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authorJuergen Gross <jgross@suse.com>2016-08-29 09:48:47 +0300
committerIngo Molnar <mingo@kernel.org>2016-09-05 14:52:41 +0300
commit27046a3ffbb01ba715e6236c170701c84759b61d (patch)
treea14915541849c1dc9355a176ef204d1cbd7580d6 /drivers/hwmon
parente23f22b5cb9e44da24cb8494707536211adff8d1 (diff)
downloadlinux-27046a3ffbb01ba715e6236c170701c84759b61d.tar.xz
hwmon: Use smp_call_on_cpu() for dell-smm i8k
Use the smp_call_on_cpu() function to call system management mode 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> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Douglas_Warzecha@dell.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akataria@vmware.com Cc: boris.ostrovsky@oracle.com Cc: chrisw@sous-sol.org Cc: david.vrabel@citrix.com Cc: hpa@zytor.com Cc: jdelvare@suse.com Cc: jeremy@goop.org Cc: linux@roeck-us.net Cc: pali.rohar@gmail.com Cc: rusty@rustcorp.com.au Cc: virtualization@lists.linux-foundation.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1472453327-19050-7-git-send-email-jgross@suse.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/hwmon')
-rw-r--r--drivers/hwmon/dell-smm-hwmon.c36
1 files changed, 20 insertions, 16 deletions
diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
index acf9c0361d9f..34704b0451b4 100644
--- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -21,6 +21,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/types.h>
@@ -36,6 +37,7 @@
#include <linux/io.h>
#include <linux/sched.h>
#include <linux/ctype.h>
+#include <linux/smp.h>
#include <linux/i8k.h>
@@ -134,11 +136,11 @@ static inline const char *i8k_get_dmi_data(int field)
/*
* Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
*/
-static int i8k_smm(struct smm_regs *regs)
+static int i8k_smm_func(void *par)
{
int rc;
+ struct smm_regs *regs = par;
int eax = regs->eax;
- cpumask_var_t old_mask;
#ifdef DEBUG
int ebx = regs->ebx;
@@ -149,16 +151,8 @@ static int i8k_smm(struct smm_regs *regs)
#endif
/* SMM requires CPU 0 */
- if (!alloc_cpumask_var(&old_mask, GFP_KERNEL))
- return -ENOMEM;
- cpumask_copy(old_mask, &current->cpus_allowed);
- rc = set_cpus_allowed_ptr(current, cpumask_of(0));
- if (rc)
- goto out;
- if (smp_processor_id() != 0) {
- rc = -EBUSY;
- goto out;
- }
+ if (smp_processor_id() != 0)
+ return -EBUSY;
#if defined(CONFIG_X86_64)
asm volatile("pushq %%rax\n\t"
@@ -216,10 +210,6 @@ static int i8k_smm(struct smm_regs *regs)
if (rc != 0 || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
rc = -EINVAL;
-out:
- set_cpus_allowed_ptr(current, old_mask);
- free_cpumask_var(old_mask);
-
#ifdef DEBUG
rettime = ktime_get();
delta = ktime_sub(rettime, calltime);
@@ -232,6 +222,20 @@ out:
}
/*
+ * Call the System Management Mode BIOS.
+ */
+static int i8k_smm(struct smm_regs *regs)
+{
+ int ret;
+
+ get_online_cpus();
+ ret = smp_call_on_cpu(0, i8k_smm_func, regs, true);
+ put_online_cpus();
+
+ return ret;
+}
+
+/*
* Read the fan status.
*/
static int i8k_get_fan_status(int fan)