Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751435AbWEIHFS (ORCPT ); Tue, 9 May 2006 03:05:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751436AbWEIHFS (ORCPT ); Tue, 9 May 2006 03:05:18 -0400 Received: from e4.ny.us.ibm.com ([32.97.182.144]:59341 "EHLO e4.ny.us.ibm.com") by vger.kernel.org with ESMTP id S1751435AbWEIHFP (ORCPT ); Tue, 9 May 2006 03:05:15 -0400 Date: Tue, 9 May 2006 12:35:08 +0530 From: Prasanna S Panchamukhi To: linux-kernel@vger.kernel.org, systemtap@sources.redhat.com Cc: akpm@osdl.org, Andi Kleen , davem@davemloft.net, suparna@in.ibm.com, richardj_moore@uk.ibm.com Subject: Re: [RFC] [PATCH 3/6] Kprobes: New interfaces for user-space probes Message-ID: <20060509070508.GC22493@in.ibm.com> Reply-To: prasanna@in.ibm.com References: <20060509065455.GA11630@in.ibm.com> <20060509065917.GA22493@in.ibm.com> <20060509070106.GB22493@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060509070106.GB22493@in.ibm.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 27220 Lines: 914 This patch provides two interfaces to insert and remove user space probes. Each probe is uniquely identified by inode and offset within that executable/library file. Insertion of a probe involves getting the code page for a given offset, mapping it into the memory and then inserting the breakpoint at the given offset. Also the probe is added to the uprobe_table hash list. A uprobe_module data structure is allocated for every probed application/library image on disk. Removal of a probe involves getting the code page for a given offset, mapping that page into the memory and then replacing the breakpoint instruction with a the original opcode. This patch also provides aggregate probe handler feature, where user can define multiple handlers per probe. Signed-off-by : Prasanna S Panchamukhi arch/i386/kernel/uprobes.c | 71 +++++ include/linux/kprobes.h | 61 ++++ include/linux/list.h | 16 + kernel/Makefile | 4 kernel/kprobes.c | 19 + kernel/uprobes.c | 579 +++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 748 insertions(+), 2 deletions(-) diff -puN include/linux/kprobes.h~kprobes_userspace_probes-base-interface include/linux/kprobes.h --- linux-2.6.17-rc3-mm1/include/linux/kprobes.h~kprobes_userspace_probes-base-interface 2006-05-09 10:08:47.000000000 +0530 +++ linux-2.6.17-rc3-mm1-prasanna/include/linux/kprobes.h 2006-05-09 12:32:50.000000000 +0530 @@ -37,6 +37,10 @@ #include #include #include +#include +#include +#include +#include #ifdef CONFIG_KPROBES #include @@ -47,6 +51,13 @@ #define KPROBE_REENTER 0x00000004 #define KPROBE_HIT_SSDONE 0x00000008 +/* uprobe_status settings */ +#define UPROBE_HIT_ACTIVE 0x00000001 +#define UPROBE_HIT_SS 0x00000002 +#define UPROBE_HIT_SSDONE 0x00000004 +#define UPROBE_SS_INLINE 0x00000008 +#define UPROBE_SSDONE_INLINE 0x00000010 + /* Attach to insert probes on any functions which should be ignored*/ #define __kprobes __attribute__((__section__(".kprobes.text"))) @@ -54,6 +65,7 @@ struct kprobe; struct pt_regs; struct kretprobe; struct kretprobe_instance; +extern struct uprobe *current_uprobe; typedef int (*kprobe_pre_handler_t) (struct kprobe *, struct pt_regs *); typedef int (*kprobe_break_handler_t) (struct kprobe *, struct pt_regs *); typedef void (*kprobe_post_handler_t) (struct kprobe *, struct pt_regs *, @@ -117,6 +129,32 @@ struct jprobe { DECLARE_PER_CPU(struct kprobe *, current_kprobe); DECLARE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); +struct uprobe { + /* pointer to the pathname of the application */ + char *pathname; + /* kprobe structure with user specified handlers */ + struct kprobe kp; + /* hlist of all