[PATCH v3 1/1] Makefile: rework u-boot-initial-env target

[Pali Rohár]

On Friday 04 November 2022 13:44:57 Max Krummenacher wrote:
> From: Max Krummenacher <max.krummenacher at toradex.com>
> 
> 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 at toradex.com>
> 
> ---
> 
> Changes in v3:
> - moved the tool from scripts/ to tools/. Suggested by Tom Rini
> - changed the dependencies to '$(env_h)' and 'tools'.
>   Suggested by Tom Rini and Pali Rohár.
> - removed the sed rule which replaces \x00 with \x0A as this is already
>   done by the tool. Suggested by Pali Rohár.
> 
> Changes in v2:
> - reworked to build a host tool which prints the configured
>   environment as proposed by Pali Rohár
>   https://lore.kernel.org/u-boot/20221018174827.1393211-1-max.oss.09@gmail.com/
> - renamed patch, v1 used "Makefile: fix u-boot-initial-env target if lto is enabled"
> 
>  Makefile                |  9 +++++----
>  tools/.gitignore        |  1 +
>  tools/Makefile          |  3 +++
>  tools/printinitialenv.c | 44 +++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 53 insertions(+), 4 deletions(-)
>  create mode 100644 tools/printinitialenv.c
> 
> diff --git a/Makefile b/Makefile
> index 0f1174718f7..b8ee2deb3ec 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -2442,11 +2442,12 @@ 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 = \
> +	tools/printinitialenv | \

Missing $(objtree)/

> +	sed -e '/^\s*$$/d' | \
> +	sort --field-separator== -k1,1 --stable -o $@
>  
> -u-boot-initial-env: u-boot.bin
> +u-boot-initial-env: $(env_h) tools FORCE
>  	$(call if_changed,genenv)
>  
>  # Consistency checks
> diff --git a/tools/.gitignore b/tools/.gitignore
> index d3a93ff294a..28e8ce2a07a 100644
> --- a/tools/.gitignore
> +++ b/tools/.gitignore
> @@ -28,6 +28,7 @@
>  /mxsboot
>  /ncb
>  /prelink-riscv
> +/printinitialenv
>  /proftool
>  /relocate-rela
>  /spl_size_limit
> diff --git a/tools/Makefile b/tools/Makefile
> index 34a1aa7a8b7..a3afdee7813 100644
> --- a/tools/Makefile
> +++ b/tools/Makefile
> @@ -245,6 +245,9 @@ hostprogs-$(CONFIG_MIPS) += mips-relocs
>  hostprogs-$(CONFIG_ASN1_COMPILER)	+= asn1_compiler
>  HOSTCFLAGS_asn1_compiler.o = -idirafter $(srctree)/include
>  
> +# host tool to dump the currently configured default environment
> +hostprogs-y				+= printinitialenv
> +
>  HOSTCFLAGS_mkeficapsule.o += \
>  	$(shell pkg-config --cflags gnutls 2> /dev/null || echo "")
>  HOSTCFLAGS_mkeficapsule.o += \
> diff --git a/tools/printinitialenv.c b/tools/printinitialenv.c
> new file mode 100644
> index 00000000000..c58b234d679
> --- /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;
> +}
> -- 
> 2.35.3
>