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Makefile: Add build time and compiler info string

When we are doing opensbi development, we want to know the build time
and compiler info for debug purpose.

To enable this message, please add "BUILD_INFO=y", like:

```
make BUILD_INFO=y
```

NOTE: Using `BUILD_INFO=y` without specifying SOURCE_DATE_EPOCH will
violate "reproducible builds". So it's ONLY for development and debug
purpose, and should NOT be used in a product which follows "reproducible
builds".

Signed-off-by: Wei Fu <wefu@redhat.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Wei Fu 2 years ago
parent
commit
422eda499c
3 changed files with 63 additions and 0 deletions
  1. 31 0
      Makefile
  2. 24 0
      README.md
  3. 8 0
      lib/sbi/sbi_init.c

+ 31 - 0
Makefile

@@ -150,6 +150,25 @@ endif
 # Check whether the linker supports creating PIEs
 OPENSBI_LD_PIE := $(shell $(CC) $(CLANG_TARGET) $(RELAX_FLAG) $(USE_LD_FLAG) -fPIE -nostdlib -Wl,-pie -x c /dev/null -o /dev/null >/dev/null 2>&1 && echo y || echo n)
 
+# Build Info:
+# OPENSBI_BUILD_TIME_STAMP -- the compilation time stamp
+# OPENSBI_BUILD_COMPILER_VERSION -- the compiler version info
+BUILD_INFO ?= n
+ifeq ($(BUILD_INFO),y)
+OPENSBI_BUILD_DATE_FMT = +%Y-%m-%d %H:%M:%S %z
+ifdef SOURCE_DATE_EPOCH
+	OPENSBI_BUILD_TIME_STAMP ?= $(shell date -u -d "@$(SOURCE_DATE_EPOCH)" \
+		"$(OPENSBI_BUILD_DATE_FMT)" 2>/dev/null || \
+		date -u -r "$(SOURCE_DATE_EPOCH)" \
+		"$(OPENSBI_BUILD_DATE_FMT)" 2>/dev/null || \
+		date -u "$(OPENSBI_BUILD_DATE_FMT)")
+else
+	OPENSBI_BUILD_TIME_STAMP ?= $(shell date "$(OPENSBI_BUILD_DATE_FMT)")
+endif
+OPENSBI_BUILD_COMPILER_VERSION=$(shell $(CC) -v 2>&1 | grep ' version ' | \
+	sed 's/[[:space:]]*$$//')
+endif
+
 # Setup list of objects.mk files
 ifdef PLATFORM
 platform-object-mks=$(shell if [ -d $(platform_src_dir)/ ]; then find $(platform_src_dir) -iname "objects.mk" | sort -r; fi)
@@ -247,6 +266,10 @@ GENFLAGS	+=	-I$(include_dir)
 ifneq ($(OPENSBI_VERSION_GIT),)
 GENFLAGS	+=	-DOPENSBI_VERSION_GIT="\"$(OPENSBI_VERSION_GIT)\""
 endif
+ifeq ($(BUILD_INFO),y)
+GENFLAGS	+=	-DOPENSBI_BUILD_TIME_STAMP="\"$(OPENSBI_BUILD_TIME_STAMP)\""
+GENFLAGS	+=	-DOPENSBI_BUILD_COMPILER_VERSION="\"$(OPENSBI_BUILD_COMPILER_VERSION)\""
+endif
 GENFLAGS	+=	$(libsbiutils-genflags-y)
 GENFLAGS	+=	$(platform-genflags-y)
 GENFLAGS	+=	$(firmware-genflags-y)
@@ -398,6 +421,11 @@ $(build_dir)/%.dep: $(src_dir)/%.c
 $(build_dir)/%.o: $(src_dir)/%.c
 	$(call compile_cc,$@,$<)
 
+ifeq ($(BUILD_INFO),y)
+$(build_dir)/lib/sbi/sbi_init.o: $(libsbi_dir)/sbi_init.c FORCE
+	$(call compile_cc,$@,$<)
+endif
+
 $(build_dir)/%.dep: $(src_dir)/%.S
 	$(call compile_as_dep,$@,$<)
 
@@ -551,3 +579,6 @@ ifeq ($(install_root_dir),$(install_root_dir_default)/usr)
 	$(if $(V), @echo " RM        $(install_root_dir_default)")
 	$(CMD_PREFIX)rm -rf $(install_root_dir_default)
 endif
+
+.PHONY: FORCE
+FORCE:

+ 24 - 0
README.md

@@ -254,6 +254,29 @@ to produce broken binaries with missing relocations; it is therefore currently
 recommended that this combination be avoided or *FW_PIC=n* be used to disable
 building OpenSBI as a position-independent binary.
 
+Building with timestamp and compiler info
+-----------------------------------------
+
+When doing development, we may want to know the build time and compiler info
+for debug purpose. OpenSBI can also be built with timestamp and compiler info.
+To build with those info and print it out at boot time, we can just simply add
+`BUILD_INFO=y`, like:
+```
+make BUILD_INFO=y
+```
+
+But if you have used `BUILD_INFO=y`, and want to switch back to `BUILD_INFO=n`,
+you must do
+```
+make clean
+```
+before the next build.
+
+NOTE: Using `BUILD_INFO=y` without specifying SOURCE_DATE_EPOCH will violate
+[reproducible builds]. This definition is ONLY for development and debug
+purpose, and should NOT be used in a product which follows "reproducible
+builds".
+
 Contributing to OpenSBI
 -----------------------
 
@@ -336,3 +359,4 @@ make I=<install_directory> install_docs
 [Doxygen manual]: http://www.doxygen.nl/manual/index.html
 [Kendryte standalone SDK]: https://github.com/kendryte/kendryte-standalone-sdk
 [third party notices]: ThirdPartyNotices.md
+[reproducible builds]: https://reproducible-builds.org

+ 8 - 0
lib/sbi/sbi_init.c

@@ -48,6 +48,14 @@ static void sbi_boot_print_banner(struct sbi_scratch *scratch)
 		   OPENSBI_VERSION_MINOR);
 #endif
 
+#ifdef OPENSBI_BUILD_TIME_STAMP
+	sbi_printf("Build time: %s\n", OPENSBI_BUILD_TIME_STAMP);
+#endif
+
+#ifdef OPENSBI_BUILD_COMPILER_VERSION
+	sbi_printf("Build compiler: %s\n", OPENSBI_BUILD_COMPILER_VERSION);
+#endif
+
 	sbi_printf(BANNER);
 }