the userspace probes per application */ + struct hlist_node ulist; + /* inode of the probed application */ + struct inode *inode; + /* probe offset within the file */ + unsigned long offset; +}; + +struct uprobe_module { + /* hlist head of all userspace probes per application */ + struct hlist_head ulist_head; + /* list of all uprobe_module for probed application */ + struct list_head mlist; + /* to hold path/dentry etc. */ + struct nameidata nd; + /* original readpage operations */ + struct address_space_operations *ori_a_ops; + /* readpage hooks added operations */ + struct address_space_operations user_a_ops; +}; + #ifdef ARCH_SUPPORTS_KRETPROBES extern void arch_prepare_kretprobe(struct kretprobe *rp, struct pt_regs *regs); #else /* ARCH_SUPPORTS_KRETPROBES */ @@ -153,6 +191,7 @@ struct kretprobe_instance { }; extern spinlock_t kretprobe_lock; +extern spinlock_t uprobe_lock; extern struct mutex kprobe_mutex; extern int arch_prepare_kprobe(struct kprobe *p); extern void arch_arm_kprobe(struct kprobe *p); @@ -162,9 +201,16 @@ extern void show_registers(struct pt_reg extern kprobe_opcode_t *get_insn_slot(void); extern void free_insn_slot(kprobe_opcode_t *slot); extern void kprobes_inc_nmissed_count(struct kprobe *p); +extern void copy_kprobe(struct kprobe *old_p, struct kprobe *p); +extern int arch_copy_uprobe(struct kprobe *p, kprobe_opcode_t *address); +extern void arch_arm_uprobe(kprobe_opcode_t *address); +extern void arch_disarm_uprobe(struct kprobe *p, kprobe_opcode_t *address); +extern void init_uprobes(void); /* Get the kprobe at this addr (if any) - called with preemption disabled */ struct kprobe *get_kprobe(void *addr); +struct kprobe *get_uprobe(void *addr); +extern int arch_alloc_insn(struct kprobe *p); struct hlist_head * kretprobe_inst_table_head(struct task_struct *tsk); /* kprobe_running() will just return the current_kprobe on this CPU */ @@ -183,6 +229,16 @@ static inline struct kprobe_ctlblk *get_ return (&__get_cpu_var(kprobe_ctlblk)); } +static inline void set_uprobe_instance(struct kprobe *p) +{ + current_uprobe = container_of(p, struct uprobe, kp); +} + +static inline void reset_uprobe_instance(void) +{ + current_uprobe = NULL; +} + int register_kprobe(struct kprobe *p); void unregister_kprobe(struct kprobe *p); int setjmp_pre_handler(struct kprobe *, struct pt_regs *); @@ -194,10 +250,15 @@ void jprobe_return(void); int register_kretprobe(struct kretprobe *rp); void unregister_kretprobe(struct kretprobe *rp); +int register_uprobe(struct uprobe *uprobe); +void unregister_uprobe(struct uprobe *uprobe); + struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp); void add_rp_inst(struct kretprobe_instance *ri); void kprobe_flush_task(struct task_struct *tk); void recycle_rp_inst(struct kretprobe_instance *ri); +void kprobes_add_pagefault_notifier(void); +void kprobes_remove_pagefault_notifier(void); #else /* CONFIG_KPROBES */ #define __kprobes /**/ diff -puN /dev/null kernel/uprobes.c --- /dev/null 2004-06-24 23:34:38.000000000 +0530 +++ linux-2.6.17-rc3-mm1-prasanna/kernel/uprobes.c 2006-05-09 12:32:57.000000000 +0530 @@ -0,0 +1,579 @@ +/* + * User-space Probes (UProbes) + * kernel/uprobes.c + * + * 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, 2006 + * + * 2006-Mar Created by Prasanna S Panchamukhi + * User-space probes initial implementation based on IBM's + * Dprobes. