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From: Paul Mackerras <paulus@ozlabs.org>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: benh@kernel.crashing.org, mpe@ellerman.id.au,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH V5 2/4] powerpc/mm: Add support for handling > 512TB address in SLB miss
Date: Wed, 21 Mar 2018 15:11:11 +1100	[thread overview]
Message-ID: <20180321041111.GA30287@fergus.ozlabs.ibm.com> (raw)
In-Reply-To: <20180318110558.30493-3-aneesh.kumar@linux.vnet.ibm.com>

On Sun, Mar 18, 2018 at 04:35:56PM +0530, Aneesh Kumar K.V wrote:

[snip]
> +static inline int get_ea_context(mm_context_t *ctx, unsigned long ea)
> +{
> +	int index = ea >> MAX_EA_BITS_PER_CONTEXT;
> +
> +	if (likely(index < ARRAY_SIZE(ctx->extended_id)))
> +		return ctx->extended_id[index];
> +	/* should never happen */
> +	BUG();

Are you absolutely sure that we can never get here with an address
greater than 4PB no matter what userspace does?

I would much prefer that we just return 0 here.  I can't see that the
kernel is in a position where it really cannot continue execution at
this point, so BUG is not appropriate.

Paul.

  reply	other threads:[~2018-03-21 10:25 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-18 11:05 [PATCH V5 0/4] Add support for 4PB virtual address space on hash Aneesh Kumar K.V
2018-03-18 11:05 ` [PATCH V5 1/4] powerpc/mm/slice: Consolidate the return path for the function Aneesh Kumar K.V
2018-03-18 11:05 ` [PATCH V5 2/4] powerpc/mm: Add support for handling > 512TB address in SLB miss Aneesh Kumar K.V
2018-03-21  4:11   ` Paul Mackerras [this message]
2018-03-18 11:05 ` [PATCH V5 3/4] powerpc/mm/hash64: Increase the VA range Aneesh Kumar K.V
2018-03-22 13:00   ` Michael Ellerman
2018-03-18 11:05 ` [PATCH V5 4/4] powerpc/mm/hash: Don't memset pgd table if not needed Aneesh Kumar K.V
2018-03-22 11:54   ` Michael Ellerman

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