[PATCH v2 2/3] i386: Remove CET support

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

CET is only support for x86_64, this patch reverts:

  - faaee1f07ed (x86: Support shadow stack pointer in setjmp/longjmp).
  - be9ccd27c09 (i386: Add _CET_ENDBR to indirect jump targets in)
    add_n.S/sub_n.S).
  - faaee1f07ed (x86: Support shadow stack pointer in setjmp/longjmp).
  - c02695d7764 (x86/CET: Update vfork to prevent child return).
  - c02695d7764 (x86: Update vfork to pop shadow stack).
  - 5d844e1b725 (i386: Enable CET support in ucontext functions).

Checked on i686-linux-gnu.
---
 sysdeps/i386/__longjmp.S                      |  73 ---------
 sysdeps/i386/add_n.S                          |  25 ----
 sysdeps/i386/bsd-_setjmp.S                    |  21 ---
 sysdeps/i386/bsd-setjmp.S                     |  21 ---
 sysdeps/i386/i686/add_n.S                     |  25 ----
 sysdeps/i386/setjmp.S                         |  21 ---
 sysdeps/i386/sub_n.S                          |  24 ---
 .../unix/sysv/linux/i386/____longjmp_chk.S    |  37 -----
 sysdeps/unix/sysv/linux/i386/getcontext.S     |  56 -------
 sysdeps/unix/sysv/linux/i386/makecontext.S    | 123 ----------------
 sysdeps/unix/sysv/linux/i386/setcontext.S     | 101 +------------
 sysdeps/unix/sysv/linux/i386/swapcontext.S    | 139 ------------------
 sysdeps/unix/sysv/linux/i386/sysdep.h         |   5 -
 sysdeps/unix/sysv/linux/i386/ucontext_i.sym   |   4 -
 sysdeps/unix/sysv/linux/i386/vfork.S          |  29 ----
 sysdeps/x86/sysdep.h                          |   2 -
 16 files changed, 3 insertions(+), 703 deletions(-)

diff --git a/sysdeps/i386/__longjmp.S b/sysdeps/i386/__longjmp.S
index 302c00ac62..bb83609d57 100644
--- a/sysdeps/i386/__longjmp.S
+++ b/sysdeps/i386/__longjmp.S
@@ -19,55 +19,14 @@
 #include <sysdep.h>
 #include <pointer_guard.h>
 #include <jmpbuf-offsets.h>
-#include <jmp_buf-ssp.h>
 #include <asm-syntax.h>
 #include <stap-probe.h>
 
-/* Don't restore shadow stack register if
-   1. Shadow stack isn't enabled.  Or
-   2. __longjmp is defined for __longjmp_cancel.
- */
-#if !SHSTK_ENABLED || defined __longjmp
-# undef SHADOW_STACK_POINTER_OFFSET
-#endif
-
 	.text
 ENTRY (__longjmp)
 #ifdef PTR_DEMANGLE
 	movl 4(%esp), %eax	/* User's jmp_buf in %eax.  */
 
