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[PATCH 04/19] nptl: x32: Fix Race conditions in pthread cancellation (BZ#12683)
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Mon, 11 Dec 2017 17:06:48 -0200
- Subject: [PATCH 04/19] nptl: x32: Fix Race conditions in pthread cancellation (BZ#12683)
- Authentication-results: sourceware.org; auth=none
- References: <1513019223-7603-1-git-send-email-adhemerval.zanella@linaro.org>
This patches adds the x32 modification required for the BZ#12683.
It basically adjust the syscall size used to pass the arguments to
the syscall cancel wrappers by zero extending pointers type while
preserting values for default types (such as off_t).
Checked on x86_64-linux-gnu-x32.
* sysdeps/unix/sysv/linux/x86_64/x32/sysdep.h (__syscall_arg_t):
Define type for x32.
(__SSC): Add platform specific macro.
* include/libc-pointer-arith.h (__integer_if_pointer_type_sub,
__integer_if_pointer_type, cast_to_integer): Parametrize integer type
cast.
(cast_to_uinteger): New macro.
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
---
ChangeLog | 8 ++++++++
include/libc-pointer-arith.h | 16 +++++++++++-----
sysdeps/unix/sysv/linux/x86_64/x32/sysdep.h | 13 +++++++++++++
3 files changed, 32 insertions(+), 5 deletions(-)
diff --git a/include/libc-pointer-arith.h b/include/libc-pointer-arith.h
index 715cbc1..4cacb6c 100644
--- a/include/libc-pointer-arith.h
+++ b/include/libc-pointer-arith.h
@@ -25,17 +25,23 @@
# define __pointer_type(type) (__builtin_classify_type ((type) 0) == 5)
/* intptr_t if P is true, or T if P is false. */
-# define __integer_if_pointer_type_sub(T, P) \
+# define __integer_if_pointer_type_sub(T, P, INTTYPE) \
__typeof__ (*(0 ? (__typeof__ (0 ? (T *) 0 : (void *) (P))) 0 \
- : (__typeof__ (0 ? (intptr_t *) 0 : (void *) (!(P)))) 0))
+ : (__typeof__ (0 ? (INTTYPE *) 0 : (void *) (!(P)))) 0))
/* intptr_t if EXPR has a pointer type, or the type of EXPR otherwise. */
-# define __integer_if_pointer_type(expr) \
+# define __integer_if_pointer_type(expr, inttype) \
__integer_if_pointer_type_sub(__typeof__ ((__typeof__ (expr)) 0), \
- __pointer_type (__typeof__ (expr)))
+ __pointer_type (__typeof__ (expr)), \
+ inttype)
/* Cast an integer or a pointer VAL to integer with proper type. */
-# define cast_to_integer(val) ((__integer_if_pointer_type (val)) (val))
+# define cast_to_integer(val) \
+ ((__integer_if_pointer_type (val, intptr_t)) (val))
+
+/* Cast an integer or a pointer VAL to unsigned integer with proper type. */
+# define cast_to_uinteger(val) \
+ ((__integer_if_pointer_type (val, uintptr_t)) (val))
/* Align a value by rounding down to closest size.
e.g. Using size of 4096, we get this behavior:
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/sysdep.h b/sysdeps/unix/sysv/linux/x86_64/x32/sysdep.h
index 04c73a2..dedff6c 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/sysdep.h
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/sysdep.h
@@ -18,6 +18,19 @@
#ifndef _LINUX_X32_SYSDEP_H
#define _LINUX_X32_SYSDEP_H 1
+#ifndef __ASSEMBLER__
+#include <libc-internal.h>
+#include <libc-diag.h>
+
+typedef long long int __syscall_arg_t;
+
+/* Syscall arguments for x32 follows x86_64 size, however pointers are 32
+ bits in size. The idea is to zero extend pointer types while cast to
+ signed 64 bit default arguments. */
+#define __SSC(__x) ((__syscall_arg_t) cast_to_uinteger (__x))
+
+#endif
+
/* There is some commonality. */
#include <sysdeps/unix/sysv/linux/x86_64/sysdep.h>
#include <sysdeps/x86_64/x32/sysdep.h>
--
2.7.4