From: Joe Lawrence <joe.lawrence@redhat.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Jiri Kosina <jikos@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Miroslav Benes <mbenes@suse.cz>,
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
Nicolai Stange <nstange@suse.de>,
live-patching@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [POC 22/23] livepatch/module: Remove obsolete copy_module_elf()
Date: Fri, 3 Apr 2020 14:03:28 -0400 [thread overview]
Message-ID: <20200403180328.GC30284@redhat.com> (raw)
In-Reply-To: <20200117150323.21801-23-pmladek@suse.com>
On Fri, Jan 17, 2020 at 04:03:22PM +0100, Petr Mladek wrote:
> The split livepatch modules can be relocated immedidately when they
> are loaded. There is no longer needed to preserve the elf sections.
>
> Signed-off-by: Petr Mladek <pmladek@suse.com>
> ---
> Documentation/livepatch/module-elf-format.rst | 18 ++++++
> include/linux/module.h | 3 -
> kernel/module.c | 87 ---------------------------
> 3 files changed, 18 insertions(+), 90 deletions(-)
>
> diff --git a/Documentation/livepatch/module-elf-format.rst b/Documentation/livepatch/module-elf-format.rst
> index 9f0c997d4940..8c6b894c4661 100644
> --- a/Documentation/livepatch/module-elf-format.rst
> +++ b/Documentation/livepatch/module-elf-format.rst
> @@ -14,6 +14,7 @@ This document outlines the Elf format requirements that livepatch modules must f
> 4. Livepatch symbols
> 4.1 A livepatch module's symbol table
> 4.2 Livepatch symbol format
> + 5. Symbol table and Elf section access
>
> 1. Background and motivation
> ============================
> @@ -295,3 +296,20 @@ See include/uapi/linux/elf.h for the actual definitions.
> [*]
> Note that the 'Ndx' (Section index) for these symbols is SHN_LIVEPATCH (0xff20).
> "OS" means OS-specific.
> +
> +5. Symbol table and Elf section access
> +======================================
> +A livepatch module's symbol table is accessible through module->symtab.
> +
> +Since apply_relocate_add() requires access to a module's section headers,
> +symbol table, and relocation section indices, Elf information is preserved for
> +livepatch modules and is made accessible by the module loader through
> +module->klp_info, which is a klp_modinfo struct. When a livepatch module loads,
> +this struct is filled in by the module loader. Its fields are documented below::
> +
> + struct klp_modinfo {
> + Elf_Ehdr hdr; /* Elf header */
> + Elf_Shdr *sechdrs; /* Section header table */
> + char *secstrings; /* String table for the section headers */
> + unsigned int symndx; /* The symbol table section index */
> + };
I think this file was inadvertently reverted, or at least the Symbol
table and Elf section access section was supposed to stay gone, right?
-- Joe
next prev parent reply other threads:[~2020-04-03 18:03 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-17 15:03 [POC 00/23] livepatch: Split livepatch module per-object Petr Mladek
2020-01-17 15:03 ` [POC 01/23] module: Allow to delete module also from inside kernel Petr Mladek
2020-01-21 11:11 ` Julien Thierry
2020-01-17 15:03 ` [POC 02/23] livepatch: Split livepatch modules per livepatched object Petr Mladek
2020-01-21 11:11 ` Julien Thierry
2020-01-28 12:16 ` Petr Mladek
2020-01-17 15:03 ` [POC 03/23] livepatch: Better checks of struct klp_object definition Petr Mladek
2020-01-21 11:27 ` Julien Thierry
2020-01-17 15:03 ` [POC 04/23] livepatch: Prevent loading livepatch sub-module unintentionally Petr Mladek
2020-04-03 17:54 ` Joe Lawrence
2020-01-17 15:03 ` [POC 05/23] livepatch: Initialize and free livepatch submodule Petr Mladek
2020-01-21 11:58 ` Julien Thierry
2020-01-17 15:03 ` [POC 06/23] livepatch: Enable the " Petr Mladek
2020-01-17 15:03 ` [POC 07/23] livepatch: Remove obsolete functionality from klp_module_coming() Petr Mladek
2020-01-17 15:03 ` [POC 08/23] livepatch: Automatically load livepatch module when the patch module is loaded Petr Mladek
2020-01-17 15:03 ` [POC 09/23] livepatch: Handle race when livepatches are reloaded during a module load Petr Mladek
2020-01-22 18:51 ` Julien Thierry
2020-01-17 15:03 ` [POC 10/23] livepatch: Handle modprobe exit code Petr Mladek
2020-01-17 15:03 ` [POC 11/23] livepatch: Safely detect forced transition when removing split livepatch modules Petr Mladek
2020-01-22 10:15 ` Julien Thierry
2020-01-17 15:03 ` [POC 12/23] livepatch: Automatically remove livepatch module when the object is freed Petr Mladek
2020-01-17 15:03 ` [POC 13/23] livepatch: Remove livepatch module when the livepatched module is unloaded Petr Mladek
2020-01-17 15:03 ` [POC 14/23] livepatch: Never block livepatch modules when the related module is being removed Petr Mladek
2020-01-17 15:03 ` [POC 15/23] livepatch: Prevent infinite loop when loading livepatch module Petr Mladek
2020-01-17 15:03 ` [POC 16/23] livepatch: Add patch into the global list early Petr Mladek
2020-01-17 15:03 ` [POC 17/23] livepatch: Load livepatches for modules when loading the main livepatch Petr Mladek
2020-01-17 15:03 ` [POC 18/23] module: Refactor add_unformed_module() Petr Mladek
2020-01-17 15:03 ` [POC 19/23] module/livepatch: Allow to use exported symbols from livepatch module for "vmlinux" Petr Mladek
2020-04-06 18:48 ` Joe Lawrence
2020-04-07 7:33 ` Miroslav Benes
2020-04-07 20:57 ` Joe Lawrence
2020-01-17 15:03 ` [POC 20/23] module/livepatch: Relocate local variables in the module loaded when the livepatch is being loaded Petr Mladek
2020-01-18 10:29 ` kbuild test robot
2020-04-03 18:00 ` Joe Lawrence
2020-01-17 15:03 ` [POC 21/23] livepatch: Remove obsolete arch_klp_init_object_loaded() Petr Mladek
2020-01-17 15:03 ` [POC 22/23] livepatch/module: Remove obsolete copy_module_elf() Petr Mladek
2020-04-03 18:03 ` Joe Lawrence [this message]
2020-01-17 15:03 ` [POC 23/23] module: Remove obsolete module_disable_ro() Petr Mladek
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