linker: sort app shared mem partition by alignment

If CONFIG_MPU_REQUIRES_POWER_OF_TWO_ALIGNMENT is enabled,
the app shared memory partition may cause waste of memory
due to the need for padding.

For example, tests/subsys/jwt and board mps2_an385:

  z_test_mem_partition: addr 0x20000000, size 52
  z_libc_partition    : addr 0x20000040, size 4
  k_mbedtls_partition : addr 0x20008000, size 32736

    ending at 0x2000ffff, taking up 65536 bytes

With power-of-two size and alignment requirement,
k_mbedtls_partition takes up 32KB memory and needs to be
aligned on 32KB boundary. If the above partitions are
ordered as shown, there needs to be a lot of padding
after z_libc_partition before k_mbedtls_partition can
start. In order to minimize padding, these partitions
need to be sort by size in descending order.

After the changes here,	the partitions are:

  k_mbedtls_partition : addr 0x20000000, size 32736
  z_test_mem_partition: addr 0x20008000, size 52
  z_libc_partition    : addr 0x20008040, size 4

    ending at 0x2000805f, taking up 32864 bytes

With the above example, sorting results in a saving
of 32672 bytes of saving.

Fixes #14121

Signed-off-by: Daniel Leung <[email protected]>

Author: dcpleung

CMakeLists.txt

@@ -363,7 +363,8 @@ zephyr_cc_option(-Wpointer-arith)
 # Declare MPU userspace dependencies before the linker scripts to make
 # sure the order of dependencies are met
 if(CONFIG_USERSPACE)
-  set(APP_SMEM_DEP app_smem_linker)
+  set(APP_SMEM_ALIGNED_DEP app_smem_aligned_linker)
+  set(APP_SMEM_UNALIGNED_DEP app_smem_unaligned_linker)
   if(CONFIG_ARM)
     set(PRIV_STACK_DEP priv_stacks_prebuilt)
   endif()
@@ -446,6 +447,8 @@ function(construct_add_custom_command_for_linker_pass linker_output_name output_
 
   if (${linker_output_name} MATCHES "^linker_pass_final$")
     set(linker_pass_define -DLINKER_PASS2)
+  elseif (${linker_output_name} MATCHES "^linker_app_smem_unaligned$")
+    set(linker_pass_define -DLINKER_APP_SMEM_UNALIGNED)
   else()
     set(linker_pass_define "")
   endif()
@@ -761,7 +764,7 @@ construct_add_custom_command_for_linker_pass(
   custom_command
   ${ALIGN_SIZING_DEP}
   ${PRIV_STACK_DEP}
-  ${APP_SMEM_DEP}
+  ${APP_SMEM_ALIGNED_DEP}
   ${CODE_RELOCATION_DEP}
   ${OFFSETS_H_TARGET}
   )
@@ -1134,14 +1137,29 @@ configure_file(
      $ENV{ZEPHYR_BASE}/include/linker/app_smem.ld
      ${PROJECT_BINARY_DIR}/include/generated/app_smem.ld)
 
+configure_file(
+     $ENV{ZEPHYR_BASE}/include/linker/app_smem_aligned.ld
+     ${PROJECT_BINARY_DIR}/include/generated/app_smem_aligned.ld)
+
+configure_file(
+     $ENV{ZEPHYR_BASE}/include/linker/app_smem_unaligned.ld
+     ${PROJECT_BINARY_DIR}/include/generated/app_smem_unaligned.ld)
+
 if(CONFIG_USERSPACE)
-  set(APP_SMEM_LD "${PROJECT_BINARY_DIR}/include/generated/app_smem.ld")
+  set(APP_SMEM_ALIGNED_LD "${PROJECT_BINARY_DIR}/include/generated/app_smem_aligned.ld")
+  set(APP_SMEM_UNALIGNED_LD "${PROJECT_BINARY_DIR}/include/generated/app_smem_unaligned.ld")
   set(OBJ_FILE_DIR "${PROJECT_BINARY_DIR}/../")
 
