sysctl: SYS_CTL_HW_CPUS_ONLINE

kernel-src/sys/ctl/hw.c

@@ -0,0 +1,44 @@
+#include <kernel/sysctl.h>
+#include <kernel/usercopy.h>
+#include <arch/smp.h>
+
+static int ctl_cpus_online(const int *, size_t name_len, void *oldp, size_t *old_lenp, void *newp, size_t) {
+	if (name_len != 0)
+		return EINVAL;
+
+	if (newp)
+		return EPERM;
+
+	if (!old_lenp)
+		return EINVAL;
+
+	size_t old_len = 0;
+	if (oldp) {
+		int error = USERCOPY_POSSIBLY_FROM_USER(&old_len, old_lenp, sizeof(old_len));
+		if (error)
+			return error;
+	}
+
+	size_t required_len = sizeof(size_t);
+	int error = USERCOPY_POSSIBLY_TO_USER(old_lenp, &required_len, sizeof(required_len));
+	if (error)
+		return error;
+
+	if (!oldp)
+		return 0;
+
+	if (old_len < required_len)
+		return ENOMEM;
+
+	size_t cpus_online = arch_smp_get_cpu_count();
+	return USERCOPY_POSSIBLY_TO_USER(oldp, &cpus_online, sizeof(cpus_online));
+}
+
+int sysctl_hw(const int *name, size_t name_len, void *oldp, size_t *old_lenp, void *newp, size_t new_len) {
+	switch (*name) {
+		case SYS_CTL_HW_CPUS_ONLINE:
+			return ctl_cpus_online(name + 1, name_len - 1, oldp, old_lenp, newp, new_len);
+	}
+
+	return EINVAL;
+}