diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index c5e42cc376048dbc9d960a6275b40c983acb7618..a20e105efa4ed824451647e56bf835ae2e94d1f8 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -33,6 +33,7 @@ config RISCV
select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAS_UBSAN_SANITIZE_ALL
+ select ARCH_HAS_VDSO_DATA
select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
select ARCH_STACKWALK
diff --git a/arch/riscv/include/asm/vdso/data.h b/arch/riscv/include/asm/vdso/data.h
new file mode 100644
index 0000000000000000000000000000000000000000..dc2f76f58b7632f0392af6aaf475076203f1a54a
--- /dev/null
+++ b/arch/riscv/include/asm/vdso/data.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __RISCV_ASM_VDSO_DATA_H
+#define __RISCV_ASM_VDSO_DATA_H
+
+#include <linux/types.h>
+#include <vdso/datapage.h>
+#include <asm/hwprobe.h>
+
+struct arch_vdso_data {
+ /* Stash static answers to the hwprobe queries when all CPUs are selected. */
+ __u64 all_cpu_hwprobe_values[RISCV_HWPROBE_MAX_KEY + 1];
+
+ /* Boolean indicating all CPUs have the same static hwprobe values. */
+ __u8 homogeneous_cpus;
+};
+
+#endif /* __RISCV_ASM_VDSO_DATA_H */
diff --git a/arch/riscv/include/asm/vdso/gettimeofday.h b/arch/riscv/include/asm/vdso/gettimeofday.h
index 77d9c2f721c464603216d18700958cce032b8b54..ba3283cf7accaa93a38512d2c17eda0eefde0612 100644
--- a/arch/riscv/include/asm/vdso/gettimeofday.h
+++ b/arch/riscv/include/asm/vdso/gettimeofday.h
@@ -9,6 +9,12 @@
#include <asm/csr.h>
#include <uapi/linux/time.h>
+/*
+ * 32-bit land is lacking generic time vsyscalls as well as the legacy 32-bit
+ * time syscalls like gettimeofday. Skip these definitions since on 32-bit.
+ */
+#ifdef CONFIG_GENERIC_TIME_VSYSCALL
+
#define VDSO_HAS_CLOCK_GETRES 1
static __always_inline
@@ -60,6 +66,8 @@ int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
return ret;
}
+#endif /* CONFIG_GENERIC_TIME_VSYSCALL */
+
static __always_inline u64 __arch_get_hw_counter(s32 clock_mode,
const struct vdso_data *vd)
{
diff --git a/arch/riscv/kernel/compat_vdso/Makefile b/arch/riscv/kernel/compat_vdso/Makefile
index 260daf3236d3a8dd08ac046410170c59f5d09b29..91a3431ae1fe9206b7d6c3ce83edf9012ffa332b 100644
--- a/arch/riscv/kernel/compat_vdso/Makefile
+++ b/arch/riscv/kernel/compat_vdso/Makefile
@@ -22,7 +22,7 @@ targets := $(obj-compat_vdso) compat_vdso.so compat_vdso.so.dbg compat_vdso.lds
obj-compat_vdso := $(addprefix $(obj)/, $(obj-compat_vdso))
obj-y += compat_vdso.o
-CPPFLAGS_compat_vdso.lds += -P -C -U$(ARCH)
+CPPFLAGS_compat_vdso.lds += -P -C -DCOMPAT_VDSO -U$(ARCH)
# Disable profiling and instrumentation for VDSO code
GCOV_PROFILE := n
diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c
index 55389e7595f60d9a6f0c934cdbdeb9a88954e530..849b4170629dc566e0322bbf0068ee019a3de1ea 100644
--- a/arch/riscv/kernel/sys_riscv.c
+++ b/arch/riscv/kernel/sys_riscv.c
@@ -14,6 +14,7 @@
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include <asm-generic/mman-common.h>
+#include <vdso/vsyscall.h>
static long riscv_sys_mmap(unsigned long addr, unsigned long len,
unsigned long prot, unsigned long flags,
@@ -243,6 +244,50 @@ static int do_riscv_hwprobe(struct riscv_hwprobe __user *pairs,
return 0;
}
+#ifdef CONFIG_MMU
+
+static int __init init_hwprobe_vdso_data(void)
+{
+ struct vdso_data *vd = __arch_get_k_vdso_data();
+ struct arch_vdso_data *avd = &vd->arch_data;
+ u64 id_bitsmash = 0;
+ struct riscv_hwprobe pair;
+ int key;
+
+ /*
+ * Initialize vDSO data with the answers for the "all CPUs" case, to
+ * save a syscall in the common case.
