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From: Thorsten Blum <thorsten.blum@linux.dev>
To: Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>
Cc: Thorsten Blum <thorsten.blum@linux.dev>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH] riscv: use sysfs_emit in cpu_show_ghostwrite
Date: Sun, 10 May 2026 18:54:21 +0200	[thread overview]
Message-ID: <20260510165420.109453-3-thorsten.blum@linux.dev> (raw)

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>
---
 arch/riscv/kernel/bugs.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

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");
 }

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WARNING: multiple messages have this Message-ID (diff)
From: Thorsten Blum <thorsten.blum@linux.dev>
To: Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>
Cc: Thorsten Blum <thorsten.blum@linux.dev>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH] riscv: use sysfs_emit in cpu_show_ghostwrite
Date: Sun, 10 May 2026 18:54:21 +0200	[thread overview]
Message-ID: <20260510165420.109453-3-thorsten.blum@linux.dev> (raw)

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>
---
 arch/riscv/kernel/bugs.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

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");
 }

             reply	other threads:[~2026-05-10 16:55 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-10 16:54 Thorsten Blum [this message]
2026-05-10 16:54 ` [PATCH] riscv: use sysfs_emit in cpu_show_ghostwrite Thorsten Blum
2026-05-13 22:58 ` Paul Walmsley
2026-05-13 22:58   ` Paul Walmsley

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