-# ifdef SHADOW_STACK_POINTER_OFFSET
-#  if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
-	/* Check if Shadow Stack is enabled.  */
-	testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
-	jz L(skip_ssp)
-#  else
-	xorl %edx, %edx
-#  endif
-	/* Check and adjust the Shadow-Stack-Pointer.  */
-	rdsspd %edx
-	/* And compare it with the saved ssp value.  */
-	subl SHADOW_STACK_POINTER_OFFSET(%eax), %edx
-	je L(skip_ssp)
-	/* Count the number of frames to adjust and adjust it
-	   with incssp instruction.  The instruction can adjust
-	   the ssp by [0..255] value only thus use a loop if
-	   the number of frames is bigger than 255.  */
-	negl %edx
-	shrl $2, %edx
-	/* NB: We saved Shadow-Stack-Pointer of setjmp.  Since we are
-	       restoring Shadow-Stack-Pointer of setjmp's caller, we
-	       need to unwind shadow stack by one more frame.  */
-	addl $1, %edx
-	movl	$255, %ebx
-L(loop):
-	cmpl	%ebx, %edx
-	cmovb	%edx, %ebx
-	incsspd	%ebx
-	subl	%ebx, %edx
-	ja	L(loop)
-L(skip_ssp):
-# endif
 	/* Save the return address now.  */
 	movl (JB_PC*4)(%eax), %edx
 	/* Get the stack pointer.  */
@@ -98,38 +57,6 @@ L(skip_ssp):
 #else
 	movl 4(%esp), %ecx	/* User's jmp_buf in %ecx.  */
 	movl 8(%esp), %eax	/* Second argument is return value.  */
-# ifdef SHADOW_STACK_POINTER_OFFSET
-#  if IS_IN (libc) && defined SHARED
-	/* Check if Shadow Stack is enabled.  */
-	testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
-	jz L(skip_ssp)
-#  endif
-	/* Check and adjust the Shadow-Stack-Pointer.  */
-	xorl %edx, %edx
-	/* Get the current ssp.  */
-	rdsspd	%edx
-	/* And compare it with the saved ssp value.  */
-	subl SHADOW_STACK_POINTER_OFFSET(%ecx), %edx
-	je L(skip_ssp)
-	/* Count the number of frames to adjust and adjust it
-	   with incssp instruction.  The instruction can adjust
-	   the ssp by [0..255] value only thus use a loop if
-	   the number of frames is bigger than 255.  */
-	negl %edx
-	shrl $2, %edx
-	/* NB: We saved Shadow-Stack-Pointer of setjmp.  Since we are
-	       restoring Shadow-Stack-Pointer of setjmp's caller, we
-	       need to unwind shadow stack by one more frame.  */
-	addl $1, %edx
-	movl	$255, %ebx
-L(loop):
-	cmpl	%ebx, %edx
-	cmovb	%edx, %ebx
-	incsspd	%ebx
-	subl	%ebx, %edx
-	ja	L(loop)
-L(skip_ssp):
-# endif
 	/* Save the return address now.  */
 	movl (JB_PC*4)(%ecx), %edx
 	LIBC_PROBE (longjmp, 3, 4@%ecx, -4@%eax, 4@%edx)
diff --git a/sysdeps/i386/add_n.S b/sysdeps/i386/add_n.S
index d4af6d92ec..c1b7098b1c 100644
--- a/sysdeps/i386/add_n.S
+++ b/sysdeps/i386/add_n.S
@@ -40,13 +40,6 @@ ENTRY (__mpn_add_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
@@ -58,9 +51,6 @@ 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 IBT_ENABLED
-	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 */
@@ -74,40 +64,30 @@ 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 IBT_ENABLED
-	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)
@@ -120,11 +100,6 @@ L(oop):	movl	(%esi),%eax
 	sbbl	%eax,%eax
 	negl	%eax
 
-#if IBT_ENABLED
-	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/bsd-_setjmp.S b/sysdeps/i386/bsd-_setjmp.S
index eb3ac9c8e9..5fd671a477 100644
--- a/sysdeps/i386/bsd-_setjmp.S
+++ b/sysdeps/i386/bsd-_setjmp.S
@@ -23,18 +23,12 @@
 #include <sysdep.h>
 #include <pointer_guard.h>
 #include <jmpbuf-offsets.h>
-#include <jmp_buf-ssp.h>
 #include <stap-probe.h>
 
 #define PARMS	4		/* no space for saved regs */
 #define JMPBUF	PARMS
 #define SIGMSK	JMPBUF+4
 
-/* Don't save shadow stack register if shadow stack isn't enabled.  */
-#if !SHSTK_ENABLED
-# undef SHADOW_STACK_POINTER_OFFSET
-#endif
-
 ENTRY (_setjmp)
 
 	xorl %eax, %eax
@@ -58,21 +52,6 @@ ENTRY (_setjmp)
 	movl %ebp, (JB_BP*4)(%edx) /* Save caller's frame pointer.  */
 
 	movl %eax, JB_SIZE(%edx) /* No signal mask set.  */
-#ifdef SHADOW_STACK_POINTER_OFFSET
-# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
-	/* Check if Shadow Stack is enabled.  */
-	testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
-	jz L(skip_ssp)
-# else
-	xorl %ecx, %ecx
-# endif
-	/* Get the current Shadow-Stack-Pointer and save it.  */
-	rdsspd %ecx
-	movl %ecx, SHADOW_STACK_POINTER_OFFSET(%edx)
-# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
-L(skip_ssp):
-# endif
-#endif
 	ret
 END (_setjmp)
 libc_hidden_def (_setjmp)
diff --git a/sysdeps/i386/bsd-setjmp.S b/sysdeps/i386/bsd-setjmp.S
index c03f235d0f..13338a6480 100644
--- a/sysdeps/i386/bsd-setjmp.S
+++ b/sysdeps/i386/bsd-setjmp.S
@@ -23,18 +23,12 @@
 #include <sysdep.h>
 #include <pointer_guard.h>
 #include <jmpbuf-offsets.h>
-#include <jmp_buf-ssp.h>
 #include <stap-probe.h>
 
 #define PARMS  4		/* no space for saved regs */
 #define JMPBUF PARMS
 #define SIGMSK JMPBUF+4
 
