Subject: Re: [PATCH] pseries: Fix endianness in cpu hotplug and hotremove

From: Thomas Falcon <[email-masked]>
Date: Mon, 08 Sep 2014 10:14:27 -0500

I guess we were both working on it independently.  I had made the 
changes to hotplug a cpu a few weeks ago, but was blocked on removing a 
cpu.  Last week I realized what was blocking me and fixed cpu removal, 
so I sent the patch along.  Since Bharata has already submitted a patch 
that will handle hotplugging, I'll resubmit this with only the changes 
needed to remove a cpu.

Tom

On 09/08/2014 09:07 AM, Nathan Fontenot wrote:
> It looks like you have a lot of the same changes as the patch Bharata
> sent out last week. Including the one issue I saw in Bharata's patch
> below.
>
> On 09/05/2014 02:09 PM, Thomas Falcon wrote:
>> This patch attempts to ensure that all values are in the proper
>> endianness format when both hotadding and hotremoving cpus.
>>
>> Signed-off-by: Thomas Falcon <[email-masked]>
>> ---
>>   arch/powerpc/platforms/pseries/dlpar.c       | 56 ++++++++++++++--------------
>>   arch/powerpc/platforms/pseries/hotplug-cpu.c | 20 +++++-----
>>   2 files changed, 38 insertions(+), 38 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
>> index a2450b8..c1d7e40 100644
>> --- a/arch/powerpc/platforms/pseries/dlpar.c
>> +++ b/arch/powerpc/platforms/pseries/dlpar.c
>> @@ -24,11 +24,11 @@
>>   #include <asm/rtas.h>
>>   
>>   struct cc_workarea {
>> -	u32	drc_index;
>> -	u32	zero;
>> -	u32	name_offset;
>> -	u32	prop_length;
>> -	u32	prop_offset;
>> +	__be32	drc_index;
>> +	__be32	zero;
>> +	__be32	name_offset;
>> +	__be32	prop_length;
>> +	__be32	prop_offset;
>>   };
>>   
>>   void dlpar_free_cc_property(struct property *prop)
>> @@ -48,11 +48,11 @@ static struct property *dlpar_parse_cc_property(struct cc_workarea *ccwa)
>>   	if (!prop)
>>   		return NULL;
>>   
>> -	name = (char *)ccwa + ccwa->name_offset;
>> +	name = (char *)ccwa + be32_to_cpu(ccwa->name_offset);
>>   	prop->name = kstrdup(name, GFP_KERNEL);
>>   
>> -	prop->length = ccwa->prop_length;
>> -	value = (char *)ccwa + ccwa->prop_offset;
>> +	prop->length = be32_to_cpu(ccwa->prop_length);
>> +	value = (char *)ccwa + be32_to_cpu(ccwa->prop_offset);
>>   	prop->value = kmemdup(value, prop->length, GFP_KERNEL);
>>   	if (!prop->value) {
>>   		dlpar_free_cc_property(prop);
>> @@ -78,7 +78,7 @@ static struct device_node *dlpar_parse_cc_node(struct cc_workarea *ccwa,
>>   	if (!dn)
>>   		return NULL;
>>   
>> -	name = (char *)ccwa + ccwa->name_offset;
>> +	name = (char *)ccwa + be32_to_cpu(ccwa->name_offset);
>>   	dn->full_name = kasprintf(GFP_KERNEL, "%s/%s", path, name);
>>   	if (!dn->full_name) {
>>   		kfree(dn);
>> @@ -148,7 +148,7 @@ struct device_node *dlpar_configure_connector(u32 drc_index,
>>   		return NULL;
>>   
>>   	ccwa = (struct cc_workarea *)&data_buf[0];
>> -	ccwa->drc_index = drc_index;
>> +	ccwa->drc_index = cpu_to_be32(drc_index);
> This will break partition migration.
>
> The drc index valued passed into dlpar_configure_connector() from the migration
> path, pseries_devicetree_update(), is already in BE format.
