Split out common part of linker script.

Bug: 223166344
Test: atest vmbase_example.integration_test
Change-Id: Idaf10e631ba33fcc7026c4e2f603778186215667
diff --git a/pvmfw/Android.bp b/pvmfw/Android.bp
index c90f262..4fcde74 100644
--- a/pvmfw/Android.bp
+++ b/pvmfw/Android.bp
@@ -38,7 +38,10 @@
     nocrt: true,
     system_shared_libs: ["libc"],
     stl: "none",
-    linker_scripts: ["image.ld"],
+    linker_scripts: [
+        "image.ld",
+        ":vmbase_sections",
+    ],
     installable: false,
     enabled: false,
     target: {
diff --git a/pvmfw/image.ld b/pvmfw/image.ld
index e122c72..aeb5046 100644
--- a/pvmfw/image.ld
+++ b/pvmfw/image.ld
@@ -20,101 +20,3 @@
 	dtb_region	: ORIGIN = 0x80000000, LENGTH = 2M
 	writable_data	: ORIGIN = 0x80400000, LENGTH = 2M
 }
-
-/*
- * Code will start running at this symbol which is placed at the start of the
- * image.
- */
-ENTRY(entry)
-
-/*
- * The following would be useful to check that .init code is not called back
- * into once it has completed but it isn't supported by ld.lld.
- *
- * NOCROSSREFS_TO(.init .text)
- */
-
-SECTIONS
-{
-	.dtb (NOLOAD) : {
-		dtb_begin = .;
-		. += LENGTH(dtb_region);
-		dtb_end = .;
-	} >dtb_region
-
-	/*
-	 * Collect together the code. This is page aligned so it can be mapped
-	 * as executable-only.
-	 */
-	.init : ALIGN(4096) {
-		text_begin = .;
-		*(.init.entry)
-		*(.init.*)
-	} >image
-	.text : {
-		*(.text.*)
-	} >image
-	text_end = .;
-
-	/*
-	 * Collect together read-only data. This is page aligned so it can be
-	 * mapped as read-only and non-executable.
-	 */
-	.rodata : ALIGN(4096) {
-		rodata_begin = .;
-		*(.rodata.*)
-	} >image
-	.got : {
-		*(.got)
-	} >image
-	rodata_end = .;
-
-	/*
-	 * Collect together the read-write data including .bss at the end which
-	 * will be zero'd by the entry code. This is page aligned so it can be
-	 * mapped as non-executable.
-	 */
-	.data : ALIGN(4096) {
-		data_begin = .;
-		*(.data.*)
-		/*
-		 * The entry point code assumes that .data is a multiple of 32
-		 * bytes long.
-		 */
-		. = ALIGN(32);
-		data_end = .;
-	} >writable_data AT>image
-	data_lma = LOADADDR(.data);
-
-	/* Everything beyond this point will not be included in the binary. */
-	bin_end = .;
-
-	/* The entry point code assumes that .bss is 16-byte aligned. */
-	.bss : ALIGN(16)  {
-		bss_begin = .;
-		*(.bss.*)
-		*(COMMON)
-		. = ALIGN(16);
-		bss_end = .;
-	} >writable_data
-
-	.stack (NOLOAD) : ALIGN(4096) {
-		boot_stack_begin = .;
-		. += 40 * 4096;
-		. = ALIGN(4096);
-		boot_stack_end = .;
-	} >writable_data
-
-	/*
-	 * Remove unused sections from the image.
