From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 098ABC4321D for ; Wed, 15 Aug 2018 15:08:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2195021475 for ; Wed, 15 Aug 2018 15:08:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="VdgOmVnk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2195021475 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730807AbeHOSBW (ORCPT ); Wed, 15 Aug 2018 14:01:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:51266 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729528AbeHOSBW (ORCPT ); Wed, 15 Aug 2018 14:01:22 -0400 Received: from jouet.infradead.org (unknown [179.97.41.186]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BE160208B1; Wed, 15 Aug 2018 15:08:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1534345728; bh=tcwPBJ8x9UEBfhreePeI1YzN+BRiKaQuHoJrBIorWFY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VdgOmVnkU7f3pvub1dCeetfMmR+osP5HV2FtwA17VPihgdFlKG32LxprujZfjezfi CljStzsL72Tgxm63wthDmrA9suQVq0tuZrRLy2xHKCAMTy2pIRdPrUUrrVsLdaZGlj MHvDzlhwHzP52XnvxYCCCrXjfRP7W6usmgZici0c= From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Alexander Shishkin , Andy Lutomirski , Dave Hansen , "H . Peter Anvin" , Jiri Olsa , Joerg Roedel , Thomas Gleixner , x86@kernel.org, Arnaldo Carvalho de Melo Subject: [PATCH 34/35] kallsyms, x86: Export addresses of PTI entry trampolines Date: Wed, 15 Aug 2018 12:06:10 -0300 Message-Id: <20180815150611.32080-35-acme@kernel.org> X-Mailer: git-send-email 2.14.4 In-Reply-To: <20180815150611.32080-1-acme@kernel.org> References: <20180815150611.32080-1-acme@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alexander Shishkin Currently, the addresses of PTI entry trampolines are not exported to user space. Kernel profiling tools need these addresses to identify the kernel code, so add a symbol and address for each CPU's PTI entry trampoline. Signed-off-by: Alexander Shishkin Acked-by: Andi Kleen Acked-by: Peter Zijlstra (Intel) Cc: Andy Lutomirski Cc: Dave Hansen Cc: H. Peter Anvin Cc: Jiri Olsa Cc: Joerg Roedel Cc: Thomas Gleixner Cc: x86@kernel.org Link: http://lkml.kernel.org/r/1528289651-4113-3-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo --- arch/x86/mm/cpu_entry_area.c | 23 +++++++++++++++++++++++ kernel/kallsyms.c | 28 +++++++++++++++++++++++++++- 2 files changed, 50 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c index b45f5aaefd74..fab49fd5190f 100644 --- a/arch/x86/mm/cpu_entry_area.c +++ b/arch/x86/mm/cpu_entry_area.c @@ -2,6 +2,7 @@ #include #include +#include #include #include @@ -150,6 +151,28 @@ static void __init setup_cpu_entry_area(int cpu) percpu_setup_debug_store(cpu); } +#ifdef CONFIG_X86_64 +int arch_get_kallsym(unsigned int symnum, unsigned long *value, char *type, + char *name) +{ + unsigned int cpu, ncpu = 0; + + if (symnum >= num_possible_cpus()) + return -EINVAL; + + for_each_possible_cpu(cpu) { + if (ncpu++ >= symnum) + break; + } + + *value = (unsigned long)&get_cpu_entry_area(cpu)->entry_trampoline; + *type = 't'; + strlcpy(name, "__entry_SYSCALL_64_trampoline", KSYM_NAME_LEN); + + return 0; +} +#endif + static __init void setup_cpu_entry_area_ptes(void) { #ifdef CONFIG_X86_32 diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index aa31aa07f2ef..02a0b01380d8 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -432,6 +432,7 @@ int sprint_backtrace(char *buffer, unsigned long address) /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */ struct kallsym_iter { loff_t pos; + loff_t pos_arch_end; loff_t pos_mod_end; loff_t pos_ftrace_mod_end; unsigned long value; @@ -443,9 +444,29 @@ struct kallsym_iter { int show_value; }; +int __weak arch_get_kallsym(unsigned int symnum, unsigned long *value, + char *type, char *name) +{ + return -EINVAL; +} + +static int get_ksymbol_arch(struct kallsym_iter *iter) +{ + int ret = arch_get_kallsym(iter->pos - kallsyms_num_syms, + &iter->value, &iter->type, + iter->name); + + if (ret < 0) { + iter->pos_arch_end = iter->pos; + return 0; + } + + return 1; +} + static int get_ksymbol_mod(struct kallsym_iter *iter) { - int ret = module_get_kallsym(iter->pos - kallsyms_num_syms, + int ret = module_get_kallsym(iter->pos - iter->pos_arch_end, &iter->value, &iter->type, iter->name, iter->module_name, &iter->exported); @@ -501,6 +522,7 @@ static void reset_iter(struct kallsym_iter *iter, loff_t new_pos) iter->nameoff = get_symbol_offset(new_pos); iter->pos = new_pos; if (new_pos == 0) { + iter->pos_arch_end = 0; iter->pos_mod_end = 0; iter->pos_ftrace_mod_end = 0; } @@ -515,6 +537,10 @@ static int update_iter_mod(struct kallsym_iter *iter, loff_t pos) { iter->pos = pos; + if ((!iter->pos_arch_end || iter->pos_arch_end > pos) && + get_ksymbol_arch(iter)) + return 1; + if ((!iter->pos_mod_end || iter->pos_mod_end > pos) && get_ksymbol_mod(iter)) return 1; -- 2.14.4