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From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H . Peter Anvin" <hpa@zytor.com>,
	linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org,
	Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
	Dave Young <dyoung@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Borislav Petkov <bp@alien8.de>
Subject: Re: [PATCH] x86/efi: Setup separate EFI page tables in kexec paths
Date: Fri, 22 Jan 2016 01:03:32 +0530	[thread overview]
Message-ID: <20160121193332.GA17206@linux.vnet.ibm.com> (raw)
In-Reply-To: <1453385519-11477-1-git-send-email-matt@codeblueprint.co.uk>

* Matt Fleming <matt@codeblueprint.co.uk> [2016-01-21 14:11:59]:

> The switch to using a new dedicated page table for EFI runtime calls
> in commit commit 67a9108ed431 ("x86/efi: Build our own page table
> structures") failed to take into account changes required for the
> kexec code paths, which are unfortunately duplicated in the EFI code.
> 
> Call the allocation and setup functions in kexec_enter_virtual_mode()
> just like we do for __efi_enter_virtual_mode() to avoid hitting
> NULL-pointer dereferences when making EFI runtime calls.
> 
> At the very least, the call to efi_setup_page_tables() should have
> existed for kexec before commit 67a9108ed431. Things just magically
> worked because we were actually using the kernel's page tables that
> contained the required mappings.
> 
> Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
> Cc: Dave Young <dyoung@redhat.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Borislav Petkov <bp@alien8.de>
> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>

Applied this patch on top of tip/x86/efi and was able to build and boot
the kernel.

-- 
Thanks and Regards
Srikar Dronamraju

  reply	other threads:[~2016-01-21 19:34 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-21 14:11 [PATCH] x86/efi: Setup separate EFI page tables in kexec paths Matt Fleming
2016-01-21 19:33 ` Srikar Dronamraju [this message]
2016-01-21 20:58   ` Matt Fleming
2016-01-25  9:42     ` Matt Fleming
2016-01-22 12:54 ` [tip:efi/core] " tip-bot for Matt Fleming

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