Changes in kernel/meson.build [c21d4d6:b169619] in mainline

File:

• kernel/meson.build (modified) (5 diffs)

kernel/meson.build

@@ -42 +42 @@
 subdir('test')
 
-## Cross-platform assembly to start a symtab.data section
-#
-symtab_section = '.section symtab.data, "a", ' + atsign + 'progbits;'
-
 kernel_include_dirs = include_directories(
         'generic/include',
@@ -52 +48 @@
         '..' / 'abi' / 'arch' / KARCH / 'include',
         '..' / 'abi' / 'include',
+        '..' / 'common' / 'include',
         'test',
 )
@@ -89 +86 @@
         '-T', meson.current_build_dir() / '_link.ld',
 ]
+# The kernel is built as ELF but then copied as a blob of bytes and
+# the permissions are not relevant anyway (needed for binutils 2.39+).
+kernel_link_args += ldflags_ignore_rwx_segments
 
 if CONFIG_LTO
@@ -94 +94 @@
 endif
 
-if CONFIG_STRIP_BINARIES
-        # TODO: do this after disassembling
-        kernel_link_args += [ '-s' ]
-endif
-
 kernel_c_args = arch_kernel_c_args + kernel_defs + [
         '-ffreestanding',
-        # TODO: remove this flag
-        cc.get_supported_arguments([ '-Wno-cast-function-type' ]),
+        '-fdebug-prefix-map=../../kernel/=',
+        '-fdebug-prefix-map=../../../kernel/=',
+
+        cc.get_supported_arguments([
+                # TODO: remove this flag
+                '-Wno-cast-function-type',
+
+                # When accessing specific memory addresses that are below
+                # normal page size, the compiler may assume that we actually
+                # dereferenced NULL pointer and warns us about that.
+                # But in kernel we often need to access these addresses
+                # directly hence we need to ignore these warnings.
+                #
+                # TODO: might make more sense to disable this selectively
+                # in specific files (or better yet, for specific lines).
+                '--param=min-pagesize=0',
+        ]),
 ]
+
+if not CONFIG_LINE_DEBUG
+        # Keep the debug info needed to get file names for kernel stack traces.
+        kernel_c_args += [ '-gdwarf-5', '-g1', '-gno-statement-frontiers' ]
+endif
 
 if CONFIG_LTO
@@ -133 +148 @@
 all_kernel_objects = [ instrumentables, noninstrumentables ]
 
-# We iterate the build several times to get symbol table right.
-# Three times is sufficient to get correct even symbols after symtab.
+kernel_name = 'kernel.elf'
+kernel_map_name = kernel_name + '.map'
+kernel_map_path = meson.current_build_dir() / kernel_map_name
+
+kernel_elf = executable(kernel_name,
+        include_directories: kernel_include_dirs,
+        implicit_include_directories: false,
+        c_args: kernel_c_args,
+        link_args: kernel_c_args + kernel_link_args + [
+                '-Wl,-Map,' + kernel_map_path,
+        ],
+        link_depends: kernel_ldscript,
+        link_whole: all_kernel_objects,
+        pie: false,
+)
+
+kernel_dbg = custom_target('kernel.dbg',
+        output: 'kernel.dbg',
+        input: kernel_elf,
+        command: [
+                objcopy,
+                '--only-keep-debug',
+                '@INPUT@',
+                '@OUTPUT@',
+        ],
+)
+
+kernel_elf_stripped = custom_target(kernel_name + '.stripped',
+        output: kernel_name + '.stripped',
+        input: kernel_elf,
+        command: [
+                objcopy,
+                '--strip-unneeded',
+                '@INPUT@',
+                '@OUTPUT@',
+        ],
+)
+
+rd_init_binaries += [[ kernel_elf_stripped, 'boot/kernel.elf' ]]
+install_files += [[ 'boot', kernel_elf_stripped.full_path(), 'kernel.elf' ]]
+install_deps += [ kernel_elf_stripped ]
 
 if CONFIG_SYMTAB
-        # Iterate build three times.
-        iterations = [ 1, 2, 3 ]
-
-        # Generates symbol table information as an object file.
-        genmap = find_program('tools/genmap.py')
-
-        # Symbol table dump needed for genmap.
-        kernel_syms = custom_target('kernel_syms.txt',
-                input: all_kernel_objects,
-                output: 'kernel_syms.txt',
-                command: [ objdump, '-t', '@INPUT@' ],
-                capture: true,
-        )
-else
-        # Build just once.
-        iterations = [ 1 ]
-endif
-
-# Empty symbol map for first iteration.
-kernel_map_S = custom_target('empty_map.S',
-        output: 'empty_map.S',
-        capture: true,
-        command: [ 'echo', kernel_as_prolog + symtab_section ],
-)
-
-foreach iter : iterations
-        is_last = (iter == iterations.length())
-        kernel_name = 'kernel.@0@.elf'.format(iter)
-        kernel_map_name = kernel_name + '.map'
-        kernel_map_path = meson.current_build_dir() / kernel_map_name
-
-        kernel_elf = executable(kernel_name, kernel_map_S,
-                include_directories: kernel_include_dirs,
-                implicit_include_directories: false,
-                c_args: kernel_c_args,
-                link_args: kernel_c_args + kernel_link_args + [
-                        '-Wl,-Map,' + kernel_map_path,
-                ],
-                link_depends: kernel_ldscript,
-                link_whole: all_kernel_objects,
-                pie: false,
-        )
-
-        # Generate symbol table if this is not the final iteration.
-        if not is_last
-
-                # TODO: Teach kernel to read its own ELF symbol table and get rid of this nonsense.
-                # Need to first make sure all architectures (even future ones with dumb bootloaders) can use ELF formatted kernel.
-
-                kernel_map_bin = custom_target(kernel_map_name + '.bin',
-                        output: kernel_map_name + '.bin',
-                        input: [ kernel_elf, kernel_syms ],
-                        command: [ genmap, kernel_map_path, '@INPUT1@', '@OUTPUT@' ],
-                )
-
-                kernel_map_S_name = kernel_name + '.map.S'
-
-                kernel_map_S = custom_target(kernel_map_S_name,
-                        input: kernel_map_bin,
-                        output: kernel_map_S_name,
-                        capture: true,
-                        command: [ 'echo', kernel_as_prolog + symtab_section + ' .incbin "@INPUT@"' ],
-                )
-        endif
-endforeach
-
-rd_init_binaries += [[ kernel_elf, 'boot/kernel.elf' ]]
-
-install_files += [[ 'boot', kernel_elf.full_path(), 'kernel.elf' ]]
-install_deps += [ kernel_elf ]
+        rd_init_binaries += [[ kernel_dbg, 'kernel.dbg' ]]
+        install_files += [[ 'boot', kernel_dbg.full_path(), 'kernel.dbg' ]]
+        install_deps += [ kernel_dbg ]
+endif
 
 kernel_disasm = custom_target('kernel.elf.disasm',