-/* Don't save shadow stack register if shadow stack isn't enabled.  */
-#if !SHSTK_ENABLED
-# undef SHADOW_STACK_POINTER_OFFSET
-#endif
-
 ENTRY (setjmp)
 	/* Note that we have to use a non-exported symbol in the next
 	   jump since otherwise gas will emit it as a jump through the
@@ -58,21 +52,6 @@ ENTRY (setjmp)
 #endif
 	movl %ecx, (JB_PC*4)(%eax)
 	movl %ebp, (JB_BP*4)(%eax) /* Save caller's frame pointer.  */
-#ifdef SHADOW_STACK_POINTER_OFFSET
-# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
-	/* Check if Shadow Stack is enabled.  */
-	testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
-	jz L(skip_ssp)
-# else
-	xorl %ecx, %ecx
-# endif
-	/* Get the current Shadow-Stack-Pointer and save it.  */
-	rdsspd %ecx
-	movl %ecx, SHADOW_STACK_POINTER_OFFSET(%eax)
-# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
-L(skip_ssp):
-# endif
-#endif
 
 	/* Call __sigjmp_save.  */
 	pushl $1
diff --git a/sysdeps/i386/i686/add_n.S b/sysdeps/i386/i686/add_n.S
index c2bc798187..bbc0cc71a2 100644
--- a/sysdeps/i386/i686/add_n.S
+++ b/sysdeps/i386/i686/add_n.S
@@ -44,13 +44,6 @@ ENTRY (__mpn_add_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
@@ -62,9 +55,6 @@ 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 IBT_ENABLED
-	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
@@ -73,40 +63,30 @@ L(0):
 #else
 /* Calculate start address in loop for non-PIC.  */
  	leal	(L(oop) - 3)(%eax,%eax,8),%eax
-#endif
-#if IBT_ENABLED
-	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)
@@ -119,11 +99,6 @@ L(oop):	movl	(%esi),%eax
 	sbbl	%eax,%eax
 	negl	%eax
 
-#if IBT_ENABLED
-	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/setjmp.S b/sysdeps/i386/setjmp.S
index ab1a8090cb..08a98f2388 100644
--- a/sysdeps/i386/setjmp.S
+++ b/sysdeps/i386/setjmp.S
@@ -19,7 +19,6 @@
 #include <sysdep.h>
 #include <pointer_guard.h>
 #include <jmpbuf-offsets.h>
-#include <jmp_buf-ssp.h>
 #include <asm-syntax.h>
 #include <stap-probe.h>
 
@@ -27,11 +26,6 @@
 #define JMPBUF	PARMS
 #define SIGMSK	JMPBUF+4
 
-/* Don't save shadow stack register if shadow stack isn't enabled.  */
-#if !SHSTK_ENABLED
-# undef SHADOW_STACK_POINTER_OFFSET
-#endif
-
 ENTRY (__sigsetjmp)
 
 	movl JMPBUF(%esp), %eax
@@ -53,21 +47,6 @@ ENTRY (__sigsetjmp)
 	movl %ecx, (JB_PC*4)(%eax)
 	movl %ebp, (JB_BP*4)(%eax) /* Save caller's frame pointer.  */
 
-#ifdef SHADOW_STACK_POINTER_OFFSET
-# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
-	/* Check if Shadow Stack is enabled.  */
-	testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
-	jz L(skip_ssp)
-# else
-	xorl %ecx, %ecx
-# endif
-	/* Get the current Shadow-Stack-Pointer and save it.  */
-	rdsspd %ecx
-	movl %ecx, SHADOW_STACK_POINTER_OFFSET(%eax)
-# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
-L(skip_ssp):
-# endif
-#endif
 #if IS_IN (rtld)
 	/* In ld.so we never save the signal mask.  */
 	xorl %eax, %eax
diff --git a/sysdeps/i386/sub_n.S b/sysdeps/i386/sub_n.S
index 3ebe984672..f463bec9ff 100644
--- a/sysdeps/i386/sub_n.S
+++ b/sysdeps/i386/sub_n.S
@@ -40,13 +40,6 @@ 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
@@ -58,9 +51,6 @@ 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 */
@@ -74,20 +64,15 @@ 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)
@@ -95,19 +80,15 @@ L(oop):	movl	(%esi),%eax
 	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)
@@ -120,11 +101,6 @@ 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/unix/sysv/linux/i386/____longjmp_chk.S b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
index 0c49010f93..35538f6df6 100644
--- a/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
+++ b/sysdeps/unix/sysv/linux/i386/____longjmp_chk.S
@@ -18,14 +18,9 @@
 #include <sysdep.h>
 #include <pointer_guard.h>
 #include <jmpbuf-offsets.h>
-#include <jmp_buf-ssp.h>
 #include <asm-syntax.h>
 #include <stap-probe.h>
 
-/* Don't restore shadow stack register if shadow stack isn't enabled.  */
-#if !SHSTK_ENABLED
-# undef SHADOW_STACK_POINTER_OFFSET
-#endif
 
