Re: [PATCH v2] xen: Strip xen.efi by default

[Frediano Ziglio <frediano.ziglio@xxxxxxxxx>]

On Thu, Jun 12, 2025 at 11:07 AM Frediano Ziglio
<frediano.ziglio@xxxxxxxxx> wrote:
>
> 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.efi.elf can be used for debugging.
>
> Signed-off-by: Frediano Ziglio <frediano.ziglio@xxxxxxxxx>
> ---
> Changes since v1:
> - avoid leaving target if some command fails
> ---
>  docs/misc/efi.pandoc  |  8 +-------
>  xen/Kconfig.debug     |  9 ++-------
>  xen/Makefile          | 19 -------------------
>  xen/arch/x86/Makefile |  8 +++++---
>  4 files changed, 8 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 d14093017e..cafbb1236c 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.
>
>  endmenu
> diff --git a/xen/Makefile b/xen/Makefile
> index 8fc4e042ff..664c4ea7b8 100644
> --- a/xen/Makefile
> +++ b/xen/Makefile
> @@ -488,22 +488,6 @@ endif
>  .PHONY: _build
>  _build: $(TARGET)$(CONFIG_XEN_INSTALL_SUFFIX)
>
> -# Strip
> -#
> -# INSTALL_EFI_STRIP, if defined, will cause xen.efi to be stripped before it
> -# is installed. If INSTALL_EFI_STRIP is '1', then the default option(s) below
> -# will be used. Otherwise, INSTALL_EFI_STRIP value will be used as the
> -# option(s) to the strip command.
> -ifdef INSTALL_EFI_STRIP
> -
> -ifeq ($(INSTALL_EFI_STRIP),1)
> -efi-strip-opt := --strip-debug --keep-file-symbols
> -else
> -efi-strip-opt := $(INSTALL_EFI_STRIP)
> -endif
> -
> -endif
> -
>  .PHONY: _install
>  _install: D=$(DESTDIR)
>  _install: T=$(notdir $(TARGET))
> @@ -530,9 +514,6 @@ _install: $(TARGET)$(CONFIG_XEN_INSTALL_SUFFIX)
>                 ln -sf $(T)-$(XEN_FULLVERSION).efi 
> $(D)$(EFI_DIR)/$(T)-$(XEN_VERSION).efi; \
>                 ln -sf $(T)-$(XEN_FULLVERSION).efi $(D)$(EFI_DIR)/$(T).efi; \
>                 if [ -n '$(EFI_MOUNTPOINT)' -a -n '$(EFI_VENDOR)' ]; then \
> -                       $(if $(efi-strip-opt), \
> -                            $(STRIP) $(efi-strip-opt) -p -o 
> $(TARGET).efi.stripped $(TARGET).efi && \
> -                            $(INSTALL_DATA) $(TARGET).efi.stripped 
> $(D)$(EFI_MOUNTPOINT)/efi/$(EFI_VENDOR)/$(T)-$(XEN_FULLVERSION).efi ||) \
>                         $(INSTALL_DATA) $(TARGET).efi 
> $(D)$(EFI_MOUNTPOINT)/efi/$(EFI_VENDOR)/$(T)-$(XEN_FULLVERSION).efi; \
>                 elif [ "$(D)" = "$(patsubst $(shell cd $(XEN_ROOT) && 
> pwd)/%,%,$(D))" ]; then \
>                         echo 'EFI installation only partially done 
> (EFI_VENDOR not set)' >&2; \
> diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
> index ce724a9daa..e0ebc8c73e 100644
> --- a/xen/arch/x86/Makefile
> +++ b/xen/arch/x86/Makefile
> @@ -232,14 +232,16 @@ 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)),:$(space))$(OBJCOPY) -O 
> elf64-x86-64 $@.tmp $@.elf
> +       $(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

Any comments on this version?

Frediano