[gdb/testsuite] Add have_mpx in lib/gdb.exp

The sources for the test-cases gdb.arch/i386-mpx*.exp contain have_mpx
functions that test whether the processor supports mpx instructions.

OTOH, the test-cases are compiled using -mmpx -fcheck-pointer-bounds, which
instrument all functions with mpx instructions.

So, the function that is supposed to test whether mpx instruction are
supported contains mpx instructions, which is a bit odd.

We could fix this by:
- factoring out the have_mpx function into a single source file, and
- compiling it without "-mmpx -fcheck-pointer-bounds".

But having the mpx support test as part of the test-cases seems like an
unnecessary complication that makes the test-cases more difficult to analyze,
reason about and modify.

So we go one step further and factor out the mpx support test in into a
gdb_caching_proc.

Tested on x86_64-linux.

gdb/testsuite/ChangeLog:

2021-01-12  Tom de Vries  <tdevries@suse.de>

	* gdb.arch/i386-mpx-call.c (have_mpx): Remove.
	(main): Remove call to have_mpx.
	* gdb.arch/i386-mpx-call.exp: Use have_mpx.
	* gdb.arch/i386-mpx-map.c (have_mpx): Remove.
	(main): Remote call to have_mpx.
	* gdb.arch/i386-mpx-map.exp: Use have_mpx.
	* gdb.arch/i386-mpx-sigsegv.c (have_mpx): Remove.
	(main): Remove call to have_mpx.
	* gdb.arch/i386-mpx-sigsegv.exp: Use have_mpx.
	* gdb.arch/i386-mpx-simple_segv.c (have_mpx): Remove.
	(main): Remove call to have_mpx.
	* gdb.arch/i386-mpx-simple_segv.exp: Use have_mpx.
	* gdb.arch/i386-mpx.c (have_mpx): Remove.
	(main): Remote call to have_mpx.
	* gdb.arch/i386-mpx.exp: Use have_mpx.
	* lib/gdb.exp (have_mpx): New proc.

12 files changed, 191 insertions, 313 deletions

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index eb42ded..8e54f8c 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,22 @@
+2021-01-12  Tom de Vries  <tdevries@suse.de>
+
+	* gdb.arch/i386-mpx-call.c (have_mpx): Remove.
+	(main): Remove call to have_mpx.
+	* gdb.arch/i386-mpx-call.exp: Use have_mpx.
+	* gdb.arch/i386-mpx-map.c (have_mpx): Remove.
+	(main): Remote call to have_mpx.
+	* gdb.arch/i386-mpx-map.exp: Use have_mpx.
+	* gdb.arch/i386-mpx-sigsegv.c (have_mpx): Remove.
+	(main): Remove call to have_mpx.
+	* gdb.arch/i386-mpx-sigsegv.exp: Use have_mpx.
+	* gdb.arch/i386-mpx-simple_segv.c (have_mpx): Remove.
+	(main): Remove call to have_mpx.
+	* gdb.arch/i386-mpx-simple_segv.exp: Use have_mpx.
+	* gdb.arch/i386-mpx.c (have_mpx): Remove.
+	(main): Remote call to have_mpx.
+	* gdb.arch/i386-mpx.exp: Use have_mpx.
+	* lib/gdb.exp (have_mpx): New proc.
+
 2021-01-12  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>
 
 	* gdb.arch/aarch64-fp.exp: Modify to test bfloat16 support.
diff --git a/gdb/testsuite/gdb.arch/i386-mpx-call.c b/gdb/testsuite/gdb.arch/i386-mpx-call.c
index d0fe71a..cc37edb 100644
--- a/gdb/testsuite/gdb.arch/i386-mpx-call.c
+++ b/gdb/testsuite/gdb.arch/i386-mpx-call.c
@@ -17,34 +17,10 @@
 
 #include <stdlib.h>
 #include <string.h>
-#include "x86-cpuid.h"
 
