replace stdatomic.h with zinnia/atomic.h

arch/x86_64/smp.c

@@ -2,6 +2,7 @@
 
 #include <zinnia/alloc.h>
 #include <zinnia/assert.h>
+#include <zinnia/atomic.h>
 #include <zinnia/clock.h>
 #include <zinnia/compiler.h>
 #include <zinnia/irq.h>
@@ -12,7 +13,6 @@
 #include <zinnia/types.h>
 #include <zinnia/utils.h>
 #include <zinnia/vma.h>
-#include <stdatomic.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <string.h>
@@ -172,7 +172,7 @@ static void ap_entry(phys_t info_addr) {
 
     // Let the BSP know that we're alive.
     // `info` must not be touched after this point.
-    atomic_store_explicit(&info->booted, 1, memory_order_release);
+    atomic_store(&info->booted, 1, ATOMIC_RELEASE);
 
     log("CPU %zu online\n", cpu->id);
 
@@ -231,7 +231,7 @@ static bool start_ap(phys_t trampoline, uint32_t temp_cr3, uint32_t lapic_id) {
     );
     clock_spin_ns(10'000'000);
 
-    for (uint64_t waited = 0; !atomic_load_explicit(&info->booted, memory_order_acquire); waited += 1'000'000) {
+    for (uint64_t waited = 0; !atomic_load(&info->booted, ATOMIC_ACQUIRE); waited += 1'000'000) {
         if (waited >= AP_BOOT_TIMEOUT_NS) {
             // The per-CPU data and boot stack are leaked on purpose, in case the AP still comes up.
             log_err("CPU %zu (LAPIC %u) did not respond\n", cpu->id, lapic_id);