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Date:   Tue, 8 Jan 2019 16:34:29 +0200
From:   Mike Rapoport <rppt@linux.ibm.com>
To:     Christophe Leroy <christophe.leroy@c-s.fr>
Cc:     Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Nicholas Piggin <npiggin@gmail.com>,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v12 01/10] powerpc/irq: use memblock functions returning
 virtual address
References: <cover.1546954233.git.christophe.leroy@c-s.fr>
 <ec01a9be000c2305eec61bb1e2c44df2f917c1a6.1546954236.git.christophe.leroy@c-s.fr>
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In-Reply-To: <ec01a9be000c2305eec61bb1e2c44df2f917c1a6.1546954236.git.christophe.leroy@c-s.fr>
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Hi,

On Tue, Jan 08, 2019 at 01:43:09PM +0000, Christophe Leroy wrote:
> 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@linux.ibm.com>
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
>  @Mike: Part of this is taken from your serie.

It seems you've found some places I've missed :)
Note that my series was merged to mmotm, so you may get a conflict with it.

>  I was not sure how to include you in the commit log, I used
>  Suggested-by: but could use any other property, so if you prefer
>  something different just tell me. Also, if you could review this patch,
>  it would be nice.

Suggested-by sounds reasonable.
 
>  arch/powerpc/kernel/irq.c      |  5 -----
>  arch/powerpc/kernel/setup_32.c | 15 +++++----------
>  arch/powerpc/kernel/setup_64.c | 16 ++--------------
>  3 files changed, 7 insertions(+), 29 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
> index 916ddc4aac44..4a44bc395fbc 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..bfe1b46a26dc 100644
> --- a/arch/powerpc/kernel/setup_32.c
> +++ b/arch/powerpc/kernel/setup_32.c
> @@ -203,10 +203,8 @@ 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] = memblock_alloc(THREAD_SIZE, THREAD_SIZE);
> +		hardirq_ctx[i] = memblock_alloc(THREAD_SIZE, THREAD_SIZE);
>  	}
>  }
>  
> @@ -224,13 +222,10 @@ 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] = memblock_alloc(THREAD_SIZE, THREAD_SIZE);
>  #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] = memblock_alloc(THREAD_SIZE, THREAD_SIZE);
> +		mcheckirq_ctx[hw_cpu] = memblock_alloc(THREAD_SIZE, THREAD_SIZE);
>  #endif
>  	}
>  }
> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index 236c1151a3a7..943503f1e2c0 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -634,19 +634,10 @@ __init u64 ppc64_bolted_size(void)
>  
>  static void *__init alloc_stack(unsigned long limit, int cpu)
>  {
> -	unsigned long pa;
> -
>  	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");
> -	}
> -
> -	return __va(pa);
> +	return memblock_alloc_try_nid(THREAD_SIZE, THREAD_SIZE, MEMBLOCK_LOW_LIMIT,
> +				      limit, early_cpu_to_node(cpu));

I'd prefer if you would keep the return value check and panic() here, as
I'm working on removing the panic() from memblock_alloc*().

Other than that, everything seems right, at least from the memblock
perspective. So, with panic retained feel free to add

Acked-by: Mike Rapoport <rppt@linux.ibm.com>

>  }
>  
>  void __init irqstack_early_init(void)
> @@ -739,20 +730,17 @@ void __init emergency_stack_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
> -- 
> 2.13.3
> 

-- 
Sincerely yours,
Mike.