 	.section .rodata.str1.1,"aMS",@progbits,1
 	.type	longjmp_msg,@object
@@ -52,38 +47,6 @@ longjmp_msg:
 ENTRY (____longjmp_chk)
 	movl	4(%esp), %ecx	/* User's jmp_buf in %ecx.  */
 
-#ifdef SHADOW_STACK_POINTER_OFFSET
-# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
-	/* Check if Shadow Stack is enabled.  */
-	testl	$X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
-	jz	L(skip_ssp)
-# else
-	xorl	%edx, %edx
-# endif
-	/* Check and adjust the Shadow-Stack-Pointer.  */
-	rdsspd	%edx
-	/* And compare it with the saved ssp value.  */
-	subl	SHADOW_STACK_POINTER_OFFSET(%ecx), %edx
-	je	L(skip_ssp)
-	/* Count the number of frames to adjust and adjust it
-	   with incssp instruction.  The instruction can adjust
-	   the ssp by [0..255] value only thus use a loop if
-	   the number of frames is bigger than 255.  */
-	negl	%edx
-	shrl	$2, %edx
-	/* NB: We saved Shadow-Stack-Pointer of setjmp.  Since we are
-	       restoring Shadow-Stack-Pointer of setjmp's caller, we
-	       need to unwind shadow stack by one more frame.  */
-	addl	$1, %edx
-	movl	$255, %ebx
-L(loop):
-	cmpl	%ebx, %edx
-	cmovb	%edx, %ebx
-	incsspd	%ebx
-	subl	%ebx, %edx
-	ja	L(loop)
-L(skip_ssp):
-#endif
 	/* Save the return address now.  */
 	movl	(JB_PC*4)(%ecx), %edx
 	/* Get the stack pointer.  */
diff --git a/sysdeps/unix/sysv/linux/i386/getcontext.S b/sysdeps/unix/sysv/linux/i386/getcontext.S
index 3202ac002e..9c1ca3c263 100644
--- a/sysdeps/unix/sysv/linux/i386/getcontext.S
+++ b/sysdeps/unix/sysv/linux/i386/getcontext.S
@@ -17,7 +17,6 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <sysdep.h>
-#include <asm/prctl.h>
 
 #include "ucontext_i.h"
 
@@ -42,61 +41,6 @@ ENTRY(__getcontext)
 	movw	%fs, %dx
 	movl	%edx, oFS(%eax)
 
-#if SHSTK_ENABLED
-	/* Check if shadow stack is enabled.  */
-	testl	$X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
-	jz	L(no_shstk)
-
-	/* Save EAX in EDX.  */
-	movl	%eax, %edx
-
-	xorl	%eax, %eax
-	cmpl	%gs:SSP_BASE_OFFSET, %eax
-	jnz	L(shadow_stack_bound_recorded)
-
-	/* Save EBX in the first scratch register slot.  */
-	movl	%ebx, oSCRATCH1(%edx)
-
-	/* Get the base address and size of the default shadow stack
-	   which must be the current shadow stack since nothing has
-	   been recorded yet.  */
-	sub	$24, %esp
-	mov	%esp, %ecx
-	movl	$ARCH_CET_STATUS, %ebx
-	movl	$__NR_arch_prctl, %eax
-	ENTER_KERNEL
-	testl	%eax, %eax
-	jz	L(continue_no_err)
-
-	/* This should never happen.  */
-	hlt
-
-L(continue_no_err):
-	/* Restore EBX from the first scratch register slot.  */
-	movl	oSCRATCH1(%edx), %ebx
-
-	/* Record the base of the current shadow stack.  */
-	movl	8(%esp), %eax
-	movl	%eax, %gs:SSP_BASE_OFFSET
-	add	$24, %esp
-
-L(shadow_stack_bound_recorded):
-	/* Load address of the context data structure.  */
-	movl	4(%esp), %eax
-
-	/* Get the current shadow stack pointer.  */
-	rdsspd	%edx
-	/* NB: Save the caller's shadow stack so that we can jump back
-	   to the caller directly.  */
-	addl	$4, %edx
-	movl	%edx, oSSP(%eax)
-
-	/* Save the current shadow stack base in ucontext.  */
-	movl	%gs:SSP_BASE_OFFSET, %edx
-	movl	%edx, (oSSP + 4)(%eax)
-
-L(no_shstk):
-#endif
 	/* We have separate floating-point register content memory on the
 	   stack.  We use the __fpregs_mem block in the context.  Set the
 	   links up correctly.  */
diff --git a/sysdeps/unix/sysv/linux/i386/makecontext.S b/sysdeps/unix/sysv/linux/i386/makecontext.S
index 814127d130..7ee56300fa 100644
--- a/sysdeps/unix/sysv/linux/i386/makecontext.S
+++ b/sysdeps/unix/sysv/linux/i386/makecontext.S
@@ -17,7 +17,6 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <sysdep.h>
-#include <asm/prctl.h>
 