   add_custom_target(
-    ${APP_SMEM_DEP}
+    ${APP_SMEM_ALIGNED_DEP}
+    DEPENDS
+    ${APP_SMEM_ALIGNED_LD}
+    )
+
+  add_custom_target(
+    ${APP_SMEM_UNALIGNED_DEP}
     DEPENDS
-    ${APP_SMEM_LD}
+    ${APP_SMEM_UNALIGNED_LD}
     )
 
   if(CONFIG_NEWLIB_LIBC)
@@ -1152,18 +1170,65 @@ if(CONFIG_USERSPACE)
   endif()
 
   add_custom_command(
-    OUTPUT ${APP_SMEM_LD}
+    OUTPUT ${APP_SMEM_UNALIGNED_LD}
     COMMAND ${PYTHON_EXECUTABLE}
     ${ZEPHYR_BASE}/scripts/gen_app_partitions.py
     -d ${OBJ_FILE_DIR}
-    -o ${APP_SMEM_LD}
+    -o ${APP_SMEM_UNALIGNED_LD}
+    ${NEWLIB_PART} ${MBEDTLS_PART}
+    $<$<BOOL:${CMAKE_VERBOSE_MAKEFILE}>:--verbose>
+    DEPENDS
+    kernel
+    ${ZEPHYR_LIBS_PROPERTY}
+    WORKING_DIRECTORY ${PROJECT_BINARY_DIR}/
+    COMMENT "Generating app_smem_unaligned linker section"
+    )
+
+  construct_add_custom_command_for_linker_pass(
+    linker_app_smem_unaligned
+    custom_command
+    ${ALIGN_SIZING_DEP}
+    ${CODE_RELOCATION_DEP}
+    ${APP_SMEM_UNALIGNED_DEP}
+    ${APP_SMEM_UNALIGNED_LD}
+    ${OFFSETS_H_TARGET}
+    )
+  add_custom_command(
+    ${custom_command}
+    )
+
+  add_custom_target(
+    linker_app_smem_unaligned_script
+    DEPENDS
+    linker_app_smem_unaligned.cmd
+    )
+
+  set_property(TARGET
+    linker_app_smem_unaligned_script
+    PROPERTY INCLUDE_DIRECTORIES
+    ${ZEPHYR_INCLUDE_DIRS}
+    )
+
+  set(APP_SMEM_UNALIGNED_LIB app_smem_unaligned_output_obj_renamed_lib)
+  add_executable(       app_smem_unaligned_prebuilt misc/empty_file.c)
+  target_link_libraries(app_smem_unaligned_prebuilt ${TOPT} ${PROJECT_BINARY_DIR}/linker_app_smem_unaligned.cmd ${zephyr_lnk} ${CODE_RELOCATION_DEP})
+  set_property(TARGET   app_smem_unaligned_prebuilt PROPERTY LINK_DEPENDS ${PROJECT_BINARY_DIR}/linker_app_smem_unaligned.cmd)
+  add_dependencies(     app_smem_unaligned_prebuilt ${ALIGN_SIZING_DEP} linker_app_smem_unaligned_script ${OFFSETS_LIB})
+
+  add_custom_command(
+    OUTPUT ${APP_SMEM_ALIGNED_LD}
+    COMMAND ${PYTHON_EXECUTABLE}
+    ${ZEPHYR_BASE}/scripts/gen_app_partitions.py
+    -e $<TARGET_FILE:app_smem_unaligned_prebuilt>
+    -o ${APP_SMEM_ALIGNED_LD}
     ${NEWLIB_PART} ${MBEDTLS_PART}
     $<$<BOOL:${CMAKE_VERBOSE_MAKEFILE}>:--verbose>
     DEPENDS
     kernel
     ${ZEPHYR_LIBS_PROPERTY}
+    app_smem_unaligned_prebuilt
     WORKING_DIRECTORY ${PROJECT_BINARY_DIR}/
-    COMMENT "Generating app_smem linker section"
+    COMMENT "Generating app_smem_aligned linker section"
     )
 endif()
 
