From: Evgeniy Baskov <baskov@ispras.ru>
To: 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, x86@kernel.org,
linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH 01/16] x86/boot: Align vmlinuz sections on page size
Date: Thu, 20 Oct 2022 14:13:04 +0300 [thread overview]
Message-ID: <be5a5bc936ca62fa0e25781375c8c2ed@ispras.ru> (raw)
In-Reply-To: <CAMj1kXGUvUwy__wD-DtHtpVMoCJsc=G2mvWLe2a7ib2ckqzpow@mail.gmail.com>
On 2022-10-19 10:01, Ard Biesheuvel wrote:
> On Tue, 6 Sept 2022 at 12:41, Evgeniy Baskov <baskov@ispras.ru> wrote:
>>
>> To protect sections on page table level each section
>> needs to be aligned on page size (4KB).
>>
>> Set sections alignment in linker script.
>>
>> Signed-off-by: Evgeniy Baskov <baskov@ispras.ru>
>> ---
>> arch/x86/boot/compressed/vmlinux.lds.S | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/arch/x86/boot/compressed/vmlinux.lds.S
>> b/arch/x86/boot/compressed/vmlinux.lds.S
>> index 112b2375d021..6be90f1a1198 100644
>> --- a/arch/x86/boot/compressed/vmlinux.lds.S
>> +++ b/arch/x86/boot/compressed/vmlinux.lds.S
>> @@ -27,21 +27,27 @@ SECTIONS
>> HEAD_TEXT
>> _ehead = . ;
>> }
>> + . = ALIGN(PAGE_SIZE);
>> .rodata..compressed : {
>> + _compressed = .;
>
> Why are you adding these?
It is used for address compressed kernel blob during memory protection
setup.
Although it can be addressed via different symbols, I though that
addressing
sections data in a common way (through linker generated symbols) would
be better.
I can remove or mention the change in commit message (for now I will do
the latter).
>
>> *(.rodata..compressed)
>> + _ecompressed = .;
>> }
>> + . = ALIGN(PAGE_SIZE);
>
> On other EFI architectures, we only distinguish between R-X and RW-
> regions, and alignment between .rodata and .text is unnecessary. Do we
> really need to deviate from that here?
I though that leaving a huge compressed kernel blob executable is
undesirable, so I decided to split it out. I can make it either RW- or
R-X
if it would be more acceptable.
>
>
>> .text : {
>> _text = .; /* Text */
>> *(.text)
>> *(.text.*)
>> _etext = . ;
>> }
>> + . = ALIGN(PAGE_SIZE);
>> .rodata : {
>> _rodata = . ;
>> *(.rodata) /* read-only data */
>> *(.rodata.*)
>> _erodata = . ;
>> }
>> + . = ALIGN(PAGE_SIZE);
>> .data : {
>> _data = . ;
>> *(.data)
>> --
>> 2.35.1
>>
next prev parent reply other threads:[~2022-10-20 11:13 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 [this message]
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
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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