powerpc/process: Add the function flush_tmregs_to_thread

This patch creates a function flush_tmregs_to_thread which
will then be used by subsequent patches in this series. The
function checks for self tracing ptrace interface attempts
while in the TM context and logs appropriate warning message.

Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h
index 17c8380673a60637c61fec5772162bf0ae5523cb..0a74ebe934e1cbcb61105b63d54a959614bca33d 100644 (file)
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -75,6 +75,14 @@ static inline void disable_kernel_spe(void)
 static inline void __giveup_spe(struct task_struct *t) { }
 #endif
 
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+extern void flush_tmregs_to_thread(struct task_struct *);
+#else
+static inline void flush_tmregs_to_thread(struct task_struct *t)
+{
+}
+#endif
+
 static inline void clear_task_ebb(struct task_struct *t)
 {
 #ifdef CONFIG_PPC_BOOK3S_64

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 9ee2623e0f674977ee8e8f07bbfb1297a2f05dc8..58ccf86415b46cd5c2db593424ecde772cd0d959 100644 (file)
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1074,6 +1074,26 @@ static inline void restore_sprs(struct thread_struct *old_thread,
 #endif
 }
 
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+void flush_tmregs_to_thread(struct task_struct *tsk)
+{
+       /*
+        * Process self tracing is not yet supported through
+        * ptrace interface. Ptrace generic code should have
+        * prevented this from happening in the first place.
+        * Warn once here with the message, if some how it
+        * is attempted.
+        */
+       WARN_ONCE(tsk == current,
+               "Not expecting ptrace on self: TM regs may be incorrect\n");
+
+       /*
+        * If task is not current, it should have been flushed
+        * already to it's thread_struct during __switch_to().
+        */
+}
+#endif
+
 struct task_struct *__switch_to(struct task_struct *prev,
        struct task_struct *new)
 {