From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@amacapital.net>,
Dmitry Safonov <dsafonov@virtuozzo.com>,
Borislav Petkov <bp@suse.de>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCHv5 06/19] x86/boot/compressed/64: Detect and handle 5-level paging at boot-time
Date: Mon, 4 Sep 2017 16:02:42 +0300 [thread overview]
Message-ID: <20170904130242.4nj3emoltk4taypp@node.shutemov.name> (raw)
In-Reply-To: <20170827112926.GA1942@uranus.lan>
On Sun, Aug 27, 2017 at 02:29:26PM +0300, Cyrill Gorcunov wrote:
> On Mon, Aug 21, 2017 at 06:29:03PM +0300, Kirill A. Shutemov wrote:
> > This patch prepare decompression code to boot-time switching between 4-
> > and 5-level paging.
> >
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > ---
> > arch/x86/boot/compressed/head_64.S | 24 ++++++++++++++++++++++++
> > 1 file changed, 24 insertions(+)
> >
> > diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
> > index fbf4c32d0b62..2e362aea3319 100644
> > --- a/arch/x86/boot/compressed/head_64.S
> > +++ b/arch/x86/boot/compressed/head_64.S
> > @@ -347,6 +347,28 @@ preferred_addr:
> > leaq boot_stack_end(%rbx), %rsp
> >
> > #ifdef CONFIG_X86_5LEVEL
> > + /* Preserve rbx across cpuid */
> > + movq %rbx, %r8
> > +
> > + /* Check if leaf 7 is supported */
> > + movl $0, %eax
>
> Use xor instead, it should be shorter
>
> > + cpuid
> > + cmpl $7, %eax
> > + jb lvl5
> > +
> > + /*
> > + * Check if la57 is supported.
> > + * The feature is enumerated with CPUID.(EAX=07H, ECX=0):ECX[bit 16]
> > + */
> > + movl $7, %eax
> > + movl $0, %ecx
>
> same
Thanks. I'll update it for the next re-spin.
--
Kirill A. Shutemov
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next prev parent reply other threads:[~2017-09-04 13:02 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-21 15:28 [PATCHv5 00/19] Boot-time switching between 4- and 5-level paging Kirill A. Shutemov
2017-08-21 15:28 ` [PATCHv5 01/19] mm/sparsemem: Allocate mem_section at runtime for SPARSEMEM_EXTREME Kirill A. Shutemov
2017-08-22 16:28 ` Borislav Petkov
2017-08-22 17:50 ` Kirill A. Shutemov
2017-08-21 15:28 ` [PATCHv5 02/19] mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 03/19] x86/kasan: Use the same shadow offset for 4- and 5-level paging Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 04/19] x86/xen: Provide pre-built page tables only for XEN_PV and XEN_PVH Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 05/19] x86/xen: Drop 5-level paging support code from XEN_PV code Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 06/19] x86/boot/compressed/64: Detect and handle 5-level paging at boot-time Kirill A. Shutemov
2017-08-27 11:29 ` Cyrill Gorcunov
2017-09-04 13:02 ` Kirill A. Shutemov [this message]
2017-08-21 15:29 ` [PATCHv5 07/19] x86/mm: Make virtual memory layout movable for CONFIG_X86_5LEVEL Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 08/19] x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 09/19] x86/mm: Make MAX_PHYSADDR_BITS and MAX_PHYSMEM_BITS dynamic Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 10/19] x86/mm: Make __PHYSICAL_MASK_SHIFT and __VIRTUAL_MASK_SHIFT dynamic Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 11/19] x86/mm: Make STACK_TOP_MAX dynamic Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 12/19] x86/mm: Adjust virtual address space layout in early boot Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 13/19] x86/mm: Make early boot code support boot-time switching of paging modes Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 14/19] x86/mm: Fold p4d page table layer at runtime Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 15/19] x86/mm: Replace compile-time checks for 5-level with runtime-time Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 16/19] x86/mm: Allow to boot without la57 if CONFIG_X86_5LEVEL=y Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 17/19] x86/xen: Allow XEN_PV and XEN_PVH to be enabled with X86_5LEVEL Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 18/19] x86/mm: Redefine some of page table helpers as macros Kirill A. Shutemov
2017-08-21 15:29 ` [PATCHv5 19/19] x86/mm: Offset boot-time paging mode switching cost Kirill A. Shutemov
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