sparc64: Fix cpu_possible_mask if nr_cpus is set

If kernel boot parameter nr_cpus is set, it should define the number
of CPUs that can ever be available in the system i.e.
cpu_possible_mask. setup_nr_cpu_ids() overrides the nr_cpu_ids based
on the cpu_possible_mask during kernel initialization. If
cpu_possible_mask is not set based on the nr_cpus value, earlier part
of the kernel would be initialized using nr_cpus value leading to a
kernel crash.

Set cpu_possible_mask based on nr_cpus value. Thus setup_nr_cpu_ids()
becomes redundant and does not corrupt nr_cpu_ids value.

Signed-off-by: Atish Patra <atish.patra@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Reviewed-by: Vijay Kumar <vijay.ac.kumar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc/include/asm/smp_64.h b/arch/sparc/include/asm/smp_64.h
index 26d9e77..87b0575 100644 (file)
--- a/arch/sparc/include/asm/smp_64.h
+++ b/arch/sparc/include/asm/smp_64.h
@@ -43,6 +43,7 @@ void arch_send_call_function_ipi_mask(const struct cpumask *mask);
 int hard_smp_processor_id(void);
 #define raw_smp_processor_id() (current_thread_info()->cpu)
 
+void smp_fill_in_cpu_possible_map(void);
 void smp_fill_in_sib_core_maps(void);
 void cpu_play_dead(void);
 

diff --git a/arch/sparc/kernel/setup_64.c b/arch/sparc/kernel/setup_64.c
index 599f120..f32cfe8 100644 (file)
--- a/arch/sparc/kernel/setup_64.c
+++ b/arch/sparc/kernel/setup_64.c
@@ -650,6 +650,7 @@ void __init setup_arch(char **cmdline_p)
 
        paging_init();
        init_sparc64_elf_hwcap();
+       smp_fill_in_cpu_possible_map();
 }
 
 extern int stop_a_enabled;

diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index 8a6151a..d3035ba 100644 (file)
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1227,6 +1227,20 @@ void __init smp_setup_processor_id(void)
                xcall_deliver_impl = hypervisor_xcall_deliver;
 }
 
+void __init smp_fill_in_cpu_possible_map(void)
+{
+       int possible_cpus = num_possible_cpus();
+       int i;
+
+       if (possible_cpus > nr_cpu_ids)
+               possible_cpus = nr_cpu_ids;
+
+       for (i = 0; i < possible_cpus; i++)
+               set_cpu_possible(i, true);
+       for (; i < NR_CPUS; i++)
+               set_cpu_possible(i, false);
+}
+
 void smp_fill_in_sib_core_maps(void)
 {
        unsigned int i;