 /* Defined size for arrays.  */
 #define ARRAY_LENGTH    5
 
-unsigned int
-have_mpx (void)
-{
-  unsigned int eax, ebx, ecx, edx;
-
-  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
-    return 0;
-
-  if ((ecx & bit_OSXSAVE) == bit_OSXSAVE)
-    {
-      if (__get_cpuid_max (0, NULL) < 7)
-	return 0;
-
-      __cpuid_count (7, 0, eax, ebx, ecx, edx);
-
-      if ((ebx & bit_MPX) == bit_MPX)
-	return 1;
-      else
-	return 0;
-    }
-  return 0;
-}
-
 
 int
 upper (int *a, int *b, int *c, int *d, int len)
@@ -99,33 +75,31 @@ char_lower (char *str, int length)
 int
 main (void)
 {
-  if (have_mpx ())
-    {
-      int sa[ARRAY_LENGTH];
-      int sb[ARRAY_LENGTH];
-      int sc[ARRAY_LENGTH];
-      int sd[ARRAY_LENGTH];
-      int *x, *a, *b, *c, *d;
-      char mchar;
-      char hello[] = "Hello";
-
-      x = malloc (sizeof (int) * ARRAY_LENGTH);
-      a = malloc (sizeof (int) * ARRAY_LENGTH);
-      b = malloc (sizeof (int) * ARRAY_LENGTH);
-      c = malloc (sizeof (int) * ARRAY_LENGTH);
-      d = malloc (sizeof (int) * ARRAY_LENGTH);
-
-      *x = upper (sa, sb, sc, sd, 0);  /* bkpt 1.  */
-      *x = lower (a, b, c, d, 0);
-
-      mchar = char_upper (hello, 10);
-      mchar = char_lower (hello, 10);
-
-      free (x);
-      free (a);
-      free (b);
-      free (c);
-      free (d);
-    }
+  int sa[ARRAY_LENGTH];
+  int sb[ARRAY_LENGTH];
+  int sc[ARRAY_LENGTH];
+  int sd[ARRAY_LENGTH];
+  int *x, *a, *b, *c, *d;
+  char mchar;
+  char hello[] = "Hello";
+
+  x = malloc (sizeof (int) * ARRAY_LENGTH);
+  a = malloc (sizeof (int) * ARRAY_LENGTH);
+  b = malloc (sizeof (int) * ARRAY_LENGTH);
+  c = malloc (sizeof (int) * ARRAY_LENGTH);
+  d = malloc (sizeof (int) * ARRAY_LENGTH);
+
+  *x = upper (sa, sb, sc, sd, 0);  /* bkpt 1.  */
+  *x = lower (a, b, c, d, 0);
+
+  mchar = char_upper (hello, 10);
+  mchar = char_lower (hello, 10);
+
+  free (x);
+  free (a);
+  free (b);
+  free (c);
+  free (d);
+
   return 0;
 }
diff --git a/gdb/testsuite/gdb.arch/i386-mpx-call.exp b/gdb/testsuite/gdb.arch/i386-mpx-call.exp
index ea96b99..360cc68 100644
--- a/gdb/testsuite/gdb.arch/i386-mpx-call.exp
+++ b/gdb/testsuite/gdb.arch/i386-mpx-call.exp
@@ -25,6 +25,11 @@ if { ![supports_mpx_check_pointer_bounds] } {
     return -1
 }
 
+if { ![have_mpx] } {
+    unsupported "processor does not support MPX"
+    return -1
+}
+
 set comp_flags "-mmpx -fcheck-pointer-bounds -I${srcdir}/../nat"
 
 if {[prepare_for_testing "failed to prepare" ${testfile} ${srcfile} \
@@ -37,18 +42,6 @@ if ![runto_main] {
     return -1
 }
 
