diff mbox series

[v10,08/40] arm64/gcs: Provide put_user_gcs()

Message ID 20240801-arm64-gcs-v10-8-699e2bd2190b@kernel.org (mailing list archive)
State New, archived
Headers show
Series arm64/gcs: Provide support for GCS in userspace | expand

Commit Message

Mark Brown Aug. 1, 2024, 12:06 p.m. UTC 
In order for EL1 to write to an EL0 GCS it must use the GCSSTTR instruction
rather than a normal STTR. Provide a put_user_gcs() which does this.

Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/include/asm/uaccess.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

Comments

Catalin Marinas Aug. 16, 2024, 11:12 a.m. UTC | #1 
On Thu, Aug 01, 2024 at 01:06:35PM +0100, Mark Brown wrote:
> In order for EL1 to write to an EL0 GCS it must use the GCSSTTR instruction
> rather than a normal STTR. Provide a put_user_gcs() which does this.
> 
> Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
> Signed-off-by: Mark Brown <broonie@kernel.org>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
diff mbox series

Patch

diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 6aba10e38d1c..ecdd47cf1d01 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -522,6 +522,24 @@  static inline int gcssttr(unsigned long __user *addr, unsigned long val)
 	return err;
 }
 
+static inline void put_user_gcs(unsigned long val, unsigned long __user *addr,
+				int *err)
+{
+	int ret;
+
+	if (!access_ok((char __user *)addr, sizeof(u64))) {
+		*err = -EFAULT;
+		return;
+	}
+
+	uaccess_ttbr0_enable();
+	ret = gcssttr(addr, val);
+	if (ret != 0)
+		*err = ret;
+	uaccess_ttbr0_disable();
+}
+
+
 #endif /* CONFIG_ARM64_GCS */
 
 #endif /* __ASM_UACCESS_H */