[06/08] nptl: ppc32: Fix Race conditions in pthread cancellation (BZ#12683)

Message ID 55E4C2F8.9010707@linaro.org
State New
Headers show

Commit Message

Adhemerval Zanella Aug. 31, 2015, 9:11 p.m.
This patches adds the ppc32 modification required for the BZ#12683
fix.  It basically removes the enable_asynccancel/disable_asynccancel
function usage on code used on ppc32.

--

	* sysdeps/unix/sysv/linux/i386/fcntl.c (NO_CANCELLATION): Replace
	by IS_IN (rtld).
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep-cancel.h (PSEUDO):
	Redefine to call __syscall_cancel function for cancellable syscalls.
	(__pthread_get_ip): Add implementation.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h
	[SYSCALL_CANCEL_ERROR]: New macro.
	[SYSCALL_CANCEL_ERRNO]: New macro.

--

Patch

diff --git a/sysdeps/unix/sysv/linux/i386/fcntl.c b/sysdeps/unix/sysv/linux/i386/fcntl.c
index 56f4bd1..ac5eed4 100644
--- a/sysdeps/unix/sysv/linux/i386/fcntl.c
+++ b/sysdeps/unix/sysv/linux/i386/fcntl.c
@@ -23,7 +23,7 @@ 
 
 #include <sys/syscall.h>
 
-#ifndef NO_CANCELLATION
+#if !IS_IN (rtld)
 int
 __fcntl_nocancel (int fd, int cmd, ...)
 {
@@ -36,7 +36,7 @@  __fcntl_nocancel (int fd, int cmd, ...)
 
   return INLINE_SYSCALL (fcntl64, 3, fd, cmd, arg);
 }
-#endif /* NO_CANCELLATION */
+#endif
 
 
 int
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep-cancel.h b/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep-cancel.h
index dd9ff1c..d625495 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep-cancel.h
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep-cancel.h
@@ -25,94 +25,83 @@ 
 
 #if IS_IN (libc) || IS_IN (libpthread) || IS_IN (librt)
 