-set test "check whether processor supports MPX"
-gdb_test_multiple "print have_mpx ()" $test {
-    -re ".*= 1\r\n$gdb_prompt " {
-        pass $test
-    }
-    -re ".*= 0\r\n$gdb_prompt " {
-        pass $test
-        untested "processor does not support MPX; skipping tests"
-        return
-    }
-}
-
 set bounds_table 0
 gdb_test_multiple "disassemble upper" "" {
     -re -wrap "bndldx.*" {
diff --git a/gdb/testsuite/gdb.arch/i386-mpx-map.c b/gdb/testsuite/gdb.arch/i386-mpx-map.c
index 527f2da..541d54a 100644
--- a/gdb/testsuite/gdb.arch/i386-mpx-map.c
+++ b/gdb/testsuite/gdb.arch/i386-mpx-map.c
@@ -21,41 +21,10 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <stdlib.h>
-#include "x86-cpuid.h"
-
-#ifndef NOINLINE
-#define NOINLINE __attribute__ ((noinline))
-#endif
-
 #define SIZE  5
 
 typedef int T;
 
-unsigned int have_mpx (void) NOINLINE;
-
-unsigned int NOINLINE
-have_mpx (void)
-{
-  unsigned int eax, ebx, ecx, edx;
-
-  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
-    return 0;
-
-  if ((ecx & bit_OSXSAVE) == bit_OSXSAVE)
-    {
-      if (__get_cpuid_max (0, NULL) < 7)
-	return 0;
-
-      __cpuid_count (7, 0, eax, ebx, ecx, edx);
-
-      if ((ebx & bit_MPX) == bit_MPX)
-	return 1;
-      else
-	return 0;
-    }
-  return 0;
-}
-
 void
 foo (T *p)
 {
@@ -78,17 +47,15 @@ foo (T *p)
 int
 main (void)
 {
-  if (have_mpx ())
-    {
-      T *a = NULL;
+  T *a = NULL;
 
-      a = calloc (SIZE, sizeof (T));	/* after-decl */
+  a = calloc (SIZE, sizeof (T));	/* after-decl */
 #if defined  __GNUC__ && !defined __INTEL_COMPILER
-      __bnd_store_ptr_bounds (a, &a);
+  __bnd_store_ptr_bounds (a, &a);
 #endif
 
-      foo (a);				/* after-alloc */
-      free (a);
-    }
+  foo (a);				/* after-alloc */
+  free (a);
+
   return 0;
 }
diff --git a/gdb/testsuite/gdb.arch/i386-mpx-map.exp b/gdb/testsuite/gdb.arch/i386-mpx-map.exp
index a98194d..55b70d1 100644
--- a/gdb/testsuite/gdb.arch/i386-mpx-map.exp
+++ b/gdb/testsuite/gdb.arch/i386-mpx-map.exp
@@ -27,6 +27,11 @@ if { ![supports_mpx_check_pointer_bounds] } {
     return -1
 }
 
+if { ![have_mpx] } {
+    unsupported "processor does not support MPX"
+    return -1
+}
+
 set comp_flags "-mmpx -fcheck-pointer-bounds -I${srcdir}/../nat/"
 
 if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile} \
@@ -39,24 +44,6 @@ if ![runto_main] {
 	return -1
 }
 
-set supports_mpx 0
-set test "probe MPX support"
-
-gdb_test_multiple "print have_mpx()" $test {
-    -re ".. = 1\r\n$gdb_prompt $" {
-        pass $test
-        set supports_mpx 1
-    }
-    -re ".. = 0\r\n$gdb_prompt $" {
-        pass $test
-    }
-}
-
-if { !$supports_mpx } {
-    unsupported "processor does not support MPX"
-    return
-}
-
 gdb_breakpoint [ gdb_get_line_number "after-decl" ]
 gdb_breakpoint [ gdb_get_line_number "after-alloc" ]
 gdb_breakpoint [ gdb_get_line_number "after-assign" ]
diff --git a/gdb/testsuite/gdb.arch/i386-mpx-sigsegv.c b/gdb/testsuite/gdb.arch/i386-mpx-sigsegv.c
index 517fb11..09e1b83 100644
--- a/gdb/testsuite/gdb.arch/i386-mpx-sigsegv.c
+++ b/gdb/testsuite/gdb.arch/i386-mpx-sigsegv.c
@@ -15,9 +15,6 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
-#include "x86-cpuid.h"
-#include <stdio.h>
-
 #define OUR_SIZE    5
 
 int gx[OUR_SIZE];
@@ -26,29 +23,6 @@ int gb[OUR_SIZE];
 int gc[OUR_SIZE];
 int gd[OUR_SIZE];
 
