V2: [PATCH 01/24] x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563]
H.J. Lu
hjl.tools@gmail.com
Fri Jul 13 13:19:00 GMT 2018
On Wed, Jun 13, 2018 at 08:31:44AM -0700, H.J. Lu wrote:
> 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.
Here is the updated patch to add feature_1 to tcbhead_t and
introduce macros for CET enabling. OK for master?
H.J.
----
feature_1 has X86_FEATURE_1_IBT and X86_FEATURE_1_SHSTK bits for CET
run-time control.
CET_ENABLED, IBT_ENABLED and SHSTK_ENABLED are defined to 1 or 0 to
indicate that if CET, IBT and SHSTK are enabled.
[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.
* sysdeps/x86/sysdep.h (X86_FEATURE_1_IBT): New.
(X86_FEATURE_1_SHSTK): Likewise.
(CET_ENABLED): Likewise.
(IBT_ENABLED): Likewise.
(SHSTK_ENABLED): Likewise.
---
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/sysdep.h | 27 ++++++++++++++++++++++++
sysdeps/x86_64/nptl/tcb-offsets.sym | 1 +
sysdeps/x86_64/nptl/tls.h | 5 ++++-
7 files changed, 66 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 afb71ce431..21e23cd809 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: X86_FEATURE_1_IBT.
+ Bit 1: X86_FEATURE_1_SHSTK.
+ */
+ unsigned int feature_1;
/* Reservation of some values for the TM ABI. */
void *__private_tm[3];
/* 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/sysdep.h b/sysdeps/x86/sysdep.h
index afcb7cfd76..976566aa37 100644
--- a/sysdeps/x86/sysdep.h
+++ b/sysdeps/x86/sysdep.h
@@ -21,6 +21,33 @@
#include <sysdeps/generic/sysdep.h>
+/* __CET__ is defined by GCC with Control-Flow Protection values:
+
+enum cf_protection_level
+{
+ CF_NONE = 0,
+ CF_BRANCH = 1 << 0,
+ CF_RETURN = 1 << 1,
+ CF_FULL = CF_BRANCH | CF_RETURN,
+ CF_SET = 1 << 2
+};
+*/
+
+/* Set if CF_BRANCH (IBT) is enabled. */
+#define X86_FEATURE_1_IBT (1U << 0)
+/* Set if CF_RETURN (SHSTK) is enabled. */
+#define X86_FEATURE_1_SHSTK (1U << 1)
+
+#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
+
#ifdef __ASSEMBLER__
/* Syntactic details of assembler. */
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 65c0051dcf..f042a0250a 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: X86_FEATURE_1_IBT.
+ Bit 1: X86_FEATURE_1_SHSTK.
+ */
+ unsigned int feature_1;
int __glibc_unused1;
/* Reservation of some values for the TM ABI. */
void *__private_tm[4];
--
2.17.1
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