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From: Arvind Sankar <nivedita@alum.mit.edu>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] x86/boot/compressed/64: Remove .bss/.pgtable from bzImage
Date: Tue, 18 Feb 2020 13:03:54 -0500	[thread overview]
Message-ID: <20200218180353.GA930230@rani.riverdale.lan> (raw)
In-Reply-To: <20200205162921.GA318609@rani.riverdale.lan>

On Wed, Feb 05, 2020 at 11:29:21AM -0500, Arvind Sankar wrote:
> On Thu, Jan 09, 2020 at 10:02:17AM -0500, Arvind Sankar wrote:
> > Commit 5b11f1cee579 ("x86, boot: straighten out ranges to copy/zero in
> > compressed/head*.S") introduced a separate .pgtable section, splitting
> > it out from the rest of .bss. This section was added without the
> > writeable flag, marking it as read-only. This results in the linker
> > putting the .rela.dyn section (containing bogus dynamic relocations from
> > head_64.o) after the .bss and .pgtable sections.
> > 
> > When we use objcopy to convert compressed/vmlinux into a binary for the
> > bzImage, the .bss and .pgtable sections get materialized as ~176KiB of
> > zero bytes in the binary in order to place .rela.dyn at the correct
> > location.
> > 
> > Fix this by marking .pgtable as writeable. This moves the .rela.dyn
> > section earlier so that .bss and .pgtable are the last allocated
> > sections and so don't appear in bzImage.
> > 
> > Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
> > ---
> >  arch/x86/boot/compressed/head_64.S | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
> > index 58a512e33d8d..6eb30f8a3ce7 100644
> > --- a/arch/x86/boot/compressed/head_64.S
> > +++ b/arch/x86/boot/compressed/head_64.S
> > @@ -709,7 +709,7 @@ SYM_DATA_END_LABEL(boot_stack, SYM_L_LOCAL, boot_stack_end)
> >  /*
> >   * Space for page tables (not in .bss so not zeroed)
> >   */
> > -	.section ".pgtable","a",@nobits
> > +	.section ".pgtable","aw",@nobits
> >  	.balign 4096
> >  SYM_DATA_LOCAL(pgtable,		.fill BOOT_PGT_SIZE, 1, 0)
> >  
> > -- 
> > 2.24.1
> > 
> 
> Gentle reminder.
> 
> https://lore.kernel.org/lkml/20200109150218.16544-1-nivedita@alum.mit.edu

Ping.

  reply	other threads:[~2020-02-18 18:03 UTC|newest]

