powerpc/irq: use memblock functions returning virtual address

Since only the virtual address of allocated blocks is used,
lets use functions returning directly virtual address.

Those functions have the advantage of also zeroing the block.

Suggested-by: Mike Rapoport <[e-mail]>
Signed-off-by: Christophe Leroy <[e-mail]>
Acked-by: Mike Rapoport <[e-mail]>
Reviewed-by: Nicholas Piggin <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>

arch/powerpc/kernel/irq.c

···
 #endif
 #endif
 
-		memset((void *)critirq_ctx[cpu_nr], 0, THREAD_SIZE);
 		tp = critirq_ctx[cpu_nr];
 		tp->cpu = cpu_nr;
 		tp->preempt_count = 0;
 
 #ifdef CONFIG_BOOKE
-		memset((void *)dbgirq_ctx[cpu_nr], 0, THREAD_SIZE);
 		tp = dbgirq_ctx[cpu_nr];
 		tp->cpu = cpu_nr;
 		tp->preempt_count = 0;
 
-		memset((void *)mcheckirq_ctx[cpu_nr], 0, THREAD_SIZE);
 		tp = mcheckirq_ctx[cpu_nr];
 		tp->cpu = cpu_nr;
 		tp->preempt_count = HARDIRQ_OFFSET;
···
 	int i;
 
 	for_each_possible_cpu(i) {
-		memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
 		tp = softirq_ctx[i];
 		tp->cpu = i;
 		klp_init_thread_info(tp);
 
-		memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
 		tp = hardirq_ctx[i];
 		tp->cpu = i;
 		klp_init_thread_info(tp);

arch/powerpc/kernel/setup_32.c

···
 }
 arch_initcall(ppc_init);
 
+static void *__init alloc_stack(void)
+{
+	void *ptr = memblock_alloc(THREAD_SIZE, THREAD_SIZE);
+
+	if (!ptr)
+		panic("cannot allocate %d bytes for stack at %pS\n",
+		      THREAD_SIZE, (void *)_RET_IP_);
+
+	return ptr;
+}
+
 void __init irqstack_early_init(void)
 {
 	unsigned int i;
···
 	/* interrupt stacks must be in lowmem, we get that for free on ppc32
 	 * as the memblock is limited to lowmem by default */
 	for_each_possible_cpu(i) {
-		softirq_ctx[i] = (struct thread_info *)
-			__va(memblock_phys_alloc(THREAD_SIZE, THREAD_SIZE));
-		hardirq_ctx[i] = (struct thread_info *)
-			__va(memblock_phys_alloc(THREAD_SIZE, THREAD_SIZE));
+		softirq_ctx[i] = alloc_stack();
+		hardirq_ctx[i] = alloc_stack();
 	}
 }
 
···
 		hw_cpu = 0;
 #endif
 
-		critirq_ctx[hw_cpu] = (struct thread_info *)
-			__va(memblock_phys_alloc(THREAD_SIZE, THREAD_SIZE));
+		critirq_ctx[hw_cpu] = alloc_stack();
 #ifdef CONFIG_BOOKE
-		dbgirq_ctx[hw_cpu] = (struct thread_info *)
-			__va(memblock_phys_alloc(THREAD_SIZE, THREAD_SIZE));
-		mcheckirq_ctx[hw_cpu] = (struct thread_info *)
-			__va(memblock_phys_alloc(THREAD_SIZE, THREAD_SIZE));
+		dbgirq_ctx[hw_cpu] = alloc_stack();
+		mcheckirq_ctx[hw_cpu] = alloc_stack();
 #endif
 	}
 }

arch/powerpc/kernel/setup_64.c

···
 
 static void *__init alloc_stack(unsigned long limit, int cpu)
 {
-	unsigned long pa;
+	void *ptr;
 
 	BUILD_BUG_ON(STACK_INT_FRAME_SIZE % 16);
 
-	pa = memblock_alloc_base_nid(THREAD_SIZE, THREAD_SIZE, limit,
-					early_cpu_to_node(cpu), MEMBLOCK_NONE);
-	if (!pa) {
-		pa = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
-		if (!pa)
-			panic("cannot allocate stacks");
-	}
+	ptr = memblock_alloc_try_nid(THREAD_SIZE, THREAD_SIZE,
+				     MEMBLOCK_LOW_LIMIT, limit,
+				     early_cpu_to_node(cpu));
+	if (!ptr)
+		panic("cannot allocate stacks");
 
-	return __va(pa);
+	return ptr;
 }
 
 void __init irqstack_early_init(void)
···
 		struct thread_info *ti;
 
 		ti = alloc_stack(limit, i);
-		memset(ti, 0, THREAD_SIZE);
 		emerg_stack_init_thread_info(ti, i);
 		paca_ptrs[i]->emergency_sp = (void *)ti + THREAD_SIZE;
 
 #ifdef CONFIG_PPC_BOOK3S_64
 		/* emergency stack for NMI exception handling. */
 		ti = alloc_stack(limit, i);
-		memset(ti, 0, THREAD_SIZE);
 		emerg_stack_init_thread_info(ti, i);
 		paca_ptrs[i]->nmi_emergency_sp = (void *)ti + THREAD_SIZE;
 
 		/* emergency stack for machine check exception handling. */
 		ti = alloc_stack(limit, i);
-		memset(ti, 0, THREAD_SIZE);
 		emerg_stack_init_thread_info(ti, i);
 		paca_ptrs[i]->mc_emergency_sp = (void *)ti + THREAD_SIZE;
 #endif