commit 9ba202c78f0aa39f49929eee63c367847da72ee4

Author: Florian Weimer <fweimer@redhat.com>

Date:   Fri Jan 14 20:16:05 2022 +0100

    Add --with-rtld-early-cflags configure option

    Reviewed-by: H.J. Lu <hjl.tools@gmail.com>

    Reviewed-by: Carlos O'Donell <carlos@redhat.com>

Conflicts:

	INSTALL

	configure

	manual/install.texi

	  (Missing --with-timeout-factor downstream.)

diff --git a/INSTALL b/INSTALL

index d6d93ec9be4262d7..d8d4e9f155f56616 100644

--- a/INSTALL

+++ b/INSTALL

@@ -106,6 +106,14 @@ if 'CFLAGS' is specified it must enable optimization.  For example:

      particular case and potentially change debugging information and

      metadata only).

+'--with-rtld-early-cflags=CFLAGS'

+     Use additional compiler flags CFLAGS to build the early startup

+     code of the dynamic linker.  These flags can be used to enable

+     early dynamic linker diagnostics to run on CPUs which are not

+     compatible with the rest of the GNU C Library, for example, due to

+     compiler flags which target a later instruction set architecture

+     (ISA).

+

 '--disable-shared'

      Don't build shared libraries even if it is possible.  Not all

      systems support shared libraries; you need ELF support and

diff --git a/config.make.in b/config.make.in

index e8630a8d0ccf874d..6d43e691f7823262 100644

--- a/config.make.in

+++ b/config.make.in

@@ -110,6 +110,7 @@ CFLAGS = @CFLAGS@

 CPPFLAGS-config = @CPPFLAGS@

 CPPUNDEFS = @CPPUNDEFS@

 extra-nonshared-cflags = @extra_nonshared_cflags@

+rtld-early-cflags = @rtld_early_cflags@

 ASFLAGS-config = @ASFLAGS_config@

 AR = @AR@

 NM = @NM@

diff --git a/configure b/configure

index e9d2b1f398c4dba0..03f4e59e754b5463 100755

--- a/configure

+++ b/configure

@@ -681,6 +681,7 @@ force_install

 bindnow

 hardcoded_path_in_tests

 enable_timezone_tools

+rtld_early_cflags

 extra_nonshared_cflags

 use_default_link

 sysheaders

@@ -761,6 +762,7 @@ with_selinux

 with_headers

 with_default_link

 with_nonshared_cflags

+with_rtld_early_cflags

 enable_sanity_checks

 enable_shared

 enable_profile

@@ -1479,6 +1481,8 @@ Optional Packages:

   --with-default-link     do not use explicit linker scripts

   --with-nonshared-cflags=CFLAGS

                           build nonshared libraries with additional CFLAGS

+  --with-rtld-early-cflags=CFLAGS

+                          build early initialization with additional CFLAGS

   --with-cpu=CPU          select code for CPU variant

 Some influential environment variables:

@@ -3383,6 +3387,16 @@ fi

+# Check whether --with-rtld-early-cflags was given.

+if test "${with_rtld_early_cflags+set}" = set; then :

+  withval=$with_rtld_early_cflags; rtld_early_cflags=$withval

+else

+  rtld_early_cflags=

+fi

+

+

+

+

 # Check whether --enable-sanity-checks was given.

 if test "${enable_sanity_checks+set}" = set; then :

   enableval=$enable_sanity_checks; enable_sanity=$enableval

diff --git a/configure.ac b/configure.ac

index 79f6822d29ce21cf..eb9431875fae1b0e 100644

--- a/configure.ac

+++ b/configure.ac

@@ -162,6 +162,12 @@ AC_ARG_WITH([nonshared-cflags],

 	    [extra_nonshared_cflags=$withval],

 	    [extra_nonshared_cflags=])

 AC_SUBST(extra_nonshared_cflags)

+AC_ARG_WITH([rtld-early-cflags],

+	    AS_HELP_STRING([--with-rtld-early-cflags=CFLAGS],

+			   [build early initialization with additional CFLAGS]),

+	    [rtld_early_cflags=$withval],

+	    [rtld_early_cflags=])

+AC_SUBST(rtld_early_cflags)

 AC_ARG_ENABLE([sanity-checks],

 	      AS_HELP_STRING([--disable-sanity-checks],

diff --git a/elf/Makefile b/elf/Makefile

index 52aafc89cec835ab..778e393395fc5248 100644

--- a/elf/Makefile

+++ b/elf/Makefile

@@ -152,6 +152,14 @@ CFLAGS-.o += $(call elide-stack-protector,.o,$(elide-routines.os))

 CFLAGS-.op += $(call elide-stack-protector,.op,$(elide-routines.os))

 CFLAGS-.os += $(call elide-stack-protector,.os,$(all-rtld-routines))

+# Add the requested compiler flags to the early startup code.

+CFLAGS-dl-printf.os += $(rtld-early-cflags)

+CFLAGS-dl-sysdep.os += $(rtld-early-cflags)

+CFLAGS-dl-tunables.os += $(rtld-early-cflags)

+CFLAGS-dl-write.os += $(rtld-early-cflags)

+CFLAGS-dl-writev.os += $(rtld-early-cflags)

+CFLAGS-rtld.os += $(rtld-early-cflags)

+

 ifeq ($(unwind-find-fde),yes)

 routines += unwind-dw2-fde-glibc

 shared-only-routines += unwind-dw2-fde-glibc

diff --git a/manual/install.texi b/manual/install.texi

index 1320ac69b3c645f2..816b77a0a25a88a7 100644

--- a/manual/install.texi

+++ b/manual/install.texi

@@ -131,6 +131,13 @@ that the objects in @file{libc_nonshared.a} are compiled with this flag

 (although this will not affect the generated code in this particular

 case and potentially change debugging information and metadata only).

+@item --with-rtld-early-cflags=@var{cflags}

+Use additional compiler flags @var{cflags} to build the early startup

+code of the dynamic linker.  These flags can be used to enable early

+dynamic linker diagnostics to run on CPUs which are not compatible with

+the rest of @theglibc{}, for example, due to compiler flags which target

+a later instruction set architecture (ISA).

+

 @c disable static doesn't work currently

 @c @item --disable-static

 @c Don't build static libraries.  Static libraries aren't that useful these