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Message-Id: <20170525203334.867-1-kirill.shutemov@linux.intel.com>
Date: Thu, 25 May 2017 23:33:26 +0300
From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To: Linus Torvalds <torvalds@...ux-foundation.org>,
Andrew Morton <akpm@...ux-foundation.org>, x86@...nel.org,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>
Cc: Andi Kleen <ak@...ux.intel.com>,
Dave Hansen <dave.hansen@...el.com>,
Andy Lutomirski <luto@...capital.net>,
linux-arch@...r.kernel.org, linux-mm@...ck.org,
linux-kernel@...r.kernel.org,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level paging
Here' my first attempt to bring boot-time between 4- and 5-level paging.
It looks not too terrible to me. I've expected it to be worse.
The basic idea is to implement the same logic as pgtable-nop4d.h provides,
but at runtime.
Runtime folding is only implemented for CONFIG_X86_5LEVEL=y case. With the
option disabled, we do compile-time folding.
Initially, I tried to fold pgd instread. I've got to shell, but it
required a lot of hacks as kernel threats pgd in a special way.
Few things are broken (see patch 7/8) and many things are not yet tested.
So more work is required.
I also haven't evaluated performance impact. We can look into some form of
boot-time code patching later if required.
Please review. Any feedback is welcome.
Kirill A. Shutemov (8):
x86/boot/compressed/64: Detect and handle 5-level paging at boot-time
x86/mm: Make virtual memory layout movable for CONFIG_X86_5LEVEL
x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable
x86/mm: Handle boot-time paging mode switching at early boot
x86/mm: Fold p4d page table layer at runtime
x86/mm: Replace compile-time checks for 5-level with runtime-time
x86/mm: Hacks for boot-time switching between 4- and 5-level paging
x86/mm: Allow to boot without la57 if CONFIG_X86_5LEVEL=y
arch/x86/Kconfig | 4 +-
arch/x86/boot/compressed/head_64.S | 37 ++++++++++++++++++
arch/x86/entry/entry_64.S | 5 +++
arch/x86/include/asm/kaslr.h | 4 --
arch/x86/include/asm/page_64.h | 4 ++
arch/x86/include/asm/page_64_types.h | 15 +++-----
arch/x86/include/asm/paravirt.h | 3 +-
arch/x86/include/asm/pgalloc.h | 5 ++-
arch/x86/include/asm/pgtable.h | 10 ++++-
arch/x86/include/asm/pgtable_32.h | 2 +
arch/x86/include/asm/pgtable_64_types.h | 46 ++++++++++++++--------
arch/x86/include/asm/processor.h | 2 +-
arch/x86/include/asm/required-features.h | 8 +---
arch/x86/kernel/head64.c | 66 ++++++++++++++++++++++++++++----
arch/x86/kernel/head_64.S | 22 +++++++----
arch/x86/mm/dump_pagetables.c | 11 ++----
arch/x86/mm/ident_map.c | 2 +-
arch/x86/mm/init_64.c | 30 +++++++++------
arch/x86/mm/kaslr.c | 16 ++------
arch/x86/platform/efi/efi_64.c | 4 +-
arch/x86/power/hibernate_64.c | 4 +-
arch/x86/xen/Kconfig | 2 +-
arch/x86/xen/mmu_pv.c | 2 +-
23 files changed, 208 insertions(+), 96 deletions(-)
--
2.11.0
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