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GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.
# Local configure fragment for sysdeps/s390/s390-64.
# Minimal checking for static PIE support in ld.
# Compare to ld testcase/bugzilla:
# <binutils-source>/ld/testsuite/ld-elf/pr22263-1.rd
AC_CACHE_CHECK([for s390-specific static PIE requirements], \
[libc_cv_s390x_staticpie_req], [dnl
cat > conftest1.c <<EOF
__thread int * foo;
void
bar (void)
{
*foo = 1;
}
EOF
cat > conftest2.c <<EOF
extern __thread int *foo;
extern void bar (void);
static int x;
int
main ()
{
foo = &x;
return 0;
}
EOF
libc_cv_s390x_staticpie_req=no
if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -fPIE -c conftest1.c -o conftest1.o]) \
&& AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -fPIE -c conftest2.c -o conftest2.o]) \
&& AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -pie -o conftest conftest1.o conftest2.o]) \
&& AC_TRY_COMMAND([! readelf -Wr conftest | grep R_390_TLS_TPOFF])
then
libc_cv_s390x_staticpie_req=yes
fi
rm -rf conftest.*])
if test $libc_cv_s390x_staticpie_req = yes; then
# Static PIE is supported only on 64bit.
# Ensure you also have those patches for:
# - binutils (ld)
# - "[PR ld/22263] s390: Avoid dynamic TLS relocs in PIE"
# https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=26b1426577b5dcb32d149c64cca3e603b81948a9
# (Tested by configure check above)
# Otherwise there will be a R_390_TLS_TPOFF relocation, which fails to
# be processed in _dl_relocate_static_pie() as static TLS map is not setup.
# - "s390: Add DT_JMPREL pointing to .rela.[i]plt with static-pie"
# https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d942d8db12adf4c9e5c7d9ed6496a779ece7149e
# (We can't test it in configure as we are not able to link a static PIE
# executable if the system glibc lacks static PIE support)
# Otherwise there won't be DT_JMPREL, DT_PLTRELA, DT_PLTRELASZ entries
# and the IFUNC symbols are not processed, which leads to crashes.
#
# - kernel (the mentioned links to the commits belong to 5.19 merge window):
# - "s390/mmap: increase stack/mmap gap to 128MB"
# https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git/commit/?h=features&id=f2f47d0ef72c30622e62471903ea19446ea79ee2
# - "s390/vdso: move vdso mapping to its own function"
# https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git/commit/?h=features&id=57761da4dc5cd60bed2c81ba0edb7495c3c740b8
# - "s390/vdso: map vdso above stack"
# https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git/commit/?h=features&id=9e37a2e8546f9e48ea76c839116fa5174d14e033
# - "s390/vdso: add vdso randomization"
# https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git/commit/?h=features&id=41cd81abafdc4e58a93fcb677712a76885e3ca25
# (We can't test the kernel of the target system)
# Otherwise if /proc/sys/kernel/randomize_va_space is turned off (0),
# static PIE executables like ldconfig will crash. While startup sbrk is
# used to enlarge the HEAP. Unfortunately the underlying brk syscall fails
# as there is not enough space after the HEAP. Then the address of the TLS
# image is invalid and the following memcpy in __libc_setup_tls() leads
# to a segfault.
# If /proc/sys/kernel/randomize_va_space is activated (default: 2), there
# is enough space after HEAP.
#
# - glibc
# - "Linux: Define MMAP_CALL_INTERNAL"
# https://sourceware.org/git/?p=glibc.git;a=commit;h=c1b68685d438373efe64e5f076f4215723004dfb
# - "i386: Remove OPTIMIZE_FOR_GCC_5 from Linux libc-do-syscall.S"
# https://sourceware.org/git/?p=glibc.git;a=commit;h=6e5c7a1e262961adb52443ab91bd2c9b72316402
# - "i386: Honor I386_USE_SYSENTER for 6-argument Linux system calls"
# https://sourceware.org/git/?p=glibc.git;a=commit;h=60f0f2130d30cfd008ca39743027f1e200592dff
# - "ia64: Always define IA64_USE_NEW_STUB as a flag macro"
# https://sourceware.org/git/?p=glibc.git;a=commit;h=18bd9c3d3b1b6a9182698c85354578d1d58e9d64
# - "Linux: Implement a useful version of _startup_fatal"
# https://sourceware.org/git/?p=glibc.git;a=commit;h=a2a6bce7d7e52c1c34369a7da62c501cc350bc31
# - "Linux: Introduce __brk_call for invoking the brk system call"
# https://sourceware.org/git/?p=glibc.git;a=commit;h=b57ab258c1140bc45464b4b9908713e3e0ee35aa
# - "csu: Implement and use _dl_early_allocate during static startup"
# https://sourceware.org/git/?p=glibc.git;a=commit;h=f787e138aa0bf677bf74fa2a08595c446292f3d7
# The mentioned patch series by Florian Weimer avoids the mentioned failing
# sbrk syscall by falling back to mmap.
AC_DEFINE(SUPPORT_STATIC_PIE)
fi
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