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From: Joerg Roedel <jroedel@suse.de>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/5] x86/head/64: Disable stack protection for head$(BITS).o
Date: Thu, 8 Oct 2020 10:42:19 +0200	[thread overview]
Message-ID: <20201008084219.GC3209@suse.de> (raw)
In-Reply-To: <20201007195351.776555-6-nivedita@alum.mit.edu>

On Wed, Oct 07, 2020 at 03:53:51PM -0400, Arvind Sankar wrote:
> On 64-bit, the startup_64_setup_env() function added in
>   866b556efa12 ("x86/head/64: Install startup GDT")
> has stack protection enabled because of set_bringup_idt_handler().
> 
> At this point, %gs is not yet initialized, and this doesn't cause a
> crash only because the #PF handler from the decompressor stub is still
> installed and handles the page fault.

Hmm, that is weird. Can you please share your config with which this
happens? I have a commit in my local branch which disables page-faulting
in the pre-decompression code before jumping to the uncompressed kernel
image, and it did not break anything here.

Also, what compiler did you use to trigger this?


  reply	other threads:[~2020-10-08  8:42 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-07 19:53 [PATCH 0/5] Couple of bugfixes to sev-es series Arvind Sankar
2020-10-07 19:53 ` [PATCH 1/5] x86/boot: Initialize boot_params in startup code Arvind Sankar
2020-10-08  9:04   ` Joerg Roedel
2020-10-08 13:44     ` Arvind Sankar
2020-10-07 19:53 ` [PATCH 2/5] x86/boot: Move get_cmd_line_ptr() and COMMAND_LINE_SIZE into misc.h Arvind Sankar
2020-10-08  9:11   ` Joerg Roedel
2020-10-08  9:30   ` Borislav Petkov
2020-10-08 13:47     ` Arvind Sankar
2020-10-08 15:10       ` Borislav Petkov
2020-10-08 15:30         ` Arvind Sankar
2020-10-08 16:16           ` Borislav Petkov
2020-10-07 19:53 ` [PATCH 3/5] x86/boot/64: Change add_identity_map() to take size for ease of use Arvind Sankar
2020-10-08  9:14   ` Joerg Roedel
2020-10-08 13:49     ` Arvind Sankar
2020-10-07 19:53 ` [PATCH 4/5] x86/boot/64: Explicitly map boot_params and command line Arvind Sankar
2020-10-08  9:17   ` Joerg Roedel
2020-10-08  9:48   ` Joerg Roedel
2020-10-08 13:57     ` Arvind Sankar
2020-10-07 19:53 ` [PATCH 5/5] x86/head/64: Disable stack protection for head$(BITS).o Arvind Sankar
2020-10-08  8:42   ` Joerg Roedel [this message]
2020-10-08 14:52     ` Arvind Sankar

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