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authorPaul E. Murphy <murphyp@linux.vnet.ibm.com>2015-08-21 14:39:01 -0500
committerTulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>2015-08-25 13:45:56 -0300
commit18173559a23e28055640b152e623d9f0d40ecca8 (patch)
treef8c6124358298856fd939b2a6cf77a34d3dfaa46 /sysdeps/unix/sysv
parentfe7faec3e56a8dd64f78023a2f4a74fc8d42e79f (diff)
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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.
Diffstat (limited to 'sysdeps/unix/sysv')
-rw-r--r--sysdeps/unix/sysv/linux/powerpc/syscall.S1
1 files changed, 1 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/powerpc/syscall.S b/sysdeps/unix/sysv/linux/powerpc/syscall.S
index 157e3e3296..44773038bc 100644
--- 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