diff mbox series

[19/23] x86: use non-set_fs based maccess routines

Message ID 20200521152301.2587579-20-hch@lst.de (mailing list archive)
State New, archived
Headers show
Series [01/23] maccess: unexport probe_kernel_write and probe_user_write | expand

Commit Message

Christoph Hellwig May 21, 2020, 3:22 p.m. UTC 
Provide arch_kernel_read and arch_kernel_write routines to implement the
maccess routines without messing with set_fs and without stac/clac that
opens up access to user space.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/include/asm/uaccess.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
diff mbox series

Patch

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index d8f283b9a569c..b3e0a56ae961a 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -523,5 +523,21 @@  do {									\
 	unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u8, label);	\
 } while (0)
 
+#define HAVE_GET_KERNEL_NOFAULT
+
+#define __get_kernel_nofault(dst, src, type, err_label)			\
+do {									\
+        int __kr_err;							\
+									\
+	__get_user_size(*((type *)dst), (__force type __user *)src,	\
+			sizeof(type), __kr_err);			\
+        if (unlikely(__kr_err))						\
+		goto err_label;						\
+} while (0)
+
+#define __put_kernel_nofault(dst, src, type, err_label)			\
+	__put_user_size(*((type *)(src)), (__force type __user *)(dst),	\
+			sizeof(type), err_label)
+
 #endif /* _ASM_X86_UACCESS_H */