-	 */
-	/DISCARD/ : {
-		/* The image loads itself so doesn't need these sections. */
-		*(.gnu.hash)
-		*(.hash)
-		*(.interp)
-		*(.eh_frame_hdr)
-		*(.eh_frame)
-		*(.note.gnu.build-id)
-	}
-}
diff --git a/vmbase/Android.bp b/vmbase/Android.bp
index 473103e..e88420e 100644
--- a/vmbase/Android.bp
+++ b/vmbase/Android.bp
@@ -39,3 +39,8 @@
     },
     apex_available: ["com.android.virt"],
 }
+
+filegroup {
+    name: "vmbase_sections",
+    srcs: ["sections.ld"],
+}
diff --git a/vmbase/README.md b/vmbase/README.md
index 8e804c0..3554ae6 100644
--- a/vmbase/README.md
+++ b/vmbase/README.md
@@ -152,7 +152,10 @@
     nocrt: true,
     system_shared_libs: ["libc"],
     stl: "none",
-    linker_scripts: ["image.ld"],
+    linker_scripts: [
+        "image.ld",
+        ":vmbase_sections",
+    ],
     installable: false,
     enabled: false,
     target: {
@@ -165,8 +168,9 @@
 
 This takes your Rust library (`libvmbase_example`), the vmbase library entry point and exception
 vector (`libvmbase_entry`) and your initial idmap (`idmap.S`) and builds a static binary with your
-linker script (`image.ld`). This is an ELF binary, but to run it as a VM bootloader you need to
-`objcopy` it to a raw binary image instead, which you can do with a `raw_binary` rule:
+linker script (`image.ld`) and the one provided by vmbase ([`sections.ld`](sections.ld)). This is an
+ELF binary, but to run it as a VM bootloader you need to `objcopy` it to a raw binary image instead,
+which you can do with a `raw_binary` rule:
 
 ```soong
 raw_binary {
diff --git a/vmbase/example/Android.bp b/vmbase/example/Android.bp
index d540f4d..c75820c 100644
--- a/vmbase/example/Android.bp
+++ b/vmbase/example/Android.bp
@@ -40,7 +40,10 @@
     nocrt: true,
     system_shared_libs: ["libc"],
     stl: "none",
-    linker_scripts: ["image.ld"],
+    linker_scripts: [
+        "image.ld",
+        ":vmbase_sections",
+    ],
     installable: false,
     enabled: false,
     target: {
diff --git a/vmbase/example/image.ld b/vmbase/example/image.ld
index 4655f68..368acbb 100644
--- a/vmbase/example/image.ld
+++ b/vmbase/example/image.ld
@@ -20,101 +20,3 @@
 	image		: ORIGIN = 0x80200000, LENGTH = 2M
 	writable_data	: ORIGIN = 0x80400000, LENGTH = 2M
 }
-
-/*
- * Code will start running at this symbol which is placed at the start of the
- * image.
- */
-ENTRY(entry)
-
-/*
- * The following would be useful to check that .init code is not called back
- * into once it has completed but it isn't supported by ld.lld.
- *
- * NOCROSSREFS_TO(.init .text)
- */
-
-SECTIONS
-{
-	.dtb (NOLOAD) : {
-		dtb_begin = .;
-		. += LENGTH(dtb_region);
-		dtb_end = .;
-	} >dtb_region
-
-	/*
-	 * Collect together the code. This is page aligned so it can be mapped
-	 * as executable-only.
-	 */
-	.init : ALIGN(4096) {
-		text_begin = .;
-		*(.init.entry)
-		*(.init.*)
-	} >image
-	.text : {
-		*(.text.*)
-	} >image
-	text_end = .;
-
-	/*
-	 * Collect together read-only data. This is page aligned so it can be
-	 * mapped as read-only and non-executable.
-	 */
-	.rodata : ALIGN(4096) {
-		rodata_begin = .;
-		*(.rodata.*)
-	} >image
-	.got : {
-		*(.got)
-	} >image
-	rodata_end = .;
-
-	/*
-	 * Collect together the read-write data including .bss at the end which
-	 * will be zero'd by the entry code. This is page aligned so it can be
-	 * mapped as non-executable.
-	 */
-	.data : ALIGN(4096) {
-		data_begin = .;
-		*(.data.*)
-		/*
-		 * The entry point code assumes that .data is a multiple of 32
-		 * bytes long.