 #include "ucontext_i.h"
 
@@ -68,127 +67,6 @@ ENTRY(__makecontext)
 	jnz	1b
 2:
 
-#if SHSTK_ENABLED
-	/* Check if Shadow Stack is enabled.  */
-	testl	$X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
-	jz	L(skip_ssp)
-
-	/* Reload the pointer to ucontext.  */
-	movl	4(%esp), %eax
-
-	/* Shadow stack is enabled.  We need to allocate a new shadow
-	   stack.  */
-	subl	oSS_SP(%eax), %edx
-	shrl	$STACK_SIZE_TO_SHADOW_STACK_SIZE_SHIFT, %edx
-
-	/* Align shadow stack size to 8 bytes.  */
-	addl	$7, %edx
-	andl	$-8, %edx
-
-	/* Store shadow stack size in __ssp[2].  */
-	movl	%edx, (oSSP + 8)(%eax)
-
-	/* Save ESI in the second scratch register slot.  */
-	movl	%esi, oSCRATCH2(%eax)
-	/* Save EDI in the third scratch register slot.  */
-	movl	%edi, oSCRATCH3(%eax)
-
-	/* Save the pointer to ucontext.  */
-	movl	%eax, %edi
-
-	/* Get the original shadow stack pointer.  */
-	rdsspd	%esi
-
-	/* Align the saved original shadow stack pointer to the next
-	   8 byte aligned boundary.  */
-	andl	$-8, %esi
-
-	/* Load the top of the new stack into EDX.  */
-	movl	oESP(%eax), %edx
-
-	/* We need to terminate the FDE here because the unwinder looks
-	   at ra-1 for unwind information.  */
-	cfi_endproc
-
-	/* Swap the original stack pointer with the top of the new
-	   stack.  */
-	xchgl	%esp, %edx
-
-	/* Add 4 bytes since CALL will push the 4-byte return address
-	   onto stack.  */
-	addl	$4, %esp
-
-	/* Allocate the new shadow stack.  Save EBX in the first scratch
-	   register slot.  */
-	movl	%ebx, oSCRATCH1(%eax)
-
-	/* CET syscall takes 64-bit sizes.  */
-	subl	$16, %esp
-	movl	(oSSP + 8)(%eax), %ecx
-	movl	%ecx, (%esp)
-	movl	$0, 4(%esp)
-	movl	%ecx, 8(%esp)
-	movl	$0, 12(%esp)
-	movl	%esp, %ecx
-
-	movl	$ARCH_CET_ALLOC_SHSTK, %ebx
-	movl	$__NR_arch_prctl, %eax
-	ENTER_KERNEL
-	testl	%eax, %eax
-	jne	L(hlt)		/* This should never happen.  */
-
-	/* Copy the base address of the new shadow stack to __ssp[1].  */
-	movl	(%esp), %eax
-	movl	%eax, (oSSP + 4)(%edi)
-
-	addl	$16, %esp
-
-	/* Restore EBX from the first scratch register slot.  */
-	movl	oSCRATCH1(%edi), %ebx
-
-	/* Get the size of the new shadow stack.  */
-	movl	(oSSP + 8)(%edi), %ecx
-
-	/* Use the restore stoken to restore the new shadow stack.  */
-	rstorssp -8(%eax, %ecx)
-
-	/* Save the restore token at the next 8 byte aligned boundary
-	   on the original shadow stack.  */
-	saveprevssp
-
-	/* Push the address of "jmp exitcode" onto the new stack as
-	   well as the new shadow stack.  */
-	call	1f
-	jmp	L(exitcode)
-1:
-
-	/* Get the new shadow stack pointer.  */
-	rdsspd	%eax
-
-	/* Use the restore stoken to restore the original shadow stack.  */
-	rstorssp -8(%esi)
-
-	/* Save the restore token on the new shadow stack.  */
-	saveprevssp
-
-	/* Store the new shadow stack pointer in __ssp[0].  */
-	movl	%eax, oSSP(%edi)
-
-	/* Restore the original stack.  */
-	mov	%edx, %esp
-
-	cfi_startproc
-
-	/* Restore ESI from the second scratch register slot.  */
-	movl	oSCRATCH2(%edi), %esi
-	/* Restore EDI from the third scratch register slot.  */
-	movl	oSCRATCH3(%edi), %edi
-
-	ret
-
-L(skip_ssp):
-#endif
-
 	/* If the function we call returns we must continue with the
 	   context which is given in the uc_link element.  To do this
 	   set the return address for the function the user provides
@@ -244,7 +122,6 @@ L(call_exit):
 	call	HIDDEN_JUMPTARGET(exit)
 	/* The 'exit' call should never return.  In case it does cause
 	   the process to terminate.  */
-L(hlt):
 	hlt
 	cfi_startproc
 END(__makecontext)
diff --git a/sysdeps/unix/sysv/linux/i386/setcontext.S b/sysdeps/unix/sysv/linux/i386/setcontext.S
index 966fcbee1e..b6d827d11f 100644
--- a/sysdeps/unix/sysv/linux/i386/setcontext.S
+++ b/sysdeps/unix/sysv/linux/i386/setcontext.S
@@ -17,7 +17,6 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <sysdep.h>
-#include <asm/prctl.h>
 
