All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Ingo Molnar <mingo@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Dave Hansen <dave.hansen@intel.com>,
	linux-arch@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/8] x86/boot/64: Add support of additional page table level during early boot
Date: Tue, 18 Apr 2017 14:10:31 +0300	[thread overview]
Message-ID: <20170418111030.5zc4zhxlrbpi4bwm@node.shutemov.name> (raw)
In-Reply-To: <20170418101534.oa3mchqyap2yvh7v@node.shutemov.name>

On Tue, Apr 18, 2017 at 01:15:34PM +0300, Kirill A. Shutemov wrote:
> On Tue, Apr 18, 2017 at 11:59:26AM +0300, Kirill A. Shutemov wrote:
> > On Mon, Apr 17, 2017 at 12:32:25PM +0200, Ingo Molnar wrote:
> > > 
> > > * Kirill A. Shutemov <kirill@shutemov.name> wrote:
> > > 
> > > > On Tue, Apr 11, 2017 at 07:09:07AM -0700, Andi Kleen wrote:
> > > > > > I'll look closer (building proccess it's rather complicated), but my
> > > > > > understanding is that VDSO is stand-alone binary and doesn't really links
> > > > > > with the rest of the kernel, rather included as blob, no?
> > > > > > 
> > > > > > Andy, may be you have an idea?
> > > > > 
> > > > > There isn't any way I know of to directly link them together. The ELF 
> > > > > format wasn't designed for that. You would need to merge blobs and then use
> > > > > manual jump vectors, like the 16bit startup code does. It would be likely
> > > > > complicated and ugly.
> > > > 
> > > > Ingo, can we proceed without coverting this assembly to C?
> > > > 
> > > > I'm committed to convert it to C later if we'll find reasonable solution
> > > > to the issue.
> > > 
> > > So one way to do it would be to build it standalone as a .o, then add it not to 
> > > the regular kernel objects link target (as you found out it's not possible to link 
> > > 32-bit and 64-bit objects), but to link it in a manual fashion, as part of 
> > > vmlinux.bin.all-y in arch/x86/boot/compressed/Makefile.
> > > 
> > > But there would be other complications with this approach, such as we'd have to 
> > > add a size field and there might be symbol linking problems ...
> > > 
> > > Another, pretty hacky way would be to generate a .S from the .c, then post-process 
> > > the .S and essentially generate today's 32-bit .S from it.
> > > 
> > > Probably not worth the trouble.
> > 
> > So, do I need to do anything else to get part 4 applied?
> 
> Doh!
> 
> I've just realized we don't really need to enable 5-level paging in
> decompression code. Leaving 4-level paging there works perfectly fine.
> 
> I'll drop changes to arch/x86/boot/compressed/head_64.S and resubmit the
> patchset.

No. This breaks KASLR. Decompression code has to use 5-level paging to
keep KASLR working.

So, v4 of part 4 is up-to-date.

Sorry for noise.

-- 
 Kirill A. Shutemov

WARNING: multiple messages have this Message-ID (diff)
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Ingo Molnar <mingo@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Dave Hansen <dave.hansen@intel.com>,
	linux-arch@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/8] x86/boot/64: Add support of additional page table level during early boot
Date: Tue, 18 Apr 2017 14:10:31 +0300	[thread overview]
Message-ID: <20170418111030.5zc4zhxlrbpi4bwm@node.shutemov.name> (raw)
In-Reply-To: <20170418101534.oa3mchqyap2yvh7v@node.shutemov.name>

On Tue, Apr 18, 2017 at 01:15:34PM +0300, Kirill A. Shutemov wrote:
> On Tue, Apr 18, 2017 at 11:59:26AM +0300, Kirill A. Shutemov wrote:
> > On Mon, Apr 17, 2017 at 12:32:25PM +0200, Ingo Molnar wrote:
> > > 
> > > * Kirill A. Shutemov <kirill@shutemov.name> wrote:
> > > 
> > > > On Tue, Apr 11, 2017 at 07:09:07AM -0700, Andi Kleen wrote:
> > > > > > I'll look closer (building proccess it's rather complicated), but my
> > > > > > understanding is that VDSO is stand-alone binary and doesn't really links
> > > > > > with the rest of the kernel, rather included as blob, no?
> > > > > > 
> > > > > > Andy, may be you have an idea?
> > > > > 
> > > > > There isn't any way I know of to directly link them together. The ELF 
> > > > > format wasn't designed for that. You would need to merge blobs and then use
> > > > > manual jump vectors, like the 16bit startup code does. It would be likely
> > > > > complicated and ugly.
> > > > 
> > > > Ingo, can we proceed without coverting this assembly to C?
> > > > 
> > > > I'm committed to convert it to C later if we'll find reasonable solution
> > > > to the issue.
> > > 
> > > So one way to do it would be to build it standalone as a .o, then add it not to 
> > > the regular kernel objects link target (as you found out it's not possible to link 
> > > 32-bit and 64-bit objects), but to link it in a manual fashion, as part of 
> > > vmlinux.bin.all-y in arch/x86/boot/compressed/Makefile.
> > > 
> > > But there would be other complications with this approach, such as we'd have to 
> > > add a size field and there might be symbol linking problems ...
> > > 
> > > Another, pretty hacky way would be to generate a .S from the .c, then post-process 
> > > the .S and essentially generate today's 32-bit .S from it.
> > > 
> > > Probably not worth the trouble.
> > 
> > So, do I need to do anything else to get part 4 applied?
> 
> Doh!
> 
> I've just realized we don't really need to enable 5-level paging in
> decompression code. Leaving 4-level paging there works perfectly fine.
> 
> I'll drop changes to arch/x86/boot/compressed/head_64.S and resubmit the
> patchset.

