X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fx86_64%2Fkernel%2Fkprobes.c;h=209c8c0bec717c226f9338faced9ac243b7904c9;hb=refs%2Fheads%2Fvserver;hp=8b866a8572cfab92546ff539b185799d695c07dc;hpb=76828883507a47dae78837ab5dec5a5b4513c667;p=linux-2.6.git diff --git a/arch/x86_64/kernel/kprobes.c b/arch/x86_64/kernel/kprobes.c index 8b866a857..209c8c0be 100644 --- a/arch/x86_64/kernel/kprobes.c +++ b/arch/x86_64/kernel/kprobes.c @@ -31,16 +31,17 @@ * Added function return probes functionality */ -#include #include #include #include #include #include +#include #include #include #include +#include void jprobe_return_end(void); static void __kprobes arch_copy_kprobe(struct kprobe *p); @@ -51,7 +52,7 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); /* * returns non-zero if opcode modifies the interrupt flag. */ -static inline int is_IF_modifier(kprobe_opcode_t *insn) +static __always_inline int is_IF_modifier(kprobe_opcode_t *insn) { switch (*insn) { case 0xfa: /* cli */ @@ -82,7 +83,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) * If it does, return the address of the 32-bit displacement word. * If not, return null. */ -static inline s32 *is_riprel(u8 *insn) +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) | \ @@ -222,12 +223,12 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p) void __kprobes arch_remove_kprobe(struct kprobe *p) { - down(&kprobe_mutex); - free_insn_slot(p->ainsn.insn); - up(&kprobe_mutex); + mutex_lock(&kprobe_mutex); + free_insn_slot(p->ainsn.insn, 0); + mutex_unlock(&kprobe_mutex); } -static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb) +static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) { kcb->prev_kprobe.kp = kprobe_running(); kcb->prev_kprobe.status = kcb->kprobe_status; @@ -235,7 +236,7 @@ static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb) kcb->prev_kprobe.saved_rflags = kcb->kprobe_saved_rflags; } -static inline void restore_previous_kprobe(struct kprobe_ctlblk *kcb) +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; @@ -243,7 +244,7 @@ static inline void restore_previous_kprobe(struct kprobe_ctlblk *kcb) kcb->kprobe_saved_rflags = kcb->prev_kprobe.saved_rflags; } -static inline void set_current_kprobe(struct kprobe *p, struct pt_regs *regs, +static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb) { __get_cpu_var(current_kprobe) = p; @@ -269,20 +270,19 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs) { unsigned long *sara = (unsigned long *)regs->rsp; - struct kretprobe_instance *ri; + struct kretprobe_instance *ri; - if ((ri = get_free_rp_inst(rp)) != NULL) { - ri->rp = rp; - ri->task = current; + if ((ri = get_free_rp_inst(rp)) != NULL) { + ri->rp = rp; + ri->task = current; ri->ret_addr = (kprobe_opcode_t *) *sara; /* Replace the return addr with trampoline addr */ *sara = (unsigned long) &kretprobe_trampoline; - - add_rp_inst(ri); - } else { - rp->nmissed++; - } + add_rp_inst(ri); + } else { + rp->nmissed++; + } } int __kprobes kprobe_handler(struct pt_regs *regs) @@ -404,14 +404,15 @@ no_kprobe: */ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) { - struct kretprobe_instance *ri = NULL; - struct hlist_head *head; - struct hlist_node *node, *tmp; + 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); + head = kretprobe_inst_table_head(current); /* * It is possible to have multiple instances associated with a given @@ -422,20 +423,20 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) * 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 + * 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) + if (ri->task != current) /* another task is sharing our hash bucket */ - continue; + continue; if (ri->rp && ri->rp->handler) ri->rp->handler(ri, regs); orig_ret_address = (unsigned long)ri->ret_addr; - recycle_rp_inst(ri); + recycle_rp_inst(ri, &empty_rp); if (orig_ret_address != trampoline_address) /* @@ -453,12 +454,16 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) spin_unlock_irqrestore(&kretprobe_lock, flags); preempt_enable_no_resched(); - /* - * By returning a non-zero value, we are telling - * kprobe_handler() that we don't want the post_handler + 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; + */ + return 1; } /* @@ -512,13 +517,13 @@ static void __kprobes resume_execution(struct kprobe *p, *tos = orig_rip + (*tos - copy_rip); break; case 0xff: - if ((*insn & 0x30) == 0x10) { + if ((insn[1] & 0x30) == 0x10) { /* call absolute, indirect */ /* Fix return addr; rip is correct. */ next_rip = regs->rip; *tos = orig_rip + (*tos - copy_rip); - } else if (((*insn & 0x31) == 0x20) || /* jmp near, absolute indirect */ - ((*insn & 0x31) == 0x21)) { /* jmp far, absolute indirect */ + } else if (((insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */ + ((insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */ /* rip is correct. */ next_rip = regs->rip; } @@ -578,16 +583,62 @@ 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; - if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) - return 1; - - if (kcb->kprobe_status & KPROBE_HIT_SS) { - resume_execution(cur, regs, kcb); + 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; - - reset_current_kprobe(); + 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; } @@ -601,6 +652,9 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self, 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))