From 27046a3ffbb01ba715e6236c170701c84759b61d Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 29 Aug 2016 08:48:47 +0200 Subject: [PATCH] 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 Signed-off-by: Peter Zijlstra (Intel) Cc: Douglas_Warzecha@dell.com Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner 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 --- drivers/hwmon/dell-smm-hwmon.c | 36 +++++++++++++++++++--------------- 1 file 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 #include #include #include @@ -36,6 +37,7 @@ #include #include #include +#include #include @@ -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, ¤t->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); @@ -231,6 +221,20 @@ out: return rc; } +/* + * 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. */