linux-kernel - Re: [PATCH -next v4 03/19] arm64: entry: Remove __enter_from_user

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: <bcce44bc-5047-18d9-6cb3-4e664d99a129@huawei.com>
Date: Thu, 31 Oct 2024 11:40:40 +0800
From: Jinjie Ruan <ruanjinjie@...wei.com>
To: Mark Rutland <mark.rutland@....com>
CC: <oleg@...hat.com>, <linux@...linux.org.uk>, <will@...nel.org>,
	<catalin.marinas@....com>, <sstabellini@...nel.org>, <maz@...nel.org>,
	<tglx@...utronix.de>, <peterz@...radead.org>, <luto@...nel.org>,
	<kees@...nel.org>, <wad@...omium.org>, <akpm@...ux-foundation.org>,
	<samitolvanen@...gle.com>, <arnd@...db.de>, <ojeda@...nel.org>,
	<rppt@...nel.org>, <hca@...ux.ibm.com>, <aliceryhl@...gle.com>,
	<samuel.holland@...ive.com>, <paulmck@...nel.org>, <aquini@...hat.com>,
	<petr.pavlu@...e.com>, <viro@...iv.linux.org.uk>,
	<rmk+kernel@...linux.org.uk>, <ardb@...nel.org>,
	<wangkefeng.wang@...wei.com>, <surenb@...gle.com>,
	<linus.walleij@...aro.org>, <yangyj.ee@...il.com>, <broonie@...nel.org>,
	<mbenes@...e.cz>, <puranjay@...nel.org>, <pcc@...gle.com>,
	<guohanjun@...wei.com>, <sudeep.holla@....com>,
	<Jonathan.Cameron@...wei.com>, <prarit@...hat.com>, <liuwei09@...tc.cn>,
	<dwmw@...zon.co.uk>, <oliver.upton@...ux.dev>, <kristina.martsenko@....com>,
	<ptosi@...gle.com>, <frederic@...nel.org>, <vschneid@...hat.com>,
	<thiago.bauermann@...aro.org>, <joey.gouly@....com>,
	<liuyuntao12@...wei.com>, <leobras@...hat.com>,
	<linux-kernel@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>,
	<xen-devel@...ts.xenproject.org>
Subject: Re: [PATCH -next v4 03/19] arm64: entry: Remove
 __enter_from_user_mode()



On 2024/10/29 22:42, Mark Rutland wrote:
> On Fri, Oct 25, 2024 at 06:06:44PM +0800, Jinjie Ruan wrote:
>> The __enter_from_user_mode() is only called by enter_from_user_mode(),
>> so replaced it with enter_from_user_mode().
> 
> As with the next two patches, all the __enter_from_*() and __exit_to_*()
> are supposed to handle the raw entry, closely matching the generic code,
> and the non-underscored enter_from_*() and exit_to_*() functions are
> supposed to be wrappers that handle (possibly instrumentable)

Sure, the __enter_from_*() and __exit_to_*() is all about the generic
code, and the enter_from_*() and exit_to_*() includes arm64-specific MTE
  check.

> arm64-specific post-entry and pre-exit logic.
> 
> I would prefer to keep that split, even though enter_from_user_mode() is
> a trivial wrapper.
> 
> Am I missing some reason we must remove the wrappers?

It is not necessary to remove these functions, just found it by chance
and cleanup them by the way, originally I thought that removing the
underline function might make the relative order of the MTE functions
look clearer.

> 
> Mark.
> 
>>
>> No functional changes.
>>
>> Signed-off-by: Jinjie Ruan <ruanjinjie@...wei.com>
>> ---
>>  arch/arm64/kernel/entry-common.c | 7 +------
>>  1 file changed, 1 insertion(+), 6 deletions(-)
>>
>> diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
>> index 68a9aecacdb9..ccf59b44464d 100644
>> --- a/arch/arm64/kernel/entry-common.c
>> +++ b/arch/arm64/kernel/entry-common.c
>> @@ -109,7 +109,7 @@ static void noinstr exit_to_kernel_mode(struct pt_regs *regs,
>>   * Before this function is called it is not safe to call regular kernel code,
>>   * instrumentable code, or any code which may trigger an exception.
>>   */
>> -static __always_inline void __enter_from_user_mode(void)
>> +static __always_inline void enter_from_user_mode(struct pt_regs *regs)
>>  {
>>  	lockdep_hardirqs_off(CALLER_ADDR0);
>>  	CT_WARN_ON(ct_state() != CT_STATE_USER);
>> @@ -118,11 +118,6 @@ static __always_inline void __enter_from_user_mode(void)
>>  	mte_disable_tco_entry(current);
>>  }
>>  
>> -static __always_inline void enter_from_user_mode(struct pt_regs *regs)
>> -{
>> -	__enter_from_user_mode();
>> -}
>> -
>>  /*
>>   * Handle IRQ/context state management when exiting to user mode.
>>   * After this function returns it is not safe to call regular kernel code,
>> -- 
>> 2.34.1
>>
>