ath: Handle errors from copyout()

[markj]

Summary

This is in preparation for annotating copyin() and related functions
with __result_use_check.

sys/dev/ath/ath_rate/sample/sample.c

static struct timecounter arm_tmr_timecount = {
         .tc_counter_mask   = ~0u,
         .tc_frequency      = 0,
         .tc_quality        = 1000,
 };
 
 static int
 get_freq(void)
 {
-        uint32_t val;
-
-        /* cntfrq */
-        __asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (val));
-
-        return (val);
+        return (cp15_cntfrq_get());
 }
 
 static long
 get_cntxct(bool physical)
 {
         uint64_t val;
 
         isb();
         if (physical)
-                /* cntpct */
-                __asm volatile("mrrc p15, 0, %Q0, %R0, c14" : "=r" (val));
+                val = cp15_cntpct_get();
         else
-                /* cntvct */
-                __asm volatile("mrrc p15, 1, %Q0, %R0, c14" : "=r" (val));
+                val = cp15_cntvct_get();
 
         return (val);
 }
 
 static int
 set_ctrl(uint32_t val, bool physical)
 {
 
         if (physical)
-                /* cntp_ctl */
-                __asm volatile("mcr p15, 0, %[val], c14, c2, 1" : :
-                    [val] "r" (val));
+                cp15_cntp_ctl_set(val);
         else
-                /* cntv_ctl */
-                __asm volatile("mcr p15, 0, %[val], c14, c3, 1" : :
-                    [val] "r" (val));
+                cp15_cntv_ctl_set(val);
         isb();
 
         return (0);
 }
 
 static int
 set_tval(uint32_t val, bool physical)
 {
 
         if (physical)
-                /* cntp_tval */
-                __asm volatile("mcr p15, 0, %[val], c14, c2, 0" : :
-                    [val] "r" (val));
+                cp15_cntp_tval_set(val);
         else
-                /* cntv_tval */
-                __asm volatile("mcr p15, 0, %[val], c14, c3, 0" : :
-                    [val] "r" (val));
+                cp15_cntv_tval_set(val);
         isb();
 
         return (0);
 }
 
 static int
 get_ctrl(bool physical)
 {
         uint32_t val;
 
         if (physical)
-                /* cntp_ctl */
-                __asm volatile("mrc p15, 0, %0, c14, c2, 1" : "=r" (val));
+                val = cp15_cntp_ctl_get();
         else
-                /* cntv_ctl */
-                __asm volatile("mrc p15, 0, %0, c14, c3, 1" : "=r" (val));
+                val = cp15_cntv_ctl_get();
 
         return (val);
 }
 
 static void
 disable_user_access(void)
 {
         uint32_t cntkctl;
 
-        __asm volatile("mrc p15, 0, %0, c14, c1, 0" : "=r" (cntkctl));
+        cntkctl = cp15_cntkctl_get();
         cntkctl &= ~(GT_CNTKCTL_PL0PTEN | GT_CNTKCTL_PL0VTEN |
             GT_CNTKCTL_EVNTEN | GT_CNTKCTL_PL0VCTEN | GT_CNTKCTL_PL0PCTEN);
-        __asm volatile("mcr p15, 0, %0, c14, c1, 0" : : "r" (cntkctl));
+        cp15_cntkctl_set(cntkctl);
         isb();
 }
 
 static unsigned
 arm_tmr_get_timecount(struct timecounter *tc)
 {
 
         return (get_cntxct(arm_tmr_sc->physical));