@@ -1173,8 +1238,8 @@ if(CONFIG_USERSPACE AND CONFIG_ARM)
     custom_command
     ${ALIGN_SIZING_DEP}
     ${CODE_RELOCATION_DEP}
-    ${APP_SMEM_DEP}
-    ${APP_SMEM_LD}
+    ${APP_SMEM_ALIGNED_DEP}
+    ${APP_SMEM_ALIGNED_LD}
     ${OFFSETS_H_TARGET}
     )
   add_custom_command(

CODEOWNERS

@@ -186,6 +186,7 @@
 /include/kernel_version.h                 @andrewboie @andyross
 /include/led.h                            @Mani-Sadhasivam
 /include/led_strip.h                      @mbolivar
+/include/linker/app_smem*.ld              @andrewboie
 /include/linker/linker-defs.h             @andrewboie @andyross
 /include/linker/linker-tool-gcc.h         @andrewboie @andyross
 /include/linker/linker-tool.h             @andrewboie @andyross

include/linker/app_smem.ld

@@ -1,2 +1,36 @@
-/* space holder  */
-APP_SMEM_SECTION()
+/*
+ * This hackish way of including files is due to CMake issues:
+ *   https://gitlab.kitware.com/cmake/cmake/issues/11985
+ *   https://gitlab.kitware.com/cmake/cmake/issues/13718
+ *
+ * When using the "Unix Makefiles" generator, CMake simply
+ * greps for "#include" to generate dependency list.
+ * So if doing it normally, both files are being included
+ * in the dependency list. This creates weird dependency
+ * issue:
+ *
+ *   1. Using A.ld to create a linker script A.cmd.
+ *   2. Using A.cmd to generate A_prebuilt.elf.
+ *   3. Using A_prebuilt.elf to create B.ld.
+ *   4. Creating B.cmd with B.ld.
+ *   5. Creating B_prebuilt.elf using B.cmd.
+ *
+ * Since the dependency list of A.cmd contains both
+ * A.ld and B.ld, when make is invoked again, B.ld
+ * is newer than A.cmd so everything from this point on
+ * gets rebuilt. In order to break this cycle, this
+ * hackish needs to be used since CMake does not parse
+ * macros, and thus these will not appear in
+ * the dependency list. The dependencies should then be
+ * put in CMakeLists.txt instead.
+ *
+ * Note: Ninja generator does not suffer from this issue.
+ */
+#ifdef LINKER_APP_SMEM_UNALIGNED
+#define APP_SMEM_LD <app_smem_unaligned.ld>
+#else
+#define APP_SMEM_LD <app_smem_aligned.ld>
+#endif
+
+#include APP_SMEM_LD
+#undef APP_SMEM_LD

include/linker/app_smem_aligned.ld

@@ -0,0 +1,2 @@
+/* space holder  */
+APP_SMEM_SECTION()

include/linker/app_smem_unaligned.ld

@@ -0,0 +1,2 @@
+/* space holder  */
+APP_SMEM_SECTION()

scripts/gen_app_partitions.py

@@ -37,9 +37,16 @@
 import os
 import re
 import string
+import subprocess
+from collections import OrderedDict
 from elf_helper import ElfHelper
 from elftools.elf.elffile import ELFFile
+from elftools.elf.sections import SymbolTableSection
+from operator import itemgetter
 
+SZ = 'size'
+SRC = 'sources'
+LIB = 'libraries'
 
 # This script will create sections and linker variables to place the
 # application shared memory partitions.
@@ -91,7 +98,9 @@
 
 section_regex = re.compile(r'data_smem_([A-Za-z0-9_]*)_(data|bss)')
 
-def find_partitions(filename, partitions, sources):
+elf_part_size_regex = re.compile(r'z_data_smem_(.*)_part_size')
+
+def find_obj_file_partitions(filename, partitions):
     with open(filename, 'rb') as f:
         full_lib = ELFFile( f)
         if (not full_lib):
@@ -106,23 +115,67 @@ def find_partitions(filename, partitions, sources):
 
             partition_name = m.groups()[0]
             if partition_name not in partitions:
-                partitions[partition_name] = []
+                partitions[partition_name] = {SZ: section.header.sh_size}
+
                 if args.verbose:
-                    sources.update({partition_name: filename})
+                    partitions[partition_name][SRC] = filename
+
+            else:
+                partitions[partition_name][SZ] += section.header.sh_size
+
+
+    return partitions
+
+
+def parse_obj_files(partitions):
+    # Iterate over all object files to find partitions
+    for dirpath, dirs, files in os.walk(args.directory):
+        for filename in files:
+            if re.match(".*\.obj$",filename):
+                fullname = os.path.join(dirpath, filename)
+                find_obj_file_partitions(fullname, partitions)
+
+
+def parse_elf_file(partitions):
+    with open(args.elf, 'rb') as f:
+        elffile = ELFFile(f)
 
