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|
Since the full ISA set used in an ELF binary is unknown to compiler,
an x86-64 ISA level marker indicates the minimum, not maximum, ISA set
required to run such an ELF binary. We never guarantee a library with
an x86-64 ISA level v3 marker doesn't contain other ISAs beyond x86-64
ISA level v3, like AVX VNNI. We check the x86-64 ISA level marker for
the minimum ISA set. Since -march=sandybridge enables only some ISAs
in x86-64 ISA level v3, we should set the needed ISA marker to v2.
Otherwise, libc is compiled with -march=sandybridge will fail to run on
Sandy Bridge:
$ ./elf/ld.so ./libc.so
./libc.so: (p) CPU ISA level is lower than required: needed: 7; got: 3
Set the minimum, instead of maximum, x86-64 ISA level marker should have
no impact on the b-hwcaps directory assignment logic in ldconfig nor
ld.so.
(cherry picked from commit 339bf918ea4830fb35614632e96f3aab3237adce)
---
config.h.in | 6 ++++++
sysdeps/x86/configure | 28 ++++++++++++++++++++++++++++
sysdeps/x86/configure.ac | 16 ++++++++++++++++
sysdeps/x86/isa-level.c | 25 ++++++++++++++-----------
4 files changed, 64 insertions(+), 11 deletions(-)
diff --git a/config.h.in b/config.h.in
--- a/config.h.in 2021-10-16 03:28:49.447573081 -0700
+++ b/config.h.in 2021-10-16 03:29:38.626741181 -0700
@@ -275,4 +275,10 @@
/* Define if x86 ISA level should be included in shared libraries. */
#undef INCLUDE_X86_ISA_LEVEL
+/* Define if -msahf is enabled by default on x86. */
+#undef HAVE_X86_LAHF_SAHF
+
+/* Define if -mmovbe is enabled by default on x86. */
+#undef HAVE_X86_MOVBE
+
#endif
diff --git a/sysdeps/x86/configure b/sysdeps/x86/configure
--- a/sysdeps/x86/configure 2021-10-16 03:28:49.587570713 -0700
+++ b/sysdeps/x86/configure 2021-10-16 03:29:39.330729277 -0700
@@ -126,6 +126,8 @@ cat > conftest2.S <<EOF
4:
EOF
libc_cv_include_x86_isa_level=no
+libc_cv_have_x86_lahf_sahf=no
+libc_cv_have_x86_movbe=no
if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -nostartfiles -nostdlib -r -o conftest conftest1.S conftest2.S'
{ { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
(eval $ac_try) 2>&5
@@ -135,6 +137,24 @@ if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS
count=`LC_ALL=C $READELF -n conftest | grep NT_GNU_PROPERTY_TYPE_0 | wc -l`
if test "$count" = 1; then
libc_cv_include_x86_isa_level=yes
+ cat > conftest.c <<EOF
+EOF
+ if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -fverbose-asm -S -o - conftest.c'
+ { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+ test $ac_status = 0; }; } | grep -q "\-msahf"; then
+ libc_cv_have_x86_lahf_sahf=yes
+ fi
+ if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS -fverbose-asm -S -o - conftest.c'
+ { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+ test $ac_status = 0; }; } | grep -q "\-mmovbe"; then
+ libc_cv_have_x86_movbe=yes
+ fi
fi
fi
rm -f conftest*
@@ -145,5 +165,13 @@ if test $libc_cv_include_x86_isa_level =
$as_echo "#define INCLUDE_X86_ISA_LEVEL 1" >>confdefs.h
fi
+if test $libc_cv_have_x86_lahf_sahf = yes; then
+ $as_echo "#define HAVE_X86_LAHF_SAHF 1" >>confdefs.h
+
+fi
+if test $libc_cv_have_x86_movbe = yes; then
+ $as_echo "#define HAVE_X86_MOVBE 1" >>confdefs.h
+
+fi
config_vars="$config_vars
enable-x86-isa-level = $libc_cv_include_x86_isa_level"
