From bb4b0f8a1bcbf8f4e3a0841aaefb3fd580d12fc9 Mon Sep 17 00:00:00 2001
From: Aleksa Paunovic <aleksa.paunovic@htecgroup.com>
Date: Thu, 24 Jul 2025 17:23:28 +0200
Subject: 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>
---
 arch/riscv/kernel/sys_hwprobe.c                    |  4 ++++
 arch/riscv/kernel/vendor_extensions/Makefile       |  1 +
 arch/riscv/kernel/vendor_extensions/mips_hwprobe.c | 23 ++++++++++++++++++++++
 3 files changed, 28 insertions(+)
 create mode 100644 arch/riscv/kernel/vendor_extensions/mips_hwprobe.c

(limited to 'arch/riscv/kernel')

diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
index 3e9259790816..000f4451a9d8 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/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 ccad4ebafb43..bf116c82b6bd 100644
--- 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
index 000000000000..dc213a2ca70d
--- /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); });
+}
-- 
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