1 files changed, 190 insertions, 35 deletions

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index a0c74bbf3454..bfdd783e3916 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -77,6 +77,13 @@
 extern unsigned long _get_SP(void);
 
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+/*
+ * Are we running in "Suspend disabled" mode? If so we have to block any
+ * sigreturn that would get us into suspended state, and we also warn in some
+ * other paths that we should never reach with suspend disabled.
+ */
+bool tm_suspend_disabled __ro_after_init = false;
+
 static void check_if_tm_restore_required(struct task_struct *tsk)
 {
 	/*
@@ -97,9 +104,23 @@ static inline bool msr_tm_active(unsigned long msr)
 {
 	return MSR_TM_ACTIVE(msr);
 }
+
+static bool tm_active_with_fp(struct task_struct *tsk)
+{
+	return msr_tm_active(tsk->thread.regs->msr) &&
+		(tsk->thread.ckpt_regs.msr & MSR_FP);
+}
+
+static bool tm_active_with_altivec(struct task_struct *tsk)
+{
+	return msr_tm_active(tsk->thread.regs->msr) &&
+		(tsk->thread.ckpt_regs.msr & MSR_VEC);
+}
 #else
 static inline bool msr_tm_active(unsigned long msr) { return false; }
 static inline void check_if_tm_restore_required(struct task_struct *tsk) { }
+static inline bool tm_active_with_fp(struct task_struct *tsk) { return false; }
+static inline bool tm_active_with_altivec(struct task_struct *tsk) { return false; }
 #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
 
 bool strict_msr_control;
@@ -232,7 +253,7 @@ EXPORT_SYMBOL(enable_kernel_fp);
 
 static int restore_fp(struct task_struct *tsk)
 {
-	if (tsk->thread.load_fp || msr_tm_active(tsk->thread.regs->msr)) {
+	if (tsk->thread.load_fp || tm_active_with_fp(tsk)) {
 		load_fp_state(&current->thread.fp_state);
 		current->thread.load_fp++;
 		return 1;
@@ -314,7 +335,7 @@ EXPORT_SYMBOL_GPL(flush_altivec_to_thread);
 static int restore_altivec(struct task_struct *tsk)
 {
 	if (cpu_has_feature(CPU_FTR_ALTIVEC) &&
-		(tsk->thread.load_vec || msr_tm_active(tsk->thread.regs->msr))) {
+		(tsk->thread.load_vec || tm_active_with_altivec(tsk))) {
 		load_vr_state(&tsk->thread.vr_state);
 		tsk->thread.used_vr = 1;
 		tsk->thread.load_vec++;
@@ -853,6 +874,10 @@ static void tm_reclaim_thread(struct thread_struct *thr,
 	if (!MSR_TM_SUSPENDED(mfmsr()))
 		return;
 
+	giveup_all(container_of(thr, struct task_struct, thread));
+
+	tm_reclaim(thr, cause);
+
 	/*
 	 * If we are in a transaction and FP is off then we can't have
 	 * used FP inside that transaction. Hence the checkpointed
@@ -871,10 +896,6 @@ static void tm_reclaim_thread(struct thread_struct *thr,
 	if ((thr->ckpt_regs.msr & MSR_VEC) == 0)
 		memcpy(&thr->ckvr_state, &thr->vr_state,
 		       sizeof(struct thread_vr_state));
-
-	giveup_all(container_of(thr, struct task_struct, thread));
-
-	tm_reclaim(thr, thr->ckpt_regs.msr, cause);
 }
 
 void tm_reclaim_current(uint8_t cause)
@@ -903,6 +924,8 @@ static inline void tm_reclaim_task(struct task_struct *tsk)
 	if (!MSR_TM_ACTIVE(thr->regs->msr))
 		goto out_and_saveregs;
 
+	WARN_ON(tm_suspend_disabled);
+
 	TM_DEBUG("--- tm_reclaim on pid %d (NIP=%lx, "
 		 "ccr=%lx, msr=%lx, trap=%lx)\n",
 		 tsk->pid, thr->regs->nip,
@@ -923,11 +946,9 @@ out_and_saveregs:
 	tm_save_sprs(thr);
 }
 
-extern void __tm_recheckpoint(struct thread_struct *thread,
-			      unsigned long orig_msr);
+extern void __tm_recheckpoint(struct thread_struct *thread);
 
-void tm_recheckpoint(struct thread_struct *thread,
-		     unsigned long orig_msr)
+void tm_recheckpoint(struct thread_struct *thread)
 {
 	unsigned long flags;
 
@@ -946,15 +967,13 @@ void tm_recheckpoint(struct thread_struct *thread,
 	 */
 	tm_restore_sprs(thread);
 
-	__tm_recheckpoint(thread, orig_msr);
+	__tm_recheckpoint(thread);
 
 	local_irq_restore(flags);
 }
 
 static inline void tm_recheckpoint_new_task(struct task_struct *new)
 {
-	unsigned long msr;
-
 	if (!cpu_has_feature(CPU_FTR_TM))
 		return;
 
