From 5bf6c07a1843813d0065feaaecba622d49148d7e Mon Sep 17 00:00:00 2001 From: Chris Metcalf Date: Thu, 30 Apr 2015 15:12:42 -0400 Subject: tile: add and enable support functions This change enables the generic strncpy_from_user() and strnlen_user() using word-at-a-time.h. The tile implementation is trivial since both tilepro and tilegx have SIMD operations that do byte-wise comparisons against immediate zero for each byte, and return an 0x01 byte in each position where there is a 0x00 byte. Signed-off-by: Chris Metcalf --- arch/tile/include/asm/uaccess.h | 66 ++++++---------------------------- arch/tile/include/asm/word-at-a-time.h | 36 +++++++++++++++++++ 2 files changed, 46 insertions(+), 56 deletions(-) create mode 100644 arch/tile/include/asm/word-at-a-time.h (limited to 'arch/tile/include') diff --git a/arch/tile/include/asm/uaccess.h b/arch/tile/include/asm/uaccess.h index f41cb53cf645..d598c11a82d9 100644 --- a/arch/tile/include/asm/uaccess.h +++ b/arch/tile/include/asm/uaccess.h @@ -64,6 +64,13 @@ static inline int is_arch_mappable_range(unsigned long addr, #define is_arch_mappable_range(addr, size) 0 #endif +/* + * Note that using this definition ignores is_arch_mappable_range(), + * so on tilepro code that uses user_addr_max() is constrained not + * to reference the tilepro user-interrupt region. + */ +#define user_addr_max() (current_thread_info()->addr_limit.seg) + /* * Test whether a block of memory is a valid user space address. * Returns 0 if the range is valid, nonzero otherwise. @@ -465,62 +472,9 @@ copy_in_user(void __user *to, const void __user *from, unsigned long n) #endif -/** - * strlen_user: - Get the size of a string in user space. - * @str: The string to measure. - * - * Context: User context only. This function may sleep. - * - * Get the size of a NUL-terminated string in user space. - * - * Returns the size of the string INCLUDING the terminating NUL. - * On exception, returns 0. - * - * If there is a limit on the length of a valid string, you may wish to - * consider using strnlen_user() instead. - */ -extern long strnlen_user_asm(const char __user *str, long n); -static inline long __must_check strnlen_user(const char __user *str, long n) -{ - might_fault(); - return strnlen_user_asm(str, n); -} -#define strlen_user(str) strnlen_user(str, LONG_MAX) - -/** - * strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking. - * @dst: Destination address, in kernel space. This buffer must be at - * least @count bytes long. - * @src: Source address, in user space. - * @count: Maximum number of bytes to copy, including the trailing NUL. - * - * Copies a NUL-terminated string from userspace to kernel space. - * Caller must check the specified block with access_ok() before calling - * this function. - * - * On success, returns the length of the string (not including the trailing - * NUL). - * - * If access to userspace fails, returns -EFAULT (some data may have been - * copied). - * - * If @count is smaller than the length of the string, copies @count bytes - * and returns @count. - */ -extern long strncpy_from_user_asm(char *dst, const char __user *src, long); -static inline long __must_check __strncpy_from_user( - char *dst, const char __user *src, long count) -{ - might_fault(); - return strncpy_from_user_asm(dst, src, count); -} -static inline long __must_check strncpy_from_user( - char *dst, const char __user *src, long count) -{ - if (access_ok(VERIFY_READ, src, 1)) - return __strncpy_from_user(dst, src, count); - return -EFAULT; -} +extern long strnlen_user(const char __user *str, long n); +extern long strlen_user(const char __user *str); +extern long strncpy_from_user(char *dst, const char __user *src, long); /** * clear_user: - Zero a block of memory in user space. diff --git a/arch/tile/include/asm/word-at-a-time.h b/arch/tile/include/asm/word-at-a-time.h new file mode 100644 index 000000000000..9e5ce0d7b292 --- /dev/null +++ b/arch/tile/include/asm/word-at-a-time.h @@ -0,0 +1,36 @@ +#ifndef _ASM_WORD_AT_A_TIME_H +#define _ASM_WORD_AT_A_TIME_H + +#include + +struct word_at_a_time { /* unused */ }; +#define WORD_AT_A_TIME_CONSTANTS {} + +/* Generate 0x01 byte values for non-zero bytes using a SIMD instruction. */ +static inline unsigned long has_zero(unsigned long val, unsigned long *data, + const struct word_at_a_time *c) +{ +#ifdef __tilegx__ + unsigned long mask = __insn_v1cmpeqi(val, 0); +#else /* tilepro */ + unsigned long mask = __insn_seqib(val, 0); +#endif + *data = mask; + return mask; +} + +/* These operations are both nops. */ +#define prep_zero_mask(val, data, c) (data) +#define create_zero_mask(data) (data) + +/* And this operation just depends on endianness. */ +static inline long find_zero(unsigned long mask) +{ +#ifdef __BIG_ENDIAN + return __builtin_clzl(mask) >> 3; +#else + return __builtin_ctzl(mask) >> 3; +#endif +} + +#endif /* _ASM_WORD_AT_A_TIME_H */ -- cgit v1.2.1