>
> -Nathan
>
>>   	ccwa->zero = 0;
>>   
>>   	do {
>> @@ -363,10 +363,10 @@ static int dlpar_online_cpu(struct device_node *dn)
>>   	int rc = 0;
>>   	unsigned int cpu;
>>   	int len, nthreads, i;
>> -	const u32 *intserv;
>> +	const __be32 *intserv_be;
>>   
>> -	intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
>> -	if (!intserv)
>> +	intserv_be = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
>> +	if (!intserv_be)
>>   		return -EINVAL;
>>   
>>   	nthreads = len / sizeof(u32);
>> @@ -374,7 +374,7 @@ static int dlpar_online_cpu(struct device_node *dn)
>>   	cpu_maps_update_begin();
>>   	for (i = 0; i < nthreads; i++) {
>>   		for_each_present_cpu(cpu) {
>> -			if (get_hard_smp_processor_id(cpu) != intserv[i])
>> +			if (get_hard_smp_processor_id(cpu) != be32_to_cpu(intserv_be[i]))
>>   				continue;
>>   			BUG_ON(get_cpu_current_state(cpu)
>>   					!= CPU_STATE_OFFLINE);
>> @@ -388,7 +388,7 @@ static int dlpar_online_cpu(struct device_node *dn)
>>   		}
>>   		if (cpu == num_possible_cpus())
>>   			printk(KERN_WARNING "Could not find cpu to online "
>> -			       "with physical id 0x%x\n", intserv[i]);
>> +			       "with physical id 0x%x\n", be32_to_cpu(intserv_be[i]));
>>   	}
>>   	cpu_maps_update_done();
>>   
>> @@ -442,18 +442,17 @@ static int dlpar_offline_cpu(struct device_node *dn)
>>   	int rc = 0;
>>   	unsigned int cpu;
>>   	int len, nthreads, i;
>> -	const u32 *intserv;
>> +	const __be32 *intserv_be;
>>   
>> -	intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
>> -	if (!intserv)
>> +	intserv_be = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
>> +	if (!intserv_be)
>>   		return -EINVAL;
>>   
>>   	nthreads = len / sizeof(u32);
>> -
>>   	cpu_maps_update_begin();
>>   	for (i = 0; i < nthreads; i++) {
>>   		for_each_present_cpu(cpu) {
>> -			if (get_hard_smp_processor_id(cpu) != intserv[i])
>> +			if (get_hard_smp_processor_id(cpu) != be32_to_cpu(intserv_be[i]))
>>   				continue;
>>   
>>   			if (get_cpu_current_state(cpu) == CPU_STATE_OFFLINE)
>> @@ -469,20 +468,19 @@ static int dlpar_offline_cpu(struct device_node *dn)
>>   				break;
>>   
>>   			}
>> -
>>   			/*
>>   			 * The cpu is in CPU_STATE_INACTIVE.
>>   			 * Upgrade it's state to CPU_STATE_OFFLINE.
>>   			 */
>>   			set_preferred_offline_state(cpu, CPU_STATE_OFFLINE);
>> -			BUG_ON(plpar_hcall_norets(H_PROD, intserv[i])
>> +			BUG_ON(plpar_hcall_norets(H_PROD, be32_to_cpu(intserv_be[i]))
>>   								!= H_SUCCESS);
>>   			__cpu_die(cpu);
>>   			break;
>>   		}
>>   		if (cpu == num_possible_cpus())
>>   			printk(KERN_WARNING "Could not find cpu to offline "
>> -			       "with physical id 0x%x\n", intserv[i]);
>> +			       "with physical id 0x%x\n", be32_to_cpu(intserv_be[i]));
>>   	}
>>   	cpu_maps_update_done();
>>   
>> @@ -494,26 +492,28 @@ out:
>>   static ssize_t dlpar_cpu_release(const char *buf, size_t count)
>>   {
>>   	struct device_node *dn;
>> -	const u32 *drc_index;
>> +	const __be32 *drc_index_be;
>> +	u32 drc_index;
>>   	int rc;
>>   
>>   	dn = of_find_node_by_path(buf);
>>   	if (!dn)
>>   		return -EINVAL;
>>   
>> -	drc_index = of_get_property(dn, "ibm,my-drc-index", NULL);
>> -	if (!drc_index) {
