diff options
| -rw-r--r-- | arch/arc/include/asm/arcregs.h | 2 | ||||
| -rw-r--r-- | arch/arc/kernel/process.c | 20 |
2 files changed, 13 insertions, 9 deletions
diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h index 7f3f9f63708c..1bd24ec3e350 100644 --- a/arch/arc/include/asm/arcregs.h +++ b/arch/arc/include/asm/arcregs.h @@ -43,12 +43,14 @@ #define STATUS_AE_BIT 5 /* Exception active */ #define STATUS_DE_BIT 6 /* PC is in delay slot */ #define STATUS_U_BIT 7 /* User/Kernel mode */ +#define STATUS_Z_BIT 11 #define STATUS_L_BIT 12 /* Loop inhibit */ /* These masks correspond to the status word(STATUS_32) bits */ #define STATUS_AE_MASK (1<<STATUS_AE_BIT) #define STATUS_DE_MASK (1<<STATUS_DE_BIT) #define STATUS_U_MASK (1<<STATUS_U_BIT) +#define STATUS_Z_MASK (1<<STATUS_Z_BIT) #define STATUS_L_MASK (1<<STATUS_L_BIT) /* diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c index 59aa43cb146e..a41a79a4f4fe 100644 --- a/arch/arc/kernel/process.c +++ b/arch/arc/kernel/process.c @@ -43,8 +43,8 @@ SYSCALL_DEFINE0(arc_gettls) SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new) { - int uval; - int ret; + struct pt_regs *regs = current_pt_regs(); + int uval = -EFAULT; /* * This is only for old cores lacking LLOCK/SCOND, which by defintion @@ -54,24 +54,26 @@ SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new) */ WARN_ON_ONCE(IS_ENABLED(CONFIG_SMP)); + /* Z indicates to userspace if operation succeded */ + regs->status32 &= ~STATUS_Z_MASK; + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) return -EFAULT; preempt_disable(); - ret = __get_user(uval, uaddr); - if (ret) + if (__get_user(uval, uaddr)) goto done; - if (uval != expected) - ret = -EAGAIN; - else - ret = __put_user(new, uaddr); + if (uval == expected) { + if (!__put_user(new, uaddr)) + regs->status32 |= STATUS_Z_MASK; + } done: preempt_enable(); - return ret; + return uval; } void arch_cpu_idle(void) |