@@ -973,13 +992,11 @@ static inline void tm_recheckpoint_new_task(struct task_struct *new)
 		tm_restore_sprs(&new->thread);
 		return;
 	}
-	msr = new->thread.ckpt_regs.msr;
 	/* Recheckpoint to restore original checkpointed register state. */
-	TM_DEBUG("*** tm_recheckpoint of pid %d "
-		 "(new->msr 0x%lx, new->origmsr 0x%lx)\n",
-		 new->pid, new->thread.regs->msr, msr);
+	TM_DEBUG("*** tm_recheckpoint of pid %d (new->msr 0x%lx)\n",
+		 new->pid, new->thread.regs->msr);
 
-	tm_recheckpoint(&new->thread, msr);
+	tm_recheckpoint(&new->thread);
 
 	/*
 	 * The checkpointed state has been restored but the live state has
@@ -1119,6 +1136,10 @@ static inline void restore_sprs(struct thread_struct *old_thread,
 		if (old_thread->tar != new_thread->tar)
 			mtspr(SPRN_TAR, new_thread->tar);
 	}
+
+	if (cpu_has_feature(CPU_FTR_ARCH_300) &&
+	    old_thread->tidr != new_thread->tidr)
+		mtspr(SPRN_TIDR, new_thread->tidr);
 #endif
 }
 
@@ -1155,7 +1176,7 @@ struct task_struct *__switch_to(struct task_struct *prev,
 	}
 #endif /* CONFIG_PPC64 */
 
-#ifdef CONFIG_PPC_STD_MMU_64
+#ifdef CONFIG_PPC_BOOK3S_64
 	batch = this_cpu_ptr(&ppc64_tlb_batch);
 	if (batch->active) {
 		current_thread_info()->local_flags |= _TLF_LAZY_MMU;
@@ -1163,7 +1184,7 @@ struct task_struct *__switch_to(struct task_struct *prev,
 			__flush_tlb_pending(batch);
 		batch->active = 0;
 	}
-#endif /* CONFIG_PPC_STD_MMU_64 */
+#endif /* CONFIG_PPC_BOOK3S_64 */
 
 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 	switch_booke_debug_regs(&new->thread.debug);
@@ -1209,7 +1230,7 @@ struct task_struct *__switch_to(struct task_struct *prev,
 
 	last = _switch(old_thread, new_thread);
 
-#ifdef CONFIG_PPC_STD_MMU_64
+#ifdef CONFIG_PPC_BOOK3S_64
 	if (current_thread_info()->local_flags & _TLF_LAZY_MMU) {
 		current_thread_info()->local_flags &= ~_TLF_LAZY_MMU;
 		batch = this_cpu_ptr(&ppc64_tlb_batch);
@@ -1223,22 +1244,22 @@ struct task_struct *__switch_to(struct task_struct *prev,
 		 * The copy-paste buffer can only store into foreign real
 		 * addresses, so unprivileged processes can not see the
 		 * data or use it in any way unless they have foreign real
-		 * mappings. We don't have a VAS driver that allocates those
-		 * yet, so no cpabort is required.
+		 * mappings. If the new process has the foreign real address
+		 * mappings, we must issue a cp_abort to clear any state and
+		 * prevent snooping, corruption or a covert channel.
+		 *
+		 * DD1 allows paste into normal system memory so we do an
+		 * unpaired copy, rather than cp_abort, to clear the buffer,
+		 * since cp_abort is quite expensive.
 		 */
-		if (cpu_has_feature(CPU_FTR_POWER9_DD1)) {
-			/*
-			 * DD1 allows paste into normal system memory, so we
-			 * do an unpaired copy here to clear the buffer and
-			 * prevent a covert channel being set up.
-			 *
-			 * cpabort is not used because it is quite expensive.
-			 */
+		if (current_thread_info()->task->thread.used_vas) {
+			asm volatile(PPC_CP_ABORT);
+		} else if (cpu_has_feature(CPU_FTR_POWER9_DD1)) {
 			asm volatile(PPC_COPY(%0, %1)
 					: : "r"(dummy_copy_buffer), "r"(0));
 		}
 	}
-#endif /* CONFIG_PPC_STD_MMU_64 */
+#endif /* CONFIG_PPC_BOOK3S_64 */
 
 	return last;
 }
@@ -1434,6 +1455,137 @@ void flush_thread(void)
 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 }
 
