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authorVineet Gupta <vgupta@synopsys.com>2013-10-07 18:10:08 +0530
committerVineet Gupta <vgupta@synopsys.com>2015-06-22 14:06:56 +0530
commit8922bc3058abbe5deaf887147e26531750ce7513 (patch)
tree647f15f01077a23afd047e3d01b125a93e2ac9b1 /arch/arc/include/asm/uaccess.h
parent1f7e3dc0baaa41217dc06d3370e1efd1aecbc1f0 (diff)
ARCv2: Adhere to Zero Delay loop restriction
Branch insn can't be scheduled as last insn of Zero Overhead loop Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch/arc/include/asm/uaccess.h')
-rw-r--r--arch/arc/include/asm/uaccess.h17
1 files changed, 8 insertions, 9 deletions
diff --git a/arch/arc/include/asm/uaccess.h b/arch/arc/include/asm/uaccess.h
index 30c9baffa96f..d1da6032b715 100644
--- a/arch/arc/include/asm/uaccess.h
+++ b/arch/arc/include/asm/uaccess.h
@@ -659,31 +659,30 @@ static inline unsigned long __arc_clear_user(void __user *to, unsigned long n)
static inline long
__arc_strncpy_from_user(char *dst, const char __user *src, long count)
{
- long res = count;
+ long res = 0;
char val;
- unsigned int hw_count;
if (count == 0)
return 0;
__asm__ __volatile__(
- " lp 2f \n"
+ " lp 3f \n"
"1: ldb.ab %3, [%2, 1] \n"
- " breq.d %3, 0, 2f \n"
+ " breq.d %3, 0, 3f \n"
" stb.ab %3, [%1, 1] \n"
- "2: sub %0, %6, %4 \n"
- "3: ;nop \n"
+ " add %0, %0, 1 # Num of NON NULL bytes copied \n"
+ "3: \n"
" .section .fixup, \"ax\" \n"
" .align 4 \n"
- "4: mov %0, %5 \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), "=l"(hw_count)
- : "g"(-EFAULT), "ir"(count), "4"(count) /* this "4" seeds lp_count */
+ : "+r"(res), "+r"(dst), "+r"(src), "=r"(val)
+ : "g"(-EFAULT), "l"(count)
: "memory");
return res;