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Commit 1ff6e97f authored by Rusty Russell's avatar Rusty Russell Committed by Dave Jones
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[CPUFREQ] cpumask: avoid playing with cpus_allowed in powernow-k8.c 



cpumask: avoid playing with cpus_allowed in powernow-k8.c

It's generally a very bad idea to mug some process's cpumask: it could
legitimately and reasonably be changed by root, which could break us
(if done before our code) or them (if we restore the wrong value).

I did not replace powernowk8_target; it needs fixing, but it grabs a
mutex (so no smp_call_function_single here) but Mark points out it can
be called multiple times per second, so work_on_cpu is too heavy.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
To: cpufreq@vger.kernel.org
Acked-by: default avatarMark Langsdorf <mark.langsdorf@amd.com>
Tested-by: default avatarMark Langsdorf <mark.langsdorf@amd.com>
Signed-off-by: default avatarDave Jones <davej@redhat.com>
parent e3f996c2

arch/x86/kernel/cpu/cpufreq/powernow-k8.c

+60 −58
Original line number Diff line number Diff line
@@ -508,41 +508,34 @@ static int core_voltage_post_transition(struct powernow_k8_data *data, 
	return 0;

}



static int check_supported_cpu(unsigned int cpu)

static void check_supported_cpu(void *_rc)

{

	cpumask_t oldmask;

	u32 eax, ebx, ecx, edx;

	unsigned int rc = 0;



	oldmask = current->cpus_allowed;

	set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));

	int *rc = _rc;



	if (smp_processor_id() != cpu) {

		printk(KERN_ERR PFX "limiting to cpu %u failed\n", cpu);

		goto out;

	}

	*rc = -ENODEV;



	if (current_cpu_data.x86_vendor != X86_VENDOR_AMD)

		goto out;

		return;



	eax = cpuid_eax(CPUID_PROCESSOR_SIGNATURE);

	if (((eax & CPUID_XFAM) != CPUID_XFAM_K8) &&

	    ((eax & CPUID_XFAM) < CPUID_XFAM_10H))

		goto out;

		return;



	if ((eax & CPUID_XFAM) == CPUID_XFAM_K8) {

		if (((eax & CPUID_USE_XFAM_XMOD) != CPUID_USE_XFAM_XMOD) ||

		    ((eax & CPUID_XMOD) > CPUID_XMOD_REV_MASK)) {

			printk(KERN_INFO PFX

				"Processor cpuid %x not supported\n", eax);

			goto out;

			return;

		}



		eax = cpuid_eax(CPUID_GET_MAX_CAPABILITIES);

		if (eax < CPUID_FREQ_VOLT_CAPABILITIES) {

			printk(KERN_INFO PFX

			       "No frequency change capabilities detected\n");

			goto out;

			return;

		}



		cpuid(CPUID_FREQ_VOLT_CAPABILITIES, &eax, &ebx, &ecx, &edx);
@@ -550,21 +543,17 @@ static int check_supported_cpu(unsigned int cpu) 
			!= P_STATE_TRANSITION_CAPABLE) {

			printk(KERN_INFO PFX

				"Power state transitions not supported\n");

			goto out;

			return;

		}

	} else { /* must be a HW Pstate capable processor */

		cpuid(CPUID_FREQ_VOLT_CAPABILITIES, &eax, &ebx, &ecx, &edx);

		if ((edx & USE_HW_PSTATE) == USE_HW_PSTATE)

			cpu_family = CPU_HW_PSTATE;

		else

			goto out;

			return;

	}



	rc = 1;



out:

	set_cpus_allowed_ptr(current, &oldmask);

	return rc;

	*rc = 0;

}



static int check_pst_table(struct powernow_k8_data *data, struct pst_s *pst,
@@ -1247,6 +1236,32 @@ static int powernowk8_verify(struct cpufreq_policy *pol) 
	return cpufreq_frequency_table_verify(pol, data->powernow_table);

}



struct init_on_cpu {

	struct powernow_k8_data *data;

	int rc;

};



static void __cpuinit powernowk8_cpu_init_on_cpu(void *_init_on_cpu)

{

	struct init_on_cpu *init_on_cpu = _init_on_cpu;



	if (pending_bit_stuck()) {

		printk(KERN_ERR PFX "failing init, change pending bit set\n");

		init_on_cpu->rc = -ENODEV;

		return;

	}



	if (query_current_values_with_pending_wait(init_on_cpu->data)) {

		init_on_cpu->rc = -ENODEV;

		return;