+int set_thread_uses_vas(void)
+{
+#ifdef CONFIG_PPC_BOOK3S_64
+	if (!cpu_has_feature(CPU_FTR_ARCH_300))
+		return -EINVAL;
+
+	current->thread.used_vas = 1;
+
+	/*
+	 * Even a process that has no foreign real address mapping can use
+	 * an unpaired COPY instruction (to no real effect). Issue CP_ABORT
+	 * to clear any pending COPY and prevent a covert channel.
+	 *
+	 * __switch_to() will issue CP_ABORT on future context switches.
+	 */
+	asm volatile(PPC_CP_ABORT);
+
+#endif /* CONFIG_PPC_BOOK3S_64 */
+	return 0;
+}
+
+#ifdef CONFIG_PPC64
+static DEFINE_SPINLOCK(vas_thread_id_lock);
+static DEFINE_IDA(vas_thread_ida);
+
+/*
+ * We need to assign a unique thread id to each thread in a process.
+ *
+ * This thread id, referred to as TIDR, and separate from the Linux's tgid,
+ * is intended to be used to direct an ASB_Notify from the hardware to the
+ * thread, when a suitable event occurs in the system.
+ *
+ * One such event is a "paste" instruction in the context of Fast Thread
+ * Wakeup (aka Core-to-core wake up in the Virtual Accelerator Switchboard
+ * (VAS) in POWER9.
+ *
+ * To get a unique TIDR per process we could simply reuse task_pid_nr() but
+ * the problem is that task_pid_nr() is not yet available copy_thread() is
+ * called. Fixing that would require changing more intrusive arch-neutral
+ * code in code path in copy_process()?.
+ *
+ * Further, to assign unique TIDRs within each process, we need an atomic
+ * field (or an IDR) in task_struct, which again intrudes into the arch-
+ * neutral code. So try to assign globally unique TIDRs for now.
+ *
+ * NOTE: TIDR 0 indicates that the thread does not need a TIDR value.
+ *	 For now, only threads that expect to be notified by the VAS
+ *	 hardware need a TIDR value and we assign values > 0 for those.
+ */
+#define MAX_THREAD_CONTEXT	((1 << 16) - 1)
+static int assign_thread_tidr(void)
+{
+	int index;
+	int err;
+
+again:
+	if (!ida_pre_get(&vas_thread_ida, GFP_KERNEL))
+		return -ENOMEM;
+
+	spin_lock(&vas_thread_id_lock);
+	err = ida_get_new_above(&vas_thread_ida, 1, &index);
+	spin_unlock(&vas_thread_id_lock);
+
+	if (err == -EAGAIN)
+		goto again;
+	else if (err)
+		return err;
+
+	if (index > MAX_THREAD_CONTEXT) {
+		spin_lock(&vas_thread_id_lock);
+		ida_remove(&vas_thread_ida, index);
+		spin_unlock(&vas_thread_id_lock);
+		return -ENOMEM;
+	}
+
+	return index;
+}
+
+static void free_thread_tidr(int id)
+{
+	spin_lock(&vas_thread_id_lock);
+	ida_remove(&vas_thread_ida, id);
+	spin_unlock(&vas_thread_id_lock);
+}
+
+/*
+ * Clear any TIDR value assigned to this thread.
+ */
+void clear_thread_tidr(struct task_struct *t)
+{
+	if (!t->thread.tidr)
+		return;
+
+	if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
+		WARN_ON_ONCE(1);
+		return;
+	}
+
+	mtspr(SPRN_TIDR, 0);
+	free_thread_tidr(t->thread.tidr);
+	t->thread.tidr = 0;
+}
+
+void arch_release_task_struct(struct task_struct *t)
+{
+	clear_thread_tidr(t);
+}
+
+/*
+ * Assign a unique TIDR (thread id) for task @t and set it in the thread
+ * structure. For now, we only support setting TIDR for 'current' task.
+ */
+int set_thread_tidr(struct task_struct *t)
+{
+	if (!cpu_has_feature(CPU_FTR_ARCH_300))
+		return -EINVAL;
+
+	if (t != current)
+		return -EINVAL;
+
+	t->thread.tidr = assign_thread_tidr();
+	if (t->thread.tidr < 0)
+		return t->thread.tidr;
+
+	mtspr(SPRN_TIDR, t->thread.tidr);
+
+	return 0;
+}
+
+#endif /* CONFIG_PPC64 */
+
 void
 release_thread(struct task_struct *t)
 {
@@ -1467,7 +1619,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 
 static void setup_ksp_vsid(struct task_struct *p, unsigned long sp)
 {
-#ifdef CONFIG_PPC_STD_MMU_64
+#ifdef CONFIG_PPC_BOOK3S_64
 	unsigned long sp_vsid;
 	unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
 
@@ -1580,6 +1732,8 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 	}
 	if (cpu_has_feature(CPU_FTR_HAS_PPR))
 		p->thread.ppr = INIT_PPR;
+
+	p->thread.tidr = 0;
 #endif
 	kregs->nip = ppc_function_entry(f);
 	return 0;
@@ -1898,7 +2052,8 @@ unsigned long get_wchan(struct task_struct *p)
 
 	do {
 		sp = *(unsigned long *)sp;
-		if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
+		if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD) ||
+		    p->state == TASK_RUNNING)
 			return 0;
 		if (count > 0) {
 			ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE];
@@ -2046,7 +2201,7 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
 	unsigned long base = mm->brk;
 	unsigned long ret;
 
-#ifdef CONFIG_PPC_STD_MMU_64
+#ifdef CONFIG_PPC_BOOK3S_64
 	/*
 	 * If we are using 1TB segments and we are allowed to randomise
 	 * the heap, we can put it above 1TB so it is backed by a 1TB