-unsigned int
-have_mpx (void)
-{
-  unsigned int eax, ebx, ecx, edx;
-
-  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
-    return 0;
-
-  if ((ecx & bit_OSXSAVE) == bit_OSXSAVE)
-    {
-      if (__get_cpuid_max (0, NULL) < 7)
-	return 0;
-
-      __cpuid_count (7, 0, eax, ebx, ecx, edx);
-
-      if ((ebx & bit_MPX) == bit_MPX)
-	return 1;
-      else
-	return 0;
-    }
-  return 0;
-}
-
 int
 bp1 (int value)
 {
@@ -87,34 +61,32 @@ lower (int * p, int * a, int * b, int * c, int * d, int len)
 int
 main (void)
 {
-  if (have_mpx ())
-    {
-      int sx[OUR_SIZE];
-      int sa[OUR_SIZE];
-      int sb[OUR_SIZE];
-      int sc[OUR_SIZE];
-      int sd[OUR_SIZE];
-      int *x, *a, *b, *c, *d;
-
-      x = calloc (OUR_SIZE, sizeof (int));
-      a = calloc (OUR_SIZE, sizeof (int));
-      b = calloc (OUR_SIZE, sizeof (int));
-      c = calloc (OUR_SIZE, sizeof (int));
-      d = calloc (OUR_SIZE, sizeof (int));
-
-      upper (x, a, b, c, d, OUR_SIZE + 2);
-      upper (sx, sa, sb, sc, sd, OUR_SIZE + 2);
-      upper (gx, ga, gb, gc, gd, OUR_SIZE + 2);
-      lower (x, a, b, c, d, 1);
-      lower (sx, sa, sb, sc, sd, 1);
-      bp1 (*x);
-      lower (gx, ga, gb, gc, gd, 1);
+  int sx[OUR_SIZE];
+  int sa[OUR_SIZE];
+  int sb[OUR_SIZE];
+  int sc[OUR_SIZE];
+  int sd[OUR_SIZE];
+  int *x, *a, *b, *c, *d;
+
+  x = calloc (OUR_SIZE, sizeof (int));
+  a = calloc (OUR_SIZE, sizeof (int));
+  b = calloc (OUR_SIZE, sizeof (int));
+  c = calloc (OUR_SIZE, sizeof (int));
+  d = calloc (OUR_SIZE, sizeof (int));
+
+  upper (x, a, b, c, d, OUR_SIZE + 2);
+  upper (sx, sa, sb, sc, sd, OUR_SIZE + 2);
+  upper (gx, ga, gb, gc, gd, OUR_SIZE + 2);
+  lower (x, a, b, c, d, 1);
+  lower (sx, sa, sb, sc, sd, 1);
+  bp1 (*x);
+  lower (gx, ga, gb, gc, gd, 1);
+
+  free (x);
+  free (a);
+  free (b);
+  free (c);
+  free (d);
 
-      free (x);
-      free (a);
-      free (b);
-      free (c);
-      free (d);
-    }
   return 0;
 }
diff --git a/gdb/testsuite/gdb.arch/i386-mpx-sigsegv.exp b/gdb/testsuite/gdb.arch/i386-mpx-sigsegv.exp
index 739bb8d..ef8fd68 100644
--- a/gdb/testsuite/gdb.arch/i386-mpx-sigsegv.exp
+++ b/gdb/testsuite/gdb.arch/i386-mpx-sigsegv.exp
@@ -27,6 +27,11 @@ if { ![supports_mpx_check_pointer_bounds] } {
     return -1
 }
 
