aarch64: make GCS configure checks aarch64-only

We only need to enable GCS tests on AArch64 targets, however previously
the configure checks for GCS support in compiler and linker were added
for all targets which was not efficient.

To enable tests for GCS we need 4 things to be true:

 - Compiler supports GCS branch protection.
 - Test compiler supports GCS branch protection.
 - Linker supports GCS marking of binaries.
 - The CRT objects provided by the toolchain have GCS marking.

To check for the latter, we add new macro to aclocal.m4 that allows to
grep output from readelf.

We check all four and then put the result in one make variable to
simplify checks in makefiles.

Reviewed-by: Wilco Dijkstra  <Wilco.Dijkstra@arm.com>

diff --git a/aclocal.m4 b/aclocal.m4
index cfe9c0b5387ef751a20e8422297abbf4ba5eb546..5c25a71d8fdb6b3a6feabf820e1f33cc99d28242 100644 (file)
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -497,3 +497,31 @@ LIBC_CHECK_TEST_CXX(
     [LIBC_TRY_CXX_OPTION([$2], [$4], [$5])])
   )
 ])
+
+dnl Check if toolchain supports generating binaries with the required
+dnl ELF marking as checked by readelf.
+dnl LIBC_CHECK_ELF_PROPERTY([message], [pattern], [action-if-true], [action-if-false])
+AC_DEFUN([LIBC_CHECK_ELF_PROPERTY],
+[AC_MSG_CHECKING([$1])
+libc_elf_property=no
+cat > conftest.c <<EOF
+int foo (void) { return 42; }
+EOF
+if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
+                 -fPIC -shared -o conftest.so conftest.c
+                 1>&AS_MESSAGE_LOG_FD])
+then
+  if AC_TRY_COMMAND([LC_ALL=C $READELF -n --wide conftest.so | grep "$2" 1>&AS_MESSAGE_LOG_FD])
+  then
+    libc_elf_property=yes
+  else
+    libc_elf_property=no
+  fi
+fi
+rm -f conftest*
+if test $libc_elf_property = yes; then
+  $3
+else
+  $4
+fi
+AC_MSG_RESULT($libc_elf_property)])

diff --git a/configure b/configure
index d2d83b40c04339c6ce742e288c6fa0f8b0889a12..09ac6ff760ba95ffb7a9733b7500df890c3d93bc 100755 (executable)
--- a/configure
+++ b/configure
@@ -9148,68 +9148,6 @@ printf "%s\n" "$libc_linker_feature" >&6; }
 config_vars="$config_vars
 load-address-ldflag = $libc_cv_load_address_ldflag"
 
-# Check if compilers support GCS in branch protection:
-
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if compiler supports -mbranch-protection=gcs" >&5
-printf %s "checking if compiler supports -mbranch-protection=gcs... " >&6; }
-if test ${libc_cv_cc_gcs+y}
-then :
-  printf %s "(cached) " >&6
-else case e in #(
-  e) if { ac_try='${CC-cc} -Werror -mbranch-protection=gcs -xc /dev/null -S -o /dev/null'
-  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; }; }
-then :
-  libc_cv_cc_gcs=yes
-else case e in #(
-  e) libc_cv_cc_gcs=no ;;
-esac
-fi ;;
-esac
-fi
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_cc_gcs" >&5
-printf "%s\n" "$libc_cv_cc_gcs" >&6; }
-if test "$TEST_CC" = "$CC"; then
-  libc_cv_test_cc_gcs=$libc_cv_cc_gcs
-else
-
-saved_CC="$CC"
-CC="$TEST_CC"
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if compiler supports -mbranch-protection=gcs in testing" >&5
-printf %s "checking if compiler supports -mbranch-protection=gcs in testing... " >&6; }
-if test ${libc_cv_test_cc_gcs+y}
-then :
-  printf %s "(cached) " >&6
-else case e in #(
-  e) if { ac_try='${CC-cc} -Werror -mbranch-protection=gcs -xc /dev/null -S -o /dev/null'
-  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; }; }
-then :
-  libc_cv_test_cc_gcs=yes
-else case e in #(
-  e) libc_cv_test_cc_gcs=no ;;
-esac
-fi ;;
-esac
-fi
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_test_cc_gcs" >&5
-printf "%s\n" "$libc_cv_test_cc_gcs" >&6; }
-
-CC="$saved_CC"
-
-fi
-
-config_vars="$config_vars
-have-cc-gcs = $libc_cv_cc_gcs"
-config_vars="$config_vars
-have-test-cc-gcs = $libc_cv_test_cc_gcs"
-
 # Check if compiler supports -fno-fp-int-builtin-inexact
 