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define UPROBE_HASH_BITS 6 +#define UPROBE_TABLE_SIZE (1 << UPROBE_HASH_BITS) + +/* user space probes lists */ +static struct list_head uprobe_module_list; +static struct hlist_head uprobe_table[UPROBE_TABLE_SIZE]; +DEFINE_SPINLOCK(uprobe_lock); /* Protects uprobe_table*/ +DEFINE_MUTEX(uprobe_mutex); /* Protects uprobe_module_table */ + +/* + * Aggregate handlers for multiple uprobes support - these handlers + * take care of invoking the individual uprobe handlers on p->list + */ +static int __kprobes aggr_user_pre_handler(struct kprobe *p, + struct pt_regs *regs) +{ + struct kprobe *kp; + + list_for_each_entry(kp, &p->list, list) { + if (kp->pre_handler) { + set_uprobe_instance(kp); + if (kp->pre_handler(kp, regs)) + return 1; + } + } + return 0; +} + +static void __kprobes aggr_user_post_handler(struct kprobe *p, + struct pt_regs *regs, unsigned long flags) +{ + struct kprobe *kp; + + list_for_each_entry(kp, &p->list, list) { + if (kp->post_handler) { + set_uprobe_instance(kp); + kp->post_handler(kp, regs, flags); + } + } +} + +static int __kprobes aggr_user_fault_handler(struct kprobe *p, + struct pt_regs *regs, int trapnr) +{ + struct kprobe *cur; + + /* + * if we faulted "during" the execution of a user specified + * probe handler, invoke just that probe's fault handler + */ + cur = ¤t_uprobe->kp; + if (cur && cur->fault_handler) + if (cur->fault_handler(cur, regs, trapnr)) + return 1; + return 0; +} + +/* + * This routine looks for an existing uprobe at the given offset and inode. + * If it's found, returns the corresponding kprobe pointer. + * This should be called with uprobe_lock held. + */ +static struct kprobe __kprobes *get_kprobe_user(struct inode *inode, + unsigned long offset) +{ + struct hlist_head *head; + struct hlist_node *node; + struct kprobe *p, *kpr; + struct uprobe *uprobe; + + head = &uprobe_table[hash_ptr((kprobe_opcode_t *) + (((unsigned long)inode) * offset), UPROBE_HASH_BITS)]; + + hlist_for_each_entry(p, node, head, hlist) { + if (p->pre_handler == aggr_user_pre_handler) { + kpr = list_entry(p->list.next, typeof(*kpr), list); + uprobe = container_of(kpr, struct uprobe, kp); + } else + uprobe = container_of(p, struct uprobe, kp); + + if ((uprobe->inode == inode) && (uprobe->offset == offset)) + return p; + } + + return NULL; +} + +/* + * Finds a uprobe at the specified user-space address in the current task. + * Points current_uprobe at that uprobe and returns the corresponding kprobe. + */ +struct kprobe __kprobes *get_uprobe(void *addr) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + struct inode *inode; + unsigned long offset; + struct kprobe *p, *kpr; + struct uprobe *uprobe; + + if (!down_read_trylock(&mm->mmap_sem)) + down_read(&mm->mmap_sem); + vma = find_vma(mm, (unsigned long)addr); + + BUG_ON(!vma); /* this should not happen, not in our memory map */ + + offset = (unsigned long)addr - (vma->vm_start + + (vma->vm_pgoff << PAGE_SHIFT)); + if (!vma->vm_file) { + up_read(&mm->mmap_sem); + return NULL; + } + + inode = vma->vm_file->f_dentry->d_inode; + up_read(&mm->mmap_sem); + + p = get_kprobe_user(inode, offset); + if (!p) + return NULL; + + if (p->pre_handler == aggr_user_pre_handler) { + /* + * Walk the uprobe aggregate list and return firt + * element on aggregate list. + */ + kpr = list_entry((p)->list.next, typeof(*kpr), list); + uprobe = container_of(kpr, struct uprobe, kp); + } else + uprobe = container_of(p, struct uprobe, kp); + + if (uprobe) + current_uprobe = uprobe; + + return p; +} + +/* + * Fill in the required fields of the "manager uprobe". Replace the + * earlier kprobe in the hlist with the manager uprobe + */ +static inline void add_aggr_uprobe(struct kprobe *ap, struct kprobe *p) +{ + copy_kprobe(p, ap); + ap->addr = p->addr; + ap->pre_handler = aggr_user_pre_handler; + ap->post_handler = aggr_user_post_handler; + ap->fault_handler = aggr_user_fault_handler; + + INIT_LIST_HEAD(&ap->list); + list_add(&p->list, &ap->list); + + hlist_replace(&p->hlist, &ap->hlist); +} + +/* + * This is the second or subsequent uprobe at the address - handle + * the intricacies + */ +static int __kprobes register_aggr_uprobe(struct kprobe *old_p, + struct kprobe *p) +{ + struct kprobe *ap; + + if (old_p->pre_handler == aggr_user_pre_handler) { + copy_kprobe(old_p, p); + list_add(&p->list, &old_p->list); + } else { + ap = kzalloc(sizeof(struct kprobe), GFP_ATOMIC); + if (!ap) + return -ENOMEM; + add_aggr_uprobe(ap, old_p); + copy_kprobe(ap, p); + list_add(&p->list, &old_p->list); + } + return 0; +} + +typedef int (*process_uprobe_func_t)(struct uprobe *uprobe, + kprobe_opcode_t *address); + +/* + * Saves the original instruction in the uprobe structure and + * inserts the breakpoint at the given address. + */ +int __kprobes insert_kprobe_user(struct uprobe *uprobe, + kprobe_opcode_t *address) +{ + int ret = 0; + + ret = arch_copy_uprobe(&uprobe->kp, address); + if (ret) { + printk("Breakpoint already present\n"); + return ret; + } + arch_arm_uprobe(address); + + return 0; +} + +/* + * Wait for the page to be unlocked if someone else had locked it, + * then map the page and insert or remove the breakpoint. + */ +static int __kprobes map_uprobe_page(struct page *page, struct uprobe *uprobe, + process_uprobe_func_t process_kprobe_user) +{ + int ret = 0; + kprobe_opcode_t *uprobe_address; + + if (!page) + return -EINVAL; /* TODO: more suitable errno */ + + lock_page(page); + + uprobe_address = (kprobe_opcode_t *)kmap_atomic(page, KM_USER0); + uprobe_address = (kprobe_opcode_t *)((unsigned long)uprobe_address + + (uprobe->offset & ~PAGE_MASK)); + ret = (*process_kprobe_user)(uprobe, uprobe_address); + kunmap_atomic(uprobe_address, KM_USER0); + + unlock_page(page); + + return ret; +} + +/* + * flush_vma walks through the list of process private mappings, + * gets the vma containing the offset and flushes all the vmas + * containing the probed page. + */ +static void __kprobes flush_vma(struct address_space *mapping, + struct page *page, struct uprobe *uprobe) +{ + struct vm_area_struct *vma = NULL; + struct prio_tree_iter iter; + struct prio_tree_root *head = &mapping->i_mmap; + unsigned long start, end, offset = uprobe->offset; + + spin_lock(&mapping->i_mmap_lock); + vma_prio_tree_foreach(vma, &iter, head, offset, offset) { + start = vma->vm_start - (vma->vm_pgoff << PAGE_SHIFT); + end = vma->vm_end - (vma->vm_pgoff << PAGE_SHIFT); + + if ((start + offset) < end) + flush_icache_user_range(vma, page, + (unsigned long)uprobe->kp.addr, + sizeof(kprobe_opcode_t)); + } + spin_unlock(&mapping->i_mmap_lock); +} + +/* + * Walk the uprobe_module_list and return the uprobe module with matching + * inode. + */ +struct uprobe_module __kprobes *get_module_by_inode(struct inode *inode) +{ + struct uprobe_module *umodule; + + list_for_each_entry(umodule, &uprobe_module_list, mlist) { + if (umodule->nd.dentry->d_inode == inode) + return umodule; + } + + return NULL; +} + +/* + * Add uprobe and uprobe_module to the appropriate hash list. + */ +static void __kprobes get_inode_ops(struct uprobe *uprobe, + struct uprobe_module *umodule) +{ + INIT_HLIST_HEAD(&umodule->ulist_head); + hlist_add_head(&uprobe->ulist, &umodule->ulist_head); + list_add(&umodule->mlist, &uprobe_module_list); +} + +/* + * Removes the specified uprobe from either aggregate uprobe list + * or individual uprobe hash table. + */ + +static int __kprobes remove_uprobe(struct uprobe *uprobe) +{ + struct kprobe *old_p, *list_p, *p; + int ret = 0; + + p = &uprobe->kp; + old_p = get_kprobe_user(uprobe->inode, uprobe->offset); + if (unlikely(!old_p)) + return 0; + + if (p != old_p) { + list_for_each_entry(list_p, &old_p->list, list) + if (list_p == p) + /* kprobe p is a valid probe */ + goto valid_p; + return 0; + } + +valid_p: + if ((old_p == p) || + ((old_p->pre_handler == aggr_user_pre_handler) && + (p->list.next == &old_p->list) && + (p->list.prev == &old_p->list))) { + /* + * Only probe on the hash list, mark the corresponding + * instruction slot for freeing by return 1. + */ + ret = 1; + hlist_del(&old_p->hlist); + if (p != old_p) { + list_del(&p->list); + kfree(old_p); + } + } else + list_del(&p->list); + + return ret; +} + +/* + * Disarms the probe and frees the corresponding instruction slot. + */ +static int __kprobes remove_kprobe_user(struct uprobe *uprobe, + kprobe_opcode_t *address) +{ + struct kprobe *p = &uprobe->kp; + + arch_disarm_uprobe(p, address); + arch_remove_kprobe(p); + + return 0; +} + +/* + * Adds the given uprobe to the uprobe_hash table if it is + * the first probe to be inserted at the given address else + * adds to the aggregate uprobe's list. + */ +static int __kprobes insert_uprobe(struct uprobe *uprobe) +{ + struct kprobe *old_p; + int ret = 0; + unsigned long offset = uprobe->offset; + unsigned long inode = (unsigned long) uprobe->inode; + struct hlist_head *head; + unsigned long flags; + + spin_lock_irqsave(&uprobe_lock, flags); + uprobe->kp.nmissed = 0; + + old_p = get_kprobe_user(uprobe->inode, uprobe->offset); + + if (old_p) + register_aggr_uprobe(old_p, &uprobe->kp); + else { + head = &uprobe_table[hash_ptr((kprobe_opcode_t *) + (offset * inode), UPROBE_HASH_BITS)]; + INIT_HLIST_NODE(&uprobe->kp.hlist); + hlist_add_head(&uprobe->kp.hlist, head); + /* + * The original instruction must be copied into the instruction + * slot, hence return 1. + */ + ret = 1; + } + + spin_unlock_irqrestore(&uprobe_lock, flags); + + return ret; +} + +/* + * unregister_uprobe: Disarms the probe, removes the uprobe + * pointers from the hash list and unhooks readpage routines. + */ +void __kprobes unregister_uprobe(struct uprobe *uprobe) +{ + struct address_space *mapping; + struct uprobe_module *umodule; + struct page *page; + unsigned long flags; + int ret = 0; + + if (!uprobe->inode) + return; + + mapping = uprobe->inode->i_mapping; + + page = find_get_page(mapping, uprobe->offset >> PAGE_CACHE_SHIFT); + + spin_lock_irqsave(&uprobe_lock, flags); + ret = remove_uprobe(uprobe); + spin_unlock_irqrestore(&uprobe_lock, flags); + + mutex_lock(&uprobe_mutex); + if (!(umodule = get_module_by_inode(uprobe->inode))) + goto out; + + hlist_del(&uprobe->ulist); + if (hlist_empty(&umodule->ulist_head)) { + list_del(&umodule->mlist); + write_access_to_inode(uprobe->inode); + path_release(&umodule->nd); + kfree(umodule); + } + /* Unregister pagefault notifier, if no probes. */ + mutex_lock(&kprobe_mutex); + kprobes_remove_pagefault_notifier(); + mutex_unlock(&kprobe_mutex); +out: + mutex_unlock(&uprobe_mutex); + if (ret) + ret = map_uprobe_page(page, uprobe, remove_kprobe_user); + + if (ret == -EINVAL) + return; + /* + * TODO: unregister_uprobe should not fail, need to handle + * if it fails. + */ + flush_vma(mapping, page, uprobe); + + if (page) + page_cache_release(page); +} + +/* + * register_uprobe(): combination of inode and offset is used to + * identify each probe uniquely. Each uprobe can be found from the + * uprobes_hash table by using inode and offset. register_uprobe(), + * inserts the breakpoint at the given address by locating and mapping + * the page. return 0 on success and error on failure. + */ +int __kprobes register_uprobe(struct