-    return (partitions, sources)
+        symbol_tbls = [s for s in elffile.iter_sections()
+                       if isinstance(s, SymbolTableSection)]
+
+        for section in symbol_tbls:
+            for nsym, symbol in enumerate(section.iter_symbols()):
+                if symbol['st_shndx'] != "SHN_ABS":
+                    continue
+
+                x = elf_part_size_regex.match(symbol.name)
+                if not x:
+                    continue
+
+                partition_name = x.groups()[0]
+                size = symbol['st_value']
+                if partition_name not in partitions:
+                    partitions[partition_name] = {SZ: size}
+
+                    if args.verbose:
+                        partitions[partition_name][SRC] = args.elf
+
+                else:
+                    partitions[partition_name][SZ] += size
 
 
 def generate_final_linker(linker_file, partitions):
     string = linker_start_seq
     size_string = ''
-    for partition, libs in partitions.items():
+    for partition, item in partitions.items():
         string += data_template.format(partition)
-        for lib in libs:
-            string += library_data_template.format(lib)
+        if LIB in item:
+            for lib in item[LIB]:
+                string += library_data_template.format(lib)
         string += bss_template.format(partition)
-        for lib in libs:
-            string += library_bss_template.format(lib)
+        if LIB in item:
+            for lib in item[LIB]:
+                string += library_bss_template.format(lib)
         string += footer_template.format(partition)
         size_string += size_cal_string.format(partition)
 
@@ -137,8 +190,10 @@ def parse_args():
     parser = argparse.ArgumentParser(
         description=__doc__,
         formatter_class=argparse.RawDescriptionHelpFormatter)
-    parser.add_argument("-d", "--directory", required=True,
+    parser.add_argument("-d", "--directory", required=False, default=None,
                         help="Root build directory")
+    parser.add_argument("-e", "--elf", required=False, default=None,
+                        help="ELF file")
     parser.add_argument("-o", "--output", required=False,
                         help="Output ld file")
     parser.add_argument("-v", "--verbose", action="count", default =0,
@@ -154,26 +209,34 @@ def main():
     parse_args()
     linker_file = args.output
     partitions = {}
-    sources = {}
 
-    for dirpath, dirs, files in os.walk(args.directory):
-        for filename in files:
-            if re.match(".*\.obj$",filename):
-                fullname = os.path.join(dirpath, filename)
-                find_partitions(fullname, partitions,
-                                sources)
+    if args.directory is not None:
+        parse_obj_files(partitions)
+    elif args.elf is not None:
+        parse_elf_file(partitions)
+    else:
+        return
 
     for lib, ptn in args.library:
         if ptn not in partitions:
-            partitions[ptn] = [lib]
+            partitions[ptn] = {}
+
+        if LIB not in partitions[ptn]:
+            partitions[ptn][LIB] = [lib]
         else:
-            partitions[ptn].append(lib)
+            partitions[ptn][LIB].append(lib)
+
+    partsorted = OrderedDict(sorted(partitions.items(),
+                                     key=lambda x: x[1][SZ], reverse=True))
 
-    generate_final_linker(args.output, partitions)
+    generate_final_linker(args.output, partsorted)
     if args.verbose:
         print("Partitions retrieved:")
-        for key in partitions:
-            print("    %s: %s\n", key, sources[key])
+        for key in partsorted:
+            print("    {0}: size {1}: {2}".format(key,
+                                                  partsorted[key][SZ],
+                                                  partsorted[key][SRC]))
+
 
 if __name__ == '__main__':
     main()