lock when changing process memory region (in syscall.c) and page-table (in process.c)

kernel/include/process.h

@@ -69,6 +69,14 @@ struct process_vm {
  	
 	// Address space private futexes 
 	struct futex_queue futex_queues[1 << FUTEX_HASHBITS];
+
+    aal_spinlock_t page_table_lock;
+    aal_spinlock_t memory_range_lock;
+    // to protect the followings:
+    // 1. addition of process "memory range" (extend_process_region, add_process_memory_range)
+    // 2. addition of process page table (allocate_pages, update_process_page_table)
+    // note that physical memory allocator (aal_mc_alloc_pages, aal_pagealloc_alloc)
+    // is protected by its own lock (see aal/manycore/generic/page_alloc.c)
 };
 
 

kernel/process.c

@@ -89,6 +89,7 @@ void update_process_page_table(struct process *process, struct vm_range *range,
 {
 	unsigned long p, pa = range->phys;
 
+    unsigned long flags = aal_mc_spinlock_lock(&process->vm->page_table_lock);
 	p = range->start;
 	while (p < range->end) {
 		aal_mc_pt_set_page(process->vm->page_table, (void *)p,
@@ -98,6 +99,7 @@ void update_process_page_table(struct process *process, struct vm_range *range,
 		p += PAGE_SIZE;
 
 	}
+    aal_mc_spinlock_unlock(&process->vm->page_table_lock, flags);
 }
 
 int add_process_large_range(struct process *process,
@@ -282,15 +284,18 @@ unsigned long extend_process_region(struct process *proc,
 int remove_process_region(struct process *proc,
                           unsigned long start, unsigned long end)
 {
+    unsigned long flags;
 	if ((start & (PAGE_SIZE - 1)) || (end & (PAGE_SIZE - 1))) {
 		return -EINVAL;
 	}
 
+    flags = aal_mc_spinlock_lock(&proc->vm->page_table_lock);
 	/* We defer freeing to the time of exit */
 	while (start < end) {
 		aal_mc_pt_clear_page(proc->vm->page_table, (void *)start);
 		start += PAGE_SIZE;
 	}
+    aal_mc_spinlock_unlock(&proc->vm->page_table_lock, flags);
 
 	return 0;
 }

kernel/syscall.c

@@ -384,6 +384,7 @@ SYSCALL_DECLARE(mmap)
     } else if ((aal_mc_syscall_arg3(ctx) & 0x20) == 0x20) {
         // #define MAP_ANONYMOUS  0x20
         kprintf("syscall.c,!MAP_FIXED,MAP_ANONYMOUS\n");
+        unsigned long flags = aal_mc_spinlock_lock(&cpu_local_var(current)->vm->memory_range_lock);
         unsigned long s = (region->map_end + PAGE_SIZE - 1) & PAGE_MASK;
 		unsigned long len = (aal_mc_syscall_arg1(ctx) + PAGE_SIZE - 1) & PAGE_MASK;
         //        lockr = aal_mc_spinlock_lock(&cpu_status_lock);
@@ -392,13 +393,14 @@ SYSCALL_DECLARE(mmap)
 			                      region->map_start,
 			                      region->map_end,
 			                      s + len);
-        //        aal_mc_spinlock_unlock(&cpu_status_lock, lockr);
+        aal_mc_spinlock_unlock(&cpu_local_var(current)->vm->memory_range_lock, flags);
 		kprintf("syscall.c,returning to caller...\n");
 		if (region->map_end == s + len) { return s; } else { return -EINVAL; }
 
 	} else if ((aal_mc_syscall_arg3(ctx) & 0x02) == 0x02) {
         // #define MAP_PRIVATE    0x02
 
+        unsigned long flags = aal_mc_spinlock_lock(&cpu_local_var(current)->vm->memory_range_lock);
         unsigned long s = (region->map_end + PAGE_SIZE - 1) & PAGE_MASK;
 		unsigned long len = (aal_mc_syscall_arg1(ctx) + PAGE_SIZE - 1) & PAGE_MASK;
         //        lockr = aal_mc_spinlock_lock(&cpu_status_lock);
@@ -407,7 +409,7 @@ SYSCALL_DECLARE(mmap)
 			                      region->map_start,
 			                      region->map_end,
 			                      s + len);
-        //        aal_mc_spinlock_unlock(&cpu_status_lock, lockr);
+        aal_mc_spinlock_unlock(&cpu_local_var(current)->vm->memory_range_lock, flags);
 		if (region->map_end != s + len) { return -EINVAL; }
 
         struct syscall_request request AAL_DMA_ALIGN;