[PATCH v16 01/21] powerpc/irq: use memblock functions returning virtual address

[Nicholas Piggin]

Michael Ellerman's on February 5, 2019 9:31 pm:
> From: Christophe Leroy <christophe.leroy at c-s.fr>
> 
> 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 <rppt at linux.ibm.com>
> Acked-by: Mike Rapoport <rppt at linux.ibm.com>
> Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>
> Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
> ---
>  arch/powerpc/kernel/irq.c      |  5 -----
>  arch/powerpc/kernel/setup_32.c | 26 ++++++++++++++++----------
>  arch/powerpc/kernel/setup_64.c | 19 +++++++------------
>  3 files changed, 23 insertions(+), 27 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
> index bb299613a462..4a5dd8800946 100644
> --- a/arch/powerpc/kernel/irq.c
> +++ b/arch/powerpc/kernel/irq.c
> @@ -725,18 +725,15 @@ void exc_lvl_ctx_init(void)
>  #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;
> @@ -754,12 +751,10 @@ void irq_ctx_init(void)
>  	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);
> diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
> index 947f904688b0..1f0b7629c1a6 100644
> --- a/arch/powerpc/kernel/setup_32.c
> +++ b/arch/powerpc/kernel/setup_32.c
> @@ -196,6 +196,17 @@ static int __init ppc_init(void)
>  }
>  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;
> @@ -203,10 +214,8 @@ void __init irqstack_early_init(void)
>  	/* 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();
>  	}
>  }
>  
> @@ -224,13 +233,10 @@ void __init exc_lvl_early_init(void)
>  		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
>  	}
>  }
> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index 236c1151a3a7..080dd515d587 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -634,19 +634,17 @@ __init u64 ppc64_bolted_size(void)
>  
>  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));

This is much nicer. Looks like removing MEMBLOCK_LOW_LIMIT would be a 
cleanup for generic kernel code. Actually some of these calls are used
only by powerpc (memblock_alloc_base_nid) which probably could get
tidied up. Something for a rainy day or a beginner.

Reviewed-by: Nicholas Piggin <npiggin at gmail.com>