>> +	drc_index_be = of_get_property(dn, "ibm,my-drc-index", NULL);
>> +	if (!drc_index_be) {
>>   		of_node_put(dn);
>>   		return -EINVAL;
>>   	}
>>   
>> +	drc_index = be32_to_cpup(drc_index_be);
>>   	rc = dlpar_offline_cpu(dn);
>>   	if (rc) {
>>   		of_node_put(dn);
>>   		return -EINVAL;
>>   	}
>>   
>> -	rc = dlpar_release_drc(*drc_index);
>> +	rc = dlpar_release_drc(drc_index);
>>   	if (rc) {
>>   		of_node_put(dn);
>>   		return rc;
>> @@ -521,7 +521,7 @@ static ssize_t dlpar_cpu_release(const char *buf, size_t count)
>>   
>>   	rc = dlpar_detach_node(dn);
>>   	if (rc) {
>> -		dlpar_acquire_drc(*drc_index);
>> +		dlpar_acquire_drc(drc_index);
>>   		return rc;
>>   	}
>>   
>> diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
>> index 20d6297..fc9c2cd 100644
>> --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
>> +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
>> @@ -90,7 +90,7 @@ static void rtas_stop_self(void)
>>   {
>>   	static struct rtas_args args = {
>>   		.nargs = 0,
>> -		.nret = 1,
>> +		.nret = cpu_to_be32(1),
>>   		.rets = &args.args[0],
>>   	};
>>   
>> @@ -247,10 +247,10 @@ static int pseries_add_processor(struct device_node *np)
>>   	unsigned int cpu;
>>   	cpumask_var_t candidate_mask, tmp;
>>   	int err = -ENOSPC, len, nthreads, i;
>> -	const u32 *intserv;
>> +	const __be32 *intserv_be;
>>   
>> -	intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len);
>> -	if (!intserv)
>> +	intserv_be = of_get_property(np, "ibm,ppc-interrupt-server#s", &len);
>> +	if (!intserv_be)
>>   		return 0;
>>   
>>   	zalloc_cpumask_var(&candidate_mask, GFP_KERNEL);
>> @@ -293,7 +293,7 @@ static int pseries_add_processor(struct device_node *np)
>>   	for_each_cpu(cpu, tmp) {
>>   		BUG_ON(cpu_present(cpu));
>>   		set_cpu_present(cpu, true);
>> -		set_hard_smp_processor_id(cpu, *intserv++);
>> +		set_hard_smp_processor_id(cpu, be32_to_cpu(*intserv_be++));
>>   	}
>>   	err = 0;
>>   out_unlock:
>> @@ -312,10 +312,10 @@ static void pseries_remove_processor(struct device_node *np)
>>   {
>>   	unsigned int cpu;
>>   	int len, nthreads, i;
>> -	const u32 *intserv;
>> +	const __be32 *intserv_be;
>>   
>> -	intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len);
>> -	if (!intserv)
>> +	intserv_be = of_get_property(np, "ibm,ppc-interrupt-server#s", &len);
>> +	if (!intserv_be)
>>   		return;
>>   
>>   	nthreads = len / sizeof(u32);
>> @@ -323,7 +323,7 @@ static void pseries_remove_processor(struct device_node *np)
>>   	cpu_maps_update_begin();
>>   	for (i = 0; i < nthreads; i++) {
>>   		for_each_present_cpu(cpu) {
>> -			if (get_hard_smp_processor_id(cpu) != intserv[i])
>> +			if (get_hard_smp_processor_id(cpu) != be32_to_cpu(intserv_be[i]))
>>   				continue;
>>   			BUG_ON(cpu_online(cpu));
>>   			set_cpu_present(cpu, false);
>> @@ -332,7 +332,7 @@ static void pseries_remove_processor(struct device_node *np)
>>   		}
>>   		if (cpu >= nr_cpu_ids)
>>   			printk(KERN_WARNING "Could not find cpu to remove "
>> -			       "with physical id 0x%x\n", intserv[i]);
>> +			       "with physical id 0x%x\n", be32_to_cpu(intserv_be[i]));
>>   	}
>>   	cpu_maps_update_done();
>>   }
>>
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