	}



	if (cpu_family == CPU_OPTERON)

		fidvid_msr_init();



	init_on_cpu->rc = 0;

}



/* per CPU init entry point to the driver */

static int __cpuinit powernowk8_cpu_init(struct cpufreq_policy *pol)

{
@@ -1254,13 +1269,14 @@ static int __cpuinit powernowk8_cpu_init(struct cpufreq_policy *pol) 
		KERN_ERR FW_BUG PFX "No compatible ACPI _PSS objects found.\n"

		KERN_ERR FW_BUG PFX "Try again with latest BIOS.\n";

	struct powernow_k8_data *data;

	cpumask_t oldmask;

	struct init_on_cpu init_on_cpu;

	int rc;



	if (!cpu_online(pol->cpu))

		return -ENODEV;



	if (!check_supported_cpu(pol->cpu))

	smp_call_function_single(pol->cpu, check_supported_cpu, &rc, 1);

	if (rc)

		return -ENODEV;



	data = kzalloc(sizeof(struct powernow_k8_data), GFP_KERNEL);
@@ -1300,27 +1316,12 @@ static int __cpuinit powernowk8_cpu_init(struct cpufreq_policy *pol) 
		pol->cpuinfo.transition_latency = get_transition_latency(data);



	/* only run on specific CPU from here on */

	oldmask = current->cpus_allowed;

	set_cpus_allowed_ptr(current, &cpumask_of_cpu(pol->cpu));



	if (smp_processor_id() != pol->cpu) {

		printk(KERN_ERR PFX "limiting to cpu %u failed\n", pol->cpu);

		goto err_out_unmask;

	}



	if (pending_bit_stuck()) {

		printk(KERN_ERR PFX "failing init, change pending bit set\n");

		goto err_out_unmask;

	}



	if (query_current_values_with_pending_wait(data))

		goto err_out_unmask;



	if (cpu_family == CPU_OPTERON)

		fidvid_msr_init();



	/* run on any CPU again */

	set_cpus_allowed_ptr(current, &oldmask);

	init_on_cpu.data = data;

	smp_call_function_single(data->cpu, powernowk8_cpu_init_on_cpu,

				 &init_on_cpu, 1);

	rc = init_on_cpu.rc;

	if (rc != 0)

		goto err_out_exit_acpi;



	if (cpu_family == CPU_HW_PSTATE)

		cpumask_copy(pol->cpus, cpumask_of(pol->cpu));
@@ -1357,8 +1358,7 @@ static int __cpuinit powernowk8_cpu_init(struct cpufreq_policy *pol) 


	return 0;



err_out_unmask:

	set_cpus_allowed_ptr(current, &oldmask);

err_out_exit_acpi:

	powernow_k8_cpu_exit_acpi(data);



err_out:
@@ -1383,24 +1383,25 @@ static int __devexit powernowk8_cpu_exit(struct cpufreq_policy *pol) 
	return 0;

}



static void query_values_on_cpu(void *_err)

{

	int *err = _err;

	struct powernow_k8_data *data = __get_cpu_var(powernow_data);



	*err = query_current_values_with_pending_wait(data);

}



static unsigned int powernowk8_get(unsigned int cpu)

{

	struct powernow_k8_data *data = per_cpu(powernow_data, cpu);

	cpumask_t oldmask = current->cpus_allowed;

	unsigned int khz = 0;

	int err;



	if (!data)

		return -EINVAL;



	set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));

	if (smp_processor_id() != cpu) {

		printk(KERN_ERR PFX

			"limiting to CPU %d failed in powernowk8_get\n", cpu);

		set_cpus_allowed_ptr(current, &oldmask);

		return 0;

	}



	if (query_current_values_with_pending_wait(data))

	smp_call_function_single(cpu, query_values_on_cpu, &err, true);

	if (err)

		goto out;



	if (cpu_family == CPU_HW_PSTATE)
@@ -1411,7 +1412,6 @@ static unsigned int powernowk8_get(unsigned int cpu) 




out:

	set_cpus_allowed_ptr(current, &oldmask);

	return khz;

}
@@ -1437,7 +1437,9 @@ static int __cpuinit powernowk8_init(void) 
	unsigned int i, supported_cpus = 0;



	for_each_online_cpu(i) {

		if (check_supported_cpu(i))

		int rc;

		smp_call_function_single(i, check_supported_cpu, &rc, 1);

		if (rc == 0)

			supported_cpus++;

	}