+if { ![have_mpx] } {
+    unsupported "processor does not support MPX"
+    return -1
+}
+
 set comp_flags "-mmpx -fcheck-pointer-bounds -I${srcdir}/../nat/"
 
 if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile} \
@@ -39,16 +44,6 @@ if ![runto_main] {
     return -1
 }
 
-gdb_test_multiple "print have_mpx ()" "have mpx" {
-    -re ".. = 1\r\n$gdb_prompt " {
-        pass "check whether processor supports MPX"
-    }
-    -re ".. = 0\r\n$gdb_prompt " {
-        verbose "processor does not support MPX; skipping MPX tests"
-        return
-    }
-}
-
 set u_fault [multi_line "Program received signal SIGSEGV, Segmentation fault" \
                         "Upper bound violation while accessing address $hex" \
                         "Bounds: \\\[lower = $hex, upper = $hex\\\]"]
diff --git a/gdb/testsuite/gdb.arch/i386-mpx-simple_segv.c b/gdb/testsuite/gdb.arch/i386-mpx-simple_segv.c
index 54b6f33..97baed7 100644
--- a/gdb/testsuite/gdb.arch/i386-mpx-simple_segv.c
+++ b/gdb/testsuite/gdb.arch/i386-mpx-simple_segv.c
@@ -15,34 +15,8 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
-#include "x86-cpuid.h"
-#include <stdio.h>
-
 #define OUR_SIZE    5
 
-unsigned int
-have_mpx (void)
-{
-  unsigned int eax, ebx, ecx, edx;
-
-  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
-    return 0;
-
-  if ((ecx & bit_OSXSAVE) == bit_OSXSAVE)
-    {
-      if (__get_cpuid_max (0, NULL) < 7)
-	return 0;
-
-      __cpuid_count (7, 0, eax, ebx, ecx, edx);
-
-      if ((ebx & bit_MPX) == bit_MPX)
-	return 1;
-      else
-	return 0;
-    }
-  return 0;
-}
-
 void
 upper (int * p, int len)
 {
@@ -54,13 +28,9 @@ upper (int * p, int len)
 int
 main (void)
 {
-  if (have_mpx ())
-    {
-      int a = 0;			/* Dummy variable for debugging purposes.  */
-      int sx[OUR_SIZE];
-      a++;				/* register-eval.  */
-      upper (sx, OUR_SIZE + 2);
-      return sx[1];
-    }
-  return 0;
+  int a = 0;			/* Dummy variable for debugging purposes.  */
+  int sx[OUR_SIZE];
+  a++;				/* register-eval.  */
+  upper (sx, OUR_SIZE + 2);
+  return sx[1];
 }
diff --git a/gdb/testsuite/gdb.arch/i386-mpx-simple_segv.exp b/gdb/testsuite/gdb.arch/i386-mpx-simple_segv.exp
index 51b1581..e5b2a89 100644
--- a/gdb/testsuite/gdb.arch/i386-mpx-simple_segv.exp
+++ b/gdb/testsuite/gdb.arch/i386-mpx-simple_segv.exp
@@ -33,6 +33,11 @@ if { ![supports_mpx_check_pointer_bounds] } {
     return -1
 }
 
+if { ![have_mpx] } {
+    unsupported "processor does not support MPX"
+    return -1
+}
+
 set comp_flags "-mmpx -fcheck-pointer-bounds -I${srcdir}/../nat/"
 
 if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile} \
@@ -45,16 +50,6 @@ if ![runto_main] {
     return -1
 }
 
