From patchwork Sun Feb 10 21:37:27 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Len Brown X-Patchwork-Id: 2122971 X-Patchwork-Delegate: lenb@kernel.org Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 710A3DF24C for ; Sun, 10 Feb 2013 21:37:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756529Ab3BJVhb (ORCPT ); Sun, 10 Feb 2013 16:37:31 -0500 Received: from mail-vc0-f180.google.com ([209.85.220.180]:59790 "EHLO mail-vc0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755786Ab3BJVha (ORCPT ); Sun, 10 Feb 2013 16:37:30 -0500 Received: by mail-vc0-f180.google.com with SMTP id fo13so3467260vcb.11 for ; Sun, 10 Feb 2013 13:37:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:sender:message-id:date:from:user-agent:mime-version:to :cc:subject:references:in-reply-to:content-type :content-transfer-encoding; bh=81FRcDHpe/xHPoCUeSpWL80hhBSbTDRmBsoFu/3MWJ8=; b=kRCDCpzHkWXLnLG6T4jh28p69F7WH3NgplrMWK1t17L6TXh1vJibQZHN/kNhLuQ7cz S9mJZZcdUsbMwQx5yu2T89ZgDjum0gOMBXiIO7CDEVGhynOcG2f232yOqvPEhUV5Bgig NwaU3n2zsNSLpYhEjv75JpE6HO1mE7vZkz+CdcM7CdMzdd65/ksYr2qr/HVFHd9inwdc zagCgR75sGZTCmumfakipWJ/QOTETwcPpb33on7bK1xAsOP4mlA3CVrC2/MmB+yhWOmh JoFpd5P4JFxzWwpFa2s3TrALReI1XccMpUQelhAkSWTKCcDpX9qpPmaX1CDEfkuxy73c JIJg== X-Received: by 10.52.29.109 with SMTP id j13mr14047848vdh.111.1360532249707; Sun, 10 Feb 2013 13:37:29 -0800 (PST) Received: from [192.168.0.98] (pool-108-7-58-246.bstnma.fios.verizon.net. [108.7.58.246]) by mx.google.com with ESMTPS id mj8sm55669034veb.8.2013.02.10.13.37.28 (version=TLSv1 cipher=RC4-SHA bits=128/128); Sun, 10 Feb 2013 13:37:28 -0800 (PST) Message-ID: <51181317.1080905@kernel.org> Date: Sun, 10 Feb 2013 16:37:27 -0500 From: Len Brown User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Len Brown CC: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Len Brown , x86@kernel.org Subject: [PATCH 2/2 v2] x86 idle: remove 32-bit-only "no-hlt" parameter, hlt_works_ok flag References: <1360483829-16349-1-git-send-email-lenb@kernel.org> In-Reply-To: Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Len Brown Remove 32-bit x86 a cmdline param "no-hlt", and the cpuinfo_x86.hlt_works_ok that it sets. If a user wants to avoid HLT, then "idle=poll" is much more useful, as it avoids invocation of HLT in idle, while "no-hlt" failed to do so. Indeed, hlt_works_ok was consulted in only 3 places. First, in /proc/cpuinfo where "hlt_bug yes" would be printed if and only if the user booted the system with "no-hlt" -- as there was no other code to set that flag. Second, check_hlt() would not invoke halt() if "no-hlt" were on the cmdline. Third, it was consulted in stop_this_cpu(), which is invoked by native_machine_halt()/reboot_interrupt()/smp_stop_nmi_callback() -- all cases where the machine is being shutdown/reset. The flag was not consulted in the more frequently invoked play_dead()/hlt_play_dead() used in processor offline and suspend. Since Linux-3.0 there has been a run-time notice upon "no-hlt" invocations indicating that it would be removed in 2012. Signed-off-by: Len Brown Cc: x86@kernel.org --- v2: remove also check_hlt() --- Documentation/kernel-parameters.txt | 4 ---- arch/x86/include/asm/processor.h | 10 ---------- arch/x86/kernel/cpu/bugs.c | 27 --------------------------- arch/x86/kernel/cpu/proc.c | 2 -- arch/x86/kernel/process.c | 6 ++---- arch/x86/xen/setup.c | 3 --- 6 files changed, 2 insertions(+), 50 deletions(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 3b0cd1e..109ee45 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1881,10 +1881,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted. wfi(ARM) instruction doesn't work correctly and not to use it. This is also useful when using JTAG debugger. - no-hlt [BUGS=X86-32] Tells the kernel that the hlt - instruction doesn't work correctly and not to - use it. - no_file_caps Tells the kernel not to honor file capabilities. The only way then for a file to be executed with privilege is to be setuid root or executed by root. diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 8a28fea..b9e7d27 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -89,7 +89,6 @@ struct cpuinfo_x86 { char wp_works_ok; /* It doesn't on 386's */ /* Problems on some 486Dx4's and old 386's: */ - char hlt_works_ok; char hard_math; char rfu; char fdiv_bug; @@ -165,15 +164,6 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info); extern const struct seq_operations cpuinfo_op; -static inline int hlt_works(int cpu) -{ -#ifdef CONFIG_X86_32 - return cpu_data(cpu).hlt_works_ok; -#else - return 1; -#endif -} - #define cache_line_size() (boot_cpu_data.x86_cache_alignment) extern void cpu_detect(struct cpuinfo_x86 *c); diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 92dfec9..af6455e 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -17,15 +17,6 @@ #include #include -static int __init no_halt(char *s) -{ - WARN_ONCE(1, "\"no-hlt\" is deprecated, please use \"idle=poll\"\n"); - boot_cpu_data.hlt_works_ok = 0; - return 1; -} - -__setup("no-hlt", no_halt); - static int __init no_387(char *s) { boot_cpu_data.hard_math = 0; @@ -89,23 +80,6 @@ static void __init check_fpu(void) pr_warn("Hmm, FPU with FDIV bug\n"); } -static void __init check_hlt(void) -{ - if (boot_cpu_data.x86 >= 5 || paravirt_enabled()) - return; - - pr_info("Checking 'hlt' instruction... "); - if (!boot_cpu_data.hlt_works_ok) { - pr_cont("disabled\n"); - return; - } - halt(); - halt(); - halt(); - halt(); - pr_cont("OK\n"); -} - /* * Check whether we are able to run this kernel safely on SMP. * @@ -129,7 +103,6 @@ void __init check_bugs(void) print_cpu_info(&boot_cpu_data); #endif check_config(); - check_hlt(); init_utsname()->machine[1] = '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86); alternative_instructions(); diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c index 3286a92..e280253 100644 --- a/arch/x86/kernel/cpu/proc.c +++ b/arch/x86/kernel/cpu/proc.c @@ -28,7 +28,6 @@ static void show_cpuinfo_misc(struct seq_file *m, struct cpuinfo_x86 *c) { seq_printf(m, "fdiv_bug\t: %s\n" - "hlt_bug\t\t: %s\n" "f00f_bug\t: %s\n" "coma_bug\t: %s\n" "fpu\t\t: %s\n" @@ -36,7 +35,6 @@ static void show_cpuinfo_misc(struct seq_file *m, struct cpuinfo_x86 *c) "cpuid level\t: %d\n" "wp\t\t: %s\n", c->fdiv_bug ? "yes" : "no", - c->hlt_works_ok ? "no" : "yes", c->f00f_bug ? "yes" : "no", c->coma_bug ? "yes" : "no", c->hard_math ? "yes" : "no", diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index cd5a4c9..aef852e 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -415,10 +415,8 @@ void stop_this_cpu(void *dummy) set_cpu_online(smp_processor_id(), false); disable_local_APIC(); - for (;;) { - if (hlt_works(smp_processor_id())) - halt(); - } + for (;;) + halt(); } /* diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 2b73b5c..94eac5c 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -556,9 +556,6 @@ void __init xen_arch_setup(void) COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE); /* Set up idle, making sure it calls safe_halt() pvop */ -#ifdef CONFIG_X86_32 - boot_cpu_data.hlt_works_ok = 1; -#endif disable_cpuidle(); disable_cpufreq(); WARN_ON(xen_set_default_idle());