riscv: hwprobe: Add MIPS vendor extension probing

Add a new hwprobe key "RISCV_HWPROBE_KEY_VENDOR_EXT_MIPS_0" which allows
userspace to probe for the new xmipsexectl vendor extension.

Signed-off-by: Aleksa Paunovic <aleksa.paunovic@htecgroup.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20250724-p8700-pause-v5-4-a6cbbe1c3412@htecgroup.com
[pjw@kernel.org: fixed some checkpatch issues]
Signed-off-by: Paul Walmsley <pjw@kernel.org>

diff --git a/arch/riscv/include/asm/hwprobe.h b/arch/riscv/include/asm/hwprobe.h
index 7fe0a379474ae2c64d300d6fee4a012173f6a6d7..948d2b34e94e84e4c2c351ffe91f4b3afcefc3f7 100644 (file)
--- a/arch/riscv/include/asm/hwprobe.h
+++ b/arch/riscv/include/asm/hwprobe.h
@@ -8,7 +8,7 @@
 
 #include <uapi/asm/hwprobe.h>
 
-#define RISCV_HWPROBE_MAX_KEY 13
+#define RISCV_HWPROBE_MAX_KEY 14
 
 static inline bool riscv_hwprobe_key_is_valid(__s64 key)
 {
@@ -22,6 +22,7 @@ static inline bool hwprobe_key_is_bitmask(__s64 key)
        case RISCV_HWPROBE_KEY_IMA_EXT_0:
        case RISCV_HWPROBE_KEY_CPUPERF_0:
        case RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0:
+       case RISCV_HWPROBE_KEY_VENDOR_EXT_MIPS_0:
        case RISCV_HWPROBE_KEY_VENDOR_EXT_SIFIVE_0:
                return true;
        }

diff --git a/arch/riscv/include/asm/vendor_extensions/mips_hwprobe.h b/arch/riscv/include/asm/vendor_extensions/mips_hwprobe.h
new file mode 100644 (file)
index 0000000..e63f664
--- /dev/null
+++ b/arch/riscv/include/asm/vendor_extensions/mips_hwprobe.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2025 MIPS.
+ */
+
+#ifndef _ASM_RISCV_VENDOR_EXTENSIONS_MIPS_HWPROBE_H_
+#define _ASM_RISCV_VENDOR_EXTENSIONS_MIPS_HWPROBE_H_
+
+#include <linux/cpumask.h>
+#include <uapi/asm/hwprobe.h>
+
+#ifdef CONFIG_RISCV_ISA_VENDOR_EXT_MIPS
+void hwprobe_isa_vendor_ext_mips_0(struct riscv_hwprobe *pair, const struct cpumask *cpus);
+#else
+static inline void hwprobe_isa_vendor_ext_mips_0(struct riscv_hwprobe *pair,
+                                                const struct cpumask *cpus)
+{
+       pair->value = 0;
+}
+#endif
+
+#endif // _ASM_RISCV_VENDOR_EXTENSIONS_MIPS_HWPROBE_H_

diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
index aaf6ad97049931381f9542bb9316c873ec6ab9f6..5d30a4fae37a82ef4d968d20b187420772ad8946 100644 (file)
--- a/arch/riscv/include/uapi/asm/hwprobe.h
+++ b/arch/riscv/include/uapi/asm/hwprobe.h
@@ -106,6 +106,7 @@ struct riscv_hwprobe {
 #define RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0   11
 #define RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE    12
 #define RISCV_HWPROBE_KEY_VENDOR_EXT_SIFIVE_0  13
+#define RISCV_HWPROBE_KEY_VENDOR_EXT_MIPS_0    14
 /* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
 
 /* Flags */

diff --git a/arch/riscv/include/uapi/asm/vendor/mips.h b/arch/riscv/include/uapi/asm/vendor/mips.h
new file mode 100644 (file)
index 0000000..e65ab26
--- /dev/null
+++ b/arch/riscv/include/uapi/asm/vendor/mips.h
@@ -0,0 +1,3 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+
+#define RISCV_HWPROBE_VENDOR_EXT_XMIPSEXECTL   BIT(0)

diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
index 3e9259790816e46092d893df6321deaac3dd9795..000f4451a9d873d5f068986a14615de3a2a5601d 100644 (file)
--- 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/mips_hwprobe.h>
 #include <asm/vendor_extensions/sifive_hwprobe.h>
 #include <asm/vendor_extensions/thead_hwprobe.h>
 #include <vdso/vsyscall.h>
@@ -307,6 +308,9 @@ static void hwprobe_one_pair(struct riscv_hwprobe *pair,
        case RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0:
                hwprobe_isa_vendor_ext_thead_0(pair, cpus);
                break;
+       case RISCV_HWPROBE_KEY_VENDOR_EXT_MIPS_0:
+               hwprobe_isa_vendor_ext_mips_0(pair, cpus);
+               break;
 
        /*
         * For forward compatibility, unknown keys don't fail the whole

diff --git a/arch/riscv/kernel/vendor_extensions/Makefile b/arch/riscv/kernel/vendor_extensions/Makefile
index ccad4ebafb43412e72e654da3bdb9face53b80c6..bf116c82b6bdb3aee23e27fc0b2a69be7c7a5ccb 100644 (file)
--- a/arch/riscv/kernel/vendor_extensions/Makefile
+++ b/arch/riscv/kernel/vendor_extensions/Makefile
@@ -2,6 +2,7 @@
 
 obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_ANDES)       += andes.o
 obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_MIPS)        += mips.o
+obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_MIPS)        += mips_hwprobe.o
 obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_SIFIVE)      += sifive.o
 obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_SIFIVE)      += sifive_hwprobe.o
 obj-$(CONFIG_RISCV_ISA_VENDOR_EXT_THEAD)       += thead.o

diff --git a/arch/riscv/kernel/vendor_extensions/mips_hwprobe.c b/arch/riscv/kernel/vendor_extensions/mips_hwprobe.c
new file mode 100644 (file)
index 0000000..dc213a2
--- /dev/null
+++ b/arch/riscv/kernel/vendor_extensions/mips_hwprobe.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2025 MIPS.
+ */
+
+#include <asm/vendor_extensions.h>
+#include <asm/vendor_extensions/mips.h>
+#include <asm/vendor_extensions/mips_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/mips.h>
+
+void hwprobe_isa_vendor_ext_mips_0(struct riscv_hwprobe *pair,
+                                  const struct cpumask *cpus)
+{
+       VENDOR_EXTENSION_SUPPORTED(pair, cpus,
+                                  riscv_isa_vendor_ext_list_mips.per_hart_isa_bitmap,
+                                  { VENDOR_EXT_KEY(XMIPSEXECTL); });
+}