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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 glibc-hwcaps directory assignment logic in ldconfig nor ld.so.
		
			
				
	
	
		
			128 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
			
		
		
	
	
			128 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
| GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.
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| # Local configure fragment for sysdeps/x86.
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| 
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| if test $enable_cet != no; then
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|   # Check if CET can be enabled.
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|   AC_CACHE_CHECK(whether CET can be enabled,
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| 		 libc_cv_x86_cet_available, [dnl
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| cat > conftest.c <<EOF
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| #if !defined __CET__ || __CET__ != 3
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| # error CET isn't available.
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| #endif
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| EOF
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| 		 if AC_TRY_COMMAND(${CC-cc} -c $CFLAGS -fcf-protection -include cet.h conftest.c 1>&AS_MESSAGE_LOG_FD); then
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| 		   libc_cv_x86_cet_available=yes
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| 		 else
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| 		   libc_cv_x86_cet_available=no
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| 		 fi
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| 		 rm -rf conftest*])
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|   if test $libc_cv_x86_cet_available != yes; then
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|     AC_MSG_ERROR([$CC doesn't support CET])
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|   fi
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| fi
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| if test $enable_cet != no; then
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|   # Check if assembler supports CET.
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|   AC_CACHE_CHECK(whether $AS supports CET,
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| 		 libc_cv_x86_cet_as, [dnl
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| cat > conftest.s <<EOF
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| 	incsspd %ecx
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| EOF
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| 		 if AC_TRY_COMMAND(${CC-cc} -c $CFLAGS conftest.s -o conftest.o 1>&AS_MESSAGE_LOG_FD); then
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| 		   libc_cv_x86_cet_as=yes
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| 		 else
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| 		   libc_cv_x86_cet_as=no
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| 		 fi
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| 		 rm -rf conftest*])
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|   if test $libc_cv_x86_cet_as = no; then
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|     AC_MSG_ERROR([$AS doesn't support CET])
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|   fi
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| fi
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| if test $enable_cet = yes; then
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|   AC_DEFINE(DEFAULT_DL_X86_CET_CONTROL, cet_elf_property)
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| elif test $enable_cet = permissive; then
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|   AC_DEFINE(DEFAULT_DL_X86_CET_CONTROL, cet_permissive)
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| fi
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| LIBC_CONFIG_VAR([enable-cet], [$enable_cet])
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| 
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| # Check if linker supports x86 ISA level.
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| AC_CACHE_CHECK([for linker x86 ISA level support],
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| 	       libc_cv_include_x86_isa_level, [dnl
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| cat > conftest1.S <<EOF
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| #ifdef __LP64__
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| # define P2ALIGN 3
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| #else
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| # define P2ALIGN 2
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| #endif
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| 	.section ".note.gnu.property", "a"
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| 	.p2align P2ALIGN
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| 	.long 1f - 0f		/* name length.  */
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| 	.long 4f - 1f		/* data length.  */
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| 	/* NT_GNU_PROPERTY_TYPE_0 */
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| 	.long 5			/* note type.  */
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| 0:
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| 	.asciz "GNU"		/* vendor name.  */
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| 1:
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| 	.p2align P2ALIGN
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| 	/* GNU_PROPERTY_X86_ISA_1_NEEDED */
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| 	.long 0xc0008002	/* pr_type.  */
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| 	.long 3f - 2f		/* pr_datasz.  */
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| 2:
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| 	.long 0x1
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| 3:
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| 	.p2align P2ALIGN
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| 4:
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| EOF
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| cat > conftest2.S <<EOF
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| #ifdef __LP64__
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| # define P2ALIGN 3
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| #else
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| # define P2ALIGN 2
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| #endif
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| 	.section ".note.gnu.property", "a"
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| 	.p2align P2ALIGN
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| 	.long 1f - 0f		/* name length.  */
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| 	.long 4f - 1f		/* data length.  */
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| 	/* NT_GNU_PROPERTY_TYPE_0 */
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| 	.long 5			/* note type.  */
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| 0:
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| 	.asciz "GNU"		/* vendor name.  */
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| 1:
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| 	.p2align P2ALIGN
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| 	/* GNU_PROPERTY_X86_ISA_1_NEEDED */
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| 	.long 0xc0008002	/* pr_type.  */
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| 	.long 3f - 2f		/* pr_datasz.  */
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| 2:
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| 	.long 0x2
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| 3:
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| 	.p2align P2ALIGN
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| 4:
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| EOF
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| libc_cv_include_x86_isa_level=no
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| libc_cv_have_x86_lahf_sahf=no
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| libc_cv_have_x86_movbe=no
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| if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS -nostartfiles -nostdlib -r -o conftest conftest1.S conftest2.S); then
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|   count=`LC_ALL=C $READELF -n conftest | grep NT_GNU_PROPERTY_TYPE_0 | wc -l`
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|   if test "$count" = 1; then
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|     libc_cv_include_x86_isa_level=yes
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|     cat > conftest.c <<EOF
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| EOF
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|     if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS -fverbose-asm -S -o - conftest.c) | grep -q "\-msahf"; then
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|       libc_cv_have_x86_lahf_sahf=yes
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|     fi
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|     if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS -fverbose-asm -S -o - conftest.c) | grep -q "\-mmovbe"; then
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|       libc_cv_have_x86_movbe=yes
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|     fi
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|   fi
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| fi
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| rm -f conftest*])
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| if test $libc_cv_include_x86_isa_level = yes; then
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|   AC_DEFINE(INCLUDE_X86_ISA_LEVEL)
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| fi
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| if test $libc_cv_have_x86_lahf_sahf = yes; then
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|   AC_DEFINE(HAVE_X86_LAHF_SAHF)
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| fi
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| if test $libc_cv_have_x86_movbe = yes; then
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|   AC_DEFINE(HAVE_X86_MOVBE)
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| fi
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| LIBC_CONFIG_VAR([enable-x86-isa-level], [$libc_cv_include_x86_isa_level])
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