[PATCH v2 2/2] pseries: Fix endian issues in cpu hot-removal

[Bharata B Rao]

On Sat, Sep 13, 2014 at 12:41 AM, Thomas Falcon
<tlfalcon at linux.vnet.ibm.com> wrote:
> When removing a cpu, this patch makes sure that values
> gotten from or passed to firmware are in the correct
> endian format.
>
> Signed-off-by: Thomas Falcon <tlfalcon at linux.vnet.ibm.com>
> ---
> Changes in v2:
>
>  Followed suggestions from Michael Ellerman:
>    Conversion of intserv to cpu endian occurs once.
>    Conversion of drc_index to cpu endian occurs once
>    using of_property_read_u32.
> ---
>  arch/powerpc/platforms/pseries/dlpar.c       | 20 +++++++++++---------
>  arch/powerpc/platforms/pseries/hotplug-cpu.c | 10 ++++++----
>  2 files changed, 17 insertions(+), 13 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
> index 9e9f30b2..343dfdf 100644
> --- a/arch/powerpc/platforms/pseries/dlpar.c
> +++ b/arch/powerpc/platforms/pseries/dlpar.c
> @@ -444,7 +444,8 @@ 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;
> +       u32 thread;
>
>         intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
>         if (!intserv)
> @@ -454,8 +455,9 @@ static int dlpar_offline_cpu(struct device_node *dn)
>
>         cpu_maps_update_begin();
>         for (i = 0; i < nthreads; i++) {
> +               thread = be32_to_cpu(intserv[i]);
>                 for_each_present_cpu(cpu) {
> -                       if (get_hard_smp_processor_id(cpu) != intserv[i])
> +                       if (get_hard_smp_processor_id(cpu) != thread)
>                                 continue;
>
>                         if (get_cpu_current_state(cpu) == CPU_STATE_OFFLINE)
> @@ -477,14 +479,14 @@ static int dlpar_offline_cpu(struct device_node *dn)
>                          * 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, thread)
>                                                                 != 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", thread);
>         }
>         cpu_maps_update_done();
>
> @@ -496,15 +498,15 @@ out:
>  static ssize_t dlpar_cpu_release(const char *buf, size_t count)
>  {
>         struct device_node *dn;
> -       const u32 *drc_index;
> +       const 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) {
> +       rc = of_property_read_u32(dn, "ibm,my-drc-index", &drc_index);

Use of const for drc_index causes compilation problems.

Warning on Fedora 20 BE

arch/powerpc/platforms/pseries/dlpar.c: In function ‘dlpar_cpu_release’:
arch/powerpc/platforms/pseries/dlpar.c:508:2: warning: passing
argument 3 of ‘of_property_read_u32’ discards ‘const’ qualifier from
pointer target type [enabled by default]
  rc = of_property_read_u32(dn, "ibm,my-drc-index", &drc_index);
  ^
In file included from arch/powerpc/platforms/pseries/dlpar.c:18:0:
include/linux/of.h:699:19: note: expected ‘u32 *’ but argument is of
type ‘const u32 *’
 static inline int of_property_read_u32(const struct device_node *np,

Error on Ubuntu 14.04 LE

arch/powerpc/platforms/pseries/dlpar.c: In function ‘dlpar_cpu_release’:
arch/powerpc/platforms/pseries/dlpar.c:508:2: error: passing argument
3 of ‘of_property_read_u32’ discards ‘const’ qualifier from pointer
target type [-Werror]
  rc = of_property_read_u32(dn, "ibm,my-drc-index", &drc_index);
  ^
In file included from arch/powerpc/platforms/pseries/dlpar.c:18:0:
include/linux/of.h:699:19: note: expected ‘u32 *’ but argument is of
type ‘const u32 *’
 static inline int of_property_read_u32(const struct device_node *np,
                   ^
cc1: all warnings being treated as errors

Regards,
Bharata.