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[PATCH 07/24] i386: Add _CET_ENDBR to indirect jump targets in add_n.S/sub_n.S
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: libc-alpha at sourceware dot org
- Date: Wed, 13 Jun 2018 08:31:50 -0700
- Subject: [PATCH 07/24] i386: Add _CET_ENDBR to indirect jump targets in add_n.S/sub_n.S
- References: <20180613153207.57232-1-hjl.tools@gmail.com>
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.
* 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.
---
sysdeps/i386/add_n.S | 27 ++++++++++++++++++++++++++-
sysdeps/i386/i686/add_n.S | 27 ++++++++++++++++++++++++++-
sysdeps/i386/sub_n.S | 26 +++++++++++++++++++++++++-
3 files changed, 77 insertions(+), 3 deletions(-)
diff --git a/sysdeps/i386/add_n.S b/sysdeps/i386/add_n.S
index d6a35237b0..d3805ba213 100644
--- a/sysdeps/i386/add_n.S
+++ b/sysdeps/i386/add_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_add_n)
cfi_rel_offset (esi, 0)
movl S2(%esp),%edx
movl SIZE(%esp),%ecx
+
+#if defined __CET__ && (__CET__ & 1) != 0
+ 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_add_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 */
@@ -64,30 +74,40 @@ L(0): leal (%eax,%eax,8),%eax
#else
/* 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
adcl (%edx),%eax
movl %eax,(%edi)
+ _CET_ENDBR
movl 4(%esi),%eax
adcl 4(%edx),%eax
movl %eax,4(%edi)
+ _CET_ENDBR
movl 8(%esi),%eax
adcl 8(%edx),%eax
movl %eax,8(%edi)
+ _CET_ENDBR
movl 12(%esi),%eax
adcl 12(%edx),%eax
movl %eax,12(%edi)
+ _CET_ENDBR
movl 16(%esi),%eax
adcl 16(%edx),%eax
movl %eax,16(%edi)
+ _CET_ENDBR
movl 20(%esi),%eax
adcl 20(%edx),%eax
movl %eax,20(%edi)
+ _CET_ENDBR
movl 24(%esi),%eax
adcl 24(%edx),%eax
movl %eax,24(%edi)
+ _CET_ENDBR
movl 28(%esi),%eax
adcl 28(%edx),%eax
movl %eax,28(%edi)
@@ -100,6 +120,11 @@ 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)
diff --git a/sysdeps/i386/i686/add_n.S b/sysdeps/i386/i686/add_n.S
index 5c6c1448d6..d2d532cd30 100644
--- a/sysdeps/i386/i686/add_n.S
+++ b/sysdeps/i386/i686/add_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 */
@@ -44,6 +44,13 @@ ENTRY (__mpn_add_n)
cfi_rel_offset (esi, 0)
movl S2(%esp),%edx
movl SIZE(%esp),%ecx
+
+#if defined __CET__ && (__CET__ & 1) != 0
+ 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
@@ -55,6 +62,9 @@ ENTRY (__mpn_add_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. */
leal (L(oop)-L(0)-3)(%eax,%eax,8),%eax
@@ -63,30 +73,40 @@ L(0):
#else
/* 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
adcl (%edx),%eax
movl %eax,(%edi)
+ _CET_ENDBR
movl 4(%esi),%eax
adcl 4(%edx),%eax
movl %eax,4(%edi)
+ _CET_ENDBR
movl 8(%esi),%eax
adcl 8(%edx),%eax
movl %eax,8(%edi)
+ _CET_ENDBR
movl 12(%esi),%eax
adcl 12(%edx),%eax
movl %eax,12(%edi)
+ _CET_ENDBR
movl 16(%esi),%eax
adcl 16(%edx),%eax
movl %eax,16(%edi)
+ _CET_ENDBR
movl 20(%esi),%eax
adcl 20(%edx),%eax
movl %eax,20(%edi)
+ _CET_ENDBR
movl 24(%esi),%eax
adcl 24(%edx),%eax
movl %eax,24(%edi)
+ _CET_ENDBR
movl 28(%esi),%eax
adcl 28(%edx),%eax
movl %eax,28(%edi)
@@ -99,6 +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)
diff --git a/sysdeps/i386/sub_n.S b/sysdeps/i386/sub_n.S
index 7c6f48c32e..8f321b8c6c 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 defined __CET__ && (__CET__ & 1) != 0
+ 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 */
@@ -64,30 +74,39 @@ L(0): leal (%eax,%eax,8),%eax
#else
/* 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)
--
2.17.1