uprobe *uprobe) +{ + struct address_space *mapping; + struct uprobe_module *umodule = NULL; + struct inode *inode; + struct nameidata nd; + struct page *page; + int error = 0; + + INIT_HLIST_NODE(&uprobe->ulist); + + /* + * TODO: Need to calculate the absolute file offset for dynamic + * shared libraries. + */ + if ((error = path_lookup(uprobe->pathname, LOOKUP_FOLLOW, &nd))) + return error; + + mutex_lock(&uprobe_mutex); + + inode = nd.dentry->d_inode; + error = deny_write_access_to_inode(inode); + if (error) + goto out; + + error = arch_alloc_insn(&uprobe->kp); + if (error) { + write_access_to_inode(inode); + goto out; + } + + /* + * Check if there are probes already on this application and + * add the corresponding uprobe to per application probe's list. + */ + umodule = get_module_by_inode(inode); + if (!umodule) { + /* + * Allocate a uprobe_module structure for this + * application if not allocated before. + */ + umodule = kzalloc(sizeof(struct uprobe_module), GFP_KERNEL); + if (!umodule) { + error = -ENOMEM; + write_access_to_inode(inode); + arch_remove_kprobe(&uprobe->kp); + goto out; + } + memcpy(&umodule->nd, &nd, sizeof(struct nameidata)); + get_inode_ops(uprobe, umodule); + } else { + path_release(&nd); + write_access_to_inode(inode); + hlist_add_head(&uprobe->ulist, &umodule->ulist_head); + } + mutex_unlock(&uprobe_mutex); + /* + * Register pagefault notifier, if not one registered. + */ + mutex_lock(&kprobe_mutex); + kprobes_add_pagefault_notifier(); + mutex_unlock(&kprobe_mutex); + + uprobe->inode = inode; + mapping = inode->i_mapping; + page = find_get_page(mapping, (uprobe->offset >> PAGE_CACHE_SHIFT)); + + if (insert_uprobe(uprobe)) + error = map_uprobe_page(page, uprobe, insert_kprobe_user); + else + arch_remove_kprobe(&uprobe->kp); + + /* + * If error == -EINVAL, return success, probes will inserted by + * readpage hooks. + * TODO: Use a more suitable errno? + */ + if (error == -EINVAL) + error = 0; + flush_vma(mapping, page, uprobe); + + if (page) + page_cache_release(page); + + return error; +out: + path_release(&nd); + mutex_unlock(&uprobe_mutex); + + return error; +} + +void init_uprobes(void) +{ + int i; + + /* FIXME allocate the probe table, currently defined statically */ + /* initialize all list heads */ + for (i = 0; i < UPROBE_TABLE_SIZE; i++) + INIT_HLIST_HEAD(&uprobe_table[i]); + + INIT_LIST_HEAD(&uprobe_module_list); +} + +EXPORT_SYMBOL_GPL(register_uprobe); +EXPORT_SYMBOL_GPL(unregister_uprobe); + + diff -puN /dev/null arch/i386/kernel/uprobes.c --- /dev/null 2004-06-24 23:34:38.000000000 +0530 +++ linux-2.6.17-rc3-mm1-prasanna/arch/i386/kernel/uprobes.c 2006-05-09 12:32:52.000000000 +0530 @@ -0,0 +1,71 @@ +/* + * User-space Probes (UProbes) + * arch/i386/kernel/uprobes.c + * + * 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, 2006. + * + * 2006-Mar Created by Prasanna S Panchamukhi + * User-space probes initial implementation based on IBM's + * Dprobes. + */ + +#include +#include +#include +#include +#include +#include +#include + +int __kprobes arch_alloc_insn(struct kprobe *p) +{ + mutex_lock(&kprobe_mutex); + p->ainsn.insn = get_insn_slot(); + mutex_unlock(&kprobe_mutex); + + if (!p->ainsn.insn) + return -ENOMEM; + + return 0; +} + +void __kprobes arch_disarm_uprobe(struct kprobe *p, kprobe_opcode_t *address) +{ + if (p->opcode != BREAKPOINT_INSTRUCTION) + *address = p->opcode; +} + +void __kprobes arch_arm_uprobe(kprobe_opcode_t *address) +{ + *address = BREAKPOINT_INSTRUCTION; +} + +int __kprobes arch_copy_uprobe(struct kprobe *p, kprobe_opcode_t *address) +{ + int ret = 1; + + /* + * TODO: Check if the given address