Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932557Ab0FIVkF (ORCPT ); Wed, 9 Jun 2010 17:40:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20833 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758492Ab0FIVkA (ORCPT ); Wed, 9 Jun 2010 17:40:00 -0400 Date: Wed, 9 Jun 2010 17:39:26 -0400 From: Jason Baron To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, mathieu.desnoyers@polymtl.ca, hpa@zytor.com, tglx@linutronix.de, rostedt@goodmis.org, andi@firstfloor.org, roland@redhat.com, rth@redhat.com, mhiramat@redhat.com, fweisbec@gmail.com, avi@redhat.com, davem@davemloft.net, vgoyal@redhat.com, sam@ravnborg.org Message-Id: In-Reply-To: References: Subject: [PATCH 09/13] jump label v9: jump_label_text_reserved() to reserve our jump points Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4905 Lines: 167 Add a jump_label_text_reserved(void *start, void *end), so that other pieces of code that want to modify kernel text, can first verify that jump label has not reserved the instruction. Signed-off-by: Jason Baron Acked-by: Masami Hiramatsu --- arch/x86/kernel/kprobes.c | 3 +- include/linux/jump_label.h | 6 +++ kernel/jump_label.c | 83 ++++++++++++++++++++++++++++++++++++++++++++ kernel/kprobes.c | 3 +- 4 files changed, 93 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index 345a4b1..87ca919 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -1201,7 +1201,8 @@ static int __kprobes copy_optimized_instructions(u8 *dest, u8 *src) } /* Check whether the address range is reserved */ if (ftrace_text_reserved(src, src + len - 1) || - alternatives_text_reserved(src, src + len - 1)) + alternatives_text_reserved(src, src + len - 1) || + jump_label_text_reserved(src, src + len - 1)) return -EBUSY; return len; diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index dc81a45..3250793 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -28,6 +28,7 @@ extern void arch_jump_label_transform(struct jump_entry *entry, extern const u8 *arch_get_jump_label_nop(void); extern void jump_label_update(const char *name, enum jump_label_type type); +extern int jump_label_text_reserved(void *start, void *end); extern void apply_jump_label_nops(struct module *mod); @@ -62,6 +63,11 @@ static inline int apply_jump_label_nops(struct module *mod) return 0; } +static inline int jump_label_text_reserved(void *start, void *end) +{ + return 0; +} + #endif #endif diff --git a/kernel/jump_label.c b/kernel/jump_label.c index 3ebe2bf..ac39662 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -181,6 +181,89 @@ void jump_label_update(const char *name, enum jump_label_type type) mutex_unlock(&jump_label_mutex); } +static int addr_conflict(struct jump_entry *entry, void *start, void *end) +{ + if (entry->code <= (unsigned long)end && + entry->code + JUMP_LABEL_NOP_SIZE > (unsigned long)start) + return 1; + + return 0; +} + +#ifdef CONFIG_MODULES + +static int module_conflict(void *start, void *end) +{ + struct hlist_head *head; + struct hlist_node *node, *node_next, *module_node, *module_node_next; + struct jump_label_entry *e; + struct jump_label_module_entry *e_module; + struct jump_entry *iter; + int i, count; + int conflict = 0; + + for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) { + head = &jump_label_table[i]; + hlist_for_each_entry_safe(e, node, node_next, head, hlist) { + hlist_for_each_entry_safe(e_module, module_node, + module_node_next, + &(e->modules), hlist) { + count = e_module->nr_entries; + iter = e_module->table; + while (count--) { + if (addr_conflict(iter, start, end)) { + conflict = 1; + goto out; + } + iter++; + } + } + } + } +out: + return conflict; +} + +#endif + +/*** + * jump_label_text_reserved - check if addr range is reserved + * @start: start text addr + * @end: end text addr + * + * checks if the text addr located between @start and @end + * overlaps with any of the jump label patch addresses. Code + * that wants to modify kernel text should first verify that + * it does not overlap with any of the jump label addresses. + * + * returns 1 if there is an overlap, 0 otherwise + */ +int jump_label_text_reserved(void *start, void *end) +{ + struct jump_entry *iter; + struct jump_entry *iter_start = __start___jump_table; + struct jump_entry *iter_stop = __start___jump_table; + int conflict = 0; + + mutex_lock(&jump_label_mutex); + iter = iter_start; + while (iter < iter_stop) { + if (addr_conflict(iter, start, end)) { + conflict = 1; + goto out; + } + iter++; + } + + /* now check modules */ +#ifdef CONFIG_MODULES + conflict = module_conflict(start, end); +#endif +out: + mutex_unlock(&jump_label_mutex); + return conflict; +} + static int init_jump_label(void) { int ret; diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 282035f..2f9bea6 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1141,7 +1141,8 @@ int __kprobes register_kprobe(struct kprobe *p) preempt_disable(); if (!kernel_text_address((unsigned long) p->addr) || in_kprobes_functions((unsigned long) p->addr) || - ftrace_text_reserved(p->addr, p->addr)) { + ftrace_text_reserved(p->addr, p->addr) || + jump_label_text_reserved(p->addr, p->addr)) { preempt_enable(); return -EINVAL; } -- 1.7.1 -- 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/