From: Thorsten Blum <thorsten.blum@linux.dev>
Date: Sun, 7 Jun 2026 02:17:52 +0000 (-0600)
Subject: riscv: use sysfs_emit in cpu_show_ghostwrite
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7d0dec57e52c7b5e14ba4ab6f86e9c17b850f1ec;p=thirdparty%2Flinux.git

riscv: use sysfs_emit in cpu_show_ghostwrite

Replace sprintf() with sysfs_emit() in cpu_show_ghostwrite(), which is
preferred for formatting sysfs output because it provides safer bounds
checking.

While the current code only emits fixed strings that fit easily within
PAGE_SIZE, use sysfs_emit() to follow secure coding best practices.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Link: https://patch.msgid.link/20260510165420.109453-3-thorsten.blum@linux.dev
Signed-off-by: Paul Walmsley <pjw@kernel.org>
---

diff --git a/arch/riscv/kernel/bugs.c b/arch/riscv/kernel/bugs.c
index 3655fe7d678c..e5758e3f1c7e 100644
--- a/arch/riscv/kernel/bugs.c
+++ b/arch/riscv/kernel/bugs.c
@@ -5,7 +5,7 @@
 
 #include <linux/cpu.h>
 #include <linux/device.h>
-#include <linux/sprintf.h>
+#include <linux/sysfs.h>
 
 #include <asm/bugs.h>
 #include <asm/vendor_extensions/thead.h>
@@ -46,15 +46,15 @@ ssize_t cpu_show_ghostwrite(struct device *dev, struct device_attribute *attr, c
 	if (IS_ENABLED(CONFIG_RISCV_ISA_XTHEADVECTOR)) {
 		switch (ghostwrite_state) {
 		case UNAFFECTED:
-			return sprintf(buf, "Not affected\n");
+			return sysfs_emit(buf, "Not affected\n");
 		case MITIGATED:
-			return sprintf(buf, "Mitigation: xtheadvector disabled\n");
+			return sysfs_emit(buf, "Mitigation: xtheadvector disabled\n");
 		case VULNERABLE:
 			fallthrough;
 		default:
-			return sprintf(buf, "Vulnerable\n");
+			return sysfs_emit(buf, "Vulnerable\n");
 		}
-	} else {
-		return sprintf(buf, "Not affected\n");
 	}
+
+	return sysfs_emit(buf, "Not affected\n");
 }