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From: Tony Lindgren <tony@atomide.com>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org, linux-efi@vger.kernel.org,
	Russell King <linux@armlinux.org.uk>,
	Marc Zyngier <maz@kernel.org>, Nicolas Pitre <nico@fluxnic.net>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Linus Walleij <linus.walleij@linaro.org>
Subject: Re: [PATCH v4 0/5] ARM: decompressor: use by-VA cache maintenance for v7 cores
Date: Wed, 26 Feb 2020 11:14:56 -0800	[thread overview]
Message-ID: <20200226191456.GZ37466@atomide.com> (raw)
In-Reply-To: <20200226165738.11201-1-ardb@kernel.org>

* Ard Biesheuvel <ardb@kernel.org> [200226 16:58]:
> While making changes to the EFI stub startup code, I noticed that we are
> still doing set/way maintenance on the caches when booting on v7 cores.
> This works today on VMs by virtue of the fact that KVM traps set/way ops
> and cleans the whole address space by VA on behalf of the guest, and on
> most v7 hardware, the set/way ops are in fact sufficient when only one
> core is running, as there usually is no system cache. But on systems
> like SynQuacer, for which 32-bit firmware is available, the current cache
> maintenance only pushes the data out to the L3 system cache, where it
> is not visible to the CPU once it turns the MMU and caches off.
> 
> So instead, switch to the by-VA cache maintenance that the architecture
> requires for v7 and later (and ARM1176, as a side effect).
> 
> Changes since v3:
> - ensure that the region that is cleaned after self-relocation of the zImage
>   covers the appended DTB, if present

I gave these a try on top of the earlier "arm: fix Kbuild issue caused
by per-task stack protector GCC plugin" and booting still works for
me on armv7 including appended dtb:

Tested-by: Tony Lindgren <tony@atomide.com>

WARNING: multiple messages have this Message-ID (diff)
From: Tony Lindgren <tony@atomide.com>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-efi@vger.kernel.org, Nicolas Pitre <nico@fluxnic.net>,
	Marc Zyngier <maz@kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Russell King <linux@armlinux.org.uk>,
	Catalin Marinas <catalin.marinas@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v4 0/5] ARM: decompressor: use by-VA cache maintenance for v7 cores
Date: Wed, 26 Feb 2020 11:14:56 -0800	[thread overview]
Message-ID: <20200226191456.GZ37466@atomide.com> (raw)
In-Reply-To: <20200226165738.11201-1-ardb@kernel.org>

* Ard Biesheuvel <ardb@kernel.org> [200226 16:58]:
> While making changes to the EFI stub startup code, I noticed that we are
> still doing set/way maintenance on the caches when booting on v7 cores.
> This works today on VMs by virtue of the fact that KVM traps set/way ops
> and cleans the whole address space by VA on behalf of the guest, and on
> most v7 hardware, the set/way ops are in fact sufficient when only one
> core is running, as there usually is no system cache. But on systems
> like SynQuacer, for which 32-bit firmware is available, the current cache
> maintenance only pushes the data out to the L3 system cache, where it
> is not visible to the CPU once it turns the MMU and caches off.
> 
> So instead, switch to the by-VA cache maintenance that the architecture
> requires for v7 and later (and ARM1176, as a side effect).
> 
> Changes since v3:
> - ensure that the region that is cleaned after self-relocation of the zImage
>   covers the appended DTB, if present

I gave these a try on top of the earlier "arm: fix Kbuild issue caused
by per-task stack protector GCC plugin" and booting still works for
me on armv7 including appended dtb:

Tested-by: Tony Lindgren <tony@atomide.com>

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  parent reply	other threads:[~2020-02-26 19:15 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-26 16:57 [PATCH v4 0/5] ARM: decompressor: use by-VA cache maintenance for v7 cores Ard Biesheuvel
2020-02-26 16:57 ` Ard Biesheuvel
2020-02-26 16:57 ` [PATCH v4 1/5] efi/arm: Work around missing cache maintenance in decompressor handover Ard Biesheuvel
2020-02-26 16:57   ` Ard Biesheuvel
2020-02-26 16:57 ` [PATCH v4 2/5] efi/arm: Pass start and end addresses to cache_clean_flush() Ard Biesheuvel
2020-02-26 16:57   ` Ard Biesheuvel
2020-02-26 16:57 ` [PATCH v4 3/5] ARM: decompressor: factor out routine to obtain the inflated image size Ard Biesheuvel
2020-02-26 16:57   ` Ard Biesheuvel
2020-02-26 16:57 ` [PATCH v4 4/5] ARM: decompressor: prepare cache_clean_flush for doing by-VA maintenance Ard Biesheuvel
2020-02-26 16:57   ` Ard Biesheuvel
2020-02-26 16:57 ` [PATCH v4 5/5] ARM: decompressor: switch to by-VA cache maintenance for v7 cores Ard Biesheuvel
2020-02-26 16:57   ` Ard Biesheuvel
2020-02-26 19:14 ` Tony Lindgren [this message]
2020-02-26 19:14   ` [PATCH v4 0/5] ARM: decompressor: use " Tony Lindgren
2020-02-27 10:11 ` Linus Walleij
2020-02-27 10:11   ` Linus Walleij
2020-02-27 16:01   ` Marc Zyngier
2020-02-27 16:01     ` Marc Zyngier
2020-02-27 16:47     ` Ard Biesheuvel
2020-02-27 16:47       ` Ard Biesheuvel
2020-02-27 16:53       ` Marc Zyngier
2020-02-27 16:53         ` Marc Zyngier

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