powerpc: Fix tabort usage in syscalls

Fix usage of tabort in generated syscalls. r0 has special meaning when used with this instruction, thus it will not generate persistent errors, nor return an error code. This mitigates poor CPU usage when performing elided critical sections. Additionally, transactions should be aborted when entering a user invoked syscall. Otherwise the results of the transaction may be undefined. 2015-08-25 Paul E. Murphy <murphyp@linux.vnet.ibm.com> * sysdeps/powerpc/powerpc32/sysdep.h (ABORT_TRANSACTION): Use register other than r0 for tabort, it has special meaning. * sysdeps/powerpc/powerpc64/sysdep.h (ABORT_TRANSACTION): Likewise * sysdeps/unix.sysv/linux/powerpc/syscall.S (syscall): Abort transaction before starting syscall.
git-mirror · Aug 25, 2015 · 1817355 · 1817355
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commit 1817355
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Showing 4 changed files with 13 additions and 4 deletions.
diff --git a/ChangeLog b/ChangeLog
@@ -1,3 +1,11 @@
+2015-08-25  Paul E. Murphy  <murphyp@linux.vnet.ibm.com>
+
+	* sysdeps/powerpc/powerpc32/sysdep.h (ABORT_TRANSACTION): Use
+	register other than r0 for tabort, it has special meaning.
+	* sysdeps/powerpc/powerpc64/sysdep.h (ABORT_TRANSACTION): Likewise
+	* sysdeps/unix.sysv/linux/powerpc/syscall.S (syscall): Abort
+	transaction before starting syscall.
+
 2015-08-25  Rajalakshmi Srinivasaraghavan  <raji@linux.vnet.ibm.com>
 
 	* sysdeps/powerpc/powerpc64/power7/strstr.S: Handle worst case.

diff --git a/sysdeps/powerpc/powerpc32/sysdep.h b/sysdeps/powerpc/powerpc32/sysdep.h
@@ -95,8 +95,8 @@ GOT_LABEL:			;					      \
     lwz      0,TM_CAPABLE(2);	\
     cmpwi    0,0;		\
     beq	     1f;		\
-    li	     0,_ABORT_SYSCALL;	\
-    tabort.  0;			\
+    li       11,_ABORT_SYSCALL;	\
+    tabort.  11;		\
     .align 4;			\
 1:
 #else

diff --git a/sysdeps/powerpc/powerpc64/sysdep.h b/sysdeps/powerpc/powerpc64/sysdep.h
@@ -279,8 +279,8 @@ LT_LABELSUFFIX(name,_name_end): ; \
     lwz      0,TM_CAPABLE(13);	\
     cmpwi    0,0;		\
     beq	     1f;		\
-    li	     0,_ABORT_SYSCALL;	\
-    tabort.  0;			\
+    li       11,_ABORT_SYSCALL;	\
+    tabort.  11;		\
     .align 4;                   \
 1:
 #else

diff --git a/sysdeps/unix/sysv/linux/powerpc/syscall.S b/sysdeps/unix/sysv/linux/powerpc/syscall.S
@@ -18,6 +18,7 @@
 #include <sysdep.h>
 
 ENTRY (syscall)
+	ABORT_TRANSACTION
 	mr   r0,r3
 	mr   r3,r4
 	mr   r4,r5