From 486aef08de091ca35386f32fe961a201c3cfa9d4 Mon Sep 17 00:00:00 2001
From: Max Krummenacher <max.krummenacher@toradex.com>
Date: Mon, 28 Nov 2022 09:41:22 +0100
Subject: [PATCH] u-boot-initial-env: rework make target
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With LTO enabled the U-Boot initial environment is no longer stored
in an easy accessible section in env/common.o. I.e. the section name
changes from build to build, its content maybe compressed and it is
annotated with additional data.

Drop trying to read the initial env with elf tools from the compiler
specific object file in favour of adding and using a host tool with
the only functionality of printing the initial env to stdout.

See also:
https://lore.kernel.org/all/927b122e-1f62-e790-f5ca-30bae4332c77@foss.st.com/

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
Acked-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
---
 Makefile                | 10 ++++++----
 tools/.gitignore        |  1 +
 tools/Makefile          |  4 ++++
 tools/printinitialenv.c | 44 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 55 insertions(+), 4 deletions(-)
 create mode 100644 tools/printinitialenv.c

diff --git a/Makefile b/Makefile
index 11efc41804..9ec2e12a06 100644
--- a/Makefile
+++ b/Makefile
@@ -2439,11 +2439,13 @@ endif
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
 
 quiet_cmd_genenv = GENENV  $@
-cmd_genenv = $(OBJCOPY) --dump-section .rodata.default_environment=$@ env/common.o; \
-	sed --in-place -e 's/\x00/\x0A/g' $@; sed --in-place -e '/^\s*$$/d' $@; \
-	sort --field-separator== -k1,1 --stable $@ -o $@
+cmd_genenv = \
+	$(objtree)/tools/printinitialenv | \
+	sed -e '/^\s*$$/d' | \
+	sort --field-separator== -k1,1 --stable -o $@
 
-u-boot-initial-env: u-boot.bin
+u-boot-initial-env: $(env_h) FORCE
+	$(Q)$(MAKE) $(build)=tools $(objtree)/tools/printinitialenv
 	$(call if_changed,genenv)
 
 # Consistency checks
diff --git a/tools/.gitignore b/tools/.gitignore
index d3a93ff294..28e8ce2a07 100644
--- a/tools/.gitignore
+++ b/tools/.gitignore
@@ -28,6 +28,7 @@
 /mxsboot
 /ncb
 /prelink-riscv
+/printinitialenv
 /proftool
 /relocate-rela
 /spl_size_limit
diff --git a/tools/Makefile b/tools/Makefile
index 26be0a7ba2..80bc62befc 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -275,6 +275,10 @@ clean-dirs := lib common
 
 always := $(hostprogs-y)
 
+# Host tool to dump the currently configured default environment,
+# build it on demand, i.e. not add it to 'always'.
+hostprogs-y += printinitialenv
+
 # Generated LCD/video logo
 LOGO_H = $(objtree)/include/bmp_logo.h
 LOGO_DATA_H = $(objtree)/include/bmp_logo_data.h
diff --git a/tools/printinitialenv.c b/tools/printinitialenv.c
new file mode 100644
index 0000000000..c58b234d67
--- /dev/null
+++ b/tools/printinitialenv.c
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2022
+ * Max Krummenacher, Toradex
+ *
+ * Snippets taken from tools/env/fw_env.c
+ *
+ * This prints the list of default environment variables as currently
+ * configured.
+ *
+ */
+
+#include <stdio.h>
+
+/* Pull in the current config to define the default environment */
+#include <linux/kconfig.h>
+
+#ifndef __ASSEMBLY__
+#define __ASSEMBLY__ /* get only #defines from config.h */
+#include <config.h>
+#undef	__ASSEMBLY__
+#else
+#include <config.h>
+#endif
+
+#define DEFAULT_ENV_INSTANCE_STATIC
+#include <generated/environment.h>
+#include <env_default.h>
+
+int main(void)
+{
+	char *env, *nxt;
+
+	for (env = default_environment; *env; env = nxt + 1) {
+		for (nxt = env; *nxt; ++nxt) {
+			if (nxt >= &default_environment[sizeof(default_environment)]) {
+				fprintf(stderr, "## Error: environment not terminated\n");
+				return -1;
+			}
+		}
+		printf("%s\n", env);
+	}
+	return 0;
+}