libhsakmt: support allocating a fixed address at mmap_aperture.

When HsaMemFlags.ui32.FixedAddress=1 allocate fixed address at mmap_aperture.

Signed-off-by: Xiaogang Chen<Xiaogang.Chen@amd.com>
Change-Id: I1f3b532ec3c1a4fb0962126a0bd56441abaf6a9c

src/fmm.c

@@ -785,14 +785,38 @@ static void *mmap_aperture_allocate_aligned(manageable_aperture_t *aper,
 	uint64_t alignment_size = PAGE_SIZE << svm.alignment_order;
 	uint64_t guard_size;
 
-	if (address)
-		return NULL;
-
 	if (!aper->is_cpu_accessible) {
 		pr_err("MMap Aperture must be CPU accessible\n");
 		return NULL;
 	}
 
+	if (address) {
+		void *addr;
+
+#ifdef MAP_FIXED_NOREPLACE
+		addr = mmap(address, size, PROT_NONE,
+			MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE | MAP_FIXED_NOREPLACE,
+			-1, 0);
+#else
+		addr = mmap(address, size, PROT_NONE,
+			MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE,
+			-1, 0);
+#endif
+		if (addr == MAP_FAILED) {
+			pr_err("mmap failed: %s\n", strerror(errno));
+			return NULL;
+		}
+
+#ifndef MAP_FIXED_NOREPLACE
+		if (address != addr) {
+			pr_err("mmap failed to return addr asked\n");
+			munmap(addr, size);
+			return NULL;
+		}
+#endif
+		return addr;
+	}
+
 	/* Align big buffers to the next power-of-2. By default, the max alignment
 	 * size is set to 2MB. This can be modified by the env variable
 	 * HSA_MAX_VA_ALIGN. This variable sets the order of the alignment size as