[PATCH v2 6/6] riscv: hwprobe: Report SiFive vector extensions only when available

[Radim Krčmář]

User-mode use of the SiFive vector extensions requires non-Off
sstatus.VS, which we set only when has_vector() (Zve32x on all harts).
Xsfvfnrclipxfqf and Xsfvfwmaccqqq also execute floating-point
instructions, which additionally require non-Off sstatus.FS and hence
has_fpu() (D on all harts).

hwprobe currently reports the extensions from the per-hart ISA bitmaps
alone, so it can advertise extensions that are always disabled in
user-mode.  Report correct environment to user-mode.

Fixes: 1a6274f03534 ("riscv: hwprobe: Add SiFive vendor extension support and probe for xsfqmaccdod and xsfqmaccqoq")
Fixes: 1d91224394c9 ("riscv: hwprobe: Add SiFive xsfvfnrclipxfqf vendor extension")
Fixes: d9669e33c8fa ("riscv: hwprobe: Add SiFive xsfvfwmaccqqq vendor extension")
Reviewed-by: Andy Chiu <tchiu at tenstorrent.com>
Signed-off-by: Radim Krčmář <radim.krcmar at oss.qualcomm.com>
---
v2:
* slightly reworded commit message
* added r-b
---
 .../kernel/vendor_extensions/sifive_hwprobe.c      | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/kernel/vendor_extensions/sifive_hwprobe.c b/arch/riscv/kernel/vendor_extensions/sifive_hwprobe.c
index 1f77f6309763..bcea4f7a81c4 100644
--- a/arch/riscv/kernel/vendor_extensions/sifive_hwprobe.c
+++ b/arch/riscv/kernel/vendor_extensions/sifive_hwprobe.c
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-only
 
+#include <asm/switch_to.h>
+#include <asm/vector.h>
 #include <asm/vendor_extensions/sifive.h>
 #include <asm/vendor_extensions/sifive_hwprobe.h>
 #include <asm/vendor_extensions/vendor_hwprobe.h>
@@ -14,9 +16,13 @@ void hwprobe_isa_vendor_ext_sifive_0(struct riscv_hwprobe *pair, const struct cp
 {
 	VENDOR_EXTENSION_SUPPORTED(pair, cpus,
 				   riscv_isa_vendor_ext_list_sifive.per_hart_isa_bitmap, {
-		VENDOR_EXT_KEY(XSFVQMACCDOD);
-		VENDOR_EXT_KEY(XSFVQMACCQOQ);
-		VENDOR_EXT_KEY(XSFVFNRCLIPXFQF);
-		VENDOR_EXT_KEY(XSFVFWMACCQQQ);
+		if (has_vector()) {
+			VENDOR_EXT_KEY(XSFVQMACCDOD);
+			VENDOR_EXT_KEY(XSFVQMACCQOQ);
+			if (has_fpu()) {
+				VENDOR_EXT_KEY(XSFVFNRCLIPXFQF);
+				VENDOR_EXT_KEY(XSFVFWMACCQQQ);
+			}
+		}
 	});
 }
-- 
2.55.0