Re: [PATCH v3 4/9] arc: use generic strncpy/strnlen from_user
From: Vineet Gupta <hidden>
Date: 2021-07-22 15:35:00
Also in:
linux-arch, linux-s390, linux-um, lkml
On 7/22/21 5:48 AM, Arnd Bergmann wrote:
From: Arnd Bergmann <arnd@arndb.de> Remove the arc implemenation of strncpy/strnlen and instead use the generic versions. The arc version is fairly slow because it always does byte accesses even for aligned data, and its checks for user_addr_max() differ from the generic code. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
LGTM. Thx for doing this Arnd ! Acked-by: Vineet Gupta <redacted> -Vineet
quoted hunk ↗ jump to hunk
--- arch/arc/Kconfig | 2 + arch/arc/include/asm/uaccess.h | 83 ++-------------------------------- arch/arc/mm/extable.c | 12 ----- 3 files changed, 7 insertions(+), 90 deletions(-)diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index d8f51eb8963b..64e5f9366401 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig@@ -27,6 +27,8 @@ config ARC select GENERIC_PENDING_IRQ if SMP select GENERIC_SCHED_CLOCK select GENERIC_SMP_IDLE_THREAD + select GENERIC_STRNCPY_FROM_USER + select GENERIC_STRNLEN_USER select HAVE_ARCH_KGDB select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE if ARC_MMU_V4diff --git a/arch/arc/include/asm/uaccess.h b/arch/arc/include/asm/uaccess.h index 3476348f361e..754a23f26736 100644 --- a/arch/arc/include/asm/uaccess.h +++ b/arch/arc/include/asm/uaccess.h@@ -655,96 +655,23 @@ static inline unsigned long __arc_clear_user(void __user *to, unsigned long n) return res; } -static inline long -__arc_strncpy_from_user(char *dst, const char __user *src, long count) -{ - long res = 0; - char val; - - if (!access_ok(src, 1)) - return -EFAULT; - - if (count == 0) - return 0; - - __asm__ __volatile__( - " mov lp_count, %5 \n" - " lp 3f \n" - "1: ldb.ab %3, [%2, 1] \n" - " breq.d %3, 0, 3f \n" - " stb.ab %3, [%1, 1] \n" - " add %0, %0, 1 # Num of NON NULL bytes copied \n" - "3: \n" - " .section .fixup, \"ax\" \n" - " .align 4 \n" - "4: mov %0, %4 # sets @res as -EFAULT \n" - " j 3b \n" - " .previous \n" - " .section __ex_table, \"a\" \n" - " .align 4 \n" - " .word 1b, 4b \n" - " .previous \n" - : "+r"(res), "+r"(dst), "+r"(src), "=r"(val) - : "g"(-EFAULT), "r"(count) - : "lp_count", "memory"); - - return res; -} - -static inline long __arc_strnlen_user(const char __user *s, long n) -{ - long res, tmp1, cnt; - char val; - - if (!access_ok(s, 1)) - return 0; - - __asm__ __volatile__( - " mov %2, %1 \n" - "1: ldb.ab %3, [%0, 1] \n" - " breq.d %3, 0, 2f \n" - " sub.f %2, %2, 1 \n" - " bnz 1b \n" - " sub %2, %2, 1 \n" - "2: sub %0, %1, %2 \n" - "3: ;nop \n" - " .section .fixup, \"ax\" \n" - " .align 4 \n" - "4: mov %0, 0 \n" - " j 3b \n" - " .previous \n" - " .section __ex_table, \"a\" \n" - " .align 4 \n" - " .word 1b, 4b \n" - " .previous \n" - : "=r"(res), "=r"(tmp1), "=r"(cnt), "=r"(val) - : "0"(s), "1"(n) - : "memory"); - - return res; -} - #ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE #define INLINE_COPY_TO_USER #define INLINE_COPY_FROM_USER #define __clear_user(d, n) __arc_clear_user(d, n) -#define strncpy_from_user(d, s, n) __arc_strncpy_from_user(d, s, n) -#define strnlen_user(s, n) __arc_strnlen_user(s, n) #else extern unsigned long arc_clear_user_noinline(void __user *to, unsigned long n); -extern long arc_strncpy_from_user_noinline (char *dst, const char __user *src, - long count); -extern long arc_strnlen_user_noinline(const char __user *src, long n); - #define __clear_user(d, n) arc_clear_user_noinline(d, n) -#define strncpy_from_user(d, s, n) arc_strncpy_from_user_noinline(d, s, n) -#define strnlen_user(s, n) arc_strnlen_user_noinline(s, n) - #endif +extern long strncpy_from_user(char *dst, const char __user *src, long count); +#define strncpy_from_user(d, s, n) strncpy_from_user(d, s, n) +extern long strnlen_user(const char __user *src, long n); +#define strnlen_user(s, n) strnlen_user(s, n) + #include <asm/segment.h> #include <asm-generic/uaccess.h>diff --git a/arch/arc/mm/extable.c b/arch/arc/mm/extable.c index b06b09ddf924..4e14c4244ea2 100644 --- a/arch/arc/mm/extable.c +++ b/arch/arc/mm/extable.c@@ -32,16 +32,4 @@ unsigned long arc_clear_user_noinline(void __user *to, } EXPORT_SYMBOL(arc_clear_user_noinline); -long arc_strncpy_from_user_noinline(char *dst, const char __user *src, - long count) -{ - return __arc_strncpy_from_user(dst, src, count); -} -EXPORT_SYMBOL(arc_strncpy_from_user_noinline); - -long arc_strnlen_user_noinline(const char __user *src, long n) -{ - return __arc_strnlen_user(src, n); -} -EXPORT_SYMBOL(arc_strnlen_user_noinline); #endif