diff options
| author | H.J. Lu <hjl.tools@gmail.com> | 2018-07-17 16:11:13 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2018-07-17 16:11:44 -0700 |
| commit | be9ccd27c09ee76c5397125bfa0fefae318a2996 (patch) | |
| tree | fedd9f2980ad4b1d2afd66a83032dc317d253bd3 /sysdeps/i386/sub_n.S | |
| parent | 5efc6777ad57c2055b618e0b8b8dc1e5bc4ab29a (diff) | |
| download | glibc-be9ccd27c09ee76c5397125bfa0fefae318a2996.tar.gz glibc-be9ccd27c09ee76c5397125bfa0fefae318a2996.tar.xz glibc-be9ccd27c09ee76c5397125bfa0fefae318a2996.zip | |
i386: Add _CET_ENDBR to indirect jump targets in add_n.S/sub_n.S
i386 add_n.S and sub_n.S use a trick to implment jump tables with LEA. We can't use conditional branches nor normal jump tables since jump table entries use EFLAGS set by jump table index. This patch adds _CET_ENDBR to indirect jump targets and adjust destination for _CET_ENDBR. Reviewed-by: Carlos O'Donell <carlos@redhat.com> * sysdeps/i386/add_n.S: Include <sysdep.h>, instead of "sysdep.h". (__mpn_add_n): Save and restore %ebx if IBT is enabed. Add _CET_ENDBR to indirect jump targets and adjust jump destination for _CET_ENDBR. * sysdeps/i386/i686/add_n.S: Include <sysdep.h>, instead of "sysdep.h". (__mpn_add_n): Save and restore %ebx if IBT is enabed. Add _CET_ENDBR to indirect jump targets and adjust jump destination for _CET_ENDBR. * sysdeps/i386/sub_n.S: Include <sysdep.h>, instead of "sysdep.h". (__mpn_sub_n): Save and restore %ebx if IBT is enabed. Add _CET_ENDBR to indirect jump targets and adjust jump destination for _CET_ENDBR.
Diffstat (limited to 'sysdeps/i386/sub_n.S')
| -rw-r--r-- | sysdeps/i386/sub_n.S | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/sysdeps/i386/sub_n.S b/sysdeps/i386/sub_n.S index 7c6f48c32e..ada0cf5ec9 100644 --- a/sysdeps/i386/sub_n.S +++ b/sysdeps/i386/sub_n.S @@ -17,7 +17,7 @@ along with the GNU MP Library; see the file COPYING.LIB. If not, see <http://www.gnu.org/licenses/>. */ -#include "sysdep.h" +#include <sysdep.h> #include "asm-syntax.h" #define PARMS 4+8 /* space for 2 saved regs */ @@ -40,6 +40,13 @@ ENTRY (__mpn_sub_n) cfi_rel_offset (esi, 0) movl S2(%esp),%edx movl SIZE(%esp),%ecx + +#if IBT_ENABLED + pushl %ebx + cfi_adjust_cfa_offset (4) + cfi_rel_offset (ebx, 0) +#endif + movl %ecx,%eax shrl $3,%ecx /* compute count for unrolled loop */ negl %eax @@ -51,6 +58,9 @@ ENTRY (__mpn_sub_n) subl %eax,%esi /* ... by a constant when we ... */ subl %eax,%edx /* ... enter the loop */ shrl $2,%eax /* restore previous value */ +#if defined __CET__ && (__CET__ & 1) != 0 + leal -4(,%eax,4),%ebx /* Count for 4-byte endbr32 */ +#endif #ifdef PIC /* Calculate start address in loop for PIC. Due to limitations in some assemblers, Loop-L0-3 cannot be put into the leal */ @@ -65,29 +75,38 @@ L(0): leal (%eax,%eax,8),%eax /* Calculate start address in loop for non-PIC. */ leal (L(oop) - 3)(%eax,%eax,8),%eax #endif +#if defined __CET__ && (__CET__ & 1) != 0 + addl %ebx,%eax /* Adjust for endbr32 */ +#endif jmp *%eax /* jump into loop */ ALIGN (3) L(oop): movl (%esi),%eax sbbl (%edx),%eax movl %eax,(%edi) + _CET_ENDBR movl 4(%esi),%eax sbbl 4(%edx),%eax movl %eax,4(%edi) + _CET_ENDBR movl 8(%esi),%eax sbbl 8(%edx),%eax movl %eax,8(%edi) movl 12(%esi),%eax sbbl 12(%edx),%eax movl %eax,12(%edi) + _CET_ENDBR movl 16(%esi),%eax sbbl 16(%edx),%eax movl %eax,16(%edi) + _CET_ENDBR movl 20(%esi),%eax sbbl 20(%edx),%eax movl %eax,20(%edi) + _CET_ENDBR movl 24(%esi),%eax sbbl 24(%edx),%eax movl %eax,24(%edi) + _CET_ENDBR movl 28(%esi),%eax sbbl 28(%edx),%eax movl %eax,28(%edi) @@ -100,6 +119,11 @@ L(oop): movl (%esi),%eax sbbl %eax,%eax negl %eax +#if defined __CET__ && (__CET__ & 1) != 0 + popl %ebx + cfi_adjust_cfa_offset (-4) + cfi_restore (ebx) +#endif popl %esi cfi_adjust_cfa_offset (-4) cfi_restore (esi) |