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authorWill Deacon <will.deacon@arm.com>2013-11-06 17:20:22 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2013-12-19 17:43:06 +0000
commit12a0ef7b0ac38677bd2d85f33df5ca0a57868819 (patch)
tree59b4be2d48b136aac65c7201a975a9463917e020 /arch/arm64/include
parentarm64: percpu: implement optimised pcpu access using tpidr_el1 (diff)
downloadlinux-dev-12a0ef7b0ac38677bd2d85f33df5ca0a57868819.tar.xz
linux-dev-12a0ef7b0ac38677bd2d85f33df5ca0a57868819.zip
arm64: use generic strnlen_user and strncpy_from_user functions
This patch implements the word-at-a-time interface for arm64 using the same algorithm as ARM. We use the fls64 macro, which expands to a clz instruction via a compiler builtin. Big-endian configurations make use of the implementation from asm-generic. With this implemented, we can replace our byte-at-a-time strnlen_user and strncpy_from_user functions with the optimised generic versions. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to '')
-rw-r--r--arch/arm64/include/asm/uaccess.h25
-rw-r--r--arch/arm64/include/asm/word-at-a-time.h54
2 files changed, 58 insertions, 21 deletions
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 7ecc2b23882e..6c0f684aca81 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -100,6 +100,7 @@ static inline void set_fs(mm_segment_t fs)
})
#define access_ok(type, addr, size) __range_ok(addr, size)
+#define user_addr_max get_fs
/*
* The "__xxx" versions of the user access functions do not verify the address
@@ -240,9 +241,6 @@ extern unsigned long __must_check __copy_to_user(void __user *to, const void *fr
extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n);
extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
-extern unsigned long __must_check __strncpy_from_user(char *to, const char __user *from, unsigned long count);
-extern unsigned long __must_check __strnlen_user(const char __user *s, long n);
-
static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
{
if (access_ok(VERIFY_READ, from, n))
@@ -276,24 +274,9 @@ static inline unsigned long __must_check clear_user(void __user *to, unsigned lo
return n;
}
-static inline long __must_check strncpy_from_user(char *dst, const char __user *src, long count)
-{
- long res = -EFAULT;
- if (access_ok(VERIFY_READ, src, 1))
- res = __strncpy_from_user(dst, src, count);
- return res;
-}
-
-#define strlen_user(s) strnlen_user(s, ~0UL >> 1)
+extern long strncpy_from_user(char *dest, const char __user *src, long count);
-static inline long __must_check strnlen_user(const char __user *s, long n)
-{
- unsigned long res = 0;
-
- if (__addr_ok(s))
- res = __strnlen_user(s, n);
-
- return res;
-}
+extern __must_check long strlen_user(const char __user *str);
+extern __must_check long strnlen_user(const char __user *str, long n);
#endif /* __ASM_UACCESS_H */
diff --git a/arch/arm64/include/asm/word-at-a-time.h b/arch/arm64/include/asm/word-at-a-time.h
new file mode 100644
index 000000000000..27a167d044d9
--- /dev/null
+++ b/arch/arm64/include/asm/word-at-a-time.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2013 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef __ASM_WORD_AT_A_TIME_H
+#define __ASM_WORD_AT_A_TIME_H
+
+#ifndef __AARCH64EB__
+
+#include <linux/kernel.h>
+
+struct word_at_a_time {
+ const unsigned long one_bits, high_bits;
+};
+
+#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
+
+static inline unsigned long has_zero(unsigned long a, unsigned long *bits,
+ const struct word_at_a_time *c)
+{
+ unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
+ *bits = mask;
+ return mask;
+}
+
+#define prep_zero_mask(a, bits, c) (bits)
+
+static inline unsigned long create_zero_mask(unsigned long bits)
+{
+ bits = (bits - 1) & ~bits;
+ return bits >> 7;
+}
+
+static inline unsigned long find_zero(unsigned long mask)
+{
+ return fls64(mask) >> 3;
+}
+
+#else /* __AARCH64EB__ */
+#include <asm-generic/word-at-a-time.h>
+#endif
+
+#endif /* __ASM_WORD_AT_A_TIME_H */