Thread overview: 115+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-09 15:02 [PATCH 1/2] x86/boot/compressed/64: Remove .bss/.pgtable from bzImage Arvind Sankar
2020-01-09 15:02 ` [PATCH 2/2] x86/boot/compressed: Remove unnecessary sections " Arvind Sankar
2020-02-06 11:44   ` Kees Cook
2020-02-19 16:55   ` [tip: x86/boot] " tip-bot2 for Arvind Sankar
2020-02-22  5:08   ` [PATCH 2/2] " Nathan Chancellor
2020-02-22  6:55     ` Borislav Petkov
2020-02-22  7:02       ` Nathan Chancellor
2020-02-22  7:21         ` Fangrui Song
2020-02-22  7:42           ` Nathan Chancellor
2020-02-22 15:37             ` Arvind Sankar
2020-02-22 16:44               ` Arvind Sankar
2020-02-22 17:18                 ` [PATCH] x86/boot/compressed: Fix compressed kernel linking with lld Arvind Sankar
2020-02-22 18:14                   ` Nathan Chancellor
2020-02-22 18:58                     ` Fangrui Song
2020-02-22 20:17                       ` Arvind Sankar
2020-02-22 21:01                         ` Fangrui Song
2020-02-22 23:33                           ` Nick Desaulniers
2020-02-22 23:57                             ` Arvind Sankar
2020-02-23 19:37                               ` [PATCH 0/2] Stop generating .eh_frame sections Arvind Sankar
2020-02-24  4:15                                 ` Nathan Chancellor
2020-02-24 20:49                                 ` Nick Desaulniers
2020-02-24 21:53                                   ` Arvind Sankar
2020-02-24 22:01                                     ` Nick Desaulniers
2020-02-23 19:37                               ` [PATCH 1/2] arch/x86: Use -fno-asynchronous-unwind-tables to suppress " Arvind Sankar
2020-02-24 20:33                                 ` Nick Desaulniers
2020-02-24 21:05                                   ` Arvind Sankar
2020-02-24 21:12                                     ` Fangrui Song
2020-02-24 21:17                                       ` Nick Desaulniers
2020-02-24 21:22                                         ` Nick Desaulniers
2020-02-23 19:37                               ` [PATCH 2/2] arch/x86: Drop unneeded linker script discard of .eh_frame Arvind Sankar
2020-02-24 20:45                                 ` Nick Desaulniers
2020-02-24 21:33                                   ` Arvind Sankar
2020-02-24 21:58                                     ` Nick Desaulniers
2020-02-24 23:21                                       ` [PATCH v2 0/2] Stop generating .eh_frame sections Arvind Sankar
2020-02-24 23:21                                       ` [PATCH v2 1/2] arch/x86: Use -fno-asynchronous-unwind-tables to suppress " Arvind Sankar
2020-02-24 23:28                                         ` Nathan Chancellor
2020-02-24 23:30                                         ` Nick Desaulniers
2020-02-25  4:10                                         ` Kees Cook
2020-02-25 16:53                                         ` [tip: x86/boot] x86/*/Makefile: " tip-bot2 for Arvind Sankar
2020-02-24 23:21                                       ` [PATCH v2 2/2] arch/x86: Drop unneeded linker script discard of .eh_frame Arvind Sankar
2020-02-24 23:28                                         ` Nathan Chancellor
2020-02-24 23:33                                         ` Nick Desaulniers
2020-02-25  4:11                                         ` Kees Cook
2020-02-25 16:53                                         ` [tip: x86/boot] x86/vmlinux: " tip-bot2 for Arvind Sankar
2020-02-23 22:00                           ` [PATCH] x86/boot/compressed: Fix compressed kernel linking with lld Kees Cook
2020-02-24  6:06                             ` Fangrui Song
2020-02-22 17:29                 ` [PATCH 2/2] x86/boot/compressed: Remove unnecessary sections from bzImage Borislav Petkov
2020-02-22 17:53                   ` Arvind Sankar
2020-02-22  7:42           ` Borislav Petkov
2020-02-22 16:22             ` Arvind Sankar
2020-02-22 23:20               ` Nick Desaulniers
2020-02-24 13:28                 ` Michael Matz
2020-02-24 20:51                   ` Nick Desaulniers
2020-02-24 21:28                     ` Fangrui Song
2020-02-24 21:48                       ` Arvind Sankar
2020-02-24 22:17                         ` Fangrui Song
2020-02-24 22:43                           ` Arvind Sankar
2020-02-24 22:50                             ` Fangrui Song
2020-02-24 23:08                               ` Arvind Sankar
2020-02-25  5:35                 ` --orphan-handling=warn (was Re: [PATCH 2/2] x86/boot/compressed: Remove unnecessary sections) " Kees Cook
2020-02-25 16:42                   ` --orphan-handling=warn Arvind Sankar
2020-02-25 18:29                   ` --orphan-handling=warn Arvind Sankar
2020-02-25 19:42                     ` --orphan-handling=warn Kees Cook
2020-02-25 20:37                       ` --orphan-handling=warn Nick Desaulniers
2020-02-25 22:02                         ` --orphan-handling=warn Kees Cook
2020-02-26  1:56                           ` --orphan-handling=warn Fangrui Song
2020-02-26  5:35                             ` --orphan-handling=warn Kees Cook
2020-02-26 19:11                               ` --orphan-handling=warn Kristen Carlson Accardi
2020-02-26 19:26                                 ` --orphan-handling=warn Nick Desaulniers
2020-02-24 11:37   ` [tip: x86/boot] x86/boot/compressed: Remove .eh_frame section from bzImage tip-bot2 for Arvind Sankar
2020-02-24 16:41     ` Arvind Sankar
2020-02-24 17:16       ` Borislav Petkov
2020-02-24 17:28         ` Arvind Sankar
2020-02-05 16:29 ` [PATCH 1/2] x86/boot/compressed/64: Remove .bss/.pgtable " Arvind Sankar
2020-02-18 18:03   ` Arvind Sankar [this message]
2020-02-19 12:09     ` Borislav Petkov
2020-02-19 17:57       ` Arvind Sankar
2020-02-19 18:22         ` Borislav Petkov
2020-02-19 19:06           ` Arvind Sankar
2020-02-06 11:18 ` Kees Cook
2020-02-19 16:55 ` [tip: x86/boot] " tip-bot2 for Arvind Sankar
2020-04-05 15:42 ` [PATCH 1/2] " Sergey Shatunov
2020-04-05 23:18   ` Arvind Sankar
2020-04-06  0:00     ` Sergey Shatunov
2020-04-06  3:51       ` Arvind Sankar
2020-04-06  7:32         ` Ard Biesheuvel
2020-04-06  8:47           ` Borislav Petkov
2020-04-06  9:11             ` Ard Biesheuvel
2020-04-06 11:20               ` Borislav Petkov
2020-04-06 13:22                 ` Arvind Sankar
2020-04-06 13:29                   ` Ard Biesheuvel
2020-04-06 16:01                     ` Arvind Sankar
2020-04-06 16:22                       ` Ard Biesheuvel
2020-04-06 16:52                         ` Arvind Sankar
2020-04-06 16:59                           ` Ard Biesheuvel
2020-04-06 18:06                             ` [PATCH 1/2] efi/x86: Move efi stub globals from .bss to .data Arvind Sankar
2020-04-06 18:06                               ` [PATCH 2/2] efi/x86: Always relocate the kernel for EFI handover entry Arvind Sankar
2020-04-14  8:20                                 ` [tip: efi/urgent] " tip-bot2 for Arvind Sankar
2020-04-06 18:29                               ` [PATCH 1/2] efi/x86: Move efi stub globals from .bss to .data Ard Biesheuvel
2020-04-08  7:43                               ` Dave Young
2020-04-08  7:49                                 ` Ard Biesheuvel
2020-04-09 14:39                                   ` Arvind Sankar
2020-04-09 14:47                                     ` Ard Biesheuvel
2020-04-09 16:35                                       ` Arvind Sankar
2020-04-10 14:47                                         ` Arvind Sankar
2020-04-10 15:26                                           ` Ard Biesheuvel
2020-04-14 14:57                                             ` Daniel Kiper
2020-04-10 11:26                               ` Thomas Meyer
2020-04-10 14:38                                 ` Arvind Sankar
2020-04-11  8:50                                   ` Thomas Meyer
2020-04-14  8:20                               ` [tip: efi/urgent] " tip-bot2 for Arvind Sankar
2020-04-06 17:21                     ` [PATCH 1/2] x86/boot/compressed/64: Remove .bss/.pgtable from bzImage Borislav Petkov
2020-04-06  8:44     ` Ard Biesheuvel
2020-04-06 12:36       ` Sergey Shatunov
2020-04-06 13:20         ` Ard Biesheuvel

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