } - *regs = kcb->jprobe_saved_regs; - memcpy((kprobe_opcode_t *) stack_addr, kcb->jprobes_stack, - MIN_STACK_SIZE(stack_addr)); - preempt_enable_no_resched(); - 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) -{ - return register_kprobe(&trampoline_p); -} - -int __kprobes arch_trampoline_kprobe(struct kprobe *p) -{ - if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline) - return 1; - - return 0; -} |