+ */
+ for (key = 0; key <= RISCV_HWPROBE_MAX_KEY; key++) {
+ pair.key = key;
+ hwprobe_one_pair(&pair, cpu_online_mask);
+
+ WARN_ON_ONCE(pair.key < 0);
+
+ avd->all_cpu_hwprobe_values[key] = pair.value;
+ /*
+ * Smash together the vendor, arch, and impl IDs to see if
+ * they're all 0 or any negative.
+ */
+ if (key <= RISCV_HWPROBE_KEY_MIMPID)
+ id_bitsmash |= pair.value;
+ }
+
+ /*
+ * If the arch, vendor, and implementation ID are all the same across
+ * all harts, then assume all CPUs are the same, and allow the vDSO to
+ * answer queries for arbitrary masks. However if all values are 0 (not
+ * populated) or any value returns -1 (varies across CPUs), then the
+ * vDSO should defer to the kernel for exotic cpu masks.
+ */
+ avd->homogeneous_cpus = (id_bitsmash > 0);
+ return 0;
+}
+
+arch_initcall_sync(init_hwprobe_vdso_data);
+
+#endif /* CONFIG_MMU */
+
SYSCALL_DEFINE5(riscv_hwprobe, struct riscv_hwprobe __user *, pairs,
size_t, pair_count, size_t, cpu_count, unsigned long __user *,
cpus, unsigned int, flags)
diff --git a/arch/riscv/kernel/vdso.c b/arch/riscv/kernel/vdso.c
index cc2d1e8c8736478c89d8d3d49d8b3219bf1f4df1..9a68e7eaae4d47e573c7c96289ddbf325164721d 100644
--- a/arch/riscv/kernel/vdso.c
+++ b/arch/riscv/kernel/vdso.c
@@ -14,13 +14,7 @@
#include <asm/page.h>
#include <asm/vdso.h>
#include <linux/time_namespace.h>
-
-#ifdef CONFIG_GENERIC_TIME_VSYSCALL
#include <vdso/datapage.h>
-#else
-struct vdso_data {
-};
-#endif
enum vvar_pages {
VVAR_DATA_PAGE_OFFSET,
diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
index 06e6b27f3bcc938ba336f32e51de459fd6c15ad2..022258426050db974128bd320fd0562da84e8c75 100644
--- a/arch/riscv/kernel/vdso/Makefile
+++ b/arch/riscv/kernel/vdso/Makefile
@@ -12,6 +12,8 @@ vdso-syms += vgettimeofday
endif
vdso-syms += getcpu
vdso-syms += flush_icache
+vdso-syms += hwprobe
+vdso-syms += sys_hwprobe
# Files to link into the vdso
obj-vdso = $(patsubst %, %.o, $(vdso-syms)) note.o
@@ -23,6 +25,8 @@ ifneq ($(c-gettimeofday-y),)
CFLAGS_vgettimeofday.o += -fPIC -include $(c-gettimeofday-y)
endif
+CFLAGS_hwprobe.o += -fPIC
+
# Build rules
targets := $(obj-vdso) vdso.so vdso.so.dbg vdso.lds
obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
diff --git a/arch/riscv/kernel/vdso/hwprobe.c b/arch/riscv/kernel/vdso/hwprobe.c
new file mode 100644
index 0000000000000000000000000000000000000000..d40bec6ac0786690374b8fde5eaddda928c788d2
--- /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;
+}
diff --git a/arch/riscv/kernel/vdso/sys_hwprobe.S b/arch/riscv/kernel/vdso/sys_hwprobe.S
new file mode 100644
index 0000000000000000000000000000000000000000..4e704146c77a092e481b8b532c19b11e3efa82e4
--- /dev/null
+++ b/arch/riscv/kernel/vdso/sys_hwprobe.S
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2023 Rivos, Inc */
+
+#include <linux/linkage.h>
+#include <asm/unistd.h>
+
+.text
+ENTRY(riscv_hwprobe)
+ .cfi_startproc
+ li a7, __NR_riscv_hwprobe
+ ecall
+ ret
+
+ .cfi_endproc
+ENDPROC(riscv_hwprobe)
diff --git a/arch/riscv/kernel/vdso/vdso.lds.S b/arch/riscv/kernel/vdso/vdso.lds.S
index 4a060663329024feffbb82d7c5d663b1099f36ce..82ce64900f3d7e7af48a211b8e24aeec0952d504 100644
--- a/arch/riscv/kernel/vdso/vdso.lds.S
+++ b/arch/riscv/kernel/vdso/vdso.lds.S
@@ -82,6 +82,9 @@ VERSION
#endif
__vdso_getcpu;
__vdso_flush_icache;
+#ifndef COMPAT_VDSO
+ __vdso_riscv_hwprobe;
+#endif
local: *;
};
}