Add virtmemFindAliasMemory to virtmem APIs

nx/include/switch/kernel/virtmem.h

@@ -59,6 +59,15 @@ void* virtmemFindStack(size_t size, size_t guard_size);
  */
 void* virtmemFindCodeMemory(size_t size, size_t guard_size);
 
+/**
+ * @brief Finds a random slice of free alias address space.
+ * @param size Desired size of the slice (rounded up to page alignment).
+ * @param guard_size Desired size of the unmapped guard areas surrounding the slice  (rounded up to page alignment).
+ * @return Pointer to the slice of address space, or NULL on failure.
+ * @note The virtual memory manager mutex must be held during the find-and-map process (see \ref virtmemLock and \ref virtmemUnlock).
+ */
+void* virtmemFindAlias(size_t size, size_t guard_size);
+
 /**
  * @brief Reserves a range of memory address space.
  * @param mem Pointer to the address space slice.

nx/source/kernel/virtmem.c

@@ -273,6 +273,11 @@ void* virtmemFindCodeMemory(size_t size, size_t guard_size) {
     return _memregionFindRandom(g_IsLegacyKernel ? &g_StackRegion : &g_AslrRegion, size, guard_size);
 }
 
+void* virtmemFindAlias(size_t size, size_t guard_size) {
+    if (!mutexIsLockedByCurrentThread(&g_VirtmemMutex)) return NULL;
+    return _memregionFindRandom(&g_AliasRegion, size, guard_size);
+}
+
 VirtmemReservation* virtmemAddReservation(void* mem, size_t size) {
     if (!mutexIsLockedByCurrentThread(&g_VirtmemMutex)) return NULL;
     VirtmemReservation* rv = (VirtmemReservation*)malloc(sizeof(VirtmemReservation));