[PATCH 5/6] [v2] asm-generic: uaccess: remove inline strncpy_from_user/strnlen_user
From: Arnd Bergmann <arnd@kernel.org>
Date: 2021-05-15 10:20:05
Also in:
linux-m68k, linux-riscv, linux-um, lkml
Subsystem:
generic include/asm header files, m68k architecture, risc-v architecture, the rest · Maintainers:
Arnd Bergmann, Geert Uytterhoeven, Paul Walmsley, Palmer Dabbelt, Albert Ou, Linus Torvalds
From: Arnd Bergmann <arnd@arndb.de> Consolidate the asm-generic implementation with the library version that is used everywhere else. These are the three versions for NOMMU kernels, which can in principle fall back to strncpy()/strnlen() as the version in asm-generic does, but this version is particularly inefficient when it scans the string one byte at a time twice. The generic version also lacks a check for user_addr_max(), but this is probably ok on NOMMU targets. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- arch/h8300/Kconfig | 2 ++ arch/m68k/Kconfig | 4 +-- arch/riscv/Kconfig | 4 +-- include/asm-generic/uaccess.h | 46 ++++++----------------------------- 4 files changed, 14 insertions(+), 42 deletions(-)
diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig
index 3e3e0f16f7e0..53dfd2d47e0e 100644
--- a/arch/h8300/Kconfig
+++ b/arch/h8300/Kconfig@@ -11,6 +11,8 @@ config H8300 select GENERIC_IRQ_SHOW select FRAME_POINTER select GENERIC_CPU_DEVICES + select GENERIC_STRNCPY_FROM_USER + select GENERIC_STRNLEN_USER select MODULES_USE_ELF_RELA select COMMON_CLK select ARCH_WANT_FRAME_POINTERS
diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index ed6b8050e3ed..5f1aafa7b2e2 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig@@ -17,8 +17,8 @@ config M68K select GENERIC_CPU_DEVICES select GENERIC_IOMAP select GENERIC_IRQ_SHOW - select GENERIC_STRNCPY_FROM_USER if MMU - select GENERIC_STRNLEN_USER if MMU + select GENERIC_STRNCPY_FROM_USER + select GENERIC_STRNLEN_USER select HAVE_AOUT if MMU select HAVE_ASM_MODVERSIONS select HAVE_DEBUG_BUGVERBOSE
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index a8ad8eb76120..ada7a2918c05 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig@@ -55,8 +55,8 @@ config RISCV select GENERIC_PTDUMP if MMU select GENERIC_SCHED_CLOCK select GENERIC_SMP_IDLE_THREAD - select GENERIC_STRNCPY_FROM_USER if MMU - select GENERIC_STRNLEN_USER if MMU + select GENERIC_STRNCPY_FROM_USER + select GENERIC_STRNLEN_USER select GENERIC_TIME_VSYSCALL if MMU && 64BIT select HANDLE_DOMAIN_IRQ select HAVE_ARCH_AUDITSYSCALL
diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h
index c03889cc904c..83a48f430951 100644
--- a/include/asm-generic/uaccess.h
+++ b/include/asm-generic/uaccess.h@@ -119,6 +119,11 @@ static inline void set_fs(mm_segment_t fs) #ifndef uaccess_kernel #define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) #endif + +#ifndef user_addr_max +#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) +#endif + #endif /* CONFIG_SET_FS */ #define access_ok(addr, size) __access_ok((unsigned long)(addr),(size))
@@ -243,44 +248,6 @@ static inline int __get_user_fn(size_t size, const void __user *ptr, void *x) extern int __get_user_bad(void) __attribute__((noreturn)); -/* - * Copy a null terminated string from userspace. - */ -#ifndef strncpy_from_user -static inline long -strncpy_from_user(char *dst, const char __user *src, long count) -{ - char *tmp; - - if (!access_ok(src, 1)) - return -EFAULT; - - strncpy(dst, (const char __force *)src, count); - for (tmp = dst; *tmp && count > 0; tmp++, count--) - ; - return (tmp - dst); -} -#endif - -#ifndef strnlen_user -/* - * Return the size of a string (including the ending 0) - * - * Return 0 on exception, a value greater than N if too long - * - * Unlike strnlen, strnlen_user includes the nul terminator in - * its returned count. Callers should check for a returned value - * greater than N as an indication the string is too long. - */ -static inline long strnlen_user(const char __user *src, long n) -{ - if (!access_ok(src, 1)) - return 0; - - return strnlen(src, n) + 1; -} -#endif - /* * Zero Userspace */
@@ -305,4 +272,7 @@ clear_user(void __user *to, unsigned long n) #include <asm/extable.h> +extern long strncpy_from_user(char *dst, const char __user *src, long count); +extern long strnlen_user(const char __user *src, long n); + #endif /* __ASM_GENERIC_UACCESS_H */
--
2.29.2