From: Fenghua Yu <fenghua.yu@intel.com>
To: "Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>, "H Peter Anvin" <hpa@zytor.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Dave Hansen" <dave.hansen@intel.com>,
"Ashok Raj" <ashok.raj@intel.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Ravi V Shankar" <ravi.v.shankar@intel.com>,
"Xiaoyao Li " <xiaoyao.li@intel.com>,
"Christopherson Sean J" <sean.j.christopherson@intel.com>,
"Kalle Valo" <kvalo@codeaurora.org>,
"Michael Chan" <michael.chan@broadcom.com>
Cc: "linux-kernel" <linux-kernel@vger.kernel.org>,
"x86" <x86@kernel.org>,
kvm@vger.kernel.org, netdev@vger.kernel.org,
linux-wireless@vger.kernel.org, Fenghua Yu <fenghua.yu@intel.com>
Subject: [PATCH v8 15/15] x86/split_lock: Add a sysfs interface to enable/disable split lock detection during run time
Date: Wed, 24 Apr 2019 12:33:02 -0700 [thread overview]
Message-ID: <1556134382-58814-16-git-send-email-fenghua.yu@intel.com> (raw)
In-Reply-To: <1556134382-58814-1-git-send-email-fenghua.yu@intel.com>
To workaround or debug a split lock issue, the administrator may need to
disable or enable split lock detection during run time without rebooting
the system.
The interface /sys/device/system/cpu/split_lock_detect is added to allow
the administrator to disable or enable split lock detection and show
current split lock detection setting.
Writing [yY1] or [oO][nN] to the file enables split lock detection and
writing [nN0] or [oO][fF] disables split lock detection. Split lock
detection is enabled or disabled on all CPUs.
Reading the file returns current global split lock detection setting:
0: disabled
1: enabled
Add an ABI document entry for /sys/devices/system/cpu/split_lock_detect.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
Not sure if the justification for the sysfs knob is valid. If not, this
patch could be removed from this patch set.
.../ABI/testing/sysfs-devices-system-cpu | 22 ++++++++
arch/x86/kernel/cpu/intel.c | 52 ++++++++++++++++++-
2 files changed, 72 insertions(+), 2 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 9605dbd4b5b5..aad7b1698065 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -67,6 +67,28 @@ Description: Discover NUMA node a CPU belongs to
/sys/devices/system/cpu/cpu42/node2 -> ../../node/node2
+What: /sys/devices/system/cpu/split_lock_detect
+Date: March 2019
+Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
+Description: (RW) Control split lock detection on Intel Tremont and
+ future CPUs
+
+ Reads return split lock detection status:
+ 0: disabled
+ 1: enabled
+
+ Writes enable or disable split lock detection:
+ The first character is one of 'Nn0' or [oO][fF] for off
+ disables the feature.
+ The first character is one of 'Yy1' or [oO][nN] for on
+ enables the feature.
+
+ Please note the interface only shows or controls global setting.
+ During run time, split lock detection on one CPU may be
+ disabled if split lock operation in kernel code happens on
+ the CPU. The interface doesn't show or control split lock
+ detection on individual CPU.
+
What: /sys/devices/system/cpu/cpu#/topology/core_id
/sys/devices/system/cpu/cpu#/topology/core_siblings
/sys/devices/system/cpu/cpu#/topology/core_siblings_list
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 959ebf25beda..f257d1e92706 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -35,6 +35,7 @@
DEFINE_PER_CPU(u64, msr_test_ctl_cache);
EXPORT_PER_CPU_SYMBOL_GPL(msr_test_ctl_cache);
+static DEFINE_MUTEX(split_lock_detect_mutex);
static bool split_lock_detect_enable;
/*
@@ -660,7 +661,7 @@ static void init_intel_misc_features(struct cpuinfo_x86 *c)
wrmsrl(MSR_MISC_FEATURES_ENABLES, msr);
}
-static void split_lock_update_msr(void)
+static void split_lock_update_msr(void *__unused)
{
if (split_lock_detect_enable) {
/* Enable split lock detection */
@@ -682,7 +683,7 @@ static void init_split_lock_detect(struct cpuinfo_x86 *c)
rdmsrl(MSR_TEST_CTL, test_ctl_val);
this_cpu_write(msr_test_ctl_cache, test_ctl_val);
- split_lock_update_msr();
+ split_lock_update_msr(NULL);
}
}
@@ -1114,3 +1115,50 @@ void handle_split_lock_kernel_mode(void)
this_cpu_and(msr_test_ctl_cache, ~TEST_CTL_SPLIT_LOCK_DETECT);
WARN_ONCE(1, "split lock operation detected\n");
}
+
+static ssize_t
+split_lock_detect_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%u\n", split_lock_detect_enable);
