linux-kernel - Re: [PATCH v5 33/40] x86/resctrl: Drop __init/_

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <2897562e-fc97-4cc4-b4ad-316e84c87c9d@intel.com>
Date: Wed, 23 Oct 2024 16:56:08 -0700
From: Reinette Chatre <reinette.chatre@...el.com>
To: James Morse <james.morse@....com>, <x86@...nel.org>,
	<linux-kernel@...r.kernel.org>
CC: Fenghua Yu <fenghua.yu@...el.com>, Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, H Peter Anvin
	<hpa@...or.com>, Babu Moger <Babu.Moger@....com>,
	<shameerali.kolothum.thodi@...wei.com>, D Scott Phillips OS
	<scott@...amperecomputing.com>, <carl@...amperecomputing.com>,
	<lcherian@...vell.com>, <bobo.shaobowang@...wei.com>,
	<tan.shaopeng@...itsu.com>, <baolin.wang@...ux.alibaba.com>, Jamie Iles
	<quic_jiles@...cinc.com>, Xin Hao <xhao@...ux.alibaba.com>,
	<peternewman@...gle.com>, <dfustini@...libre.com>, <amitsinght@...vell.com>,
	David Hildenbrand <david@...hat.com>, Rex Nie <rex.nie@...uarmicro.com>,
	"Dave Martin" <dave.martin@....com>, Shaopeng Tan
	<tan.shaopeng@...fujitsu.com>
Subject: Re: [PATCH v5 33/40] x86/resctrl: Drop __init/__exit on assorted
 symbols

Hi James,

On 10/4/24 11:03 AM, James Morse wrote:
> Because ARM's MPAM controls are probed using MMIO, resctrl can't be
> initialised until enough CPUs are online to have determined the
> system-wide supported num_closid. Arm64 also supports 'late onlined
> secondaries', where only a subset of CPUs are online during boot.
> 
> These two combine to mean the MPAM driver may not be able to initialise
> resctrl until user-space has brought 'enough' CPUs online.
> 
> To allow MPAM to initialise resctrl after __init text has been free'd,
> remove all the __init markings from resctrl.
> 
> The existing __exit markings cause these functions to be removed by the
> linker as it has never been possible to build resctrl as a module. MPAM
> has an error interrupt which causes the driver to reset and disable
> itself. Remove the __exit markings to allow the MPAM driver to tear down
> resctrl when an error occurs.
> 
> Signed-off-by: James Morse <james.morse@....com>
> Tested-by: Carl Worth <carl@...amperecomputing.com> # arm64
> Tested-by: Shaopeng Tan <tan.shaopeng@...fujitsu.com>
> Reviewed-by: Shaopeng Tan <tan.shaopeng@...fujitsu.com>
> ---
> Changes since v4:
>  * Earlier __init marker removal migrated here.
> ---
>  arch/x86/kernel/cpu/resctrl/core.c     |  6 +++---
>  arch/x86/kernel/cpu/resctrl/internal.h |  6 +++---
>  arch/x86/kernel/cpu/resctrl/monitor.c  |  2 +-
>  arch/x86/kernel/cpu/resctrl/rdtgroup.c | 10 +++++-----
>  include/linux/resctrl.h                |  6 +++---
>  5 files changed, 15 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index f484726a2588..f713ac628444 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -775,7 +775,7 @@ struct rdt_options {
>  	bool	force_off, force_on;
>  };
>  
> -static struct rdt_options rdt_options[]  __initdata = {
> +static struct rdt_options rdt_options[]  __ro_after_init = {
>  	RDT_OPT(RDT_FLAG_CMT,	    "cmt",	X86_FEATURE_CQM_OCCUP_LLC),
>  	RDT_OPT(RDT_FLAG_MBM_TOTAL, "mbmtotal", X86_FEATURE_CQM_MBM_TOTAL),
>  	RDT_OPT(RDT_FLAG_MBM_LOCAL, "mbmlocal", X86_FEATURE_CQM_MBM_LOCAL),
> @@ -815,7 +815,7 @@ static int __init set_rdt_options(char *str)
>  }
>  __setup("rdt", set_rdt_options);
>  
> -bool __init rdt_cpu_has(int flag)
> +bool rdt_cpu_has(int flag)

I assume this can be dropped when resctrl_arch_is_evt_configurable() uses
a helper instead?


Reinette