[PATCH v10 10/14] riscv: hwprobe: Add thead vendor extension probing
From: Charlie Jenkins
Date: Thu Sep 12 2024 - 01:58:27 EST
Add a new hwprobe key "RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0" which
allows userspace to probe for the new RISCV_ISA_VENDOR_EXT_XTHEADVECTOR
vendor extension.
This new key will allow userspace code to probe for which thead vendor
extensions are supported. This API is modeled to be consistent with
RISCV_HWPROBE_KEY_IMA_EXT_0. The bitmask returned will have each bit
corresponding to a supported thead vendor extension of the cpumask set.
Just like RISCV_HWPROBE_KEY_IMA_EXT_0, this allows a userspace program
to determine all of the supported thead vendor extensions in one call.
Signed-off-by: Charlie Jenkins <charlie@xxxxxxxxxxxx>
Reviewed-by: Evan Green <evan@xxxxxxxxxxxx>
---
arch/riscv/include/asm/hwprobe.h | 3 +-
.../include/asm/vendor_extensions/thead_hwprobe.h | 19 +++++++++++
.../include/asm/vendor_extensions/vendor_hwprobe.h | 37 ++++++++++++++++++++++
arch/riscv/include/uapi/asm/hwprobe.h | 3 +-
arch/riscv/include/uapi/asm/vendor/thead.h | 3 ++
arch/riscv/kernel/sys_hwprobe.c | 5 +++
arch/riscv/kernel/vendor_extensions/Makefile | 1 +
.../riscv/kernel/vendor_extensions/thead_hwprobe.c | 19 +++++++++++
8 files changed, 88 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/include/asm/hwprobe.h b/arch/riscv/include/asm/hwprobe.h
index ef01c182af2b..6148e1eab64c 100644
--- a/arch/riscv/include/asm/hwprobe.h
+++ b/arch/riscv/include/asm/hwprobe.h
@@ -1,6 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/*
- * Copyright 2023 Rivos, Inc
+ * Copyright 2023-2024 Rivos, Inc
*/
#ifndef _ASM_HWPROBE_H
@@ -21,6 +21,7 @@ static inline bool hwprobe_key_is_bitmask(__s64 key)
case RISCV_HWPROBE_KEY_BASE_BEHAVIOR:
case RISCV_HWPROBE_KEY_IMA_EXT_0:
case RISCV_HWPROBE_KEY_CPUPERF_0:
+ case RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0:
return true;
}
diff --git a/arch/riscv/include/asm/vendor_extensions/thead_hwprobe.h b/arch/riscv/include/asm/vendor_extensions/thead_hwprobe.h
new file mode 100644
index 000000000000..65a9c5612466
--- /dev/null
+++ b/arch/riscv/include/asm/vendor_extensions/thead_hwprobe.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_HWPROBE_H
+#define _ASM_RISCV_VENDOR_EXTENSIONS_THEAD_HWPROBE_H
+
+#include <linux/cpumask.h>
+
+#include <uapi/asm/hwprobe.h>
+
+#ifdef CONFIG_RISCV_ISA_VENDOR_EXT_THEAD
+void hwprobe_isa_vendor_ext_thead_0(struct riscv_hwprobe *pair, const struct cpumask *cpus);
+#else
+static inline void hwprobe_isa_vendor_ext_thead_0(struct riscv_hwprobe *pair,
+ const struct cpumask *cpus)
+{
+ pair->value = 0;
+}
+#endif
+
+#endif
diff --git a/arch/riscv/include/asm/vendor_extensions/vendor_hwprobe.h b/arch/riscv/include/asm/vendor_extensions/vendor_hwprobe.h
new file mode 100644
index 000000000000..6b9293e984a9
--- /dev/null
+++ b/arch/riscv/include/asm/vendor_extensions/vendor_hwprobe.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2024 Rivos, Inc
+ */
+
+#ifndef _ASM_RISCV_SYS_HWPROBE_H
+#define _ASM_RISCV_SYS_HWPROBE_H
+
+#include <asm/cpufeature.h>
+
+#define VENDOR_EXT_KEY(ext) \
+ do { \
+ if (__riscv_isa_extension_available(isainfo->isa, RISCV_ISA_VENDOR_EXT_##ext)) \
+ pair->value |= RISCV_HWPROBE_VENDOR_EXT_##ext; \
+ else \
+ missing |= RISCV_HWPROBE_VENDOR_EXT_##ext; \
+ } while (false)
+
+/*
+ * Loop through and record extensions that 1) anyone has, and 2) anyone
+ * doesn't have.
