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>,
Peter Jones <pjones@redhat.com>,
"Limonciello, Mario" <mario.limonciello@amd.com>,
joeyli <jlee@suse.com>,
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 v4 17/26] x86/boot: Reduce size of the DOS stub
Date: Sat, 11 Mar 2023 17:49:19 +0300 [thread overview]
Message-ID: <ec07e6f7af7b901ad3ff1aa9a8c8fbcb@ispras.ru> (raw)
In-Reply-To: <CAMj1kXHnQZ2EDg1F_whTPHajYvqox7Ss35aqUyJuC8RLyiuCxg@mail.gmail.com>
On 2023-03-10 17:59, Ard Biesheuvel wrote:
> On Thu, 15 Dec 2022 at 13:40, Evgeniy Baskov <baskov@ispras.ru> wrote:
>>
>> This is required to fit more sections in PE section tables,
>> since its size is restricted by zero page located at specific offset
>> after the PE header.
>>
>> Tested-by: Mario Limonciello <mario.limonciello@amd.com>
>> Tested-by: Peter Jones <pjones@redhat.com>
>> Signed-off-by: Evgeniy Baskov <baskov@ispras.ru>
>
> I'd prefer to rip this out altogether.
>
> https://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git/commit/?id=9510f6f04f579b9a3f54ad762c75ab2d905e37d8
Sounds great! Can I replace this patch with yours in v5?
>
> (and refer to the other thread in linux-efi@)
Which thread exactly? The one about the removal of
real-mode code?
>
>> ---
>> arch/x86/boot/header.S | 14 ++++++--------
>> 1 file changed, 6 insertions(+), 8 deletions(-)
>>
>> diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
>> index 9338c68e7413..9fec80bc504b 100644
>> --- a/arch/x86/boot/header.S
>> +++ b/arch/x86/boot/header.S
>> @@ -59,17 +59,16 @@ start2:
>> cld
>>
>> movw $bugger_off_msg, %si
>> + movw $bugger_off_msg_size, %cx
>>
>> msg_loop:
>> lodsb
>> - andb %al, %al
>> - jz bs_die
>> movb $0xe, %ah
>> movw $7, %bx
>> int $0x10
>> - jmp msg_loop
>> + decw %cx
>> + jnz msg_loop
>>
>> -bs_die:
>> # Allow the user to press a key, then reboot
>> xorw %ax, %ax
>> int $0x16
>> @@ -90,10 +89,9 @@ bs_die:
>>
>> .section ".bsdata", "a"
>> bugger_off_msg:
>> - .ascii "Use a boot loader.\r\n"
>> - .ascii "\n"
>> - .ascii "Remove disk and press any key to reboot...\r\n"
>> - .byte 0
>> + .ascii "Use a boot loader. "
>> + .ascii "Press a key to reboot"
>> + .set bugger_off_msg_size, . - bugger_off_msg
>>
>> #ifdef CONFIG_EFI_STUB
>> pe_header:
>> --
>> 2.37.4
>>
next prev parent reply other threads:[~2023-03-11 14:49 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-15 12:37 [PATCH v4 00/26] x86_64: Improvements at compressed kernel stage Evgeniy Baskov
2022-12-15 12:37 ` [PATCH v4 01/26] x86/boot: Align vmlinuz sections on page size Evgeniy Baskov
2023-03-10 14:43 ` Ard Biesheuvel
2023-03-11 14:30 ` Evgeniy Baskov
2023-03-11 14:42 ` Ard Biesheuvel
2022-12-15 12:37 ` [PATCH v4 02/26] x86/build: Remove RWX sections and align on 4KB Evgeniy Baskov
2023-03-10 14:45 ` Ard Biesheuvel
2023-03-11 14:31 ` Evgeniy Baskov
2022-12-15 12:37 ` [PATCH v4 03/26] x86/boot: Set cr0 to known state in trampoline Evgeniy Baskov
2023-03-10 14:48 ` Ard Biesheuvel
2022-12-15 12:37 ` [PATCH v4 04/26] x86/boot: Increase boot page table size Evgeniy Baskov
2023-03-08 9:24 ` Ard Biesheuvel
2022-12-15 12:37 ` [PATCH v4 05/26] x86/boot: Support 4KB pages for identity mapping Evgeniy Baskov
2023-03-08 9:42 ` Ard Biesheuvel
2023-03-08 16:11 ` Evgeniy Baskov
2022-12-15 12:37 ` [PATCH v4 06/26] x86/boot: Setup memory protection for bzImage code Evgeniy Baskov
2023-03-08 10:47 ` Ard Biesheuvel
2023-03-08 16:15 ` Evgeniy Baskov
