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asm-generic: improve the nommu {get,put}_user handling
Instead of reusing raw_{copy,to}_from_user implement separate handlers using {get,put}_unaligned. This ensures unaligned access is handled correctly, and avoid the need for the small constant size optimization in raw_{copy,to}_from_user. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
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1 changed files with 51 additions and 40 deletions
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@ -10,28 +10,60 @@
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#include <linux/string.h>
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#include <linux/string.h>
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#ifdef CONFIG_UACCESS_MEMCPY
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#ifdef CONFIG_UACCESS_MEMCPY
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#include <asm/unaligned.h>
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static inline int __get_user_fn(size_t size, const void __user *from, void *to)
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{
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BUILD_BUG_ON(!__builtin_constant_p(size));
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switch (size) {
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case 1:
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*(u8 *)to = get_unaligned((u8 __force *)from);
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return 0;
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case 2:
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*(u16 *)to = get_unaligned((u16 __force *)from);
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return 0;
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case 4:
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*(u32 *)to = get_unaligned((u32 __force *)from);
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return 0;
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case 8:
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*(u64 *)to = get_unaligned((u64 __force *)from);
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return 0;
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default:
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BUILD_BUG();
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return 0;
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}
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}
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#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
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static inline int __put_user_fn(size_t size, void __user *to, void *from)
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{
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BUILD_BUG_ON(!__builtin_constant_p(size));
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switch (size) {
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case 1:
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put_unaligned(*(u8 *)from, (u8 __force *)to);
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return 0;
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case 2:
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put_unaligned(*(u16 *)from, (u16 __force *)to);
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return 0;
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case 4:
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put_unaligned(*(u32 *)from, (u32 __force *)to);
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return 0;
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case 8:
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put_unaligned(*(u64 *)from, (u64 __force *)to);
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return 0;
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default:
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BUILD_BUG();
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return 0;
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}
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}
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#define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
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static inline __must_check unsigned long
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static inline __must_check unsigned long
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raw_copy_from_user(void *to, const void __user * from, unsigned long n)
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raw_copy_from_user(void *to, const void __user * from, unsigned long n)
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{
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{
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if (__builtin_constant_p(n)) {
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switch(n) {
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case 1:
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*(u8 *)to = *(u8 __force *)from;
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return 0;
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case 2:
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*(u16 *)to = *(u16 __force *)from;
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return 0;
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case 4:
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*(u32 *)to = *(u32 __force *)from;
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return 0;
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#ifdef CONFIG_64BIT
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case 8:
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*(u64 *)to = *(u64 __force *)from;
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return 0;
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#endif
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}
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}
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memcpy(to, (const void __force *)from, n);
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memcpy(to, (const void __force *)from, n);
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return 0;
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return 0;
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}
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}
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@ -39,27 +71,6 @@ raw_copy_from_user(void *to, const void __user * from, unsigned long n)
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static inline __must_check unsigned long
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static inline __must_check unsigned long
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raw_copy_to_user(void __user *to, const void *from, unsigned long n)
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raw_copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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{
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if (__builtin_constant_p(n)) {
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switch(n) {
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case 1:
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*(u8 __force *)to = *(u8 *)from;
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return 0;
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case 2:
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*(u16 __force *)to = *(u16 *)from;
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return 0;
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case 4:
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*(u32 __force *)to = *(u32 *)from;
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return 0;
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#ifdef CONFIG_64BIT
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case 8:
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*(u64 __force *)to = *(u64 *)from;
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return 0;
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#endif
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default:
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break;
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}
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}
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memcpy((void __force *)to, from, n);
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memcpy((void __force *)to, from, n);
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return 0;
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return 0;
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}
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}
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