diff options
Diffstat (limited to 'arch/x86/kernel/kprobes_32.c')
| -rw-r--r-- | arch/x86/kernel/kprobes_32.c | 756 |
1 files changed, 0 insertions, 756 deletions
diff --git a/arch/x86/kernel/kprobes_32.c b/arch/x86/kernel/kprobes_32.c deleted file mode 100644 index 3a020f79f82..00000000000 --- a/arch/x86/kernel/kprobes_32.c +++ /dev/null @@ -1,756 +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. - * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston - * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi - * <prasanna@in.ibm.com> added function-return probes. - */ - -#include <linux/kprobes.h> -#include <linux/ptrace.h> -#include <linux/preempt.h> -#include <linux/kdebug.h> -#include <asm/cacheflush.h> -#include <asm/desc.h> -#include <asm/uaccess.h> -#include <asm/alternative.h> - -void jprobe_return_end(void); - -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); - -/* insert a jmp code */ -static __always_inline void set_jmp_op(void *from, void *to) -{ - struct __arch_jmp_op { - char op; - long raddr; - } __attribute__((packed)) *jop; - jop = (struct __arch_jmp_op *)from; - jop->raddr = (long)(to) - ((long)(from) + 5); - jop->op = RELATIVEJUMP_INSTRUCTION; -} - -/* - * returns non-zero if opcodes can be boosted. - */ -static __always_inline int can_boost(kprobe_opcode_t *opcodes) -{ -#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 % 32)) - /* - * Undefined/reserved opcodes, conditional jump, Opcode Extension - * Groups, and some special opcodes can not be boost. - */ - static const unsigned long twobyte_is_boostable[256 / 32] = { - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ - /* ------------------------------- */ - W(0x00, 0,0,1,1,0,0,1,0,1,1,0,0,0,0,0,0)| /* 00 */ - W(0x10, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 10 */ - W(0x20, 1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0)| /* 20 */ - W(0x30, 0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 30 */ - W(0x40, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 40 */ - W(0x50, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 50 */ - W(0x60, 1,1,1,1,1,1,1,1,1,1,1,1,0,0,1,1)| /* 60 */ - W(0x70, 0,0,0,0,1,1,1,1,0,0,0,0,0,0,1,1), /* 70 */ - W(0x80, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 80 */ - W(0x90, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1), /* 90 */ - W(0xa0, 1,1,0,1,1,1,0,0,1,1,0,1,1,1,0,1)| /* a0 */ - W(0xb0, 1,1,1,1,1,1,1,1,0,0,0,1,1,1,1,1), /* b0 */ - W(0xc0, 1,1,0,0,0,0,0,0,1,1,1,1,1,1,1,1)| /* c0 */ - W(0xd0, 0,1,1,1,0,1,0,0,1,1,0,1,1,1,0,1), /* d0 */ - W(0xe0, 0,1,1,0,0,1,0,0,1,1,0,1,1,1,0,1)| /* e0 */ - W(0xf0, 0,1,1,1,0,1,0,0,1,1,1,0,1,1,1,0) /* f0 */ - /* ------------------------------- */ - /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */ - }; -#undef W - kprobe_opcode_t opcode; - kprobe_opcode_t *orig_opcodes = opcodes; -retry: - if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1) - return 0; - opcode = *(opcodes++); - - /* 2nd-byte opcode */ - if (opcode == 0x0f) { - if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1) - return 0; - return test_bit(*opcodes, twobyte_is_boostable); - } - - switch (opcode & 0xf0) { - case 0x60: - if (0x63 < opcode && opcode < 0x67) - goto retry; /* prefixes */ - /* can't boost Address-size override and bound */ - return (opcode != 0x62 && opcode != 0x67); - case 0x70: - return 0; /* can't boost conditional jump */ - case 0xc0: - /* can't boost software-interruptions */ - return (0xc1 < opcode && opcode < 0xcc) || opcode == 0xcf; - case 0xd0: - /* can boost AA* and XLAT */ - return (opcode == 0xd4 || opcode == 0xd5 || opcode == 0xd7); - case 0xe0: - /* can boost in/out and absolute jmps */ - return ((opcode & 0x04) || opcode == 0xea); - case 0xf0: - if ((opcode & 0x0c) == 0 && opcode != 0xf1) - goto retry; /* lock/rep(ne) prefix */ - /* clear and set flags can be boost */ - return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe)); - default: - if (opcode == 0x26 || opcode == 0x36 || opcode == 0x3e) - goto retry; /* prefixes */ - /* can't boost CS override and call */ - return (opcode != 0x2e && opcode != 0x9a); - } -} - -/* - * returns non-zero if opcode modifies the interrupt flag. - */ -static