From: Yu Chien Peter Lin <peterlin@andestech.com>
Date: Sat, 5 Nov 2022 06:02:14 +0000 (+0800)
Subject: riscv: Fix detecting FPU support in standard extension
X-Git-Url: http://git.dujemihanovic.xyz/img/sics.gif?a=commitdiff_plain;h=c277c787a09254ebdf919c7cfc94631fe854677d;p=u-boot.git

riscv: Fix detecting FPU support in standard extension

We should check the string until it hits underscore, in case it
searches multi-letter extensions. For example, "rv64imac_xandes"
will be treated as D extension support since there is a "d" in
"andes", resulting illegal instruction caused by initializing FCSR.

Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Rick Chen <rick@andestech.com>
Reviewed-by: Padmarao Begari <padmarao.begari@microchip.com>
Reviewed-by: Samuel Holland <samuel@sholland.org>
---

diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c
index 52ab02519f..d34c8efce0 100644
--- a/arch/riscv/cpu/cpu.c
+++ b/arch/riscv/cpu/cpu.c
@@ -36,6 +36,7 @@ static inline bool supports_extension(char ext)
 #ifdef CONFIG_CPU
 	struct udevice *dev;
 	char desc[32];
+	int i;
 
 	uclass_find_first_device(UCLASS_CPU, &dev);
 	if (!dev) {
@@ -43,9 +44,16 @@ static inline bool supports_extension(char ext)
 		return false;
 	}
 	if (!cpu_get_desc(dev, desc, sizeof(desc))) {
-		/* skip the first 4 characters (rv32|rv64) */
-		if (strchr(desc + 4, ext))
-			return true;
+		/*
+		 * skip the first 4 characters (rv32|rv64) and
+		 * check until underscore
+		 */
+		for (i = 4; i < sizeof(desc); i++) {
+			if (desc[i] == '_' || desc[i] == '\0')
+				break;
+			if (desc[i] == ext)
+				return true;
+		}
 	}
 
 	return false;