libsys: mark regions allocated for DMA as special

This ensures that they will not be relocated.

Edited by David van Moolenbroek.

Change-Id: Ic2a97bc65b94dfcf364c06577aa340a9a5299e74

minix/include/minix/sef.h

@@ -366,6 +366,9 @@ void sef_llvm_stack_refs_restore(char *stack_buff);
 int sef_llvm_state_transfer(sef_init_info_t *info);
 int sef_llvm_add_special_mem_region(void *addr, size_t len, const char* name);
 int sef_llvm_del_special_mem_region_by_addr(void *addr);
+void *sef_llvm_ac_mmap(void *buf, size_t len, int prot, int flags, int fd,
+	off_t offset);
+int sef_llvm_ac_munmap(void *buf, size_t len);
 
 int sef_llvm_ltckpt_enabled(void);
 int sef_llvm_get_ltckpt_offset(void);

minix/lib/libsys/alloc_util.c

@@ -8,7 +8,7 @@
 
 void *alloc_contig(size_t len, int flags, phys_bytes *phys)
 {
-	vir_bytes buf;
+	void* buf;
 	int mmapflags = MAP_PREALLOC|MAP_CONTIG|MAP_ANON;
 
 	if(flags & AC_LOWER16M)
@@ -23,21 +23,21 @@ void *alloc_contig(size_t len, int flags, phys_bytes *phys)
 	 * pre-allocated and contiguous.
 	 */
 	errno = 0;
-	buf = (vir_bytes) mmap(0, len, PROT_READ|PROT_WRITE, mmapflags, -1, 0);
+	buf = sef_llvm_ac_mmap(0, len, PROT_READ|PROT_WRITE, mmapflags, -1, 0);
-
+	if(buf == MAP_FAILED) {
-	if(buf == (vir_bytes) MAP_FAILED) {
 		return NULL;
 	}
 
 	/* Get physical address, if requested. */
-        if(phys != NULL && sys_umap(SELF, VM_D, buf, len, phys) != OK)
+        if(phys != NULL && sys_umap(SELF, VM_D, (vir_bytes)buf, len,
+	    phys) != OK)
 		panic("sys_umap_data_fb failed");
 
-	return (void *) buf;
+	return buf;
 }
 
 int free_contig(void *addr, size_t len)
 {
-	return munmap(addr, len);
+	return sef_llvm_ac_munmap(addr, len);
 }
 

minix/lib/libsys/sef_llvm.c

@@ -153,6 +153,46 @@ int sef_llvm_del_special_mem_region_by_addr(void *addr)
     return st_del_special_mmapped_region_by_addr(addr);
 }
 
+/*===========================================================================*
+ *				sef_llvm_ac_mmap			     *
+ *===========================================================================*/
+void* sef_llvm_ac_mmap(void *buf, size_t len, int prot, int flags, int fd,
+	off_t offset)
+{
+    int r;
+    extern void* __attribute__((weak))
+       _magic_real_mmap(void*, size_t, int, int, int, off_t);
+    if (!_magic_real_mmap)
+        return mmap(buf, len, prot, flags, fd, offset);
+
+    /* Avoid regular dsentries for non-relocatable regions (e.g., DMA buffers).
+     */
+    buf = _magic_real_mmap(buf, len, prot, flags, fd, offset);
+    if(buf == MAP_FAILED)
+        return buf;
+    r = sef_llvm_add_special_mem_region(buf, len, NULL);
+    if(r < 0)
+        printf("sef_llvm_add_special_mem_region failed: %d\n", r);
+    return buf;
+}
+
+/*===========================================================================*
+ *				sef_llvm_ac_munmap			     *
+ *===========================================================================*/
+int sef_llvm_ac_munmap(void *buf, size_t len)
+{
+    int r;
+    extern int __attribute__((weak)) _magic_real_munmap(void*, size_t);
+    if (!_magic_real_munmap)
+        return munmap(buf, len);
+
+    if ((r = _magic_real_munmap(buf, len)) != 0)
+        return r;
+    if ((r = sef_llvm_del_special_mem_region_by_addr(buf)) < 0)
+        printf("sef_llvm_del_special_mem_region_by_addr failed: %d\n", r);
+    return 0;
+}
+
 /*===========================================================================*
  *      	             sef_llvm_ltckpt_enabled                         *
  *===========================================================================*/