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[PATCH 1/3] x86/CET: Extend arch_prctl syscall for CET control


 /* CET features:
    IBT:   GNU_PROPERTY_X86_FEATURE_1_IBT
    SHSTK: GNU_PROPERTY_X86_FEATURE_1_SHSTK
  */

 /* Return CET features in unsigned long long *addr:
      features: addr[0].
      shadow stack base address: addr[1].
      shadow stack size: addr[2].
  */
 # define ARCH_CET_STATUS		0x3001
 /* Disable CET features in unsigned int features.  */
 # define ARCH_CET_DISABLE		0x3002
 /* Lock all CET features.  */
 # define ARCH_CET_LOCK			0x3003
 /* Allocate a new shadow stack with unsigned long long *addr:
      IN: requested shadow stack size: *addr.
      OUT: allocated shadow stack address: *addr.
  */
 # define ARCH_CET_ALLOC_SHSTK		0x3004
 /* Return legacy region bitmap info in unsigned long long *addr:
     address: addr[0].
     size: addr[1].
  */
 # define ARCH_CET_LEGACY_BITMAP	0x3005

	* sysdeps/unix/sysv/linux/Makefile (sysdep_headers): Add
	bits/prctl.h.
	* sysdeps/unix/sysv/linux/bits/prctl.h: New file.
	* sysdeps/unix/sysv/linux/x86/bits/prctl.h: Likewise.
	* sysdeps/unix/sysv/linux/sys/prctl.h: Include <bits/prctl.h>.
	* sysdeps/unix/sysv/linux/x86/cpu-features.c: Include
	<sys/prctl.h>.
	(get_cet_status): Call arch_prctl with ARCH_CET_STATUS.
	* sysdeps/unix/sysv/linux/x86/dl-cet.h: Include  <sys/prctl.h>.
	(dl_cet_allocate_legacy_bitmap): Call arch_prctl with
	ARCH_CET_LEGACY_BITMAP.
	(dl_cet_disable_cet): Call arch_prctl with ARCH_CET_DISABLE.
	(dl_cet_lock_cet): Call arch_prctl with ARCH_CET_LOCK.
	* sysdeps/x86/libc-start.c: Include <startup.h>.
---
 sysdeps/unix/sysv/linux/Makefile           |  3 +-
 sysdeps/unix/sysv/linux/bits/prctl.h       | 21 ++++++++++
 sysdeps/unix/sysv/linux/sys/prctl.h        |  1 +
 sysdeps/unix/sysv/linux/x86/bits/prctl.h   | 48 ++++++++++++++++++++++
 sysdeps/unix/sysv/linux/x86/cpu-features.c |  7 ++++
 sysdeps/unix/sysv/linux/x86/dl-cet.h       | 29 ++++++++++---
 sysdeps/x86/libc-start.c                   |  3 ++
 7 files changed, 105 insertions(+), 7 deletions(-)
 create mode 100644 sysdeps/unix/sysv/linux/bits/prctl.h
 create mode 100644 sysdeps/unix/sysv/linux/x86/bits/prctl.h

diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index f71cc39c7e..0bcc5287d9 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -40,7 +40,8 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \
 		  bits/signalfd.h bits/timerfd.h bits/epoll.h \
 		  bits/socket_type.h bits/syscall.h bits/sysctl.h \
 		  bits/mman-linux.h bits/mman-shared.h bits/ptrace-shared.h \
-		  bits/siginfo-arch.h bits/siginfo-consts-arch.h
+		  bits/siginfo-arch.h bits/siginfo-consts-arch.h \
+		  bits/prctl.h
 
 tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
 	 tst-quota tst-sync_file_range tst-sysconf-iov_max tst-ttyname \
diff --git a/sysdeps/unix/sysv/linux/bits/prctl.h b/sysdeps/unix/sysv/linux/bits/prctl.h
new file mode 100644
index 0000000000..be96218066
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/bits/prctl.h
@@ -0,0 +1,21 @@
+/* Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_PRCTL_H
+#define _BITS_PRCTL_H	1
+
+#endif  /* bits/prctl.h */
diff --git a/sysdeps/unix/sysv/linux/sys/prctl.h b/sysdeps/unix/sysv/linux/sys/prctl.h
index 683d16748f..6c4f643c75 100644
--- a/sysdeps/unix/sysv/linux/sys/prctl.h
+++ b/sysdeps/unix/sysv/linux/sys/prctl.h
@@ -20,6 +20,7 @@
 
 #include <features.h>
 #include <linux/prctl.h>  /*  The magic values come from here  */
+#include <bits/prctl.h>
 
