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.

(cherry picked from commit 18173559a23e28055640b152e623d9f0d40ecca8)

diff --git a/ChangeLog b/ChangeLog
index 6c8f1adff6b252e7846bba48066d06989b27c646..0b6deab1f2883abe946a32104b851f63e6d9535f 100644 (file)
--- 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.
+
 2016-04-04  Stefan Liebler  <stli@linux.vnet.ibm.com>
 
        * sysdeps/s390/bits/link.h: (La_s390_vr) New typedef.

diff --git a/sysdeps/powerpc/powerpc32/sysdep.h b/sysdeps/powerpc/powerpc32/sysdep.h
index e16fe3e2241ecccf4c698a164323075624b56cb9..ecb492a5abad741132bebbadc7f91f4d92443550 100644 (file)
--- 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
index bf2a884b99acb56c9f05bc1eb3fc2f5ac35fdb75..a9d37ad437309949c199088cb2347367de244b8e 100644 (file)
--- 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
index 157e3e329611253938ea918c3e3e3857c79f24d2..44773038bc317f7130c7576d895ab8d83781f369 100644 (file)
--- 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