From: Andrew Cooper <Andrew.Cooper3@citrix.com>
To: Evgeniy Baskov <baskov@ispras.ru>, Ard Biesheuvel <ardb@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Alexey Khoroshilov <khoroshilov@ispras.ru>,
"lvc-project@linuxtesting.org" <lvc-project@linuxtesting.org>,
"x86@kernel.org" <x86@kernel.org>,
"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-hardening@vger.kernel.org"
<linux-hardening@vger.kernel.org>,
Andrew Cooper <Andrew.Cooper3@citrix.com>
Subject: Re: [PATCH 03/16] x86/boot: Set cr0 to known state in trampoline
Date: Wed, 19 Oct 2022 07:44:32 +0000 [thread overview]
Message-ID: <7dce2b16-c652-8b6d-5594-d110c8ac4645@citrix.com> (raw)
In-Reply-To: <a155c20eec6343d34b3bdf40c024ce8b35a90e02.1662459668.git.baskov@ispras.ru>
On 06/09/2022 11:41, Evgeniy Baskov wrote:
> diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
> index d33f060900d2..5273367283b7 100644
> --- a/arch/x86/boot/compressed/head_64.S
> +++ b/arch/x86/boot/compressed/head_64.S
> @@ -619,9 +619,8 @@ SYM_CODE_START(trampoline_32bit_src)
> /* Set up new stack */
> leal TRAMPOLINE_32BIT_STACK_END(%ecx), %esp
>
> - /* Disable paging */
> - movl %cr0, %eax
> - btrl $X86_CR0_PG_BIT, %eax
> + /* Disable paging and setup CR0 */
> + movl $(CR0_STATE & ~X86_CR0_PG), %eax
Why here? WP is ignored when PG is disabled.
~Andrew
next prev parent reply other threads:[~2022-10-19 7:44 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-06 10:41 [PATCH 00/16] x86_64: Improvements at compressed kernel stage Evgeniy Baskov
2022-09-06 10:41 ` [PATCH 01/16] x86/boot: Align vmlinuz sections on page size Evgeniy Baskov
2022-10-19 7:01 ` Ard Biesheuvel
2022-10-20 11:13 ` Evgeniy Baskov
2022-09-06 10:41 ` [PATCH 02/16] x86/build: Remove RWX sections and align on 4KB Evgeniy Baskov
2022-10-19 7:04 ` Ard Biesheuvel
2022-10-20 11:15 ` Evgeniy Baskov
2022-09-06 10:41 ` [PATCH 03/16] x86/boot: Set cr0 to known state in trampoline Evgeniy Baskov
2022-10-19 7:06 ` Ard Biesheuvel
2022-10-20 11:23 ` Evgeniy Baskov
2022-10-19 7:44 ` Andrew Cooper [this message]
2022-10-20 13:25 ` Evgeniy Baskov
2022-09-06 10:41 ` [PATCH 04/16] x86/boot: Increase boot page table size Evgeniy Baskov
2022-10-19 7:08 ` Ard Biesheuvel
2022-10-20 11:29 ` Evgeniy Baskov
2022-09-06 10:41 ` [PATCH 05/16] x86/boot: Support 4KB pages for identity mapping Evgeniy Baskov
2022-10-19 7:11 ` Ard Biesheuvel
2022-10-20 11:30 ` Evgeniy Baskov
2022-09-06 10:41 ` [PATCH 06/16] x86/boot: Setup memory protection for bzImage code Evgeniy Baskov
2022-10-19 7:17 ` Ard Biesheuvel
2022-10-20 12:07 ` Evgeniy Baskov
2022-10-19 7:57 ` Andrew Cooper
2022-10-20 13:30 ` Evgeniy Baskov
2022-10-20 16:51 ` Andrew Cooper
2022-09-06 10:41 ` [PATCH 07/16] x86/boot: Map memory explicitly Evgeniy Baskov
2022-09-06 10:41 ` [PATCH 08/16] x86/boot: Remove mapping from page fault handler Evgeniy Baskov
2022-10-19 7:20 ` Ard Biesheuvel
2022-09-06 10:41 ` [PATCH 09/16] efi/libstub: Move helper function to related file Evgeniy Baskov
2022-10-19 7:21 ` Ard Biesheuvel
2022-09-06 10:41 ` [PATCH 10/16] x86/boot: Make console interface more abstract Evgeniy Baskov
2022-10-19 7:23 ` Ard Biesheuvel
2022-10-20 12:10 ` Evgeniy Baskov
2022-09-06 10:41 ` [PATCH 11/16] x86/boot: Split trampoline and pt init code Evgeniy Baskov
2022-09-06 10:41 ` [PATCH 12/16] x86/boot: Add EFI kernel extraction interface Evgeniy Baskov
2022-10-19 7:27 ` Ard Biesheuvel
2022-10-20 12:14 ` Evgeniy Baskov
2022-09-06 10:41 ` [PATCH 13/16] efi/x86: Support extracting kernel from libstub Evgeniy Baskov
2022-10-19 7:35 ` Ard Biesheuvel
2022-10-20 12:36 ` Evgeniy Baskov
2022-09-06 10:41 ` [PATCH 14/16] x86/build: Make generated PE more spec compliant Evgeniy Baskov
2022-10-19 7:39 ` Ard Biesheuvel
2022-10-20 13:07 ` Evgeniy Baskov
2022-09-06 10:41 ` [PATCH 15/16] efi/libstub: Add memory attribute protocol definitions Evgeniy Baskov
2022-10-19 7:39 ` Ard Biesheuvel
2022-09-06 10:41 ` [PATCH 16/16] efi/libstub: Use memory attribute protocol Evgeniy Baskov
2022-10-18 20:51 ` [PATCH] efi/libstub: make memory protection warnings include newlines Peter Jones
2022-10-19 7:44 ` Ard Biesheuvel
2022-10-19 7:42 ` [PATCH 16/16] efi/libstub: Use memory attribute protocol Ard Biesheuvel
2022-10-20 13:13 ` Evgeniy Baskov
2022-10-18 21:04 ` [PATCH 00/16] x86_64: Improvements at compressed kernel stage Peter Jones
2022-10-20 11:05 ` Evgeniy Baskov
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