[ARM] Fix SMP initialisation oops
A change to the SMP initialisation caused the following oops:
CPU1: Booted secondary processor
CPU1: D VIPT write-back cache
CPU1: I cache: 32768 bytes, associativity 4, 32 byte lines, 256 sets
CPU1: D cache: 32768 bytes, associativity 4, 32 byte lines, 256 sets
<7>Calibrating delay loop... 83.14 BogoMIPS (lpj=415744)
<1>Unable to handle kernel NULL pointer dereference at virtual address 0000001c
...
PC is at enqueue_task+0x1c/0x64
LR is at activate_task+0xcc/0xe4
SMP initialisation now requires cpu_possible_map to be initialised in
setup_arch(). Move this from smp_prepare_cpus() to smp_init_cpus()
and call it from our setup_arch() if CONFIG_SMP is enabled.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index c45d10d..68273b4 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -23,6 +23,7 @@
#include <linux/root_dev.h>
#include <linux/cpu.h>
#include <linux/interrupt.h>
+#include <linux/smp.h>
#include <asm/cpu.h>
#include <asm/elf.h>
@@ -771,6 +772,10 @@
paging_init(&meminfo, mdesc);
request_standard_resources(&meminfo, mdesc);
+#ifdef CONFIG_SMP
+ smp_init_cpus();
+#endif
+
cpu_init();
/*
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 7338948..02aa300 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -338,7 +338,6 @@
per_cpu(cpu_data, cpu).idle = current;
- cpu_set(cpu, cpu_possible_map);
cpu_set(cpu, cpu_present_map);
cpu_set(cpu, cpu_online_map);
}
diff --git a/arch/arm/mach-integrator/platsmp.c b/arch/arm/mach-integrator/platsmp.c
index ea10bd8..1bc8534 100644
--- a/arch/arm/mach-integrator/platsmp.c
+++ b/arch/arm/mach-integrator/platsmp.c
@@ -140,6 +140,18 @@
mb();
}
+/*
+ * Initialise the CPU possible map early - this describes the CPUs
+ * which may be present or become present in the system.
+ */
+void __init smp_init_cpus(void)
+{
+ unsigned int i, ncores = get_core_count();
+
+ for (i = 0; i < ncores; i++)
+ cpu_set(i, cpu_possible_map);
+}
+
void __init smp_prepare_cpus(unsigned int max_cpus)
{
unsigned int ncores = get_core_count();
@@ -176,14 +188,11 @@
max_cpus = ncores;
/*
- * Initialise the possible/present maps.
- * cpu_possible_map describes the set of CPUs which may be present
- * cpu_present_map describes the set of CPUs populated
+ * Initialise the present map, which describes the set of CPUs
+ * actually populated at the present time.
*/
- for (i = 0; i < max_cpus; i++) {
- cpu_set(i, cpu_possible_map);
+ for (i = 0; i < max_cpus; i++)
cpu_set(i, cpu_present_map);
- }
/*
* Do we need any more CPUs? If so, then let them know where
diff --git a/arch/arm/mach-realview/platsmp.c b/arch/arm/mach-realview/platsmp.c
index a8fbd76d..b8484e1 100644
--- a/arch/arm/mach-realview/platsmp.c
+++ b/arch/arm/mach-realview/platsmp.c
@@ -143,6 +143,18 @@
mb();
}
+/*
+ * Initialise the CPU possible map early - this describes the CPUs
+ * which may be present or become present in the system.
+ */
+void __init smp_init_cpus(void)
+{
+ unsigned int i, ncores = get_core_count();
+
+ for (i = 0; i < ncores; i++)
+ cpu_set(i, cpu_possible_map);
+}
+
void __init smp_prepare_cpus(unsigned int max_cpus)
{
unsigned int ncores = get_core_count();
@@ -179,14 +191,11 @@
local_timer_setup(cpu);
/*
- * Initialise the possible/present maps.
- * cpu_possible_map describes the set of CPUs which may be present
- * cpu_present_map describes the set of CPUs populated
+ * Initialise the present map, which describes the set of CPUs
+ * actually populated at the present time.
*/
- for (i = 0; i < max_cpus; i++) {
- cpu_set(i, cpu_possible_map);
+ for (i = 0; i < max_cpus; i++)
cpu_set(i, cpu_present_map);
- }
/*
* Do we need any more CPUs? If so, then let them know where