soc: intel_adsp: add support for .cold* sections

Add support for .cold and .coldrodata sections, used to implement
a cold module. Assigning code and read-only data to those sections
makes them suitable for use in a cold module, stored and executed in
slow memory.

Signed-off-by: Guennadi Liakhovetski <[email protected]>

Author: lyakh

scripts/west_commands/sign.py

@@ -12,6 +12,8 @@
 import subprocess
 import sys
 
+from elftools.elf.elffile import ELFFile
+
 from west import manifest
 from west.commands import Verbosity
 from west.util import quote_sh_list
@@ -474,6 +476,7 @@ def sign(self, command, build_dir, build_conf, formats):
         kernel_name = build_conf.get('CONFIG_KERNEL_BIN_NAME', 'zephyr')
 
         bootloader = None
+        cold = None
         kernel = str(b / 'zephyr' / f'{kernel_name}.elf')
         out_bin = str(b / 'zephyr' / f'{kernel_name}.ri')
         out_xman = str(b / 'zephyr' / f'{kernel_name}.ri.xman')
@@ -484,6 +487,12 @@ def sign(self, command, build_dir, build_conf, formats):
         # zephyr.elf directly.
         if os.path.exists(str(b / 'zephyr' / 'boot.mod')):
             bootloader = str(b / 'zephyr' / 'boot.mod')
+        if os.path.exists(str(b / 'zephyr' / 'cold.mod')):
+            cold = str(b / 'zephyr' / 'cold.mod')
+            with open(cold, 'rb') as f_cold:
+                elf = ELFFile(f_cold)
+                if elf.get_section_by_name('.cold') is None:
+                    cold = None
         if os.path.exists(str(b / 'zephyr' / 'main.mod')):
             kernel = str(b / 'zephyr' / 'main.mod')
 
@@ -556,7 +565,10 @@ def sign(self, command, build_dir, build_conf, formats):
         if not args.quiet and args.verbose:
             sign_base += ['-v'] * args.verbose
 
+        # Order is important
         components = [ ] if bootloader is None else [ bootloader ]
+        if cold is not None:
+            components += [ cold ]
         components += [ kernel ]
 
         sign_config_extra_args = command.config_get_words('rimage.extra-args', [])

soc/intel/intel_adsp/ace/ace-link.ld

@@ -171,6 +171,16 @@ SECTIONS {
    */
   .imrdata : ALIGN(4096) {
     *(.imrdata .imrdata.*)
+  } >imr
+
+  /* Cold code in IMR memory */
+  .cold : ALIGN(4096) {
+    *(.cold .cold.* )
+  } >imr
+
+  /* Cold data. */
+  .coldrodata : ALIGN(4096) {
+    *(.coldrodata .coldrodata.*)
     _imr_end = .;
   } >imr
 
@@ -553,6 +563,7 @@ SECTIONS {
 
   /* rimage module manifest headers */
   .module.boot : { KEEP(*(.module.boot)) } >noload
+  .module.cold : { KEEP(*(.module.cold)) } >noload
   .module.main : { KEEP(*(.module.main)) } >noload
 
  .static_uuid_entries : {

soc/intel/intel_adsp/common/CMakeLists.txt

@@ -82,11 +82,22 @@ add_custom_command(
       --rename-section .module.boot=.module
       ${KERNEL_REMAPPED} ${CMAKE_BINARY_DIR}/zephyr/boot.mod 2>${NULL_FILE}
 
+  COMMAND ${CMAKE_OBJCOPY}
+      --only-section .cold
+      --only-section .coldrodata
+      --only-section .module.cold
+      --set-section-flags .module.cold=noload,readonly
+      --rename-section .module.cold=.module
+      ${KERNEL_REMAPPED} ${CMAKE_BINARY_DIR}/zephyr/cold.mod 2>${NULL_FILE}
+
   # Remove .fw_metadata here...
   COMMAND ${CMAKE_OBJCOPY}
       --remove-section .imr
       --remove-section .imrdata
+      --remove-section .cold
+      --remove-section .coldrodata
       --remove-section .module.boot
+      --remove-section .module.cold
       --remove-section .fw_metadata
       --set-section-flags .module.main=noload,readonly
       --set-section-flags .static_uuid_entries=noload,readonly