Merge "Reland "check_elf_file: check prebuilts are aligned"" into main am: 69e8c9be5f am: 9830e817d6

Original change: https://android-review.googlesource.com/c/platform/build/+/3110301

Change-Id: I482fad100593b127dd8fb9e35bdabcfc4cfcd123
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

core/check_elf_file.mk

@@ -7,9 +7,12 @@
 #
 # Inputs:
 # - LOCAL_ALLOW_UNDEFINED_SYMBOLS
+# - LOCAL_IGNORE_MAX_PAGE_SIZE
 # - LOCAL_BUILT_MODULE
 # - LOCAL_IS_HOST_MODULE
 # - LOCAL_MODULE_CLASS
+# - TARGET_CHECK_PREBUILT_MAX_PAGE_SIZE
+# - TARGET_MAX_PAGE_SIZE_SUPPORTED
 # - intermediates
 # - my_installed_module_stem
 # - my_prebuilt_src_file
@@ -26,6 +29,21 @@ $(check_elf_files_stamp): PRIVATE_SYSTEM_SHARED_LIBRARIES := $(my_system_shared_
 # In addition to $(my_check_elf_file_shared_lib_files), some file paths are
 # added by `resolve-shared-libs-for-elf-file-check` from `core/main.mk`.
 $(check_elf_files_stamp): PRIVATE_SHARED_LIBRARY_FILES := $(my_check_elf_file_shared_lib_files)
+
+# For different page sizes to work, we must support a larger max page size
+# as well as properly reflect page size at runtime. Limit this check, since many
+# devices set the max page size (for future proof) than actually use the
+# larger page size.
+ifeq ($(strip $(TARGET_CHECK_PREBUILT_MAX_PAGE_SIZE)),true)
+ifeq ($(strip $(LOCAL_IGNORE_MAX_PAGE_SIZE)),true)
+$(check_elf_files_stamp): PRIVATE_MAX_PAGE_SIZE :=
+else
+$(check_elf_files_stamp): PRIVATE_MAX_PAGE_SIZE := $(TARGET_MAX_PAGE_SIZE_SUPPORTED)
+endif
+else
+$(check_elf_files_stamp): PRIVATE_MAX_PAGE_SIZE :=
+endif
+
 $(check_elf_files_stamp): $(my_prebuilt_src_file) $(my_check_elf_file_shared_lib_files) $(CHECK_ELF_FILE) $(LLVM_READOBJ)
 	@echo Check prebuilt ELF binary: $<
 	$(hide) mkdir -p $(dir $@)
@@ -33,6 +51,7 @@ $(check_elf_files_stamp): $(my_prebuilt_src_file) $(my_check_elf_file_shared_lib
 	$(hide) $(CHECK_ELF_FILE) \
 	    --skip-bad-elf-magic \
 	    --skip-unknown-elf-machine \
+	    $(if $(PRIVATE_MAX_PAGE_SIZE),--max-page-size=$(PRIVATE_MAX_PAGE_SIZE)) \
 	    $(if $(PRIVATE_SONAME),--soname $(PRIVATE_SONAME)) \
 	    $(foreach l,$(PRIVATE_SHARED_LIBRARY_FILES),--shared-lib $(l)) \
 	    $(foreach l,$(PRIVATE_SYSTEM_SHARED_LIBRARIES),--system-shared-lib $(l)) \

core/clear_vars.mk

@@ -106,6 +106,7 @@ LOCAL_GTEST:=true
 LOCAL_HEADER_LIBRARIES:=
 LOCAL_HOST_PREFIX:=
 LOCAL_HOST_REQUIRED_MODULES:=
+LOCAL_IGNORE_MAX_PAGE_SIZE:=
 LOCAL_INIT_RC:=
 LOCAL_INJECT_BSSL_HASH:=
 LOCAL_INSTALLED_MODULE:=

core/config.mk

@@ -419,6 +419,13 @@ else
 endif
 .KATI_READONLY := TARGET_MAX_PAGE_SIZE_SUPPORTED
 
+ifdef PRODUCT_CHECK_PREBUILT_MAX_PAGE_SIZE
+  TARGET_CHECK_PREBUILT_MAX_PAGE_SIZE := $(PRODUCT_CHECK_PREBUILT_MAX_PAGE_SIZE)
+else
+  TARGET_CHECK_PREBUILT_MAX_PAGE_SIZE := false
+endif
+.KATI_READONLY := TARGET_CHECK_PREBUILT_MAX_PAGE_SIZE
+
 # Boolean variable determining if AOSP relies on bionic's PAGE_SIZE macro.
 ifdef PRODUCT_NO_BIONIC_PAGE_SIZE_MACRO
   TARGET_NO_BIONIC_PAGE_SIZE_MACRO := $(PRODUCT_NO_BIONIC_PAGE_SIZE_MACRO)

core/product.mk

@@ -32,6 +32,7 @@ _product_single_value_vars += PRODUCT_MODEL_FOR_ATTESTATION
 # PRODUCT_MAX_PAGE_SIZE_SUPPORTED=65536, the possible values for PAGE_SIZE could be
 # 4096, 16384 and 65536.
 _product_single_value_vars += PRODUCT_MAX_PAGE_SIZE_SUPPORTED
+_product_single_value_vars += PRODUCT_CHECK_PREBUILT_MAX_PAGE_SIZE
 
