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-rw-r--r--arch/arm/kernel/devtree.c10
-rw-r--r--arch/arm/kernel/machine_kexec.c4
-rw-r--r--arch/arm/kernel/process.c43
-rw-r--r--arch/arm/kernel/setup.c2
-rw-r--r--arch/arm/kernel/smp.c13
5 files changed, 49 insertions, 23 deletions
diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
index 5af04f6daa3..5859c8bc727 100644
--- a/arch/arm/kernel/devtree.c
+++ b/arch/arm/kernel/devtree.c
@@ -82,7 +82,7 @@ void __init arm_dt_init_cpu_maps(void)
u32 i, j, cpuidx = 1;
u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
- u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = UINT_MAX };
+ u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
bool bootcpu_valid = false;
cpus = of_find_node_by_path("/cpus");
@@ -92,6 +92,9 @@ void __init arm_dt_init_cpu_maps(void)
for_each_child_of_node(cpus, cpu) {
u32 hwid;
+ if (of_node_cmp(cpu->type, "cpu"))
+ continue;
+
pr_debug(" * %s...\n", cpu->full_name);
/*
* A device tree containing CPU nodes with missing "reg"
@@ -149,9 +152,10 @@ void __init arm_dt_init_cpu_maps(void)
tmp_map[i] = hwid;
}
- if (WARN(!bootcpu_valid, "DT missing boot CPU MPIDR[23:0], "
- "fall back to default cpu_logical_map\n"))
+ if (!bootcpu_valid) {
+ pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
return;
+ }
/*
* Since the boot CPU node contains proper data, and all nodes have
diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
index 8ef8c933780..4fb074c446b 100644
--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c
@@ -134,6 +134,10 @@ void machine_kexec(struct kimage *image)
unsigned long reboot_code_buffer_phys;
void *reboot_code_buffer;
+ if (num_online_cpus() > 1) {
+ pr_err("kexec: error: multiple CPUs still online\n");
+ return;
+ }
page_list = image->head & PAGE_MASK;
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 282de4826ab..6e8931ccf13 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -184,30 +184,61 @@ int __init reboot_setup(char *str)
__setup("reboot=", reboot_setup);
+/*
+ * Called by kexec, immediately prior to machine_kexec().
+ *
+ * This must completely disable all secondary CPUs; simply causing those CPUs
+ * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
+ * kexec'd kernel to use any and all RAM as it sees fit, without having to
+ * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
+ * functionality embodied in disable_nonboot_cpus() to achieve this.
+ */
void machine_shutdown(void)
{
-#ifdef CONFIG_SMP
- smp_send_stop();
-#endif
+ disable_nonboot_cpus();
}
+/*
+ * Halting simply requires that the secondary CPUs stop performing any
+ * activity (executing tasks, handling interrupts). smp_send_stop()
+ * achieves this.
+ */
void machine_halt(void)
{
- machine_shutdown();
+ smp_send_stop();
+
local_irq_disable();
while (1);
}
+/*
+ * Power-off simply requires that the secondary CPUs stop performing any
+ * activity (executing tasks, handling interrupts). smp_send_stop()
+ * achieves this. When the system power is turned off, it will take all CPUs
+ * with it.
+ */
void machine_power_off(void)
{
- machine_shutdown();
+ smp_send_stop();
+
if (pm_power_off)
pm_power_off();
}
+/*
+ * Restart requires that the secondary CPUs stop performing any activity
+ * while the primary CPU resets the system. Systems with a single CPU can
+ * use soft_restart() as their machine descriptor's .restart hook, since that
+ * will cause the only available CPU to reset. Systems with multiple CPUs must
+ * provide a HW restart implementation, to ensure that all CPUs reset at once.
+ * This is required so that any code running after reset on the primary CPU
+ * doesn't have to co-ordinate with other CPUs to ensure they aren't still
+ * executing pre-reset code, and using RAM that the primary CPU's code wishes
+ * to use. Implementing such co-ordination would be essentially impossible.
+ */
void machine_restart(char *cmd)
{
- machine_shutdown();
+ smp_send_stop();
arm_pm_restart(reboot_mode, cmd);
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 1522c7ae31b..b4b1d397592 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -444,7 +444,7 @@ void notrace cpu_init(void)
: "r14");
}
-int __cpu_logical_map[NR_CPUS];
+u32 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
void __init smp_setup_processor_id(void)
{
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 550d63cef68..5919eb451bb 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -651,17 +651,6 @@ void smp_send_reschedule(int cpu)
smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
}
-#ifdef CONFIG_HOTPLUG_CPU
-static void smp_kill_cpus(cpumask_t *mask)
-{
- unsigned int cpu;
- for_each_cpu(cpu, mask)
- platform_cpu_kill(cpu);
-}
-#else
-static void smp_kill_cpus(cpumask_t *mask) { }
-#endif
-
void smp_send_stop(void)
{
unsigned long timeout;
@@ -679,8 +668,6 @@ void smp_send_stop(void)
if (num_online_cpus() > 1)
pr_warning("SMP: failed to stop secondary CPUs\n");
-
- smp_kill_cpus(&mask);
}
/*