No. This breaks KASLR. Decompression code has to use 5-level paging to
keep KASLR working.

So, v4 of part 4 is up-to-date.

Sorry for noise.

-- 
 Kirill A. Shutemov

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  reply	other threads:[~2017-04-18 11:10 UTC|newest]

Thread overview: 101+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-06 14:00 [PATCH 0/8] x86: 5-level paging enabling for v4.12, Part 4 Kirill A. Shutemov
2017-04-06 14:00 ` Kirill A. Shutemov
2017-04-06 14:00 ` [PATCH 1/8] x86/boot/64: Rewrite startup_64 in C Kirill A. Shutemov
2017-04-06 14:00   ` Kirill A. Shutemov
2017-04-11  7:58   ` [tip:x86/mm] x86/boot/64: Rewrite startup_64() " tip-bot for Kirill A. Shutemov
2017-04-11  8:54     ` Ingo Molnar
2017-04-11 12:29       ` Kirill A. Shutemov
2017-04-06 14:01 ` [PATCH 2/8] x86/boot/64: Rename init_level4_pgt and early_level4_pgt Kirill A. Shutemov
2017-04-06 14:01   ` Kirill A. Shutemov
2017-04-11  7:59   ` [tip:x86/mm] x86/boot/64: Rename init_level4_pgt() and early_level4_pgt[] tip-bot for Kirill A. Shutemov
2017-04-06 14:01 ` [PATCH 3/8] x86/boot/64: Add support of additional page table level during early boot Kirill A. Shutemov
2017-04-06 14:01   ` Kirill A. Shutemov
2017-04-11  7:02   ` Ingo Molnar
2017-04-11  7:02     ` Ingo Molnar
2017-04-11 10:51     ` Kirill A. Shutemov
2017-04-11 10:51       ` Kirill A. Shutemov
2017-04-11 11:28       ` Ingo Molnar
2017-04-11 11:28         ` Ingo Molnar
2017-04-11 11:46         ` Kirill A. Shutemov
2017-04-11 11:46           ` Kirill A. Shutemov
2017-04-11 14:09           ` Andi Kleen
2017-04-11 14:09             ` Andi Kleen
2017-04-12 10:18             ` Kirill A. Shutemov
2017-04-12 10:18               ` Kirill A. Shutemov
2017-04-17 10:32               ` Ingo Molnar
2017-04-17 10:32                 ` Ingo Molnar
2017-04-18  8:59                 ` Kirill A. Shutemov
2017-04-18  8:59                   ` Kirill A. Shutemov
2017-04-18 10:15                   ` Kirill A. Shutemov
2017-04-18 10:15                     ` Kirill A. Shutemov
2017-04-18 11:10                     ` Kirill A. Shutemov [this message]
2017-04-18 11:10                       ` Kirill A. Shutemov
2017-04-06 14:01 ` [PATCH 4/8] x86/mm: Add sync_global_pgds() for configuration with 5-level paging Kirill A. Shutemov
2017-04-06 14:01   ` Kirill A. Shutemov
2017-04-06 14:01 ` [PATCH 5/8] x86/mm: Make kernel_physical_mapping_init() support " Kirill A. Shutemov
2017-04-06 14:01   ` Kirill A. Shutemov
2017-04-06 14:01 ` [PATCH 6/8] x86/mm: Add support for 5-level paging for KASLR Kirill A. Shutemov
2017-04-06 14:01   ` Kirill A. Shutemov
2017-04-06 14:01 ` [PATCH 7/8] x86: Enable 5-level paging support Kirill A. Shutemov
2017-04-06 14:01   ` Kirill A. Shutemov
2017-04-06 14:52   ` Juergen Gross
2017-04-06 14:52     ` Juergen Gross
2017-04-06 15:24     ` Kirill A. Shutemov
2017-04-06 15:24       ` Kirill A. Shutemov
2017-04-06 15:56       ` Juergen Gross
2017-04-06 15:56         ` Juergen Gross
2017-04-06 14:01 ` [PATCH 8/8] x86/mm: Allow to have userspace mappings above 47-bits Kirill A. Shutemov
2017-04-06 14:01   ` Kirill A. Shutemov
2017-04-06 18:43   ` Dmitry Safonov
2017-04-06 18:43     ` Dmitry Safonov
2017-04-06 18:43     ` Dmitry Safonov
2017-04-06 19:15     ` Dmitry Safonov
2017-04-06 19:15       ` Dmitry Safonov
2017-04-06 19:15       ` Dmitry Safonov
2017-04-06 23:21       ` Kirill A. Shutemov
2017-04-06 23:21         ` Kirill A. Shutemov