 #include "ucontext_i.h"
 
@@ -56,6 +55,9 @@ ENTRY(__setcontext)
 	movl	oFS(%eax), %ecx
 	movw	%cx, %fs
 
+	/* Fetch the address to return to.  */
+	movl	oEIP(%eax), %ecx
+
 	/* Load the new stack pointer.  */
 	cfi_def_cfa (eax, 0)
 	cfi_offset (edi, oEDI)
@@ -64,103 +66,6 @@ ENTRY(__setcontext)
 	cfi_offset (ebx, oEBX)
 	movl	oESP(%eax), %esp
 
-#if SHSTK_ENABLED
-	/* Check if Shadow Stack is enabled.  */
-	testl	$X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
-	jz	L(no_shstk)
-
-	/* If the base of the target shadow stack is the same as the
-	   base of the current shadow stack, we unwind the shadow
-	   stack.  Otherwise it is a stack switch and we look for a
-	   restore token.  */
-	movl	oSSP(%eax), %esi
-	movl	%esi, %edi
-
-	/* Get the base of the target shadow stack.  */
-	movl	(oSSP + 4)(%eax), %ecx
-	cmpl	%gs:SSP_BASE_OFFSET, %ecx
-	je	L(unwind_shadow_stack)
-
-	/* Align the saved original shadow stack pointer to the next
-	   8 byte aligned boundary.  */
-	andl	$-8, %esi
-
-L(find_restore_token_loop):
-	/* Look for a restore token.  */
-	movl	-8(%esi), %ebx
-	andl	$-8, %ebx
-	cmpl	%esi, %ebx
-	je	L(restore_shadow_stack)
-
-	/* Try the next slot.  */
-	subl	$8, %esi
-	jmp	L(find_restore_token_loop)
-
-L(restore_shadow_stack):
-	/* Pop return address from the shadow stack since setcontext
-	   will not return.  */
-	movl	$1, %ebx
-	incsspd	%ebx
-
-	/* Use the restore stoken to restore the target shadow stack.  */
-	rstorssp -8(%esi)
-
-	/* Save the restore token on the old shadow stack.  NB: This
-	   restore token may be checked by setcontext or swapcontext
-	   later.  */
-	saveprevssp
-
-	/* Record the new shadow stack base that was switched to.  */
-	movl	(oSSP + 4)(%eax), %ebx
-	movl	%ebx, %gs:SSP_BASE_OFFSET
-
-L(unwind_shadow_stack):
-	rdsspd	%ebx
-	subl	%edi, %ebx
-	je	L(skip_unwind_shadow_stack)
-	negl	%ebx
-	shrl	$2, %ebx
-	movl	$255, %esi
-L(loop):
-	cmpl	%esi, %ebx
-	cmovb	%ebx, %esi
-	incsspd	%esi
-	subl	%esi, %ebx
-	ja	L(loop)
-
-L(skip_unwind_shadow_stack):
-
-	/* Load the values of all the preserved registers (except ESP).  */
-	movl	oEDI(%eax), %edi
-	movl	oESI(%eax), %esi
-	movl	oEBP(%eax), %ebp
-	movl	oEBX(%eax), %ebx
-
-	/* Get the return address set with getcontext.  */
-	movl	oEIP(%eax), %ecx
-
-	/* Check if return address is valid for the case when setcontext
-	   is invoked from L(exitcode) with linked context.  */
-	rdsspd	%eax
-	cmpl	(%eax), %ecx
-	/* Clear EAX to indicate success.  NB: Don't use xorl to keep
-	   EFLAGS for jne.  */
-	movl	$0, %eax
-	jne	L(jmp)
-	/* Return to the new context if return address valid.  */
-	pushl	%ecx
-	ret
-
-L(jmp):
-	/* Jump to the new context directly.  */
-	jmp	*%ecx
-
-L(no_shstk):
-#endif
-
-	/* Fetch the address to return to.  */
-	movl	oEIP(%eax), %ecx
-
 	/* Push the return address on the new stack so we can return there.  */
 	pushl	%ecx
 
diff --git a/sysdeps/unix/sysv/linux/i386/swapcontext.S b/sysdeps/unix/sysv/linux/i386/swapcontext.S
index b8367f025e..bb736ae7d2 100644
--- a/sysdeps/unix/sysv/linux/i386/swapcontext.S
+++ b/sysdeps/unix/sysv/linux/i386/swapcontext.S
@@ -17,7 +17,6 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <sysdep.h>
-#include <asm/prctl.h>
 