int __kprobes is_IF_modifier(kprobe_opcode_t opcode) -{ - switch (opcode) { - case 0xfa: /* cli */ - case 0xfb: /* sti */ - case 0xcf: /* iret/iretd */ - case 0x9d: /* popf/popfd */ - return 1; - } - return 0; -} - -int __kprobes arch_prepare_kprobe(struct kprobe *p) -{ - /* insn: must be on special executable page on i386. */ - p->ainsn.insn = get_insn_slot(); - if (!p->ainsn.insn) - return -ENOMEM; - - memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); - p->opcode = *p->addr; - if (can_boost(p->addr)) { - p->ainsn.boostable = 0; - } else { - p->ainsn.boostable = -1; - } - return 0; -} - -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, (p->ainsn.boostable == 1)); - 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_eflags = kcb->kprobe_old_eflags; - kcb->prev_kprobe.saved_eflags = kcb->kprobe_saved_eflags; -} - -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_eflags = kcb->prev_kprobe.old_eflags; - kcb->kprobe_saved_eflags = kcb->prev_kprobe.saved_eflags; -} - -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_eflags = kcb->kprobe_old_eflags - = (regs->eflags & (TF_MASK | IF_MASK)); - if (is_IF_modifier(p->opcode)) - kcb->kprobe_saved_eflags &= ~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->eip = (unsigned long)p->addr; - else - regs->eip = (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 *)®s->esp; - - ri->ret_addr = (kprobe_opcode_t *) *sara; - - /* Replace the return addr with trampoline addr */ - *sara = (unsigned long) &kretprobe_trampoline; -} - -/* - * Interrupts are disabled on entry as trap3 is an interrupt gate and they - * remain disabled thorough out this function. - */ -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->eip - sizeof(kprobe_opcode_t)); - - /* - * 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_eflags; - 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_INSTRUCTION) { - /* The breakpoint instruction was removed by - * another cpu right after we hit, no further - * handling of this interrupt is appropriate - */ - regs->eip -= sizeof(kprobe_opcode_t); - 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->eip -= sizeof(kprobe_opcode_t); - 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: -#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PM) - if (p->ainsn.boostable == 1 && !p->post_handler){ - /* Boost up -- we can execute copied instructions directly */ - reset_current_kprobe(); - regs->eip = (unsigned long)p->ainsn.insn; - preempt_enable_no_resched(); - return 1; - } -#endif - 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 __kprobes kretprobe_trampoline_holder(void) - { - asm volatile ( ".global kretprobe_trampoline\n" - "kretprobe_trampoline: \n" - " pushf\n" - /* skip cs, eip, orig_eax */ - " subl $12, %esp\n" - " pushl %fs\n" - " pushl %ds\n" - " pushl %es\n" - " pushl %eax\n" - " pushl %ebp\n" - " pushl %edi\n" - " pushl %esi\n" - " pushl %edx\n" - " pushl %ecx\n" - " pushl %ebx\n" - " movl %esp, %eax\n" - " call trampoline_handler\n" - /* move eflags to cs */ - " movl 52(%esp), %edx\n" - " movl %edx, 48(%esp)\n" - /* save true return address on eflags */ - " movl %eax, 52(%esp)\n" - " popl %ebx\n" - " popl %ecx\n" - " popl %edx\n" - " popl %esi\n" - " popl %edi\n" - " popl %ebp\n" - " popl %eax\n" - /* skip eip, orig_eax, es, ds, fs */ - " addl $20, %esp\n" - " popf\n" - " ret\n"); -} - -/* - * Called from kretprobe_trampoline - */ -fastcall void *__kprobes trampoline_handler(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); - /* fixup registers */ - regs->xcs = __KERNEL_CS | get_kernel_rpl(); - regs->eip = trampoline_address; - regs->orig_eax = 0xffffffff; - - /* - * 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){ - __get_cpu_var(current_kprobe) = &ri->rp->kp; - get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE; - ri->rp->handler(ri, regs); - __get_cpu_var(current_kprobe) = NULL; - } - - 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); - spin_unlock_irqrestore(&kretprobe_lock, flags); - - hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { - hlist_del(&ri->hlist); - kfree(ri); - } - return (void*)orig_ret_address; -} - -/* - * 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 