From patchwork Fri Apr 4 21:27:50 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rabin Vincent X-Patchwork-Id: 3941071 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id E8C129F1EE for ; Fri, 4 Apr 2014 21:31:34 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 0D090203B6 for ; Fri, 4 Apr 2014 21:31:34 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 009BD20381 for ; Fri, 4 Apr 2014 21:31:33 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WWBg9-0007MM-Bc; Fri, 04 Apr 2014 21:29:39 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WWBfn-00088E-Ae; Fri, 04 Apr 2014 21:29:15 +0000 Received: from mail-lb0-x22c.google.com ([2a00:1450:4010:c04::22c]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WWBfM-000831-Eb for linux-arm-kernel@lists.infradead.org; Fri, 04 Apr 2014 21:28:50 +0000 Received: by mail-lb0-f172.google.com with SMTP id c11so2950898lbj.3 for ; Fri, 04 Apr 2014 14:28:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=bidBbjqQBcEZt5Lc+z1Yp2+5lBiLLuMQq7iYLUetMBY=; b=FGJekM1/PEDWrCgx081e5ZJtd7rFlLwsELCfz9YO4sbgnFQ+lgaEqPo57igGJu3s// Geu+wr1oClcz6rFohFX21FXwXLyEqjuQvBE2STRpMRr5mZ+TDLwsnKe3rxx3/djoj4lx RpbkFpdvwnuK8Y1knqRqsr4549KDo56qLDaDVDorV3tCFD27+9XD79VrHxzBsSI0Q1pa KOE6PDdXXCh+arzFECZ09itFHEvstqSg3eGQiDhqX2ce2YT8WGRGX5AmWjyqBedNiYtC 1a4SxM1Jc2dXz97L8E6S6AhwyRW8sfDeY+aX59hiGz+eFYsoiOw0EXUcfq7YkeiVRQSw vLjw== X-Received: by 10.152.203.129 with SMTP id kq1mr2596667lac.6.1396646905208; Fri, 04 Apr 2014 14:28:25 -0700 (PDT) Received: from localhost.localdomain (217-211-190-200-no39.tbcn.telia.com. [217.211.190.200]) by mx.google.com with ESMTPSA id dl4sm6419114lbc.4.2014.04.04.14.28.22 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 04 Apr 2014 14:28:24 -0700 (PDT) From: Rabin Vincent To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 2/2] arm: use fixmap for text patching when text is RO Date: Fri, 4 Apr 2014 23:27:50 +0200 Message-Id: <1396646870-29695-2-git-send-email-rabin@rab.in> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1396646870-29695-1-git-send-email-rabin@rab.in> References: <1396646870-29695-1-git-send-email-rabin@rab.in> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140404_172848_733460_CF311E35 X-CRM114-Status: GOOD ( 16.70 ) X-Spam-Score: -1.9 (-) Cc: Jon Medhurst , Rabin Vincent , Laura Abbott , linux-kernel@vger.kernel.org, Kees Cook X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.7 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Use fixmaps for text patching when the kernel text is read-only, inspired by x86. This makes jump labels and kprobes work with the currently available CONFIG_DEBUG_SET_MODULE_RONX and the upcoming CONFIG_DEBUG_RODATA options. Signed-off-by: Rabin Vincent --- arch/arm/include/asm/fixmap.h | 3 ++ arch/arm/kernel/jump_label.c | 2 +- arch/arm/kernel/patch.c | 66 ++++++++++++++++++++++++++++++++++++++----- arch/arm/kernel/patch.h | 12 +++++++- 4 files changed, 74 insertions(+), 9 deletions(-) diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h index 55ed076..79c1719 100644 --- a/arch/arm/include/asm/fixmap.h +++ b/arch/arm/include/asm/fixmap.h @@ -18,6 +18,9 @@ #define FIXADDR_TOP (FIXADDR_END - PAGE_SIZE) enum fixed_addresses { + FIX_TEXT_POKE0, + FIX_TEXT_POKE1, + FIX_KMAP_BEGIN, FIX_KMAP_END = (FIXADDR_TOP - FIXADDR_START) >> PAGE_SHIFT, __end_of_fixed_addresses diff --git a/arch/arm/kernel/jump_label.c b/arch/arm/kernel/jump_label.c index 4ce4f78..afeeb9e 100644 --- a/arch/arm/kernel/jump_label.c +++ b/arch/arm/kernel/jump_label.c @@ -19,7 +19,7 @@ static void __arch_jump_label_transform(struct jump_entry *entry, insn = arm_gen_nop(); if (is_static) - __patch_text(addr, insn); + __patch_text_early(addr, insn); else patch_text(addr, insn); } diff --git a/arch/arm/kernel/patch.c b/arch/arm/kernel/patch.c index 07314af..761c5b6 100644 --- a/arch/arm/kernel/patch.c +++ b/arch/arm/kernel/patch.c @@ -1,8 +1,11 @@ #include +#include #include +#include #include #include +#include #include #include @@ -13,21 +16,67 @@ struct patch { unsigned int insn; }; -void __kprobes __patch_text(void *addr, unsigned int insn) +static DEFINE_SPINLOCK(patch_lock); + +static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags) +{ + unsigned int uintaddr = (uintptr_t) addr; + bool module = !core_kernel_text(uintaddr); + struct page *page; + + if (module && IS_ENABLED(CONFIG_DEBUG_SET_MODULE_RONX)) { + page = vmalloc_to_page(addr); + } else if (!module && IS_ENABLED(CONFIG_ARM_KERNMEM_PERMS)) { + page = virt_to_page(addr); + } else { + return addr; + } + + if (flags) + spin_lock_irqsave(&patch_lock, *flags); + + set_fixmap(fixmap, page_to_phys(page)); + + return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK)); +} + +static void __kprobes patch_unmap(int fixmap, unsigned long *flags) +{ + clear_fixmap(fixmap); + + if (flags) + spin_unlock_irqrestore(&patch_lock, *flags); +} + +void __kprobes __patch_text_real(void *addr, unsigned int insn, bool remap) { bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL); + unsigned int uintaddr = (uintptr_t) addr; + unsigned long flags; + void *waddr = addr; int size; + if (remap) + waddr = patch_map(addr, FIX_TEXT_POKE0, &flags); + if (thumb2 && __opcode_is_thumb16(insn)) { - *(u16 *)addr = __opcode_to_mem_thumb16(insn); + *(u16 *)waddr = __opcode_to_mem_thumb16(insn); size = sizeof(u16); - } else if (thumb2 && ((uintptr_t)addr & 2)) { + } else if (thumb2 && (uintaddr & 2)) { + bool twopage = (uintaddr & ~PAGE_MASK) == PAGE_SIZE - 2; u16 first = __opcode_thumb32_first(insn); u16 second = __opcode_thumb32_second(insn); - u16 *addrh = addr; + u16 *addrh0 = waddr; + u16 *addrh1 = waddr + 2; + + if (remap && twopage) + addrh1 = patch_map(addr + 2, FIX_TEXT_POKE1, NULL); - addrh[0] = __opcode_to_mem_thumb16(first); - addrh[1] = __opcode_to_mem_thumb16(second); + *addrh0 = __opcode_to_mem_thumb16(first); + *addrh1 = __opcode_to_mem_thumb16(second); + + if (twopage && addrh1 != addr + 2) + patch_unmap(FIX_TEXT_POKE1, NULL); size = sizeof(u32); } else { @@ -36,10 +85,13 @@ void __kprobes __patch_text(void *addr, unsigned int insn) else insn = __opcode_to_mem_arm(insn); - *(u32 *)addr = insn; + *(u32 *)waddr = insn; size = sizeof(u32); } + if (waddr != addr) + patch_unmap(FIX_TEXT_POKE0, &flags); + flush_icache_range((uintptr_t)(addr), (uintptr_t)(addr) + size); } diff --git a/arch/arm/kernel/patch.h b/arch/arm/kernel/patch.h index b4731f2..77e054c 100644 --- a/arch/arm/kernel/patch.h +++ b/arch/arm/kernel/patch.h @@ -2,6 +2,16 @@ #define _ARM_KERNEL_PATCH_H void patch_text(void *addr, unsigned int insn); -void __patch_text(void *addr, unsigned int insn); +void __patch_text_real(void *addr, unsigned int insn, bool remap); + +static inline void __patch_text(void *addr, unsigned int insn) +{ + __patch_text_real(addr, insn, true); +} + +static inline void __patch_text_early(void *addr, unsigned int insn) +{ + __patch_text_real(addr, insn, false); +} #endif