 __BEGIN_DECLS
 
diff --git a/sysdeps/unix/sysv/linux/x86/bits/prctl.h b/sysdeps/unix/sysv/linux/x86/bits/prctl.h
new file mode 100644
index 0000000000..37e5fc8212
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/bits/prctl.h
@@ -0,0 +1,48 @@
+/* Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_PRCTL_H
+#define _BITS_PRCTL_H	1
+
+#ifndef ARCH_CET_STATUS
+/* CET features:
+   IBT:   GNU_PROPERTY_X86_FEATURE_1_IBT
+   SHSTK: GNU_PROPERTY_X86_FEATURE_1_SHSTK
+ */
+/* Return CET features in unsigned long long *addr:
+     features: addr[0].
+     shadow stack base address: addr[1].
+     shadow stack size: addr[2].
+ */
+# define ARCH_CET_STATUS	0x3001
+/* Disable CET features in unsigned int features.  */
+# define ARCH_CET_DISABLE	0x3002
+/* Lock all CET features.  */
+# define ARCH_CET_LOCK		0x3003
+/* Allocate a new shadow stack with unsigned long long *addr:
+     IN: requested shadow stack size: *addr.
+     OUT: allocated shadow stack address: *addr.
+ */
+# define ARCH_CET_ALLOC_SHSTK	0x3004
+/* Return legacy region bitmap info in unsigned long long *addr:
+     address: addr[0].
+     size: addr[1].
+ */
+# define ARCH_CET_LEGACY_BITMAP	0x3005
+#endif /* ARCH_CET_STATUS */
+
+#endif  /* bits/prctl.h */
diff --git a/sysdeps/unix/sysv/linux/x86/cpu-features.c b/sysdeps/unix/sysv/linux/x86/cpu-features.c
index 7c9df9b794..c7c59055dc 100644
--- a/sysdeps/unix/sysv/linux/x86/cpu-features.c
+++ b/sysdeps/unix/sysv/linux/x86/cpu-features.c
@@ -17,9 +17,16 @@
    <http://www.gnu.org/licenses/>.  */
 
 #if CET_ENABLED
+# include <sys/prctl.h>
+
 static inline int __attribute__ ((always_inline))
 get_cet_status (void)
 {
+  unsigned long long cet_status[3];
+  INTERNAL_SYSCALL_DECL (err);
+  if (INTERNAL_SYSCALL (arch_prctl, err, 2, ARCH_CET_STATUS,
+			cet_status) == 0)
+    return cet_status[0];
   return 0;
 }
 
diff --git a/sysdeps/unix/sysv/linux/x86/dl-cet.h b/sysdeps/unix/sysv/linux/x86/dl-cet.h
index ae81e2f2ca..787368292d 100644
--- a/sysdeps/unix/sysv/linux/x86/dl-cet.h
+++ b/sysdeps/unix/sysv/linux/x86/dl-cet.h
@@ -15,23 +15,40 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+#include <sys/prctl.h>
+
 static inline int __attribute__ ((always_inline))
 dl_cet_allocate_legacy_bitmap (unsigned long *legacy_bitmap)
 {
-  /* FIXME: Need syscall support.  */
-  return -1;
+  /* Allocate legacy bitmap.  */
+  INTERNAL_SYSCALL_DECL (err);
+#ifdef __LP64__
+  return (int) INTERNAL_SYSCALL (arch_prctl, err, 2,
+				 ARCH_CET_LEGACY_BITMAP, legacy_bitmap);
+#else
+  unsigned long long legacy_bitmap_u64[2];
+  int res = INTERNAL_SYSCALL (arch_prctl, err, 2,
+			      ARCH_CET_LEGACY_BITMAP, legacy_bitmap_u64);
+  if (res == 0)
+    {
+      legacy_bitmap[0] = legacy_bitmap_u64[0];
+      legacy_bitmap[1] = legacy_bitmap_u64[1];
+    }
+  return res;
+#endif
 }
 
 static inline int __attribute__ ((always_inline))
 dl_cet_disable_cet (unsigned int cet_feature)
 {
-  /* FIXME: Need syscall support.  */
-  return -1;
+  INTERNAL_SYSCALL_DECL (err);
+  return (int) INTERNAL_SYSCALL (arch_prctl, err, 2, ARCH_CET_DISABLE,
+				 cet_feature);
 }
 
 static inline int __attribute__ ((always_inline))
 dl_cet_lock_cet (void)
 {
-  /* FIXME: Need syscall support.  */
-  return -1;
+  INTERNAL_SYSCALL_DECL (err);
+  return (int) INTERNAL_SYSCALL (arch_prctl, err, 2, ARCH_CET_LOCK, 0);
 }
diff --git a/sysdeps/x86/libc-start.c b/sysdeps/x86/libc-start.c
index 43aba9d061..eb5335c154 100644
--- a/sysdeps/x86/libc-start.c
+++ b/sysdeps/x86/libc-start.c
@@ -16,6 +16,9 @@
    <http://www.gnu.org/licenses/>.  */
 
 #ifndef SHARED
+/* Define I386_USE_SYSENTER to support syscall during startup in static
+   PIE.  */
+# include <startup.h>
 # include <ldsodefs.h>
 # include <cpu-features.h>
 # include <cpu-features.c>
-- 
2.17.1


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