linux-kernel - Re: [RFC/RFT PATCH 0/6] Switch GHES ioremap_page

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Date:   Thu, 2 Nov 2017 10:19:33 +0000
From:   Will Deacon <will.deacon@....com>
To:     James Morse <james.morse@....com>
Cc:     linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, x86@...nel.org,
        Catalin Marinas <catalin.marinas@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>, Borislav Petkov <bp@...e.de>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>, Tony Luck <tony.luck@...el.com>,
        Tyler Baicar <tbaicar@...eaurora.org>,
        Dongjiu Geng <gengdongjiu@...wei.com>,
        Xie XiuQi <xiexiuqi@...wei.com>, torvalds@...ux-foundation.org
Subject: Re: [RFC/RFT PATCH 0/6] Switch GHES ioremap_page_range() to use
 fixmap

On Tue, Oct 31, 2017 at 03:38:26PM +0000, James Morse wrote:
> GHES is doing ioremap_page_range() in both NMI and irq context, neither
> are safe as it may sleep to allocate intermediate levels of page table.
> 
> Replace the NMI/irq GHES_IOREMAP_PAGES to use a fixmap entry each.
> 
> After this nothing uses ghes_ioremap_area or arch_apei_flush_tlb_one(),
> rip them out.
> 
> RFC as I've only build-tested this on x86. For arm64 I've tested it on a
> software model. Any more testing would be welcome. These patches are based
> on rc7.
> 
> Thanks,
> 
> James Morse (6):
>   arm64: fixmap: Add GHES fixmap entries
>   x86/mm/fixmap: Add GHES fixmap entries
>   ACPI / APEI:  Replace ioremap_page_range() with fixmap
>   ACPI / APEI: Remove ghes_ioremap_area
>   arm64: mm: Remove arch_apei_flush_tlb_one()
>   ACPI / APEI: Remove arch_apei_flush_tlb_one()
> 
>  arch/arm64/include/asm/acpi.h   | 12 ------
>  arch/arm64/include/asm/fixmap.h |  5 +++
>  arch/arm64/mm/mmu.c             |  4 ++

If you need it:

Acked-by: Will Deacon <will.deacon@....com>

for the arm64 bits.

Will