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if compiler supports -fno-fp-int-builtin-inexact" >&5
@@ -9270,42 +9208,6 @@ fi
 config_vars="$config_vars
 config-cflags-no-fp-builtin-inexact = $libc_cv_cc_no_fp_builtin_inexact"
 
-# Check if linker supports GCS marking
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for linker that supports -z gcs=always" >&5
-printf %s "checking for linker that supports -z gcs=always... " >&6; }
-libc_linker_feature=no
-cat > conftest.c <<EOF
-int _start (void) { return 42; }
-EOF
-if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
-                 -Wl,-z,gcs=always -nostdlib -nostartfiles
-                 -fPIC -shared -o conftest.so conftest.c
-                 1>&5'
-  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; }; }
-then
-  if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,-z,gcs=always -nostdlib \
-      -nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
-      | grep "warning: -z gcs=always ignored" > /dev/null 2>&1; then
-    true
-  else
-    libc_linker_feature=yes
-  fi
-fi
-rm -f conftest*
-if test $libc_linker_feature = yes; then
-  libc_cv_ld_gcs=yes
-else
-  libc_cv_ld_gcs=no
-fi
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_linker_feature" >&5
-printf "%s\n" "$libc_linker_feature" >&6; }
-config_vars="$config_vars
-have-ld-gcs = $libc_cv_ld_gcs"
-
 
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for linker that supports --undefined-version" >&5
 printf %s "checking for linker that supports --undefined-version... " >&6; }

diff --git a/configure.ac b/configure.ac
index 3b9f3688f10973c0a6ca3b98cf3682dcb3a91477..73176840cccd44ad843e5a3b61345d0550a3070b 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -2049,18 +2049,6 @@ LIBC_LINKER_FEATURE([-Ttext-segment=$libc_cv_pde_load_address],
                    [libc_cv_load_address_ldflag=])
 LIBC_CONFIG_VAR([load-address-ldflag], [$libc_cv_load_address_ldflag])
 
-# Check if compilers support GCS in branch protection:
-LIBC_TRY_CC_AND_TEST_CC_OPTION([if compiler supports -mbranch-protection=gcs],
-  [-Werror -mbranch-protection=gcs],
-  libc_cv_cc_gcs,
-  [libc_cv_cc_gcs=yes],
-  [libc_cv_cc_gcs=no],
-  libc_cv_test_cc_gcs,
-  [libc_cv_test_cc_gcs=yes],
-  [libc_cv_test_cc_gcs=no])
-LIBC_CONFIG_VAR([have-cc-gcs], [$libc_cv_cc_gcs])
-LIBC_CONFIG_VAR([have-test-cc-gcs], [$libc_cv_test_cc_gcs])
-
 # Check if compiler supports -fno-fp-int-builtin-inexact
 LIBC_TRY_CC_AND_TEST_CC_OPTION([if compiler supports -fno-fp-int-builtin-inexact],
   [-Werror -fno-fp-int-builtin-inexact],
@@ -2072,11 +2060,6 @@ LIBC_TRY_CC_AND_TEST_CC_OPTION([if compiler supports -fno-fp-int-builtin-inexact
   [libc_cv_test_cc_no_fp_builtin_inexact=])
 LIBC_CONFIG_VAR([config-cflags-no-fp-builtin-inexact], [$libc_cv_cc_no_fp_builtin_inexact])
 