eip 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. - * - * This function also checks instruction size for preparing direct execution. - */ -static void __kprobes resume_execution(struct kprobe *p, - struct pt_regs *regs, struct kprobe_ctlblk *kcb) -{ - unsigned long *tos = (unsigned long *)®s->esp; - unsigned long copy_eip = (unsigned long)p->ainsn.insn; - unsigned long orig_eip = (unsigned long)p->addr; - - regs->eflags &= ~TF_MASK; - switch (p->ainsn.insn[0]) { - case 0x9c: /* pushfl */ - *tos &= ~(TF_MASK | IF_MASK); - *tos |= kcb->kprobe_old_eflags; - break; - case 0xc2: /* iret/ret/lret */ - case 0xc3: - case 0xca: - case 0xcb: - case 0xcf: - case 0xea: /* jmp absolute -- eip is correct */ - /* eip is already adjusted, no more changes required */ - p->ainsn.boostable = 1; - goto no_change; - case 0xe8: /* call relative - Fix return addr */ - *tos = orig_eip + (*tos - copy_eip); - break; - case 0x9a: /* call absolute -- same as call absolute, indirect */ - *tos = orig_eip + (*tos - copy_eip); - goto no_change; - case 0xff: - if ((p->ainsn.insn[1] & 0x30) == 0x10) { - /* - * call absolute, indirect - * Fix return addr; eip is correct. - * But this is not boostable - */ - *tos = orig_eip + (*tos - copy_eip); - goto no_change; - } else if (((p->ainsn.insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */ - ((p->ainsn.insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */ - /* eip is correct. And this is boostable */ - p->ainsn.boostable = 1; - goto no_change; - } - default: - break; - } - - if (p->ainsn.boostable == 0) { - if ((regs->eip > copy_eip) && - (regs->eip - copy_eip) + 5 < MAX_INSN_SIZE) { - /* - * These instructions can be executed directly if it - * jumps back to correct address. - */ - set_jmp_op((void *)regs->eip, - (void *)orig_eip + (regs->eip - copy_eip)); - p->ainsn.boostable = 1; - } else { - p->ainsn.boostable = -1; - } - } - - regs->eip = orig_eip + (regs->eip - copy_eip); - -no_change: - return; -} - -/* - * Interrupts are disabled on entry as trap1 is an interrupt gate and they - * remain disabled thoroughout this function. - */ -static 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_eflags; - trace_hardirqs_fixup_flags(regs->eflags); - - /*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(); - - /* - * 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(); - - 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 eip points back to the probe address - * and allow the page fault handler to continue as a - * normal page fault. - */ - regs->eip = (unsigned long)cur->addr; - regs->eflags |= kcb->kprobe_old_eflags; - 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. - */ - if (fixup_exception(regs)) - return 1; - - /* - * fixup_exception() could not handle it, - * Let do_page_fault() fix it. - */ - break; - default: - break; - } - return 0; -} - -/* - * Wrapper routine to 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_vm(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_esp = ®s->esp; - addr = (unsigned long)(kcb->jprobe_saved_esp); - - /* - * TBD: 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->eip = (unsigned long)(jp->entry); - return 1; -} - -void __kprobes jprobe_return(void) -{ - struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - - asm volatile (" xchgl %%ebx,%%esp \n" - " int3 \n" - " .globl jprobe_return_end \n" - " jprobe_return_end: \n" - " nop \n"::"b" - (kcb->jprobe_saved_esp):"memory"); -} - -int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) -{ - struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - u8 *addr = (u8 *) (regs->eip - 1); - unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_esp); - struct jprobe *jp = container_of(p, struct jprobe, kp); - - if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) { - if (®s->esp != kcb->jprobe_saved_esp) { - struct pt_regs *saved_regs = &kcb->jprobe_saved_regs; - printk("current esp %p does not match saved esp %p\n", - ®s->esp, kcb->jprobe_saved_esp); - 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; -} - -int __kprobes arch_trampoline_kprobe(struct kprobe *p) -{ - return 0; -} - -int __init arch_init_kprobes(void) -{ - return 0; -} |