-		 */
-		. = ALIGN(32);
-		data_end = .;
-	} >writable_data AT>image
-	data_lma = LOADADDR(.data);
-
-	/* Everything beyond this point will not be included in the binary. */
-	bin_end = .;
-
-	/* The entry point code assumes that .bss is 16-byte aligned. */
-	.bss : ALIGN(16)  {
-		bss_begin = .;
-		*(.bss.*)
-		*(COMMON)
-		. = ALIGN(16);
-		bss_end = .;
-	} >writable_data
-
-	.stack (NOLOAD) : ALIGN(4096) {
-		boot_stack_begin = .;
-		. += 40 * 4096;
-		. = ALIGN(4096);
-		boot_stack_end = .;
-	} >writable_data
-
-	/*
-	 * Remove unused sections from the image.
-	 */
-	/DISCARD/ : {
-		/* The image loads itself so doesn't need these sections. */
-		*(.gnu.hash)
-		*(.hash)
-		*(.interp)
-		*(.eh_frame_hdr)
-		*(.eh_frame)
-		*(.note.gnu.build-id)
-	}
-}
diff --git a/vmbase/sections.ld b/vmbase/sections.ld
new file mode 100644
index 0000000..88033e3
--- /dev/null
+++ b/vmbase/sections.ld
@@ -0,0 +1,113 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Code will start running at this symbol which is placed at the start of the
+ * image.
+ */
+ENTRY(entry)
+
+/*
+ * The following would be useful to check that .init code is not called back
+ * into once it has completed but it isn't supported by ld.lld.
+ *
+ * NOCROSSREFS_TO(.init .text)
+ */
+
+SECTIONS
+{
+	.dtb (NOLOAD) : {
+		dtb_begin = .;
+		. += LENGTH(dtb_region);
+		dtb_end = .;
+	} >dtb_region
+
+	/*
+	 * Collect together the code. This is page aligned so it can be mapped
+	 * as executable-only.
+	 */
+	.init : ALIGN(4096) {
+		text_begin = .;
+		*(.init.entry)
+		*(.init.*)
+	} >image
+	.text : {
+		*(.text.*)
+	} >image
+	text_end = .;
+
+	/*
+	 * Collect together read-only data. This is page aligned so it can be
+	 * mapped as read-only and non-executable.
+	 */
+	.rodata : ALIGN(4096) {
+		rodata_begin = .;
+		*(.rodata.*)
+	} >image
+	.got : {
+		*(.got)
+	} >image
+	rodata_end = .;
+
+	/*
+	 * Collect together the read-write data including .bss at the end which
+	 * will be zero'd by the entry code. This is page aligned so it can be
+	 * mapped as non-executable.
+	 */
+	.data : ALIGN(4096) {
+		data_begin = .;
+		*(.data.*)
+		/*
+		 * The entry point code assumes that .data is a multiple of 32
+		 * bytes long.
+		 */
+		. = ALIGN(32);
+		data_end = .;
+	} >writable_data AT>image
+	data_lma = LOADADDR(.data);
+
+	/* Everything beyond this point will not be included in the binary. */
+	bin_end = .;
+
+	/* The entry point code assumes that .bss is 16-byte aligned. */
+	.bss : ALIGN(16)  {
+		bss_begin = .;
+		*(.bss.*)
+		*(COMMON)
+		. = ALIGN(16);
+		bss_end = .;
+	} >writable_data
+
+	.stack (NOLOAD) : ALIGN(4096) {
+		boot_stack_begin = .;
+		. += 40 * 4096;
+		. = ALIGN(4096);
+		boot_stack_end = .;
+	} >writable_data
+
+	/*
+	 * Remove unused sections from the image.
+	 */
+	/DISCARD/ : {
+		/* The image loads itself so doesn't need these sections. */
+		*(.gnu.hash)
+		*(.hash)
+		*(.interp)
+		*(.eh_frame_hdr)
+		*(.eh_frame)
+		*(.note.gnu.build-id)
+	}
+}