-gdb_test_multiple "print have_mpx ()" "have mpx" {
-    -re ".. = 1\r\n$gdb_prompt " {
-        pass "check whether processor supports MPX"
-    }
-    -re ".. = 0\r\n$gdb_prompt " {
-        verbose "processor does not support MPX; skipping MPX tests"
-        return
-    }
-}
-
 set violation [multi_line "Program received signal SIGSEGV, Segmentation fault" \
                           "Upper bound violation while accessing address $hex" \
                           "Bounds: \\\[lower = $hex, upper = $hex\\\]"]
diff --git a/gdb/testsuite/gdb.arch/i386-mpx.c b/gdb/testsuite/gdb.arch/i386-mpx.c
index 178c34a..b96da54 100644
--- a/gdb/testsuite/gdb.arch/i386-mpx.c
+++ b/gdb/testsuite/gdb.arch/i386-mpx.c
@@ -17,77 +17,43 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
-#include <stdio.h>
-#include "x86-cpuid.h"
-
-#ifndef NOINLINE
-#define NOINLINE __attribute__ ((noinline))
-#endif
-
-unsigned int have_mpx (void) NOINLINE;
-
-unsigned int NOINLINE
-have_mpx (void)
-{
-  unsigned int eax, ebx, ecx, edx;
-
-  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
-    return 0;
-
-  if ((ecx & bit_OSXSAVE) == bit_OSXSAVE)
-    {
-      if (__get_cpuid_max (0, NULL) < 7)
-	return 0;
-
-      __cpuid_count (7, 0, eax, ebx, ecx, edx);
-
-      if ((ebx & bit_MPX) == bit_MPX)
-	return 1;
-      else
-	return 0;
-    }
-  return 0;
-}
-
 int
 main (int argc, char **argv)
 {
-  if (have_mpx ())
-    {
 #ifdef __x86_64__
-      asm ("mov $10, %rax\n\t"
-	  "mov $9, %rdx\n\t"
-	  "bndmk (%rax,%rdx), %bnd0\n\t"
-	  "mov $20, %rax\n\t"
-	  "mov $9, %rdx\n\t"
-	  "bndmk (%rax,%rdx), %bnd1\n\t"
-	  "mov $30, %rax\n\t"
-	  "mov $9, %rdx\n\t"
-	  "bndmk (%rax,%rdx), %bnd2\n\t"
-	  "mov $40, %rax\n\t"
-	  "mov $9, %rdx\n\t"
-	  "bndmk (%rax,%rdx), %bnd3\n\t"
-	  "bndstx %bnd3, (%rax) \n\t"
-	  "nop\n\t"
-         );
+  asm ("mov $10, %rax\n\t"
+       "mov $9, %rdx\n\t"
+       "bndmk (%rax,%rdx), %bnd0\n\t"
+       "mov $20, %rax\n\t"
+       "mov $9, %rdx\n\t"
+       "bndmk (%rax,%rdx), %bnd1\n\t"
+       "mov $30, %rax\n\t"
+       "mov $9, %rdx\n\t"
+       "bndmk (%rax,%rdx), %bnd2\n\t"
+       "mov $40, %rax\n\t"
+       "mov $9, %rdx\n\t"
+       "bndmk (%rax,%rdx), %bnd3\n\t"
+       "bndstx %bnd3, (%rax) \n\t"
+       "nop\n\t"
+       );
 #else
-      asm ("mov $10, %eax\n\t"
-	   "mov $9, %edx\n\t"
-	   "bndmk (%eax,%edx), %bnd0\n\t"
-	   "mov $20, %eax\n\t"
-	   "mov $9, %edx\n\t"
-	   "bndmk (%eax,%edx), %bnd1\n\t"
-	   "mov $30, %eax\n\t"
-	   "mov $9, %edx\n\t"
-	   "bndmk (%eax,%edx), %bnd2\n\t"
-	   "mov $40, %eax\n\t"
-	   "mov $9, %edx\n\t"
-	   "bndmk (%eax,%edx), %bnd3\n\t"
-	   "bndstx  %bnd3, (%eax)\n\t"
-	   "nop\n\t"
-	  );
+  asm ("mov $10, %eax\n\t"
+       "mov $9, %edx\n\t"
+       "bndmk (%eax,%edx), %bnd0\n\t"
+       "mov $20, %eax\n\t"
+       "mov $9, %edx\n\t"
+       "bndmk (%eax,%edx), %bnd1\n\t"
+       "mov $30, %eax\n\t"
+       "mov $9, %edx\n\t"
+       "bndmk (%eax,%edx), %bnd2\n\t"
+       "mov $40, %eax\n\t"
+       "mov $9, %edx\n\t"
+       "bndmk (%eax,%edx), %bnd3\n\t"
+       "bndstx  %bnd3, (%eax)\n\t"
+       "nop\n\t"
+       );
 #endif
-	asm ("nop\n\t");	/* break here.  */
-    }
+  asm ("nop\n\t");	/* break here.  */
+
   return 0;
 }
diff --git a/gdb/testsuite/gdb.arch/i386-mpx.exp b/gdb/testsuite/gdb.arch/i386-mpx.exp
index 639f7cd..a6b74ce 100644
--- a/gdb/testsuite/gdb.arch/i386-mpx.exp
+++ b/gdb/testsuite/gdb.arch/i386-mpx.exp
@@ -31,6 +31,11 @@ if { ![supports_mpx_check_pointer_bounds] } {
     return -1
 }
 
