Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753660AbZCHPxN (ORCPT ); Sun, 8 Mar 2009 11:53:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753168AbZCHPwS (ORCPT ); Sun, 8 Mar 2009 11:52:18 -0400 Received: from hera.kernel.org ([140.211.167.34]:34117 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752949AbZCHPwQ (ORCPT ); Sun, 8 Mar 2009 11:52:16 -0400 Date: Sun, 8 Mar 2009 15:51:50 GMT From: Masami Hiramatsu To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, mathieu.desnoyers@polymtl.ca, hpa@zytor.com, mingo@redhat.com, tglx@linutronix.de, mhiramat@redhat.com, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, mathieu.desnoyers@polymtl.ca, linux-kernel@vger.kernel.org, tglx@linutronix.de, mhiramat@redhat.com, mingo@elte.hu In-Reply-To: <49B14352.2040705@redhat.com> References: <49B14352.2040705@redhat.com> Subject: [tip:tracing/core] x86: implement atomic text_poke() via fixmap Message-ID: Git-Commit-ID: 78ff7fae04554b49d29226ed12536268c2500d1f X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Sun, 08 Mar 2009 15:51:52 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3481 Lines: 102 Commit-ID: 78ff7fae04554b49d29226ed12536268c2500d1f Gitweb: http://git.kernel.org/tip/78ff7fae04554b49d29226ed12536268c2500d1f Author: "Masami Hiramatsu" AuthorDate: Fri, 6 Mar 2009 10:37:54 -0500 Commit: Ingo Molnar CommitDate: Fri, 6 Mar 2009 16:49:01 +0100 x86: implement atomic text_poke() via fixmap Use fixmaps instead of vmap/vunmap in text_poke() for avoiding page allocation and delayed unmapping. At the result of above change, text_poke() becomes atomic and can be called from stop_machine() etc. Signed-off-by: Masami Hiramatsu Acked-by: Mathieu Desnoyers LKML-Reference: <49B14352.2040705@redhat.com> Signed-off-by: Ingo Molnar --- arch/x86/include/asm/fixmap.h | 2 ++ arch/x86/kernel/alternative.c | 24 +++++++++++++++--------- 2 files changed, 17 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index 63a79c7..81937a5 100644 --- a/arch/x86/include/asm/fixmap.h +++ b/arch/x86/include/asm/fixmap.h @@ -111,6 +111,8 @@ enum fixed_addresses { #ifdef CONFIG_PARAVIRT FIX_PARAVIRT_BOOTMAP, #endif + FIX_TEXT_POKE0, /* reserve 2 pages for text_poke() */ + FIX_TEXT_POKE1, __end_of_permanent_fixed_addresses, #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT FIX_OHCI1394_BASE, diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 092a7b8..2d903b7 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -13,7 +13,9 @@ #include #include #include +#include #include +#include #define MAX_PATCH_LEN (255-1) @@ -505,15 +507,16 @@ void *text_poke_early(void *addr, const void *opcode, size_t len) * It means the size must be writable atomically and the address must be aligned * in a way that permits an atomic write. It also makes sure we fit on a single * page. + * + * Note: Must be called under text_mutex. */ void *__kprobes text_poke(void *addr, const void *opcode, size_t len) { + unsigned long flags; char *vaddr; - int nr_pages = 2; struct page *pages[2]; int i; - might_sleep(); if (!core_kernel_text((unsigned long)addr)) { pages[0] = vmalloc_to_page(addr); pages[1] = vmalloc_to_page(addr + PAGE_SIZE); @@ -523,14 +526,17 @@ void *__kprobes text_poke(void *addr, const void *opcode, size_t len) pages[1] = virt_to_page(addr + PAGE_SIZE); } BUG_ON(!pages[0]); - if (!pages[1]) - nr_pages = 1; - vaddr = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL); - BUG_ON(!vaddr); - local_irq_disable(); + set_fixmap(FIX_TEXT_POKE0, page_to_phys(pages[0])); + if (pages[1]) + set_fixmap(FIX_TEXT_POKE1, page_to_phys(pages[1])); + vaddr = (char *)fix_to_virt(FIX_TEXT_POKE0); + local_irq_save(flags); memcpy(&vaddr[(unsigned long)addr & ~PAGE_MASK], opcode, len); - local_irq_enable(); - vunmap(vaddr); + local_irq_restore(flags); + clear_fixmap(FIX_TEXT_POKE0); + if (pages[1]) + clear_fixmap(FIX_TEXT_POKE1); + local_flush_tlb(); sync_core(); /* Could also do a CLFLUSH here to speed up CPU recovery; but that causes hangs on some VIA CPUs. */ -- 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/