Re: [PATCH] csu: Fix static when PIE is enabled but static PIE is not supported (BZ #29575)

[Siddhesh Poyarekar <siddhesh@sourceware.org>]

On 2022-10-05 13:08, Adhemerval Zanella wrote:
> On architectures where static PIE is not supported, both libc and
> static binaries are built still with -fPIE and -DPIC.  It leads to
> wrong code for some architectures (for instance sparc).
> 
> This patch only enables -DPIC for .o files iff static-pie is also
> supported.  Since the same rule is used for both libc.a objects and
> installed binaries, the -fno-pie is added if static-pie is not
> supported (with a strategy similar to how stack protector is
> disabled for some architectures).
> 
> Checked on x86_64-linux-gnu (with and without --disable-static-pie)
> and I also checked on sparc64-linux-gnu to verify that static binaries
> are not broken and both binaries and tests continue to be built
> for PIE.
> ---

It should be --disable-default-pie.  Can you please check again and confirm?

Thanks,
Sid

>   Makeconfig            | 15 +++++++++++++++
>   Makerules             |  7 +++++++
>   csu/Makefile          |  4 ++++
>   stdio-common/Makefile |  4 ++--
>   4 files changed, 28 insertions(+), 2 deletions(-)
> 
> diff --git a/Makeconfig b/Makeconfig
> index 842f49eb58..4b0d9003cd 100644
> --- a/Makeconfig
> +++ b/Makeconfig
> @@ -404,6 +404,9 @@ else
>   # for PIE to support exception.
>   static-pie-ldflag = -Wl,-pie,--no-dynamic-linker,--eh-frame-hdr,-z,text
>   endif # have-static-pie
> +else
> +no-static-pie = $(no-pie-ccflag)
> +no-pic-flag = -UPIC
>   endif # enable-static-pie
>   endif # build-pie-default
>   
> @@ -901,6 +904,18 @@ define elide-stack-protector
>   $(if $(filter $(@F),$(patsubst %,%$(1),$(2))), $(no-stack-protector))
>   endef
>   
> +# If static-pie is not supported, add the compiler option to avoid building it
> +# for pie and to remove the PIC define.  The first argument is the extension
> +# (.o, .os, .oS) and the second is a list of routines that this path should be
> +# applied to.
> +define elide-pie
> +$(if $(filter $(@F),$(patsubst %,%$(1),$(2))), $(no-static-pie))
> +endef
> +# Smae as elide-pie, but remove the PIC flag.

s/Smae/Same/

> +define elide-pic-flag
> +$(if $(filter $(@F),$(patsubst %,%$(1),$(2))), $(no-pic-flag))
> +endef
> +
>   # The program that makes Emacs-style TAGS files.
>   ETAGS	:= etags
>   
> diff --git a/Makerules b/Makerules
> index 09c0cf8357..0fcaf565eb 100644
> --- a/Makerules
> +++ b/Makerules
> @@ -1239,6 +1239,13 @@ tests += $(foreach t,$(tests-time64),$(t))
>   xtests += $(foreach t,$(xtests-time64),$(t))
>   endif
>   
> +# Disable static-pie for libc.a if target does not support it.
> +CFLAGS-.o += $(call elide-pie,.o,$(routines))
> +CFLAGS-.op += $(call elide-pie,.op,$(routines))
> +# And also remove the PIC flag.
> +CPPFLAGS-.o += $(call elide-pic-flag,.o,$(routines))
> +CPPFLAGS-.op += $(call elide-pic-flag,.op,$(routines))

All static routines.  OK.

> +
>   # The only difference between MODULE_NAME=testsuite and MODULE_NAME=nonlib is
>   # that almost all internal declarations from config.h, libc-symbols.h, and
>   # include/*.h are not available to 'testsuite' code, but are to 'nonlib' code.
> diff --git a/csu/Makefile b/csu/Makefile
> index f71a5eb6c6..62a819608f 100644
> --- a/csu/Makefile
> +++ b/csu/Makefile
> @@ -66,6 +66,10 @@ CFLAGS-.os += $(call elide-stack-protector,.os,$(filter-out \
>   						 $(ssp-safe.os), \
>   						 $(routines) $(extra-no-ssp)))
>   
> +# Remove PIC flag for init objects.
> +CPPFLAGS-.o += $(call elide-pic-flag,.o,$(basename $(extra-objs)))
> +CPPFLAGS-.op += $(call elide-pic-flag,.op,$(basename $(extra-objs)))
> +

crt* too.  OK.

>   ifeq (yes,$(build-shared))
>   extra-objs += S$(start-installed-name) gmon-start.os
>   ifneq ($(start-installed-name),$(static-start-installed-name))
> diff --git a/stdio-common/Makefile b/stdio-common/Makefile
> index 9c98c02884..6eee9ba73c 100644
> --- a/stdio-common/Makefile
> +++ b/stdio-common/Makefile
> @@ -265,7 +265,7 @@ $(objpfx)errlist-data-aux-shared.S: errlist-data-gen.c
>   
>   $(objpfx)errlist-data-aux.S: errlist-data-gen.c
>   	$(make-target-directory)
> -	$(compile-command.c) $(pie-default) $(no-stack-protector) -S
> +	$(compile-command.c) $(pic-cppflags) $(pic-ccflag) $(no-stack-protector) -S
>   
>   ifndef no_deps
>   -include $(objpfx)errlist-data-aux.S.d $(objpfx)errlist-data-aux-shared.S.d
> @@ -280,7 +280,7 @@ $(objpfx)siglist-aux-shared.S: siglist-gen.c
>   
>   $(objpfx)siglist-aux.S: siglist-gen.c
>   	$(make-target-directory)
> -	$(compile-command.c) $(pie-default) $(no-stack-protector) -S
> +	$(compile-command.c) $(pic-cppflags) $(pic-ccflag) $(no-stack-protector) -S
>   
>   ifndef no_deps
>   -include $(objpfx)siglist-aux.S.d $(objpfx)siglist-aux-shared.S.d