diff --git a/sysdeps/x86/configure.ac b/sysdeps/x86/configure.ac
--- a/sysdeps/x86/configure.ac 2021-10-16 03:28:49.587570713 -0700
+++ b/sysdeps/x86/configure.ac 2021-10-16 03:29:40.038717306 -0700
@@ -98,14 +98,30 @@ cat > conftest2.S <<EOF
4:
EOF
libc_cv_include_x86_isa_level=no
+libc_cv_have_x86_lahf_sahf=no
+libc_cv_have_x86_movbe=no
if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS -nostartfiles -nostdlib -r -o conftest conftest1.S conftest2.S); then
count=`LC_ALL=C $READELF -n conftest | grep NT_GNU_PROPERTY_TYPE_0 | wc -l`
if test "$count" = 1; then
libc_cv_include_x86_isa_level=yes
+ cat > conftest.c <<EOF
+EOF
+ if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS -fverbose-asm -S -o - conftest.c) | grep -q "\-msahf"; then
+ libc_cv_have_x86_lahf_sahf=yes
+ fi
+ if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS -fverbose-asm -S -o - conftest.c) | grep -q "\-mmovbe"; then
+ libc_cv_have_x86_movbe=yes
+ fi
fi
fi
rm -f conftest*])
if test $libc_cv_include_x86_isa_level = yes; then
AC_DEFINE(INCLUDE_X86_ISA_LEVEL)
fi
+if test $libc_cv_have_x86_lahf_sahf = yes; then
+ AC_DEFINE(HAVE_X86_LAHF_SAHF)
+fi
+if test $libc_cv_have_x86_movbe = yes; then
+ AC_DEFINE(HAVE_X86_MOVBE)
+fi
LIBC_CONFIG_VAR([enable-x86-isa-level], [$libc_cv_include_x86_isa_level])
diff --git a/sysdeps/x86/isa-level.c b/sysdeps/x86/isa-level.c
--- a/sysdeps/x86/isa-level.c 2021-10-16 03:28:49.587570713 -0700
+++ b/sysdeps/x86/isa-level.c 2021-10-16 03:29:40.766704997 -0700
@@ -29,32 +29,35 @@
/* ELF program property for x86 ISA level. */
#ifdef INCLUDE_X86_ISA_LEVEL
-# if defined __x86_64__ || defined __FXSR__ || !defined _SOFT_FLOAT \
- || defined __MMX__ || defined __SSE__ || defined __SSE2__
+# if defined __SSE__ && defined __SSE2__
+/* NB: ISAs, excluding MMX, in x86-64 ISA level baseline are used. */
# define ISA_BASELINE GNU_PROPERTY_X86_ISA_1_BASELINE
# else
# define ISA_BASELINE 0
# endif
-# if defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_16 \
- || (defined __x86_64__ && defined __LAHF_SAHF__) \
- || defined __POPCNT__ || defined __SSE3__ \
- || defined __SSSE3__ || defined __SSE4_1__ || defined __SSE4_2__
+# if ISA_BASELINE && defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_16 \
+ && defined HAVE_X86_LAHF_SAHF && defined __POPCNT__ \
+ && defined __SSE3__ && defined __SSSE3__ && defined __SSE4_1__ \
+ && defined __SSE4_2__
+/* NB: ISAs in x86-64 ISA level v2 are used. */
# define ISA_V2 GNU_PROPERTY_X86_ISA_1_V2
# else
# define ISA_V2 0
# endif
-# if defined __AVX__ || defined __AVX2__ || defined __F16C__ \
- || defined __FMA__ || defined __LZCNT__ || defined __MOVBE__ \
- || defined __XSAVE__
+# if ISA_V2 && defined __AVX__ && defined __AVX2__ && defined __F16C__ \
+ && defined __FMA__ && defined __LZCNT__ && defined HAVE_X86_MOVBE
+/* NB: ISAs in x86-64 ISA level v3 are used. */
# define ISA_V3 GNU_PROPERTY_X86_ISA_1_V3
# else
# define ISA_V3 0
# endif
-# if defined __AVX512F__ || defined __AVX512BW__ || defined __AVX512CD__ \
- || defined __AVX512DQ__ || defined __AVX512VL__
+# if ISA_V3 && defined __AVX512F__ && defined __AVX512BW__ \
+ && defined __AVX512CD__ && defined __AVX512DQ__ \
+ && defined __AVX512VL__
+/* NB: ISAs in x86-64 ISA level v4 are used. */
# define ISA_V4 GNU_PROPERTY_X86_ISA_1_V4
# else
# define ISA_V4 0
|
