x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563]

Message ID CAMe9rOqorP9aXjhpgnmj_XTG67iEpAMgeB9LAG8s2z3XRyzv3w@mail.gmail.com
State New
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Series
  • x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563]
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Commit Message

H.J. Lu May 17, 2018, 4:25 p.m.
On Wed, May 16, 2018 at 7:28 AM, Florian Weimer <fweimer@redhat.com> wrote:
> On 05/08/2018 10:39 PM, H.J. Lu wrote:

>>

>> diff --git a/sysdeps/i386/nptl/tls.h b/sysdeps/i386/nptl/tls.h

>> index 8ca0924692..c3a0edd253 100644

>> --- a/sysdeps/i386/nptl/tls.h

>> +++ b/sysdeps/i386/nptl/tls.h

>> @@ -50,6 +50,10 @@ typedef struct

>>     void *__private_tm[4];

>>     /* GCC split stack support.  */

>>     void *__private_ss;

>> +  /* Bit 0: IBT.

>> +     Bit 1: SHSTK.

>> +   */

>> +  unsigned int feature_1;

>>   } tcbhead_t;

>

>

> It might be nicer to reuse __glibc_reserved1 for that (I think

> __ASSUME_PRIVATE_FUTEX is always defined these days), in case some extern

> tools hard-code the tcbhead_t layout.

>


Now __ASSUME_PRIVATE_FUTEX has been removed.   Here is the patch
to rename __glibc_reserved1 to feature_1 in tcbhead_t.

-- 
H.J.

Patch

From 4ce4deb87a4ded83073fc935acc6a24e7a436b23 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Thu, 7 Dec 2017 05:47:21 -0800
Subject: [PATCH] x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ
 #22563]

This will be used by CET run-time control.

	[BZ #22563]
	* nptl/pthread_create.c (__pthread_create_2_1): Use
	THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
	* sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
	* sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
	Likewise.
	* sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
	to feature_1.
	* sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
	* sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
---
 nptl/pthread_create.c                    |  5 +++++
 sysdeps/i386/nptl/tcb-offsets.sym        |  1 +
 sysdeps/i386/nptl/tls.h                  |  5 ++++-
 sysdeps/unix/sysv/linux/x86/pthreaddef.h | 24 ++++++++++++++++++++++++
 sysdeps/x86_64/nptl/tcb-offsets.sym      |  1 +
 sysdeps/x86_64/nptl/tls.h                |  5 ++++-
 6 files changed, 39 insertions(+), 2 deletions(-)
 create mode 100644 sysdeps/unix/sysv/linux/x86/pthreaddef.h

diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c
index 92c945b12b..16998f4bbd 100644
--- a/nptl/pthread_create.c
+++ b/nptl/pthread_create.c
@@ -712,6 +712,11 @@  __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
   THREAD_COPY_POINTER_GUARD (pd);
 #endif
 
+  /* Copy additonal info.  */
+#ifdef THREAD_COPY_ADDITONAL_INFO
+  THREAD_COPY_ADDITONAL_INFO (pd);
+#endif
+
   /* Verify the sysinfo bits were copied in allocate_stack if needed.  */
 #ifdef NEED_DL_SYSINFO
   CHECK_THREAD_SYSINFO (pd);
diff --git a/sysdeps/i386/nptl/tcb-offsets.sym b/sysdeps/i386/nptl/tcb-offsets.sym
index 7d7fe5e71c..fbac241c45 100644
--- a/sysdeps/i386/nptl/tcb-offsets.sym
+++ b/sysdeps/i386/nptl/tcb-offsets.sym
@@ -12,3 +12,4 @@  CLEANUP			offsetof (struct pthread, cleanup)
 CLEANUP_PREV		offsetof (struct _pthread_cleanup_buffer, __prev)
 MUTEX_FUTEX		offsetof (pthread_mutex_t, __data.__lock)
 POINTER_GUARD		offsetof (tcbhead_t, pointer_guard)
+FEATURE_1_OFFSET	offsetof (tcbhead_t, feature_1)
diff --git a/sysdeps/i386/nptl/tls.h b/sysdeps/i386/nptl/tls.h
index 6c36e58e9c..40d10f2e85 100644
--- a/sysdeps/i386/nptl/tls.h
+++ b/sysdeps/i386/nptl/tls.h
@@ -41,7 +41,10 @@  typedef struct
   uintptr_t stack_guard;
   uintptr_t pointer_guard;
   int gscope_flag;
-  int __glibc_reserved1;
+  /* Bit 0: IBT.
+     Bit 1: SHSTK.
+   */
+  unsigned int feature_1;
   /* Reservation of some values for the TM ABI.  */
   void *__private_tm[4];
   /* GCC split stack support.  */
diff --git a/sysdeps/unix/sysv/linux/x86/pthreaddef.h b/sysdeps/unix/sysv/linux/x86/pthreaddef.h
new file mode 100644
index 0000000000..539f6540d0
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/pthreaddef.h
@@ -0,0 +1,24 @@ 
+/* Pthread macros.  Linux/x86 version.
+   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/>.  */
+
+#include_next <pthreaddef.h>
+
+/* Wee need to copy feature_1 in pthread_create.  */
+#define THREAD_COPY_ADDITONAL_INFO(descr)				\
+  ((descr)->header.feature_1						\
+   = THREAD_GETMEM (THREAD_SELF, header.feature_1))
diff --git a/sysdeps/x86_64/nptl/tcb-offsets.sym b/sysdeps/x86_64/nptl/tcb-offsets.sym
index be63404a16..387621e88c 100644
--- a/sysdeps/x86_64/nptl/tcb-offsets.sym
+++ b/sysdeps/x86_64/nptl/tcb-offsets.sym
@@ -12,6 +12,7 @@  MUTEX_FUTEX		offsetof (pthread_mutex_t, __data.__lock)
 MULTIPLE_THREADS_OFFSET	offsetof (tcbhead_t, multiple_threads)
 POINTER_GUARD		offsetof (tcbhead_t, pointer_guard)
 VGETCPU_CACHE_OFFSET	offsetof (tcbhead_t, vgetcpu_cache)
+FEATURE_1_OFFSET	offsetof (tcbhead_t, feature_1)
 
 -- Not strictly offsets, but these values are also used in the TCB.
 TCB_CANCELSTATE_BITMASK	 CANCELSTATE_BITMASK
diff --git a/sysdeps/x86_64/nptl/tls.h b/sysdeps/x86_64/nptl/tls.h
index 6da1c04a98..5c4201d988 100644
--- a/sysdeps/x86_64/nptl/tls.h
+++ b/sysdeps/x86_64/nptl/tls.h
@@ -51,7 +51,10 @@  typedef struct
   uintptr_t stack_guard;
   uintptr_t pointer_guard;
   unsigned long int vgetcpu_cache[2];
-  int __glibc_reserved1;
+  /* Bit 0: IBT.
+     Bit 1: SHSTK.
+   */
+  unsigned int feature_1;
   int __glibc_unused1;
   /* Reservation of some values for the TM ABI.  */
   void *__private_tm[4];
-- 
2.17.0