From patchwork Thu Apr 4 19:14:09 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sven Schnelle X-Patchwork-Id: 10886107 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 582E918E8 for ; Thu, 4 Apr 2019 19:14:54 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 44BB328662 for ; Thu, 4 Apr 2019 19:14:54 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 396C4288B4; Thu, 4 Apr 2019 19:14:54 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BC83728A5A for ; Thu, 4 Apr 2019 19:14:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730227AbfDDTOx (ORCPT ); Thu, 4 Apr 2019 15:14:53 -0400 Received: from smtp.duncanthrax.net ([89.31.1.170]:33669 "EHLO smtp.duncanthrax.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730153AbfDDTOw (ORCPT ); Thu, 4 Apr 2019 15:14:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=duncanthrax.net; s=dkim; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=PI3QXVP21UgPhNF1NtkE/QPJJoKeIS2W7rD+TROp/zs=; b=AHJeR66Am13Nh8pVDt7TjOlyc8 fuK1qToJHPaONWGsUTfDmdluQtHVo2SqRs20F9+glyFtul4uLH43Wz6SXgHm0PYlEbDy9qvpwlGTU 7M+pMepsK7RhpYhgmtmFnXg1MXcD3UY20zvxiAD9NMP9An5+DdQyJagQjfw90FyUKq9I=; Received: from [134.3.47.207] (helo=t470p.stackframe.org) by smtp.eurescom.eu with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1hC7p5-00012K-HH; Thu, 04 Apr 2019 21:14:51 +0200 From: Sven Schnelle To: deller@gmx.de Cc: linux-parisc@vger.kernel.org, Sven Schnelle Subject: [PATCH v2 2/3] parisc: add parisc code patching Date: Thu, 4 Apr 2019 21:14:09 +0200 Message-Id: <20190404191410.3444-3-svens@stackframe.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190404191410.3444-1-svens@stackframe.org> References: <20190404191410.3444-1-svens@stackframe.org> MIME-Version: 1.0 Sender: linux-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Instead of re-mapping the whole kernel text with RWX rights add a patch_text() which can be used to replace instructions in the kernel .text section. Based on the ARM implementation. Signed-off-by: Sven Schnelle --- arch/parisc/include/asm/patch.h | 11 +++++ arch/parisc/kernel/Makefile | 3 +- arch/parisc/kernel/patch.c | 78 +++++++++++++++++++++++++++++++++ 3 files changed, 91 insertions(+), 1 deletion(-) create mode 100644 arch/parisc/include/asm/patch.h create mode 100644 arch/parisc/kernel/patch.c diff --git a/arch/parisc/include/asm/patch.h b/arch/parisc/include/asm/patch.h new file mode 100644 index 000000000000..685b58a13968 --- /dev/null +++ b/arch/parisc/include/asm/patch.h @@ -0,0 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _PARISC_KERNEL_PATCH_H +#define _PARISC_KERNEL_PATCH_H + +/* stop machine and patch kernel text */ +void patch_text(void *addr, unsigned int insn); + +/* patch kernel text with machine already stopped (e.g. in kgdb) */ +void __patch_text(void *addr, unsigned int insn); + +#endif diff --git a/arch/parisc/kernel/Makefile b/arch/parisc/kernel/Makefile index 8e5f1ab65c68..d29bbd1a73b2 100644 --- a/arch/parisc/kernel/Makefile +++ b/arch/parisc/kernel/Makefile @@ -9,7 +9,8 @@ obj-y := cache.o pacache.o setup.o pdt.o traps.o time.o irq.o \ pa7300lc.o syscall.o entry.o sys_parisc.o firmware.o \ ptrace.o hardware.o inventory.o drivers.o alternative.o \ signal.o hpmc.o real2.o parisc_ksyms.o unaligned.o \ - process.o processor.o pdc_cons.o pdc_chassis.o unwind.o + process.o processor.o pdc_cons.o pdc_chassis.o unwind.o \ + patch.o ifdef CONFIG_FUNCTION_TRACER # Do not profile debug and lowlevel utilities diff --git a/arch/parisc/kernel/patch.c b/arch/parisc/kernel/patch.c new file mode 100644 index 000000000000..4a3bff87b177 --- /dev/null +++ b/arch/parisc/kernel/patch.c @@ -0,0 +1,78 @@ +// SPDX-License-Identifier: GPL-2.0 + /* + * functions to patch RO kernel text during runtime + * + * Copyright (c) 2019 Sven Schnelle + */ + +#include +#include +#include +#include +#include + +#include +#include +#include + +struct patch { + void *addr; + unsigned int insn; +}; + +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_STRICT_MODULE_RWX)) + page = vmalloc_to_page(addr); + else if (!module && IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) + page = virt_to_page(addr); + else + return addr; + + 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); +} + +void __kprobes __patch_text(void *addr, unsigned int insn) +{ + unsigned long flags; + void *waddr = addr; + int size; + + waddr = patch_map(addr, FIX_TEXT_POKE0, &flags); + *(u32 *)waddr = insn; + size = sizeof(u32); + flush_kernel_vmap_range(waddr, size); + patch_unmap(FIX_TEXT_POKE0, &flags); + flush_icache_range((uintptr_t)(addr), + (uintptr_t)(addr) + size); +} + +static int __kprobes patch_text_stop_machine(void *data) +{ + struct patch *patch = data; + + __patch_text(patch->addr, patch->insn); + + return 0; +} + +void __kprobes patch_text(void *addr, unsigned int insn) +{ + struct patch patch = { + .addr = addr, + .insn = insn, + }; + + stop_machine_cpuslocked(patch_text_stop_machine, &patch, NULL); +}