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Subject[PATCH 7/8] riscv: implement __get_kernel_nofault and __put_user_nofault
Date
Implement the non-faulting kernel access helpers directly instead of
abusing the uaccess routines under set_fs(KERNEL_DS).

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
arch/riscv/include/asm/uaccess.h | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h
index b67d1c616ec348..264e52fb62b143 100644
--- a/arch/riscv/include/asm/uaccess.h
+++ b/arch/riscv/include/asm/uaccess.h
@@ -486,6 +486,26 @@ unsigned long __must_check clear_user(void __user *to, unsigned long n)
__ret; \
})

+#define HAVE_GET_KERNEL_NOFAULT
+
+#define __get_kernel_nofault(dst, src, type, err_label) \
+do { \
+ long __kr_err; \
+ \
+ __get_user_nocheck(*((type *)(dst)), (type *)(src), __kr_err); \
+ if (unlikely(__kr_err)) \
+ goto err_label; \
+} while (0)
+
+#define __put_kernel_nofault(dst, src, type, err_label) \
+do { \
+ long __kr_err; \
+ \
+ __put_user_nocheck(*((type *)(dst)), (type *)(src), __kr_err); \
+ if (unlikely(__kr_err)) \
+ goto err_label; \
+} while (0)
+
#else /* CONFIG_MMU */
#include <asm-generic/uaccess.h>
#endif /* CONFIG_MMU */
--
2.28.0
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