1 files changed, 52 insertions, 0 deletions
diff --git a/arch/riscv/kernel/vdso/hwprobe.c b/arch/riscv/kernel/vdso/hwprobe.c
new file mode 100644
index 000000000000..d40bec6ac078
--- /dev/null
+++ b/arch/riscv/kernel/vdso/hwprobe.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2023 Rivos, Inc
+ */
+
+#include <linux/types.h>
+#include <vdso/datapage.h>
+#include <vdso/helpers.h>
+
+extern int riscv_hwprobe(struct riscv_hwprobe *pairs, size_t pair_count,
+			 size_t cpu_count, unsigned long *cpus,
+			 unsigned int flags);
+
+/* Add a prototype to avoid -Wmissing-prototypes warning. */
+int __vdso_riscv_hwprobe(struct riscv_hwprobe *pairs, size_t pair_count,
+			 size_t cpu_count, unsigned long *cpus,
+			 unsigned int flags);
+
+int __vdso_riscv_hwprobe(struct riscv_hwprobe *pairs, size_t pair_count,
+			 size_t cpu_count, unsigned long *cpus,
+			 unsigned int flags)
+{
+	const struct vdso_data *vd = __arch_get_vdso_data();
+	const struct arch_vdso_data *avd = &vd->arch_data;
+	bool all_cpus = !cpu_count && !cpus;
+	struct riscv_hwprobe *p = pairs;
+	struct riscv_hwprobe *end = pairs + pair_count;
+
+	/*
+	 * Defer to the syscall for exotic requests. The vdso has answers
+	 * stashed away only for the "all cpus" case. If all CPUs are
+	 * homogeneous, then this function can handle requests for arbitrary
+	 * masks.
+	 */
+	if ((flags != 0) || (!all_cpus && !avd->homogeneous_cpus))
+		return riscv_hwprobe(pairs, pair_count, cpu_count, cpus, flags);
+
+	/* This is something we can handle, fill out the pairs. */
+	while (p < end) {
+		if (p->key <= RISCV_HWPROBE_MAX_KEY) {
+			p->value = avd->all_cpu_hwprobe_values[p->key];
+
+		} else {
+			p->key = -1;
+			p->value = 0;
+		}
+
+		p++;
+	}
+
+	return 0;
+}