2022-12-15 12:37 ` [PATCH v4 07/26] x86/build: Check W^X of vmlinux during build Evgeniy Baskov
2023-03-08 9:34 ` Ard Biesheuvel
2023-03-08 16:05 ` Evgeniy Baskov
2022-12-15 12:37 ` [PATCH v4 08/26] x86/boot: Map memory explicitly Evgeniy Baskov
2023-03-08 9:38 ` Ard Biesheuvel
2023-03-08 10:28 ` Ard Biesheuvel
2023-03-08 16:09 ` Evgeniy Baskov
2022-12-15 12:38 ` [PATCH v4 09/26] x86/boot: Remove mapping from page fault handler Evgeniy Baskov
2023-03-10 14:49 ` Ard Biesheuvel
2022-12-15 12:38 ` [PATCH v4 10/26] efi/libstub: Move helper function to related file Evgeniy Baskov
2022-12-15 12:38 ` [PATCH v4 11/26] x86/boot: Make console interface more abstract Evgeniy Baskov
2022-12-15 12:38 ` [PATCH v4 12/26] x86/boot: Make kernel_add_identity_map() a pointer Evgeniy Baskov
2023-03-10 14:52 ` Ard Biesheuvel
2023-03-11 14:34 ` Evgeniy Baskov
2022-12-15 12:38 ` [PATCH v4 13/26] x86/boot: Split trampoline and pt init code Evgeniy Baskov
2023-03-10 14:56 ` Ard Biesheuvel
2023-03-11 14:37 ` Evgeniy Baskov
2022-12-15 12:38 ` [PATCH v4 14/26] x86/boot: Add EFI kernel extraction interface Evgeniy Baskov
2022-12-15 12:38 ` [PATCH v4 15/26] efi/x86: Support extracting kernel from libstub Evgeniy Baskov
2023-03-09 16:00 ` Ard Biesheuvel
2023-03-09 17:05 ` Evgeniy Baskov
2023-03-09 16:49 ` Ard Biesheuvel
2023-03-09 17:10 ` Evgeniy Baskov
2023-03-09 17:11 ` Ard Biesheuvel
2023-03-10 15:08 ` Ard Biesheuvel
2022-12-15 12:38 ` [PATCH v4 16/26] x86/boot: Reduce lower limit of physical KASLR Evgeniy Baskov
2022-12-15 12:38 ` [PATCH v4 17/26] x86/boot: Reduce size of the DOS stub Evgeniy Baskov
2023-03-10 14:59 ` Ard Biesheuvel
2023-03-11 14:49 ` Evgeniy Baskov [this message]
2023-03-11 17:27 ` Ard Biesheuvel
2023-03-12 12:10 ` Evgeniy Baskov
2022-12-15 12:38 ` [PATCH v4 18/26] tools/include: Add simplified version of pe.h Evgeniy Baskov
2023-03-10 15:01 ` Ard Biesheuvel
2022-12-15 12:38 ` [PATCH v4 19/26] x86/build: Cleanup tools/build.c Evgeniy Baskov
2023-03-09 15:57 ` Ard Biesheuvel
2023-03-09 16:25 ` Evgeniy Baskov
2023-03-09 16:50 ` Ard Biesheuvel
2023-03-09 17:22 ` Evgeniy Baskov
2023-03-09 17:37 ` Ard Biesheuvel
2022-12-15 12:38 ` [PATCH v4 20/26] x86/build: Make generated PE more spec compliant Evgeniy Baskov
2023-03-10 15:17 ` Ard Biesheuvel
2023-03-11 15:02 ` Evgeniy Baskov
2023-03-11 17:31 ` Ard Biesheuvel
2023-03-12 12:01 ` Evgeniy Baskov
2023-03-12 13:09 ` Ard Biesheuvel
2023-03-13 9:11 ` Evgeniy Baskov
2022-12-15 12:38 ` [PATCH v4 21/26] efi/x86: Explicitly set sections memory attributes Evgeniy Baskov
2023-03-10 15:20 ` Ard Biesheuvel
2023-03-11 15:09 ` Evgeniy Baskov
2023-03-11 17:39 ` Ard Biesheuvel
2023-03-12 12:10 ` Evgeniy Baskov
2022-12-15 12:38 ` [PATCH v4 22/26] efi/libstub: Add memory attribute protocol definitions Evgeniy Baskov
2022-12-15 12:38 ` [PATCH v4 23/26] efi/libstub: Use memory attribute protocol Evgeniy Baskov
2023-03-10 16:13 ` Ard Biesheuvel
2023-03-11 15:14 ` Evgeniy Baskov
2022-12-15 12:38 ` [PATCH v4 24/26] efi/libstub: make memory protection warnings include newlines Evgeniy Baskov
2022-12-15 12:38 ` [PATCH v4 25/26] efi/x86: don't try to set page attributes on 0-sized regions Evgeniy Baskov
2022-12-15 12:38 ` [PATCH v4 26/26] efi/x86: don't set unsupported memory attributes Evgeniy Baskov
2022-12-15 19:21 ` [PATCH v4 00/26] x86_64: Improvements at compressed kernel stage Peter Jones
2022-12-19 14:08 ` Evgeniy Baskov
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