[PATCH v3 5/9] csky: use generic strncpy/strnlen from_user
From: Arnd Bergmann <arnd@kernel.org>
Date: 2021-07-22 12:49:33
Also in:
linux-arch, linux-s390, linux-um, lkml
Subsystem:
c-sky architecture, the rest · Maintainers:
Guo Ren, Linus Torvalds
From: Arnd Bergmann <arnd@arndb.de> Remove the csky implemenation of strncpy/strnlen and instead use the generic versions. The csky version is fairly slow because it always does byte accesses even for aligned data, and it lacks a checks for user_addr_max(). Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- arch/csky/Kconfig | 2 + arch/csky/include/asm/uaccess.h | 6 -- arch/csky/lib/usercopy.c | 108 -------------------------------- 3 files changed, 2 insertions(+), 114 deletions(-)
diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index 2716f6395ba7..5043e221ced4 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig@@ -35,6 +35,8 @@ config CSKY select GENERIC_IRQ_MULTI_HANDLER select GENERIC_SCHED_CLOCK select GENERIC_SMP_IDLE_THREAD + select GENERIC_STRNCPY_FROM_USER + select GENERIC_STRNLEN_USER select GENERIC_TIME_VSYSCALL select GENERIC_VDSO_32 select GENERIC_GETTIMEOFDAY
diff --git a/arch/csky/include/asm/uaccess.h b/arch/csky/include/asm/uaccess.h
index e17c02a6709f..c40f06ee8d3e 100644
--- a/arch/csky/include/asm/uaccess.h
+++ b/arch/csky/include/asm/uaccess.h@@ -209,12 +209,6 @@ unsigned long raw_copy_to_user(void *to, const void *from, unsigned long n); unsigned long __clear_user(void __user *to, unsigned long n); #define __clear_user __clear_user -long strncpy_from_user(char *dst, const char *src, long count); -#define strncpy_from_user strncpy_from_user - -long strnlen_user(const char *s, long n); -#define strnlen_user strnlen_user - #include <asm/segment.h> #include <asm-generic/uaccess.h>
diff --git a/arch/csky/lib/usercopy.c b/arch/csky/lib/usercopy.c
index 938b750d2fb1..3c01c54421ca 100644
--- a/arch/csky/lib/usercopy.c
+++ b/arch/csky/lib/usercopy.c@@ -142,114 +142,6 @@ unsigned long raw_copy_to_user(void *to, const void *from, } EXPORT_SYMBOL(raw_copy_to_user); -/* - * __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. - */ -long strncpy_from_user(char *dst, const char *src, long count) -{ - long res, faultres; - int tmp; - - if (!access_ok(src, 1)) - return -EFAULT; - - __asm__ __volatile__( - " cmpnei %3, 0 \n" - " bf 4f \n" - "1: cmpnei %1, 0 \n" - " bf 5f \n" - "2: ldb %4, (%3, 0) \n" - " stb %4, (%2, 0) \n" - " cmpnei %4, 0 \n" - " bf 3f \n" - " addi %3, 1 \n" - " addi %2, 1 \n" - " subi %1, 1 \n" - " br 1b \n" - "3: subu %0, %1 \n" - " br 5f \n" - "4: mov %0, %5 \n" - " br 5f \n" - ".section __ex_table, \"a\" \n" - ".align 2 \n" - ".long 2b, 4b \n" - ".previous \n" - "5: \n" - : "=r"(res), "=r"(count), "=r"(dst), - "=r"(src), "=r"(tmp), "=r"(faultres) - : "5"(-EFAULT), "0"(count), "1"(count), - "2"(dst), "3"(src) - : "memory"); - - return res; -} -EXPORT_SYMBOL(strncpy_from_user); - -/* - * strnlen_user: - Get the size of a string in user space. - * @str: The string to measure. - * @n: The maximum valid length - * - * 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 the string is too long, returns a value greater than @n. - */ -long strnlen_user(const char *s, long n) -{ - unsigned long res, tmp; - - if (!access_ok(src, 1)) - return -EFAULT; - - __asm__ __volatile__( - " cmpnei %1, 0 \n" - " bf 3f \n" - "1: cmpnei %0, 0 \n" - " bf 3f \n" - "2: ldb %3, (%1, 0) \n" - " cmpnei %3, 0 \n" - " bf 3f \n" - " subi %0, 1 \n" - " addi %1, 1 \n" - " br 1b \n" - "3: subu %2, %0 \n" - " addi %2, 1 \n" - " br 5f \n" - "4: movi %0, 0 \n" - " br 5f \n" - ".section __ex_table, \"a\" \n" - ".align 2 \n" - ".long 2b, 4b \n" - ".previous \n" - "5: \n" - : "=r"(n), "=r"(s), "=r"(res), "=r"(tmp) - : "0"(n), "1"(s), "2"(n) - : "memory"); - - return res; -} -EXPORT_SYMBOL(strnlen_user); - /* * __clear_user: - Zero a block of memory in user space, with less checking. * @to: Destination address, in user space.
--
2.29.2