powerpc/ptrace: Enable in transaction NT_PPC_VMX ptrace requests

This patch enables in transaction NT_PPC_VMX ptrace requests. The
function vr_get which gets the running value of all VMX registers
and the function vr_set which sets the running value of of all VMX
registers work on the running set of VMX registers whose location
will be different if transaction is active. This patch makes these
functions adapt to situations when the transaction is active.

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>

arch/powerpc/kernel/ptrace.c

@@ -518,10 +518,28 @@ static int vr_active(struct task_struct *target,
 	return target->thread.used_vr ? regset->n : 0;
 }
 
+/*
+ * When the transaction is active, 'transact_vr' holds the current running
+ * value of all the VMX registers and 'vr_state' holds the last checkpointed
+ * value of all the VMX registers for the current transaction to fall back
+ * on in case it aborts. When transaction is not active 'vr_state' holds
+ * the current running state of all the VMX registers. So this function which
+ * gets the current running values of all the VMX registers, needs to know
+ * whether any transaction is active or not.
+ *
+ * Userspace interface buffer layout:
+ *
+ * struct data {
+ *	vector128	vr[32];
+ *	vector128	vscr;
+ *	vector128	vrsave;
+ * };
+ */
 static int vr_get(struct task_struct *target, const struct user_regset *regset,
 		  unsigned int pos, unsigned int count,
 		  void *kbuf, void __user *ubuf)
 {
+	struct thread_vr_state *addr;
 	int ret;
 
 	flush_altivec_to_thread(target);
@@ -529,8 +547,19 @@ static int vr_get(struct task_struct *target, const struct user_regset *regset,
 	BUILD_BUG_ON(offsetof(struct thread_vr_state, vscr) !=
 		     offsetof(struct thread_vr_state, vr[32]));
 
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+	if (MSR_TM_ACTIVE(target->thread.regs->msr)) {
+		flush_fp_to_thread(target);
+		flush_tmregs_to_thread(target);
+		addr = &target->thread.transact_vr;
+	} else {
+		addr = &target->thread.vr_state;
+	}
+#else
+	addr = &target->thread.vr_state;
+#endif
 	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				  &target->thread.vr_state, 0,
+				  addr, 0,
 				  33 * sizeof(vector128));
 	if (!ret) {
 		/*
@@ -541,7 +570,16 @@ static int vr_get(struct task_struct *target, const struct user_regset *regset,
 			u32 word;
 		} vrsave;
 		memset(&vrsave, 0, sizeof(vrsave));
+
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+		if (MSR_TM_ACTIVE(target->thread.regs->msr))
+			vrsave.word = target->thread.transact_vrsave;
+		else
+			vrsave.word = target->thread.vrsave;
+#else
 		vrsave.word = target->thread.vrsave;
+#endif
+
 		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &vrsave,
 					  33 * sizeof(vector128), -1);
 	}
@@ -549,10 +587,28 @@ static int vr_get(struct task_struct *target, const struct user_regset *regset,
 	return ret;
 }
 
+/*
+ * When the transaction is active, 'transact_vr' holds the current running
+ * value of all the VMX registers and 'vr_state' holds the last checkpointed
+ * value of all the VMX registers for the current transaction to fall back
+ * on in case it aborts. When transaction is not active 'vr_state' holds
+ * the current running state of all the VMX registers. So this function which
+ * sets the current running values of all the VMX registers, needs to know
+ * whether any transaction is active or not.
+ *
+ * Userspace interface buffer layout:
+ *
+ * struct data {
+ *	vector128	vr[32];
+ *	vector128	vscr;
+ *	vector128	vrsave;
+ * };
+ */
 static int vr_set(struct task_struct *target, const struct user_regset *regset,
 		  unsigned int pos, unsigned int count,
 		  const void *kbuf, const void __user *ubuf)
 {
+	struct thread_vr_state *addr;
 	int ret;
 
 	flush_altivec_to_thread(target);
@@ -560,8 +616,19 @@ static int vr_set(struct task_struct *target, const struct user_regset *regset,
 	BUILD_BUG_ON(offsetof(struct thread_vr_state, vscr) !=
 		     offsetof(struct thread_vr_state, vr[32]));
 
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+	if (MSR_TM_ACTIVE(target->thread.regs->msr)) {
+		flush_fp_to_thread(target);
+		flush_tmregs_to_thread(target);
+		addr = &target->thread.transact_vr;
+	} else {
+		addr = &target->thread.vr_state;
+	}
+#else
+	addr = &target->thread.vr_state;
+#endif
 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
-				 &target->thread.vr_state, 0,
+				 addr, 0,
 				 33 * sizeof(vector128));
 	if (!ret && count > 0) {
 		/*
@@ -572,11 +639,28 @@ static int vr_set(struct task_struct *target, const struct user_regset *regset,
 			u32 word;
 		} vrsave;
 		memset(&vrsave, 0, sizeof(vrsave));
+
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+		if (MSR_TM_ACTIVE(target->thread.regs->msr))
+			vrsave.word = target->thread.transact_vrsave;
+		else
+			vrsave.word = target->thread.vrsave;
+#else
 		vrsave.word = target->thread.vrsave;
+#endif
 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &vrsave,
 					 33 * sizeof(vector128), -1);
-		if (!ret)
+		if (!ret) {
+
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+			if (MSR_TM_ACTIVE(target->thread.regs->msr))
+				target->thread.transact_vrsave = vrsave.word;
+			else
+				target->thread.vrsave = vrsave.word;
+#else
 			target->thread.vrsave = vrsave.word;
+#endif
+		}
 	}
 
 	return ret;