-# Check if linker supports GCS marking
-LIBC_LINKER_FEATURE([-z gcs=always], [-Wl,-z,gcs=always],
-                   [libc_cv_ld_gcs=yes], [libc_cv_ld_gcs=no])
-LIBC_CONFIG_VAR([have-ld-gcs], [$libc_cv_ld_gcs])
-
 
 LIBC_LINKER_FEATURE([--undefined-version], [-Wl,--undefined-version],
                    [libc_cv_ld_undefined_version=-Wl,--undefined-version],

diff --git a/sysdeps/aarch64/configure b/sysdeps/aarch64/configure
index f364e65fe7a7dfbbd4f28c2448fd626476805f85..eecdd324b2cd460cfd942072d0afc69b4424efe2 100755 (executable)
--- a/sysdeps/aarch64/configure
+++ b/sysdeps/aarch64/configure
@@ -196,3 +196,147 @@ fi
 
 libc_cv_support_sframe=yes
 
+# Check if compilers support GCS in branch protection:
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if compiler supports -mbranch-protection=gcs" >&5
+printf %s "checking if compiler supports -mbranch-protection=gcs... " >&6; }
+if test ${libc_cv_cc_gcs+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if { ac_try='${CC-cc} -Werror -mbranch-protection=gcs -xc /dev/null -S -o /dev/null'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+then :
+  libc_cv_cc_gcs=yes
+else case e in #(
+  e) libc_cv_cc_gcs=no ;;
+esac
+fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_cc_gcs" >&5
+printf "%s\n" "$libc_cv_cc_gcs" >&6; }
+if test "$TEST_CC" = "$CC"; then
+  libc_cv_test_cc_gcs=$libc_cv_cc_gcs
+else
+
+saved_CC="$CC"
+CC="$TEST_CC"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if compiler supports -mbranch-protection=gcs in testing" >&5
+printf %s "checking if compiler supports -mbranch-protection=gcs in testing... " >&6; }
+if test ${libc_cv_test_cc_gcs+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) if { ac_try='${CC-cc} -Werror -mbranch-protection=gcs -xc /dev/null -S -o /dev/null'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+then :
+  libc_cv_test_cc_gcs=yes
+else case e in #(
+  e) libc_cv_test_cc_gcs=no
+ ;;
+esac
+fi ;;
+esac
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_test_cc_gcs" >&5
+printf "%s\n" "$libc_cv_test_cc_gcs" >&6; }
+
+CC="$saved_CC"
+
+fi
+
+
+# Check if linker supports GCS marking
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for linker that supports -z gcs=always" >&5
+printf %s "checking for linker that supports -z gcs=always... " >&6; }
+libc_linker_feature=no
+cat > conftest.c <<EOF
+int _start (void) { return 42; }
+EOF
+if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
+                 -Wl,-z,gcs=always -nostdlib -nostartfiles
+                 -fPIC -shared -o conftest.so conftest.c
+                 1>&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+then
+  if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,-z,gcs=always -nostdlib \
+      -nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
+      | grep "warning: -z gcs=always ignored" > /dev/null 2>&1; then
+    true
+  else
+    libc_linker_feature=yes
+  fi
+fi
+rm -f conftest*
+if test $libc_linker_feature = yes; then
+  libc_cv_ld_gcs=yes
+else
+  libc_cv_ld_gcs=no
+
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_linker_feature" >&5
+printf "%s\n" "$libc_linker_feature" >&6; }
+
+# Check if toolchain is enabled to support GCS
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if toolchain is enabled to support GCS" >&5
+printf %s "checking if toolchain is enabled to support GCS... " >&6; }
+libc_elf_property=no
+cat > conftest.c <<EOF
+int foo (void) { return 42; }
+EOF
+if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
+                 -fPIC -shared -o conftest.so conftest.c
+                 1>&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+then
+  if { ac_try='LC_ALL=C $READELF -n --wide conftest.so | grep "AArch64 feature: .*GCS" 1>&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+  then
+    libc_elf_property=yes
+  else
+    libc_elf_property=no
+  fi
+fi
+rm -f conftest*
+if test $libc_elf_property = yes; then
+  libc_cv_gcs_supported=yes
+else
+  libc_cv_gcs_supported=no
+
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_elf_property" >&5
+printf "%s\n" "$libc_elf_property" >&6; }
+
+if test $libc_cv_cc_gcs = yes && \
+  test $libc_cv_test_cc_gcs = yes && \
+  test $libc_cv_ld_gcs = yes && \
+  test $libc_cv_gcs_supported = yes
+then
+  config_vars="$config_vars
+have-test-gcs = yes"
+else
+  config_vars="$config_vars
+have-test-gcs = no"
+fi
+