+ *
+ * _extension_checks is an arbitrary C block to set the values of pair->value
+ * and missing. It should be filled with VENDOR_EXT_KEY expressions.
+ */
+#define VENDOR_EXTENSION_SUPPORTED(pair, cpus, per_hart_vendor_bitmap, _extension_checks) \
+ do { \
+ int cpu; \
+ u64 missing = 0; \
+ for_each_cpu(cpu, (cpus)) { \
+ struct riscv_isavendorinfo *isainfo = &(per_hart_vendor_bitmap)[cpu]; \
+ _extension_checks \
+ } \
+ (pair)->value &= ~missing; \
+ } while (false) \
+
+#endif /* _ASM_RISCV_SYS_HWPROBE_H */
diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
index b706c8e47b02..452d0b84f17f 100644
--- a/arch/riscv/include/uapi/asm/hwprobe.h
+++ b/arch/riscv/include/uapi/asm/hwprobe.h
@@ -1,6 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/*
- * Copyright 2023 Rivos, Inc
+ * Copyright 2023-2024 Rivos, Inc
*/
#ifndef _UAPI_ASM_HWPROBE_H
@@ -82,6 +82,7 @@ struct riscv_hwprobe {
#define RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE 6
#define RISCV_HWPROBE_KEY_HIGHEST_VIRT_ADDRESS 7
#define RISCV_HWPROBE_KEY_TIME_CSR_FREQ 8
+#define RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0 9
/* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
/* Flags */
diff --git a/arch/riscv/include/uapi/asm/vendor/thead.h b/arch/riscv/include/uapi/asm/vendor/thead.h
new file mode 100644
index 000000000000..43790ebe5faf
--- /dev/null
+++ b/arch/riscv/include/uapi/asm/vendor/thead.h
@@ -0,0 +1,3 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+
+#define RISCV_HWPROBE_VENDOR_EXT_XTHEADVECTOR (1 << 0)
diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
index 8d1b5c35d2a7..5a3dc8e66c85 100644
--- a/arch/riscv/kernel/sys_hwprobe.c
+++ b/arch/riscv/kernel/sys_hwprobe.c
@@ -15,6 +15,7 @@
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include <asm/vector.h>
+#include <asm/vendor_extensions/thead_hwprobe.h>
#include <vdso/vsyscall.h>
@@ -241,6 +242,10 @@ static void hwprobe_one_pair(struct riscv_hwprobe *pair,
pair->value = riscv_timebase;
break;
+ case RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0:
+ hwprobe_isa_vendor_ext_thead_0(pair, cpus);
+ break;
+
/*
* For forward compatibility, unknown keys don't fail the whole
* call, but get their element key set to -1 and value set to 0
diff --git a/arch/riscv/kernel/vendor_extensions/Makefile b/arch/riscv/kernel/vendor_extensions/Makefile
index 353522cb3bf0..866414c81a9f 100644
--- a/arch/riscv/kernel/vendor_extensions/Makefile
+++ b/arch/riscv/kernel/vendor_extensions/Makefile
@@ -2,3 +2,4 @@
obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_ANDES) += andes.o
obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_THEAD) += thead.o
+obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_THEAD) += thead_hwprobe.o
diff --git a/arch/riscv/kernel/vendor_extensions/thead_hwprobe.c b/arch/riscv/kernel/vendor_extensions/thead_hwprobe.c
new file mode 100644
index 000000000000..2eba34011786
--- /dev/null
+++ b/arch/riscv/kernel/vendor_extensions/thead_hwprobe.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <asm/vendor_extensions/thead.h>
+#include <asm/vendor_extensions/thead_hwprobe.h>
+#include <asm/vendor_extensions/vendor_hwprobe.h>
+
+#include <linux/cpumask.h>
+#include <linux/types.h>
+
+#include <uapi/asm/hwprobe.h>
+#include <uapi/asm/vendor/thead.h>
+
+void hwprobe_isa_vendor_ext_thead_0(struct riscv_hwprobe *pair, const struct cpumask *cpus)
+{
+ VENDOR_EXTENSION_SUPPORTED(pair, cpus,
+ riscv_isa_vendor_ext_list_thead.per_hart_isa_bitmap, {
+ VENDOR_EXT_KEY(XTHEADVECTOR);
+ });
+}
--
2.45.0