 #include "ucontext_i.h"
 
@@ -76,144 +75,6 @@ ENTRY(__swapcontext)
 	movl	oFS(%eax), %edx
 	movw	%dx, %fs
 
-#if SHSTK_ENABLED
-	/* Check if Shadow Stack is enabled.  */
-	testl	$X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
-	jz	L(no_shstk)
-
-	xorl	%eax, %eax
-	cmpl	%gs:SSP_BASE_OFFSET, %eax
-	jnz	L(shadow_stack_bound_recorded)
-
-	/* Get the base address and size of the default shadow stack
-	   which must be the current shadow stack since nothing has
-	   been recorded yet.  */
-	sub	$24, %esp
-	mov	%esp, %ecx
-	movl	$ARCH_CET_STATUS, %ebx
-	movl	$__NR_arch_prctl, %eax
-	ENTER_KERNEL
-	testl	%eax, %eax
-	jz	L(continue_no_err)
-
-	/* This should never happen.  */
-	hlt
-
-L(continue_no_err):
-	/* Record the base of the current shadow stack.  */
-	movl	8(%esp), %eax
-	movl	%eax, %gs:SSP_BASE_OFFSET
-	add	$24, %esp
-
-L(shadow_stack_bound_recorded):
-	/* Load address of the context data structure we save in.  */
-	movl	4(%esp), %eax
-
-	/* Load address of the context data structure we swap in  */
-	movl	8(%esp), %edx
-
-       /* If we unwind the stack, we can't undo stack unwinding.  Just
-	   save the target shadow stack pointer as the current shadow
-	   stack pointer.   */
-	movl	oSSP(%edx), %ecx
-	movl	%ecx, oSSP(%eax)
-
-	/* Save the current shadow stack base in ucontext.  */
-	movl	%gs:SSP_BASE_OFFSET, %ecx
-	movl	%ecx, (oSSP + 4)(%eax)
-
-	/* If the base of the target shadow stack is the same as the
-	   base of the current shadow stack, we unwind the shadow
-	   stack.  Otherwise it is a stack switch and we look for a
-	   restore token.  */
-	movl	oSSP(%edx), %esi
-	movl	%esi, %edi
-
-	/* Get the base of the target shadow stack.  */
-	movl	(oSSP + 4)(%edx), %ecx
-	cmpl	%gs:SSP_BASE_OFFSET, %ecx
-	je	L(unwind_shadow_stack)
-
-	/* Align the saved original shadow stack pointer to the next
-	   8 byte aligned boundary.  */
-	andl	$-8, %esi
-
-L(find_restore_token_loop):
-	/* Look for a restore token.  */
-	movl	-8(%esi), %ebx
-	andl	$-8, %ebx
-	cmpl	%esi, %ebx
-	je	L(restore_shadow_stack)
-
-	/* Try the next slot.  */
-	subl	$8, %esi
-	jmp	L(find_restore_token_loop)
-
-L(restore_shadow_stack):
-	/* The target shadow stack will be restored.  Save the current
-	   shadow stack pointer.  */
-	rdsspd	%ecx
-	movl	%ecx, oSSP(%eax)
-
-	/* Use the restore stoken to restore the target shadow stack.  */
-	rstorssp -8(%esi)
-
-	/* Save the restore token on the old shadow stack.  NB: This
-	   restore token may be checked by setcontext or swapcontext
-	   later.  */
-	saveprevssp
-
-	/* Record the new shadow stack base that was switched to.  */
-	movl	(oSSP + 4)(%edx), %ebx
-	movl	%ebx, %gs:SSP_BASE_OFFSET
-
-L(unwind_shadow_stack):
-	rdsspd	%ebx
-	subl	%edi, %ebx
-	je	L(skip_unwind_shadow_stack)
-	negl	%ebx
-	shrl	$2, %ebx
-	movl	$255, %esi
-L(loop):
-	cmpl	%esi, %ebx
-	cmovb	%ebx, %esi
-	incsspd	%esi
-	subl	%esi, %ebx
-	ja	L(loop)
-
-L(skip_unwind_shadow_stack):
-
-	/* Load the new stack pointer.  */
-	movl	oESP(%edx), %esp
-
-	/* Load the values of all the preserved registers (except ESP).  */
-	movl	oEDI(%edx), %edi
-	movl	oESI(%edx), %esi
-	movl	oEBP(%edx), %ebp
-	movl	oEBX(%edx), %ebx
-
-	/* Get the return address set with getcontext.  */
-	movl	oEIP(%edx), %ecx
-
-	/* Check if return address is valid for the case when setcontext
-	   is invoked from L(exitcode) with linked context.  */
-	rdsspd	%eax
-	cmpl	(%eax), %ecx
-	/* Clear EAX to indicate success.  NB: Don't use xorl to keep
-	   EFLAGS for jne.  */
-	movl	$0, %eax
-	jne	L(jmp)
-	/* Return to the new context if return address valid.  */
-	pushl	%ecx
-	ret
-
-L(jmp):
-	/* Jump to the new context directly.  */
-	jmp	*%ecx
-
-L(no_shstk):
-#endif
-
 	/* Fetch the address to return to.  */
 	movl	oEIP(%eax), %ecx
 
diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.h b/sysdeps/unix/sysv/linux/i386/sysdep.h
index 516a85ce12..25852f894e 100644
--- a/sysdeps/unix/sysv/linux/i386/sysdep.h
+++ b/sysdeps/unix/sysv/linux/i386/sysdep.h
@@ -446,9 +446,4 @@ struct libc_do_syscall_args
 
 #endif	/* __ASSEMBLER__ */
 
-/* Each shadow stack slot takes 4 bytes.  Assuming that each stack
-   frame takes 128 bytes, this is used to compute shadow stack size
-   from stack size.  */
-#define STACK_SIZE_TO_SHADOW_STACK_SIZE_SHIFT 5
-
 #endif /* linux/i386/sysdep.h */
diff --git a/sysdeps/unix/sysv/linux/i386/ucontext_i.sym b/sysdeps/unix/sysv/linux/i386/ucontext_i.sym
index 1d8608eafc..1dfe03d2cc 100644
--- a/sysdeps/unix/sysv/linux/i386/ucontext_i.sym
+++ b/sysdeps/unix/sysv/linux/i386/ucontext_i.sym
@@ -22,10 +22,6 @@ oEBP		mreg (EBP)
 oESP		mreg (ESP)
 oEBX		mreg (EBX)
 oEIP		mreg (EIP)
-oSCRATCH1	mreg (EAX)
-oSCRATCH2	mreg (ECX)
-oSCRATCH3	mreg (EDX)
 oFPREGS		mcontext (fpregs)
 oSIGMASK	ucontext (uc_sigmask)
 oFPREGSMEM	ucontext (__fpregs_mem)
-oSSP		ucontext (__ssp)
diff --git a/sysdeps/unix/sysv/linux/i386/vfork.S b/sysdeps/unix/sysv/linux/i386/vfork.S
index 80c2058f1e..4352ebea46 100644
--- a/sysdeps/unix/sysv/linux/i386/vfork.S
+++ b/sysdeps/unix/sysv/linux/i386/vfork.S
@@ -36,39 +36,10 @@ ENTRY (__vfork)
 	movl	$SYS_ify (vfork), %eax
 	int	$0x80
 
-	/* Jump to the return PC.  Don't jump directly since this
-	   disturbs the branch target cache.  Instead push the return
-	   address back on the stack.  */
-	pushl	%ecx
-	cfi_adjust_cfa_offset (4)
-
 	cmpl	$-4095, %eax
 	/* Branch forward if it failed.  */
 	jae	SYSCALL_ERROR_LABEL
 
-#if SHSTK_ENABLED
-	/* Check if shadow stack is in use.  */
-	xorl	%edx, %edx
-	rdsspd	%edx
-	testl	%edx, %edx
-	/* Normal return if shadow stack isn't in use.  */
-	je	L(no_shstk)
-
-	testl	%eax, %eax
-	/* In parent, normal return.  */
-	jnz	L(no_shstk)
-
-	/* NB: In child, jump back to caller via indirect branch without
-	   popping shadow stack which is shared with parent.  Keep shadow
-	   stack mismatched so that child returns in the vfork-calling
-	   function will trigger SIGSEGV.  */
-	popl	%ecx
-	cfi_adjust_cfa_offset (-4)
-	jmp	*%ecx
-
-L(no_shstk):
-#endif
-
 	ret
 
 PSEUDO_END (__vfork)
diff --git a/sysdeps/x86/sysdep.h b/sysdeps/x86/sysdep.h
index 5a14ca5110..5b27a50cb7 100644
--- a/sysdeps/x86/sysdep.h
+++ b/sysdeps/x86/sysdep.h
@@ -40,11 +40,9 @@ enum cf_protection_level
 
 #ifdef __CET__
 # define CET_ENABLED	1
-# define IBT_ENABLED	(__CET__ & X86_FEATURE_1_IBT)
 # define SHSTK_ENABLED	(__CET__ & X86_FEATURE_1_SHSTK)
 #else
 # define CET_ENABLED	0
-# define IBT_ENABLED	0
 # define SHSTK_ENABLED	0
 #endif
 
-- 
2.34.1