Re: [PATCH v3] xen: Strip xen.efi by default

[Jan Beulich <jbeulich@xxxxxxxx>]

On 05.11.2025 16:38, Frediano Ziglio wrote:
> From: Frediano Ziglio <frediano.ziglio@xxxxxxxxx>
> 
> For xen.gz file we strip all symbols and have an additional
> xen-syms file version with all symbols.
> Make xen.efi more coherent stripping all symbols too.
> xen-syms.efi can be used for debugging.
> 
> Signed-off-by: Frediano Ziglio <frediano.ziglio@xxxxxxxxx>
> ---
> Changes since v1:
> - avoid leaving target if some command fails.
> 
> Changes since v2:
> - do not convert type but retain PE format;
> = use xen-syms.efi for new file name, more consistent with ELF.
> ---
>  docs/misc/efi.pandoc  |  8 +-------
>  xen/Kconfig.debug     |  9 ++-------
>  xen/Makefile          | 19 -------------------
>  xen/arch/x86/Makefile |  9 ++++++---
>  4 files changed, 9 insertions(+), 36 deletions(-)
> 
> diff --git a/docs/misc/efi.pandoc b/docs/misc/efi.pandoc
> index 11c1ac3346..c66b18a66b 100644
> --- a/docs/misc/efi.pandoc
> +++ b/docs/misc/efi.pandoc
> @@ -20,13 +20,7 @@ Xen to load the configuration file even if multiboot 
> modules are found.
>  Once built, `make install-xen` will place the resulting binary directly into
>  the EFI boot partition, provided `EFI_VENDOR` is set in the environment (and
>  `EFI_MOUNTPOINT` is overridden as needed, should the default of `/boot/efi` 
> not
> -match your system). When built with debug info, the binary can be quite 
> large.
> -Setting `INSTALL_EFI_STRIP=1` in the environment will cause it to be stripped
> -of debug info in the process of installing. `INSTALL_EFI_STRIP` can also be 
> set
> -to any combination of options suitable to pass to `strip`, in case the 
> default
> -ones don't do. The xen.efi binary will also be installed in 
> `/usr/lib64/efi/`,
> -unless `EFI_DIR` is set in the environment to override this default. This
> -binary will not be stripped in the process.
> +match your system).
>  
>  The binary itself will require a configuration file (names with the `.efi`
>  extension of the binary's name replaced by `.cfg`, and - until an existing
> diff --git a/xen/Kconfig.debug b/xen/Kconfig.debug
> index d900d926c5..58ee10ee3e 100644
> --- a/xen/Kconfig.debug
> +++ b/xen/Kconfig.debug
> @@ -147,12 +147,7 @@ config DEBUG_INFO
>         Say Y here if you want to build Xen with debug information. This
>         information is needed e.g. for doing crash dump analysis of the
>         hypervisor via the "crash" tool.
> -       Saying Y will increase the size of the xen-syms and xen.efi
> -       binaries. In case the space on the EFI boot partition is rather
> -       limited, you may want to install a stripped variant of xen.efi in
> -       the EFI boot partition (look for "INSTALL_EFI_STRIP" in
> -       docs/misc/efi.pandoc for more information - when not using
> -       "make install-xen" for installing xen.efi, stripping needs to be
> -       done outside the Xen build environment).
> +       Saying Y will increase the size of the xen-syms and xen.efi.elf
> +       binaries.

Why xen.efi.elf and not xen-syms.efi?

> --- a/xen/arch/x86/Makefile
> +++ b/xen/arch/x86/Makefile
> @@ -228,14 +228,17 @@ endif
>       $(MAKE) $(build)=$(@D) .$(@F).1r.o .$(@F).1s.o
>       $(LD) $(call EFI_LDFLAGS,$(VIRT_BASE)) -T $(obj)/efi.lds $< \
>             $(dot-target).1r.o $(dot-target).1s.o $(orphan-handling-y) \
> -           $(note_file_option) -o $@
> -     $(NM) -pa --format=sysv $@ \
> +           $(note_file_option) -o $@.tmp
> +     $(NM) -pa --format=sysv $@.tmp \
>               | $(objtree)/tools/symbols --all-symbols --xensyms --sysv 
> --sort \
>               > $@.map
>  ifeq ($(CONFIG_DEBUG_INFO),y)
> -     $(if $(filter --strip-debug,$(EFI_LDFLAGS)),:$(space))$(OBJCOPY) -O 
> elf64-x86-64 $@ $@.elf
> +     $(if $(filter --strip-debug,$(EFI_LDFLAGS)),:$(space))cp -f \
> +        $@.tmp $(TARGET)-syms.efi
> +     $(if $(filter --strip-debug,$(EFI_LDFLAGS)),:$(space))$(STRIP) $@.tmp
>  endif
>       rm -f $(dot-target).[0-9]* $(@D)/..$(@F).[0-9]*
> +     mv -f $@.tmp $@
>  ifeq ($(CONFIG_XEN_IBT),y)
>       $(SHELL) $(srctree)/tools/check-endbr.sh $@
>  endif

I see $@.tmp here, but no sign of xen-syms. Did you submit a stake patch? Am
I missing something?

I also think the mv should sit ahead of the cleaning-up rm.

Jan

Jan