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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/powerpc32/sysdep.h
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/powerpc32/sysdep.h')
-rw-r--r--sysdeps/powerpc/powerpc32/sysdep.h16
1 files changed, 16 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc32/sysdep.h b/sysdeps/powerpc/powerpc32/sysdep.h
index ff05e76047..e16fe3e224 100644
--- a/sysdeps/powerpc/powerpc32/sysdep.h
+++ b/sysdeps/powerpc/powerpc32/sysdep.h
@@ -88,7 +88,23 @@ GOT_LABEL:			;					      \
   cfi_endproc;								      \
   ASM_SIZE_DIRECTIVE(name)
 
+#if ! IS_IN(rtld) && defined (ENABLE_LOCK_ELISION)
+# define ABORT_TRANSACTION \
+    cmpwi    2,0;		\
+    beq      1f;		\
+    lwz      0,TM_CAPABLE(2);	\
+    cmpwi    0,0;		\
+    beq	     1f;		\
+    li	     0,_ABORT_SYSCALL;	\
+    tabort.  0;			\
+    .align 4;			\
+1:
+#else
+# define ABORT_TRANSACTION
+#endif
+
 #define DO_CALL(syscall)						      \
+    ABORT_TRANSACTION							      \
     li 0,syscall;							      \
     sc