+if { ![have_mpx] } {
+    unsupported "processor does not support MPX"
+    return -1
+}
+
 set comp_flags "-mmpx -fcheck-pointer-bounds -I${srcdir}/../nat/"
 
 if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile} \
@@ -43,23 +48,6 @@ if ![runto_main] {
     return -1
 }
 
-set supports_mpx 0
-set test "probe MPX support"
-gdb_test_multiple "print have_mpx()" $test {
-    -re ".. = 1\r\n$gdb_prompt $" {
-        pass $test
-        set supports_mpx 1
-    }
-    -re ".. = 0\r\n$gdb_prompt $" {
-        pass $test
-    }
-}
-
-if { !$supports_mpx } {
-    unsupported "processor does not support MPX"
-    return
-}
-
 # Test bndcfg register and bndstatus at startup
 set test_string "\\\{raw = 0x\[0-9a-f\]+, config = \\\{base = \[0-9\]+,\
 reserved = \[0-9\]+, preserved = \[0-9\]+, enabled = \[0-9\]+\\\}\\\}"
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 140e396..ae24fe2 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -7771,5 +7771,57 @@ gdb_caching_proc supports_gnuc {
     return [gdb_simple_compile $me $src object ""]
 }
 
+# Return 1 if target supports mpx, otherwise return 0.
+gdb_caching_proc have_mpx {
+    global srcdir
+
+    set me "have_mpx"
+    if { ![istarget "i?86-*-*"] && ![istarget "x86_64-*-*"] } {
+        verbose "$me: target does not support mpx, returning 0" 2
+        return 0
+    }
+
+    # Compile a test program.
+    set src {
+       #include "nat/x86-cpuid.h"
+
+        int main() {
+	  unsigned int eax, ebx, ecx, edx;
+
+	  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
+	    return 0;
+
+	  if ((ecx & bit_OSXSAVE) == bit_OSXSAVE)
+	    {
+	      if (__get_cpuid_max (0, (void *)0) < 7)
+		return 0;
+
+		__cpuid_count (7, 0, eax, ebx, ecx, edx);
+
+		if ((ebx & bit_MPX) == bit_MPX)
+		  return 1;
+
+	    }
+	  return 0;
+	}
+    }
+    set compile_flags "incdir=${srcdir}/.."
+    if {![gdb_simple_compile $me $src executable $compile_flags]} {
+        return 0
+    }
+
+    set result [remote_exec target $obj]
+    set status [lindex $result 0]
+    set output [lindex $result 1]
+    if { $output != "" } {
+	set status 0
+    }
+
+    remote_file build delete $obj
+
+    verbose "$me:  returning $status" 2
+    return $status
+}
+
 # Always load compatibility stuff.
 load_lib future.exp