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authorAdhemerval Zanella <azanella@linux.vnet.ibm.com>2014-11-07 12:34:52 -0500
committerAdhemerval Zanella <azanella@linux.vnet.ibm.com>2015-01-12 06:32:08 -0500
commit56cf2763819d2f721c98f2b8bcc04a3c673837d3 (patch)
tree5d2fde37897779f64b83951c1ef99406fd384055 /sysdeps/powerpc/nptl
parent4b45943a6f62cfc239e79ad8902f5c7f71fd13ec (diff)
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powerpc: abort transaction in syscalls
Linux kernel powerpc documentation states issuing a syscall inside a
transaction is not recommended and may lead to undefined behavior. It
also states syscalls does not abort transactoin neither they run in
transactional state.

To avoid side-effects being visible outside transactions, GLIBC with
lock elision enabled will issue a transaction abort instruction just
before all syscalls if hardware supports hardware transactions.
Diffstat (limited to 'sysdeps/powerpc/nptl')
-rw-r--r--sysdeps/powerpc/nptl/tcb-offsets.sym1
-rw-r--r--sysdeps/powerpc/nptl/tls.h19
2 files changed, 18 insertions, 2 deletions
diff --git a/sysdeps/powerpc/nptl/tcb-offsets.sym b/sysdeps/powerpc/nptl/tcb-offsets.sym
index f996759027..d955142aff 100644
--- a/sysdeps/powerpc/nptl/tcb-offsets.sym
+++ b/sysdeps/powerpc/nptl/tcb-offsets.sym
@@ -19,6 +19,7 @@ POINTER_GUARD			(offsetof (tcbhead_t, pointer_guard) - TLS_TCB_OFFSET - sizeof (
 TAR_SAVE			(offsetof (tcbhead_t, tar_save) - TLS_TCB_OFFSET - sizeof (tcbhead_t))
 DSO_SLOT1			(offsetof (tcbhead_t, dso_slot1) - TLS_TCB_OFFSET - sizeof (tcbhead_t))
 DSO_SLOT2			(offsetof (tcbhead_t, dso_slot2) - TLS_TCB_OFFSET - sizeof (tcbhead_t))
+TM_CAPABLE			(offsetof (tcbhead_t, tm_capable) - TLS_TCB_OFFSET - sizeof (tcbhead_t))
 #ifndef __ASSUME_PRIVATE_FUTEX
 PRIVATE_FUTEX_OFFSET		thread_offsetof (header.private_futex)
 #endif
diff --git a/sysdeps/powerpc/nptl/tls.h b/sysdeps/powerpc/nptl/tls.h
index 753381f95d..1f3d97a995 100644
--- a/sysdeps/powerpc/nptl/tls.h
+++ b/sysdeps/powerpc/nptl/tls.h
@@ -63,6 +63,8 @@ typedef union dtv
    are private.  */
 typedef struct
 {
+  /* Indicate if HTM capable (ISA 2.07).  */
+  int tm_capable;
   /* Reservation for Dynamic System Optimizer ABI.  */
   uintptr_t dso_slot2;
   uintptr_t dso_slot1;
@@ -130,11 +132,17 @@ register void *__thread_register __asm__ ("r13");
    special attention since 'errno' is not yet available and if the
    operation can cause a failure 'errno' must not be touched.  */
 # define TLS_INIT_TP(tcbp) \
-    (__thread_register = (void *) (tcbp) + TLS_TCB_OFFSET, NULL)
+  ({ 									      \
+    __thread_register = (void *) (tcbp) + TLS_TCB_OFFSET;		      \
+    THREAD_SET_TM_CAPABLE (GLRO (dl_hwcap2) & PPC_FEATURE2_HAS_HTM ? 1 : 0);  \
+    NULL;								      \
+  })
 
 /* Value passed to 'clone' for initialization of the thread register.  */
 # define TLS_DEFINE_INIT_TP(tp, pd) \
-  void *tp = (void *) (pd) + TLS_TCB_OFFSET + TLS_PRE_TCB_SIZE
+    void *tp = (void *) (pd) + TLS_TCB_OFFSET + TLS_PRE_TCB_SIZE;	      \
+    (((tcbhead_t *) ((char *) tp - TLS_TCB_OFFSET))[-1].tm_capable) =	      \
+      THREAD_GET_TM_CAPABLE ();
 
 /* Return the address of the dtv for the current thread.  */
 # define THREAD_DTV() \
@@ -188,6 +196,13 @@ register void *__thread_register __asm__ ("r13");
 		     + TLS_PRE_TCB_SIZE))[-1].pointer_guard		      \
      = THREAD_GET_POINTER_GUARD())
 
+/* tm_capable field in TCB head.  */
+# define THREAD_GET_TM_CAPABLE() \
+    (((tcbhead_t *) ((char *) __thread_register				      \
+		     - TLS_TCB_OFFSET))[-1].tm_capable)
+# define THREAD_SET_TM_CAPABLE(value) \
+    (THREAD_GET_TM_CAPABLE () = (value))
+
 /* l_tls_offset == 0 is perfectly valid on PPC, so we have to use some
    different value to mean unset l_tls_offset.  */
 # define NO_TLS_OFFSET		-1