+}
+
+static ssize_t
+split_lock_detect_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ bool val;
+ int ret;
+
+ ret = strtobool(buf, &val);
+ if (ret)
+ return ret;
+
+ mutex_lock(&split_lock_detect_mutex);
+
+ split_lock_detect_enable = val;
+
+ /* Update the split lock detection setting in MSR on all online CPUs. */
+ on_each_cpu(split_lock_update_msr, NULL, 1);
+
+ if (split_lock_detect_enable)
+ pr_info("enabled\n");
+ else
+ pr_info("disabled\n");
+
+ mutex_unlock(&split_lock_detect_mutex);
+
+ return count;
+}
+
+static DEVICE_ATTR_RW(split_lock_detect);
+
+static int __init split_lock_init(void)
+{
+ if (!boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT))
+ return -ENODEV;
+
+ return device_create_file(cpu_subsys.dev_root,
+ &dev_attr_split_lock_detect);
+}
+subsys_initcall(split_lock_init);
--
2.19.1
next prev parent reply other threads:[~2019-04-24 19:41 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-24 19:32 [PATCH v8 00/15] x86/split_lock: Enable split lock detection Fenghua Yu
2019-04-24 19:32 ` [PATCH v8 01/15] x86/common: Align cpu_caps_cleared and cpu_caps_set to unsigned long Fenghua Yu
2019-04-24 19:32 ` [PATCH v8 02/15] drivers/net/b44: Align pwol_mask to unsigned long for better performance Fenghua Yu
2019-04-24 19:32 ` [PATCH v8 03/15] wlcore: simplify/fix/optimize reg_ch_conf_pending operations Fenghua Yu
2019-04-25 17:12 ` Kalle Valo
2019-04-24 19:32 ` [PATCH v8 04/15] x86/split_lock: Align x86_capability to unsigned long to avoid split locked access Fenghua Yu
2019-04-24 19:32 ` [PATCH v8 05/15] x86/msr-index: Define MSR_IA32_CORE_CAPABILITY and split lock detection bit Fenghua Yu
2019-04-25 5:45 ` Ingo Molnar
2019-04-25 19:01 ` Fenghua Yu
2019-04-25 19:47 ` Ingo Molnar
2019-04-25 19:51 ` Fenghua Yu
2019-04-25 20:08 ` Ingo Molnar
2019-04-25 20:22 ` Fenghua Yu
2019-04-26 6:00 ` Ingo Molnar
2019-05-06 0:12 ` Fenghua Yu
2019-04-24 19:32 ` [PATCH v8 06/15] x86/cpufeatures: Enumerate MSR_IA32_CORE_CAPABILITY Fenghua Yu
2019-04-24 19:32 ` [PATCH v8 07/15] x86/split_lock: Enumerate split lock detection by MSR_IA32_CORE_CAPABILITY Fenghua Yu
2019-04-24 19:32 ` [PATCH v8 08/15] x86/split_lock: Enumerate split lock detection on Icelake mobile processor Fenghua Yu
2019-04-24 19:32 ` [PATCH v8 09/15] x86/split_lock: Define MSR TEST_CTL register Fenghua Yu
2019-04-25 6:21 ` Ingo Molnar
2019-04-25 19:48 ` Fenghua Yu
2019-04-24 19:32 ` [PATCH v8 10/15] x86/split_lock: Handle #AC exception for split lock Fenghua Yu
2019-04-25 6:07 ` Ingo Molnar
2019-04-25 7:29 ` Thomas Gleixner
2019-04-24 19:32 ` [PATCH v8 11/15] kvm/x86: Emulate MSR IA32_CORE_CAPABILITY Fenghua Yu
2019-04-24 19:32 ` [PATCH v8 12/15] kvm/vmx: Emulate MSR TEST_CTL Fenghua Yu
2019-04-25 7:42 ` Thomas Gleixner
2019-04-27 12:20 ` Xiaoyao Li
2019-04-28 7:09 ` Thomas Gleixner
2019-04-28 7:34 ` Xiaoyao Li
2019-04-29 7:31 ` Thomas Gleixner
2019-04-29 5:21 ` Xiaoyao Li
2019-04-24 19:33 ` [PATCH v8 13/15] x86/split_lock: Enable split lock detection by default Fenghua Yu
2019-04-25 7:50 ` Thomas Gleixner
2019-05-06 21:39 ` Fenghua Yu
2019-04-25 10:52 ` David Laight
2019-04-25 10:58 ` Thomas Gleixner
2019-04-25 11:13 ` David Laight
2019-04-25 11:41 ` Peter Zijlstra
2019-04-25 13:04 ` Thomas Gleixner
2019-05-07 20:48 ` Fenghua Yu
2019-04-24 19:33 ` [PATCH v8 14/15] x86/split_lock: Disable split lock detection by kernel parameter "nosplit_lock_detect" Fenghua Yu
2019-04-24 19:33 ` Fenghua Yu [this message]
2019-04-25 6:31 ` [PATCH v8 15/15] x86/split_lock: Add a sysfs interface to enable/disable split lock detection during run time Ingo Molnar
2019-05-06 0:21 ` Fenghua Yu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1556134382-58814-16-git-send-email-fenghua.yu@intel.com \
--to=fenghua.yu@intel.com \
--cc=ashok.raj@intel.com \
--cc=bp@alien8.de \
--cc=dave.hansen@intel.com \
--cc=hpa@zytor.com \
--cc=kvalo@codeaurora.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-wireless@vger.kernel.org \
--cc=michael.chan@broadcom.com \
--cc=mingo@redhat.com \
--cc=netdev@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=ravi.v.shankar@intel.com \
--cc=sean.j.christopherson@intel.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
--cc=xiaoyao.li@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).