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>
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@ -21,6 +21,7 @@
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/cpu.h>
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#include <linux/delay.h>
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#include <linux/module.h>
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#include <linux/types.h>
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@ -36,6 +37,7 @@
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#include <linux/io.h>
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#include <linux/sched.h>
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#include <linux/ctype.h>
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#include <linux/smp.h>
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#include <linux/i8k.h>
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@ -134,11 +136,11 @@ static inline const char *i8k_get_dmi_data(int field)
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/*
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* Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
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*/
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static int i8k_smm(struct smm_regs *regs)
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static int i8k_smm_func(void *par)
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{
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int rc;
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struct smm_regs *regs = par;
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int eax = regs->eax;
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cpumask_var_t old_mask;
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#ifdef DEBUG
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int ebx = regs->ebx;
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@ -149,16 +151,8 @@ static int i8k_smm(struct smm_regs *regs)
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#endif
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/* SMM requires CPU 0 */
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if (!alloc_cpumask_var(&old_mask, GFP_KERNEL))
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return -ENOMEM;
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cpumask_copy(old_mask, ¤t->cpus_allowed);
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rc = set_cpus_allowed_ptr(current, cpumask_of(0));
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if (rc)
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goto out;
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if (smp_processor_id() != 0) {
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rc = -EBUSY;
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goto out;
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}
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if (smp_processor_id() != 0)
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return -EBUSY;
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#if defined(CONFIG_X86_64)
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asm volatile("pushq %%rax\n\t"
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@ -216,10 +210,6 @@ static int i8k_smm(struct smm_regs *regs)
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if (rc != 0 || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
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rc = -EINVAL;
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out:
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set_cpus_allowed_ptr(current, old_mask);
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free_cpumask_var(old_mask);
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#ifdef DEBUG
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rettime = ktime_get();
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delta = ktime_sub(rettime, calltime);
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@ -231,6 +221,20 @@ out:
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return rc;
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}
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/*
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* Call the System Management Mode BIOS.
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*/
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static int i8k_smm(struct smm_regs *regs)
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{
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int ret;
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get_online_cpus();
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ret = smp_call_on_cpu(0, i8k_smm_func, regs, true);
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put_online_cpus();
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return ret;
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}
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/*
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* Read the fan status.
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*/
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