+# if !IS_IN (libc)
+#  define SETUP_PIC							\
+    bcl     20,31,got_label;						\
+got_label:
+
+#  define CANCEL_JUMPTARGET						\
+    stw   r30,8(r1);							\
+    mflr  r30;								\
+    addis r30,r30,_GLOBAL_OFFSET_TABLE_-got_label@ha;			\
+    addi  r30,r30,_GLOBAL_OFFSET_TABLE_-got_label@l;			\
+    bl    __syscall_cancel@plt;						\
+    lwz   r30,8(r1)
+# else
+#  define SETUP_PIC
+#  if defined SHARED && defined PIC
+#   define CANCEL_JUMPTARGET						\
+    bl    __GI___syscall_cancel@locaL
+#  else
+#   define CANCEL_JUMPTARGET						\
+    bl    __syscall_cancel
+#  endif
+# endif
+
 # undef PSEUDO
 # define PSEUDO(name, syscall_name, args)				\
   .section ".text";							\
   ENTRY (name)								\
     SINGLE_THREAD_P;							\
-    bne- .Lpseudo_cancel;						\
-  .type __##syscall_name##_nocancel,@function;				\
-  .globl __##syscall_name##_nocancel;					\
-  __##syscall_name##_nocancel:						\
+    bne- L(pseudo_cancel);						\
     DO_CALL (SYS_ify (syscall_name));					\
-    PSEUDO_RET;								\
-  .size __##syscall_name##_nocancel,.-__##syscall_name##_nocancel;	\
-  .Lpseudo_cancel:							\
-    stwu 1,-48(1);							\
-    cfi_adjust_cfa_offset (48);						\
-    mflr 9;								\
-    stw 9,52(1);							\
+    bnslr+;								\
+    b __syscall_error@local;						\
+  L(pseudo_cancel):							\
+    stwu r1,-16(r1);							\
+    cfi_adjust_cfa_offset (16);						\
+    mflr r0;								\
+    SETUP_PIC;								\
+    stw  r0,20(r1);							\
     cfi_offset (lr, 4);							\
-    DOCARGS_##args;	/* save syscall args around CENABLE.  */	\
-    CENABLE;								\
-    stw 3,16(1);	/* store CENABLE return value (MASK).  */	\
-    UNDOCARGS_##args;	/* restore syscall args.  */			\
-    DO_CALL (SYS_ify (syscall_name));					\
-    mfcr 0;		/* save CR/R3 around CDISABLE.  */		\
-    stw 3,8(1);								\
-    stw 0,12(1);							\
-    lwz 3,16(1);	/* pass MASK to CDISABLE.  */			\
-    CDISABLE;								\
-    lwz 4,52(1);							\
-    lwz 0,12(1);	/* restore CR/R3. */				\
-    lwz 3,8(1);								\
-    mtlr 4;								\
-    mtcr 0;								\
-    addi 1,1,48;
-
-# define DOCARGS_0
-# define UNDOCARGS_0
-
-# define DOCARGS_1	stw 3,20(1); DOCARGS_0
-# define UNDOCARGS_1	lwz 3,20(1); UNDOCARGS_0
-
-# define DOCARGS_2	stw 4,24(1); DOCARGS_1
-# define UNDOCARGS_2	lwz 4,24(1); UNDOCARGS_1
-
-# define DOCARGS_3	stw 5,28(1); DOCARGS_2
-# define UNDOCARGS_3	lwz 5,28(1); UNDOCARGS_2
-
-# define DOCARGS_4	stw 6,32(1); DOCARGS_3
-# define UNDOCARGS_4	lwz 6,32(1); UNDOCARGS_3
-
-# define DOCARGS_5	stw 7,36(1); DOCARGS_4
-# define UNDOCARGS_5	lwz 7,36(1); UNDOCARGS_4
-
-# define DOCARGS_6	stw 8,40(1); DOCARGS_5
-# define UNDOCARGS_6	lwz 8,40(1); UNDOCARGS_5
-
-# if IS_IN (libpthread)
-#  define CENABLE	bl __pthread_enable_asynccancel@local
-#  define CDISABLE	bl __pthread_disable_asynccancel@local
-# elif IS_IN (libc)
-#  define CENABLE	bl __libc_enable_asynccancel@local
-#  define CDISABLE	bl __libc_disable_asynccancel@local
-# elif IS_IN (librt)
-#  define CENABLE	bl __librt_enable_asynccancel@local
-#  define CDISABLE	bl __librt_disable_asynccancel@local
-# else
-#  error Unsupported library
-# endif
+    mr   r9,r8;								\
+    mr   r8,r7;								\
+    mr   r7,r6;								\
+    mr   r6,r5;								\
+    mr   r5,r4;								\
+    mr   r4,r3;								\
+    li   r3,SYS_ify (syscall_name);					\
+    CANCEL_JUMPTARGET;							\
+    lwz  r0,20(r1);							\
+    addi r1,r1,16;							\
+    cfi_adjust_cfa_offset (-16);					\
+    mtlr r0;								\
+    cfi_restore (lr);							\
+    b    __syscall_cancel_error@local;
+
+# undef PSEUDO_RET
+# define PSEUDO_RET
 
 # ifndef __ASSEMBLER__
-#  define SINGLE_THREAD_P						\
-  __builtin_expect (THREAD_GETMEM (THREAD_SELF,				\
-				   header.multiple_threads) == 0, 1)
+#  define SINGLE_THREAD_P                                               \
+  __builtin_expect (THREAD_GETMEM (THREAD_SELF,                         \
+                                   header.multiple_threads) == 0, 1)
 # else
-#  define SINGLE_THREAD_P						\
-  lwz 10,MULTIPLE_THREADS_OFFSET(2);					\
+#  define SINGLE_THREAD_P                                               \
+  lwz 10,MULTIPLE_THREADS_OFFSET(2);                                    \
   cmpwi 10,0
 # endif
 
-#elif !defined __ASSEMBLER__
-
-# define SINGLE_THREAD_P (1)
-# define NO_CANCELLATION 1
-
 #endif
 
 #ifndef __ASSEMBLER__
 # define RTLD_SINGLE_THREAD_P \
   __builtin_expect (THREAD_GETMEM (THREAD_SELF, \
 				   header.multiple_threads) == 0, 1)
+
+static inline
+const char * __pthread_get_ip (const ucontext_t *uc)
+{
+  return (char *)uc->uc_mcontext.uc_regs->gregs[PT_NIP];
+}
 #endif
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h b/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h
index dc56bea..46fd267 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h
@@ -100,6 +100,14 @@ 
     sc_ret;								\
   })
 
+#undef SYSCALL_CANCEL_ERROR
+#define SYSCALL_CANCEL_ERROR(err)					\
+  (err > 0xfffffffffffff000UL)
+
+#undef SYSCALL_CANCEL_ERRNO
+#define SYSCALL_CANCEL_ERRNO(err)					\
+  (-err)
+
 /* Define a macro which expands inline into the wrapper code for a system
    call. This use is for internal calls that do not need to handle errors
    normally. It will never touch errno.