is a valid to access user memory. + */ + if (*address != BREAKPOINT_INSTRUCTION) { + memcpy(p->ainsn.insn, address, MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); + ret = 0; + } + p->opcode = *(kprobe_opcode_t *)address; + + return ret; +} diff -puN kernel/kprobes.c~kprobes_userspace_probes-base-interface kernel/kprobes.c --- linux-2.6.17-rc3-mm1/kernel/kprobes.c~kprobes_userspace_probes-base-interface 2006-05-09 10:08:47.000000000 +0530 +++ linux-2.6.17-rc3-mm1-prasanna/kernel/kprobes.c 2006-05-09 10:08:47.000000000 +0530 @@ -47,7 +47,7 @@ static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; -static atomic_t kprobe_count; +atomic_t kprobe_count; DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */ @@ -58,6 +58,20 @@ static struct notifier_block kprobe_page .priority = 0x7fffffff /* we need to notified first */ }; +void kprobes_add_pagefault_notifier(void) +{ + if (atomic_add_return(1, &kprobe_count) == \ + (ARCH_INACTIVE_KPROBE_COUNT + 1)) + register_page_fault_notifier(&kprobe_page_fault_nb); +} + +void kprobes_remove_pagefault_notifier(void) +{ + if (atomic_add_return(-1, &kprobe_count) == \ + ARCH_INACTIVE_KPROBE_COUNT) + unregister_page_fault_notifier(&kprobe_page_fault_nb); +} + #ifdef __ARCH_WANT_KPROBES_INSN_SLOT /* * kprobe->ainsn.insn points to the copy of the instruction to be @@ -362,7 +376,7 @@ static inline void free_rp_inst(struct k /* * Keep all fields in the kprobe consistent */ -static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p) +void copy_kprobe(struct kprobe *old_p, struct kprobe *p) { memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t)); memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn)); @@ -693,6 +707,7 @@ static int __init init_kprobes(void) } atomic_set(&kprobe_count, 0); + init_uprobes(); err = arch_init_kprobes(); if (!err) err = register_die_notifier(&kprobe_exceptions_nb); diff -puN include/linux/list.h~kprobes_userspace_probes-base-interface include/linux/list.h --- linux-2.6.17-rc3-mm1/include/linux/list.h~kprobes_userspace_probes-base-interface 2006-05-09 10:08:47.000000000 +0530 +++ linux-2.6.17-rc3-mm1-prasanna/include/linux/list.h 2006-05-09 10:08:47.000000000 +0530 @@ -655,6 +655,22 @@ static inline void hlist_replace_rcu(str old->pprev = LIST_POISON2; } +/* + * The old entry will be replaced with the new entry atomically. + */ +static inline void hlist_replace(struct hlist_node *old, + struct hlist_node *new) +{ + struct hlist_node *next = old->next; + + new->next = next; + new->pprev = old->pprev; + if (next) + new->next->pprev = &new->next; + *new->pprev = new; + old->pprev = LIST_POISON2; +} + static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) { struct hlist_node *first = h->first; diff -puN kernel/Makefile~kprobes_userspace_probes-base-interface kernel/Makefile --- linux-2.6.17-rc3-mm1/kernel/Makefile~kprobes_userspace_probes-base-interface 2006-05-09 10:08:47.000000000 +0530 +++ linux-2.6.17-rc3-mm1-prasanna/kernel/Makefile 2006-05-09 10:08:47.000000000 +0530 @@ -35,7 +35,11 @@ obj-$(CONFIG_IKCONFIG) += configs.o obj-$(CONFIG_STOP_MACHINE) += stop_machine.o obj-$(CONFIG_AUDIT) += audit.o auditfilter.o obj-$(CONFIG_AUDITSYSCALL) += auditsc.o +ifeq ($(CONFIG_X86_32),y) +obj-$(CONFIG_KPROBES) += kprobes.o uprobes.o +else obj-$(CONFIG_KPROBES) += kprobes.o +endif obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_SYSFS) += ksysfs.o obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o _ -- Prasanna S Panchamukhi Linux Technology Center India Software Labs, IBM Bangalore Email: prasanna@in.ibm.com Ph: 91-80-41776329 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/