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From: Juergen Gross <jgross@suse.com>
To: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org
Cc: Juergen Gross <jgross@suse.com>,
	jeremy@goop.org, jdelvare@suse.com, peterz@infradead.org,
	hpa@zytor.com, akataria@vmware.com, x86@kernel.org,
	rusty@rustcorp.com.au, virtualization@lists.linux-foundation.org,
	chrisw@sous-sol.org, mingo@redhat.com, david.vrabel@citrix.com,
	Douglas_Warzecha@dell.com, pali.rohar@gmail.com,
	boris.ostrovsky@oracle.com, tglx@linutronix.de,
	linux@roeck-us.net
Subject: [PATCH v5 5/6] dcdbas: make use of smp_call_on_cpu()
Date: Wed,  6 Apr 2016 16:17:45 +0200	[thread overview]
Message-ID: <1459952266-3687-6-git-send-email-jgross__38399.3027768613$1459952351$gmane$org@suse.com> (raw)
In-Reply-To: <1459952266-3687-1-git-send-email-jgross@suse.com>

Use smp_call_on_cpu() to raise SMI on cpu 0.
Make call secure by adding get_online_cpus() to avoid e.g. suspend
resume cycles in between.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
V4: add call to get_online_cpus()
---
 drivers/firmware/dcdbas.c | 51 ++++++++++++++++++++++++-----------------------
 1 file changed, 26 insertions(+), 25 deletions(-)

diff --git a/drivers/firmware/dcdbas.c b/drivers/firmware/dcdbas.c
index 829eec8..2fe1a13 100644
--- a/drivers/firmware/dcdbas.c
+++ b/drivers/firmware/dcdbas.c
@@ -23,6 +23,7 @@
 #include <linux/platform_device.h>
 #include <linux/dma-mapping.h>
 #include <linux/errno.h>
+#include <linux/cpu.h>
 #include <linux/gfp.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -238,33 +239,14 @@ static ssize_t host_control_on_shutdown_store(struct device *dev,
 	return count;
 }
 
-/**
- * dcdbas_smi_request: generate SMI request
- *
- * Called with smi_data_lock.
- */
-int dcdbas_smi_request(struct smi_cmd *smi_cmd)
+static int raise_smi(void *par)
 {
-	cpumask_var_t old_mask;
-	int ret = 0;
+	struct smi_cmd *smi_cmd = par;
 
-	if (smi_cmd->magic != SMI_CMD_MAGIC) {
-		dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n",
-			 __func__);
-		return -EBADR;
-	}
-
-	/* SMI requires CPU 0 */
-	if (!alloc_cpumask_var(&old_mask, GFP_KERNEL))
-		return -ENOMEM;
-
-	cpumask_copy(old_mask, &current->cpus_allowed);
-	set_cpus_allowed_ptr(current, cpumask_of(0));
 	if (smp_processor_id() != 0) {
 		dev_dbg(&dcdbas_pdev->dev, "%s: failed to get CPU 0\n",
 			__func__);
-		ret = -EBUSY;
-		goto out;
+		return -EBUSY;
 	}
 
 	/* generate SMI */
@@ -280,9 +262,28 @@ int dcdbas_smi_request(struct smi_cmd *smi_cmd)
 		: "memory"
 	);
 
-out:
-	set_cpus_allowed_ptr(current, old_mask);
-	free_cpumask_var(old_mask);
+	return 0;
+}
+/**
+ * dcdbas_smi_request: generate SMI request
+ *
+ * Called with smi_data_lock.
+ */
+int dcdbas_smi_request(struct smi_cmd *smi_cmd)
+{
+	int ret;
+
+	if (smi_cmd->magic != SMI_CMD_MAGIC) {
+		dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n",
+			 __func__);
+		return -EBADR;
+	}
+
+	/* SMI requires CPU 0 */
+	get_online_cpus();
+	ret = smp_call_on_cpu(0, raise_smi, smi_cmd, true);
+	put_online_cpus();
+
 	return ret;
 }
 
-- 
2.6.6


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  parent reply	other threads:[~2016-04-06 14:17 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1459952266-3687-1-git-send-email-jgross@suse.com>
2016-04-06 14:17 ` [PATCH v5 1/6] xen: sync xen header Juergen Gross
2016-04-06 14:17 ` [PATCH v5 2/6] virt, sched: add generic vcpu pinning support Juergen Gross
2016-04-06 14:17 ` [PATCH v5 3/6] smp: add function to execute a function synchronously on a cpu Juergen Gross
2016-04-06 14:17 ` [PATCH v5 4/6] xen: add xen_pin_vcpu() to support calling functions on a dedicated pcpu Juergen Gross
2016-04-06 14:17 ` Juergen Gross [this message]
2016-04-06 14:17 ` [PATCH v5 6/6] hwmon: use smp_call_on_cpu() for dell-smm i8k Juergen Gross
     [not found] ` <1459952266-3687-4-git-send-email-jgross@suse.com>
2016-04-06 18:04   ` [PATCH v5 3/6] smp: add function to execute a function synchronously on a cpu Peter Zijlstra
2016-04-13  8:49 ` [PATCH v5 0/6] Support calling functions on dedicated physical cpu Juergen Gross
     [not found] ` <570E07FD.4030403@suse.com>
2016-05-17 11:21   ` Juergen Gross
     [not found] ` <1459952266-3687-7-git-send-email-jgross@suse.com>
2016-06-13 19:05   ` [PATCH v5 6/6] hwmon: use smp_call_on_cpu() for dell-smm i8k Pali Rohár
     [not found] ` <1459952266-3687-3-git-send-email-jgross@suse.com>
2016-06-15 11:18   ` [PATCH v5 2/6] virt, sched: add generic vcpu pinning support Juergen Gross
     [not found] ` <1459952266-3687-6-git-send-email-jgross@suse.com>
2016-06-15 11:19   ` [PATCH v5 5/6] dcdbas: make use of smp_call_on_cpu() Juergen Gross
2016-06-20  8:40 ` [PATCH v5 0/6] Support calling functions on dedicated physical cpu Juergen Gross
2016-06-27 10:34 ` Juergen Gross

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