diff --git a/sysdeps/aarch64/configure.ac b/sysdeps/aarch64/configure.ac
index a9a1b747f1c8fe3364f169233132a7fa8d0422a9..8b01aa843d9ad178a9d5809832604d1502458b54 100644 (file)
--- a/sysdeps/aarch64/configure.ac
+++ b/sysdeps/aarch64/configure.ac
@@ -33,3 +33,39 @@ if test $build_mathvec = no; then
 fi
 
 libc_cv_support_sframe=yes
+
+# Check if compilers support GCS in branch protection:
+LIBC_TRY_CC_AND_TEST_CC_OPTION(
+  [if compiler supports -mbranch-protection=gcs],
+  [-Werror -mbranch-protection=gcs],
+  libc_cv_cc_gcs,
+  [libc_cv_cc_gcs=yes],
+  [libc_cv_cc_gcs=no],
+  libc_cv_test_cc_gcs,
+  [libc_cv_test_cc_gcs=yes],
+  [libc_cv_test_cc_gcs=no]
+)
+
+# Check if linker supports GCS marking
+LIBC_LINKER_FEATURE(
+  [-z gcs=always], [-Wl,-z,gcs=always],
+  [libc_cv_ld_gcs=yes], [libc_cv_ld_gcs=no]
+)
+
+# Check if toolchain is enabled to support GCS
+LIBC_CHECK_ELF_PROPERTY(
+  [if toolchain is enabled to support GCS],
+  [AArch64 feature: .*GCS],
+  [libc_cv_gcs_supported=yes],
+  [libc_cv_gcs_supported=no]
+)
+
+if test $libc_cv_cc_gcs = yes && \
+  test $libc_cv_test_cc_gcs = yes && \
+  test $libc_cv_ld_gcs = yes && \
+  test $libc_cv_gcs_supported = yes
+then
+  LIBC_CONFIG_VAR([have-test-gcs], [yes])
+else
+  LIBC_CONFIG_VAR([have-test-gcs], [no])
+fi

diff --git a/sysdeps/unix/sysv/linux/aarch64/Makefile b/sysdeps/unix/sysv/linux/aarch64/Makefile
index e0b5b7d5b285a50ba2b1eb3074acff368e24127f..6741f8ec009f50ee25dcb45f4d60cf39ed2c3d7d 100644 (file)
--- a/sysdeps/unix/sysv/linux/aarch64/Makefile
+++ b/sysdeps/unix/sysv/linux/aarch64/Makefile
@@ -17,7 +17,7 @@ tests += \
   tst-aarch64-pkey \
   # tests
 
-ifneq (no,$(findstring no,$(have-cc-gcs) $(have-test-cc-gcs) $(have-ld-gcs)))
+ifeq (yes,$(have-test-gcs))
 
 gcs-tests-dynamic = \
   tst-gcs-disabled \
@@ -141,7 +141,7 @@ LDFLAGS-tst-gcs-noreturn = -Wl,-z,gcs=always
 
 tst-gcs-noreturn-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=0
 
-endif # ifeq ($(have-test-cc-gcs),yes)
+endif # ifeq ($(have-test-gcs),yes)
 
 endif # ifeq ($(subdir),misc)