Patchwork [v3,04/21] nptl: x32: Fix Race conditions in pthread cancellation (BZ#12683)

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Submitter Adhemerval Zanella Netto
Date Oct. 14, 2019, 8:56 p.m.
Message ID <20191014205656.29834-5-adhemerval.zanella@linaro.org>
Download mbox | patch
Permalink /patch/34956/
State New
Headers show

Comments

Adhemerval Zanella Netto - Oct. 14, 2019, 8:56 p.m.
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.
---
 include/libc-pointer-arith.h                | 16 +++++++++++-----
 sysdeps/unix/sysv/linux/x86_64/x32/sysdep.h | 13 +++++++++++++
 2 files changed, 24 insertions(+), 5 deletions(-)
Florian Weimer - Oct. 15, 2019, 11:06 a.m.
* Adhemerval Zanella:

> 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).

The commit message does not discuss the changes to
include/libc-pointer-arith.h, but I think it should.

I've already raised in the first patch whether

> +typedef long long int __syscall_arg_t;

should affect the return value of the syscall wrapper, too.

Thanks,
Florian

Patch

diff --git a/include/libc-pointer-arith.h b/include/libc-pointer-arith.h
index b32df719d1..0e5bb83f56 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 60a144a474..568ca1c959 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>