 # Boolean variable determining if AOSP relies on bionic's PAGE_SIZE macro.
 _product_single_value_vars += PRODUCT_NO_BIONIC_PAGE_SIZE_MACRO

tools/check_elf_file.py

@@ -67,7 +67,7 @@ ELFHeader = collections.namedtuple(
 
 ELF = collections.namedtuple(
   'ELF',
-  ('dt_soname', 'dt_needed', 'imported', 'exported', 'header'))
+  ('alignments', 'dt_soname', 'dt_needed', 'imported', 'exported', 'header'))
 
 
 def _get_os_name():
@@ -195,7 +195,8 @@ class ELFParser(object):
   @classmethod
   def _read_llvm_readobj(cls, elf_file_path, header, llvm_readobj):
     """Run llvm-readobj and parse the output."""
-    cmd = [llvm_readobj, '--dynamic-table', '--dyn-symbols', elf_file_path]
+    cmd = [llvm_readobj, '--program-headers', '--dynamic-table',
+           '--dyn-symbols', elf_file_path]
     out = subprocess.check_output(cmd, text=True)
     lines = out.splitlines()
     return cls._parse_llvm_readobj(elf_file_path, header, lines)
@@ -205,9 +206,56 @@ class ELFParser(object):
   def _parse_llvm_readobj(cls, elf_file_path, header, lines):
     """Parse the output of llvm-readobj."""
     lines_it = iter(lines)
+    alignments = cls._parse_program_headers(lines_it)
     dt_soname, dt_needed = cls._parse_dynamic_table(elf_file_path, lines_it)
     imported, exported = cls._parse_dynamic_symbols(lines_it)
-    return ELF(dt_soname, dt_needed, imported, exported, header)
+    return ELF(alignments, dt_soname, dt_needed, imported, exported, header)
+
+
+  _PROGRAM_HEADERS_START_PATTERN = 'ProgramHeaders ['
+  _PROGRAM_HEADERS_END_PATTERN = ']'
+  _PROGRAM_HEADER_START_PATTERN = 'ProgramHeader {'
+  _PROGRAM_HEADER_TYPE_PATTERN = re.compile('^\\s+Type:\\s+(.*)$')
+  _PROGRAM_HEADER_ALIGN_PATTERN = re.compile('^\\s+Alignment:\\s+(.*)$')
+  _PROGRAM_HEADER_END_PATTERN = '}'
+
+
+  @classmethod
+  def _parse_program_headers(cls, lines_it):
+    """Parse the dynamic table section."""
+    alignments = []
+
+    if not cls._find_prefix(cls._PROGRAM_HEADERS_START_PATTERN, lines_it):
+      raise ELFError()
+
+    for line in lines_it:
+      # Parse each program header
+      if line.strip() == cls._PROGRAM_HEADER_START_PATTERN:
+        p_align = None
+        p_type = None
+        for line in lines_it:
+          if line.strip() == cls._PROGRAM_HEADER_END_PATTERN:
+            if not p_align:
+              raise ELFError("Could not parse alignment from program header!")
+            if not p_type:
+              raise ELFError("Could not parse type from program header!")
+
+            if p_type.startswith("PT_LOAD "):
+              alignments.append(int(p_align))
+            break
+
+          match = cls._PROGRAM_HEADER_TYPE_PATTERN.match(line)
+          if match:
+            p_type = match.group(1)
+
+          match = cls._PROGRAM_HEADER_ALIGN_PATTERN.match(line)
+          if match:
+            p_align = match.group(1)
+
+      if line == cls._PROGRAM_HEADERS_END_PATTERN:
+        break
+
+    return alignments
 
 
   _DYNAMIC_SECTION_START_PATTERN = 'DynamicSection ['
@@ -434,6 +482,24 @@ class Checker(object):
 
       sys.exit(2)
 
+  def check_max_page_size(self, max_page_size):
+    for alignment in self._file_under_test.alignments:
+      if alignment % max_page_size != 0:
+        self._error(f'Load segment has alignment {alignment} but '
+                    f'{max_page_size} required.')
+        self._note()
+        self._note('Fix suggestions:')
+        self._note(f'  use linker flag "-Wl,-z,max-page-size={max_page_size}" '
+                   f'when compiling this lib')
+        self._note()
+        self._note('If the fix above doesn\'t work, bypass this check with:')
+        self._note('  Android.bp: ignore_max_page_size: true,')
+        self._note('  Android.mk: LOCAL_IGNORE_MAX_PAGE_SIZE := true')
+        self._note('  Device mk: PRODUCT_CHECK_PREBUILT_MAX_PAGE_SIZE := false')
+
+        # TODO: instead of exiting immediately, we may want to collect the
+        # errors from all checks and emit them at once
+        sys.exit(2)
 
   @staticmethod
   def _find_symbol(lib, name, version):
@@ -514,6 +580,8 @@ def _parse_args():
                       help='Ignore the input file with unknown machine ID')
   parser.add_argument('--allow-undefined-symbols', action='store_true',
                       help='Ignore unresolved undefined symbols')
+  parser.add_argument('--max-page-size', action='store', type=int,
+                      help='Required page size alignment support')
 
   # Other options
   parser.add_argument('--llvm-readobj',
@@ -542,6 +610,9 @@ def main():
 
   checker.check_dt_needed(args.system_shared_lib)
 
+  if args.max_page_size:
+    checker.check_max_page_size(args.max_page_size)
+
   if not args.allow_undefined_symbols:
     checker.check_symbols()