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authorAlex Auvolat <alex.auvolat@ens.fr>2014-12-06 23:15:06 +0100
committerAlex Auvolat <alex.auvolat@ens.fr>2014-12-06 23:15:06 +0100
commitacc786cb5805d057932ada3e7c571bb8e901cd67 (patch)
treefe6a9da99a9c5492f1004363a2a1a7aa8bfc8fed /kernel/lib
parent0b5d6568c468075b6c1a2de065332b270345611b (diff)
downloadmacroscope-acc786cb5805d057932ada3e7c571bb8e901cd67.tar.gz
macroscope-acc786cb5805d057932ada3e7c571bb8e901cd67.zip
Begin review of taking model : making things thread safe.
Diffstat (limited to 'kernel/lib')
-rw-r--r--kernel/lib/mutex.c27
-rw-r--r--kernel/lib/slab_alloc.c3
2 files changed, 30 insertions, 0 deletions
diff --git a/kernel/lib/mutex.c b/kernel/lib/mutex.c
new file mode 100644
index 0000000..cda8049
--- /dev/null
+++ b/kernel/lib/mutex.c
@@ -0,0 +1,27 @@
+#include <mutex.h>
+
+/* Internal use only. This function is atomic, meaning it cannot be interrupted by a system task switch. */
+static uint32_t atomic_exchange(uint32_t* ptr, uint32_t newval) {
+ uint32_t r;
+ asm volatile("xchg (%%ecx), %%eax" : "=a"(r) : "c"(ptr), "a"(newval));
+ return r;
+}
+
+void mutex_lock(uint32_t* mutex) {
+ while (atomic_exchange(mutex, MUTEX_LOCKED) == MUTEX_LOCKED) {
+ yield();
+ }
+}
+
+int mutex_try_lock(uint32_t* mutex) {
+ if (atomic_exchange(mutex, MUTEX_LOCKED) == MUTEX_LOCKED) {
+ return 0;
+ }
+ return 1;
+}
+
+void mutex_unlock(uint32_t* mutex) {
+ *mutex = MUTEX_UNLOCKED;
+}
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/kernel/lib/slab_alloc.c b/kernel/lib/slab_alloc.c
index 63ee0e0..714c49f 100644
--- a/kernel/lib/slab_alloc.c
+++ b/kernel/lib/slab_alloc.c
@@ -278,3 +278,6 @@ void slab_free(mem_allocator_t* a, void* addr) {
ASSERT(false);
}
}
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/
+