From: Ard Biesheuvel <ardb@kernel.org>
To: Evgeniy Baskov <baskov@ispras.ru>
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 01/26] x86/boot: Align vmlinuz sections on page size
Date: Sat, 11 Mar 2023 15:42:31 +0100 [thread overview]
Message-ID: <CAMj1kXHBMMr+EyEQxcn-P4DT+12aeUsbfPMzJB4NWtRqtKUTaQ@mail.gmail.com> (raw)
In-Reply-To: <1df839eccd88063485d1702d5f98d5b8@ispras.ru>
On Sat, 11 Mar 2023 at 15:30, Evgeniy Baskov <baskov@ispras.ru> wrote:
>
> On 2023-03-10 17:43, Ard Biesheuvel wrote:
> > On Thu, 15 Dec 2022 at 13:38, 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.
> >>
> >> Tested-by: Mario Limonciello <mario.limonciello@amd.com>
> >> Tested-by: Peter Jones <pjones@redhat.com>
> >> 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 = .;
> >> *(.rodata..compressed)
> >
> > Can you just move this bit into the rodata section below?
>
> I don't think that easily possible, as the layout need
> to stay compatible with in-place extraction for non-UEFI boot.
> For that execution path the code in .head.text moves everything
> behind it to the end of the extraction buffer and extraction
> code overwrites compressed kernel blob progressively during
> extraction. And that is why we have effectively have two code
> sections...
>
A right - thanks for explaining that to me.
So in the end, I think it doesn't matter in any case if we just stick
to a single .text section with R-X attributes and a single .data
section with RW- attributes.
> >
> >> + _ecompressed = .;
> >> }
> >> + . = ALIGN(PAGE_SIZE);
> >> .text : {
> >
> > Please use
> >
> > .text : ALIGN(PAGE_SIZE) {
> >
> > which marks the section as being page aligned, rather than just being
> > placed on a 4k boundary.
>
> Will fix in v5.
>
> >
> >> _text = .; /* Text */
> >> *(.text)
> >> *(.text.*)
> >> _etext = . ;
> >> }
> >> + . = ALIGN(PAGE_SIZE);
> >> .rodata : {
> >> _rodata = . ;
> >> *(.rodata) /* read-only data */
> >> *(.rodata.*)
> >> _erodata = . ;
> >> }
> >> + . = ALIGN(PAGE_SIZE);
> >> .data : {
> >> _data = . ;
> >> *(.data)
> >> --
> >> 2.37.4
> >>
next prev parent reply other threads:[~2023-03-11 14:42 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 [this message]
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
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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