linux-kernel - Re: [PATCH] efi/arm: fix allocation failure when reserving the kernel base

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Date:   Tue, 20 Aug 2019 12:56:46 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Chester Lin <clin@...e.com>
Cc:     "ard.biesheuvel@...aro.org" <ard.biesheuvel@...aro.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "rppt@...ux.ibm.com" <rppt@...ux.ibm.com>,
        "ren_guo@...ky.com" <ren_guo@...ky.com>,
        Juergen Gross <JGross@...e.com>,
        "geert@...ux-m68k.org" <geert@...ux-m68k.org>,
        "mingo@...nel.org" <mingo@...nel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
        "guillaume.gardet@....com" <guillaume.gardet@....com>,
        Joey Lee <JLee@...e.com>, Gary Lin <GLin@...e.com>
Subject: Re: [PATCH] efi/arm: fix allocation failure when reserving the
 kernel base

On Fri, Aug 02, 2019 at 05:38:54AM +0000, Chester Lin wrote:
> diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
> index f3ce34113f89..909b11ba48d8 100644
> --- a/arch/arm/mm/mmu.c
> +++ b/arch/arm/mm/mmu.c
> @@ -1184,6 +1184,9 @@ void __init adjust_lowmem_bounds(void)
>  		phys_addr_t block_start = reg->base;
>  		phys_addr_t block_end = reg->base + reg->size;
>  
> +		if (memblock_is_nomap(reg))
> +			continue;
> +
>  		if (reg->base < vmalloc_limit) {
>  			if (block_end > lowmem_limit)
>  				/*

I think this hunk is sane - if the memory is marked nomap, then it isn't
available for the kernel's use, so as far as calculating where the
lowmem/highmem boundary is, it effectively doesn't exist and should be
skipped.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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