[v3,3/5] arm64: vdso: Initialise the per-CPU vDSO data

Commit Message

Mark Brown Aug. 19, 2020, 12:13 p.m. UTC

Register with the CPU hotplug system to initialise the per-CPU data for
getcpu().

Signed-off-by: Mark Brown <[e-mail]>
---
 arch/arm64/kernel/vdso.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

Patch

diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 2a8d7ab76bee..d9743c659341 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -9,6 +9,7 @@ 
 
 #include <linux/cache.h>
 #include <linux/clocksource.h>
+#include <linux/cpuhotplug.h>
 #include <linux/elf.h>
 #include <linux/err.h>
 #include <linux/errno.h>
@@ -18,6 +19,7 @@ 
 #include <linux/sched.h>
 #include <linux/signal.h>
 #include <linux/slab.h>
+#include <linux/smp.h>
 #include <linux/time_namespace.h>
 #include <linux/timekeeper_internal.h>
 #include <linux/vmalloc.h>
@@ -466,6 +468,26 @@  int aarch32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 }
 #endif /* CONFIG_COMPAT */
 
+static void vdso_cpu_init(void *p)
+{
+	struct arm64_vdso_data *data = (struct arm64_vdso_data *)vdso_data;
+	unsigned int cpu;
+
+	if (vdso_cpu_offset()) {
+		cpu = smp_processor_id();
+
+		data->cpu_data[cpu].cpu = cpu;
+		data->cpu_data[cpu].node = cpu_to_node(cpu);
+	}
+}
+
+static int vdso_cpu_online(unsigned int cpu)
+{
+	smp_call_function_single(cpu, vdso_cpu_init, NULL, 1);
+
+	return 0;
+}
+
 static int vdso_mremap(const struct vm_special_mapping *sm,
 		struct vm_area_struct *new_vma)
 {
@@ -494,6 +516,12 @@  static int __init vdso_init(void)
 	vdso_info[VDSO_ABI_AA64].dm = &aarch64_vdso_maps[AA64_MAP_VVAR];
 	vdso_info[VDSO_ABI_AA64].cm = &aarch64_vdso_maps[AA64_MAP_VDSO];
 
+	/*
+	 * Initialize per-CPU data, callback runs for all current and
+	 * future CPUs.
+	 */
+	cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "vdso", vdso_cpu_online, NULL);
+
 	return __vdso_init(VDSO_ABI_AA64);
 }
 arch_initcall(vdso_init);