2017-04-06 23:24         ` [PATCHv2 " Kirill A. Shutemov
2017-04-06 23:24           ` Kirill A. Shutemov
2017-04-07 11:32           ` Dmitry Safonov
2017-04-07 11:32             ` Dmitry Safonov
2017-04-07 11:32             ` Dmitry Safonov
2017-04-07 15:44             ` [PATCHv3 " Kirill A. Shutemov
2017-04-07 15:44               ` Kirill A. Shutemov
2017-04-07 16:37               ` Dmitry Safonov
2017-04-07 16:37                 ` Dmitry Safonov
2017-04-07 16:37                 ` Dmitry Safonov
2017-04-13 11:30             ` [PATCHv4 0/9] x86: 5-level paging enabling for v4.12, Part 4 Kirill A. Shutemov
2017-04-13 11:30               ` Kirill A. Shutemov
2017-04-13 11:30               ` [PATCHv4 1/9] x86/asm: Fix comment in return_from_SYSCALL_64 Kirill A. Shutemov
2017-04-13 11:30                 ` Kirill A. Shutemov
2017-04-13 11:30               ` [PATCHv4 2/9] x86/boot/64: Rewrite startup_64 in C Kirill A. Shutemov
2017-04-13 11:30                 ` Kirill A. Shutemov
2017-04-13 11:30               ` [PATCHv4 3/9] x86/boot/64: Rename init_level4_pgt and early_level4_pgt Kirill A. Shutemov
2017-04-13 11:30                 ` Kirill A. Shutemov
2017-04-13 11:30               ` [PATCHv4 4/9] x86/boot/64: Add support of additional page table level during early boot Kirill A. Shutemov
2017-04-13 11:30                 ` Kirill A. Shutemov
2017-04-13 11:30               ` [PATCHv4 5/9] x86/mm: Add sync_global_pgds() for configuration with 5-level paging Kirill A. Shutemov
2017-04-13 11:30                 ` Kirill A. Shutemov
2017-04-13 11:30               ` [PATCHv4 6/9] x86/mm: Make kernel_physical_mapping_init() support " Kirill A. Shutemov
2017-04-13 11:30                 ` Kirill A. Shutemov
2017-04-13 11:30               ` [PATCHv4 7/9] x86/mm: Add support for 5-level paging for KASLR Kirill A. Shutemov
2017-04-13 11:30                 ` Kirill A. Shutemov
2017-04-13 11:30               ` [PATCHv4 8/9] x86: Enable 5-level paging support Kirill A. Shutemov
2017-04-13 11:30                 ` Kirill A. Shutemov
2017-04-13 11:30               ` [PATCHv4 9/9] x86/mm: Allow to have userspace mappings above 47-bits Kirill A. Shutemov
2017-04-13 11:30                 ` Kirill A. Shutemov
2017-04-07 10:06         ` [PATCH 8/8] " Dmitry Safonov
2017-04-07 10:06           ` Dmitry Safonov
2017-04-07 10:06           ` Dmitry Safonov
2017-04-07 13:35   ` Anshuman Khandual
2017-04-07 13:35     ` Anshuman Khandual
2017-04-07 15:59     ` Kirill A. Shutemov
2017-04-07 15:59       ` Kirill A. Shutemov
2017-04-07 16:09       ` hpa
2017-04-07 16:09         ` hpa
2017-04-07 16:20         ` Kirill A. Shutemov
2017-04-07 16:20           ` Kirill A. Shutemov
2017-04-12 10:41       ` Michael Ellerman
2017-04-12 10:41         ` Michael Ellerman
2017-04-12 11:11         ` Kirill A. Shutemov
2017-04-12 11:11           ` Kirill A. Shutemov

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20170418111030.5zc4zhxlrbpi4bwm@node.shutemov.name \
    --to=kirill@shutemov.name \
    --cc=ak@linux.intel.com \
    --cc=akpm@linux-foundation.org \
    --cc=dave.hansen@intel.com \
    --cc=hpa@zytor.com \
    --cc=kirill.shutemov@linux.intel.com \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=luto@amacapital.net \
    --cc=mingo@kernel.org \
    --cc=mingo@redhat.com \
    --cc=tglx@linutronix.de \
    --cc=torvalds@linux-foundation.org \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.