Re: [PATCH] riscv: Protect kernel linear mapping only if CONFIG_STRICT_KERNEL_RWX is set

From: Alex Ghiti <alex@ghiti.fr>
To: Anup Patel <anup@brainfault.org>
Cc: Jonathan Corbet <corbet@lwn.net>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>, Arnd Bergmann <arnd@arndb.de>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Alexander Potapenko <glider@google.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	linux-doc@vger.kernel.org,
	linux-riscv <linux-riscv@lists.infradead.org>,
	"linux-kernel@vger.kernel.org List"
	<linux-kernel@vger.kernel.org>,
	kasan-dev@googlegroups.com,
	linux-arch <linux-arch@vger.kernel.org>,
	Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: [PATCH] riscv: Protect kernel linear mapping only if CONFIG_STRICT_KERNEL_RWX is set
Date: Fri, 16 Apr 2021 06:47:19 -0400	[thread overview]
Message-ID: <f659c498-a273-f249-a81b-cab1ed1ba2bb@ghiti.fr> (raw)
In-Reply-To: <CAAhSdy2pD2q99-g3QSSHbpqw1ZD402fStFmbKNFzht2m=MS8mQ@mail.gmail.com>

Hi Anup,

Le 4/16/21 à 6:41 AM, Anup Patel a écrit :
> On Thu, Apr 15, 2021 at 4:34 PM Alexandre Ghiti <alex@ghiti.fr> wrote:
>>
>> If CONFIG_STRICT_KERNEL_RWX is not set, we cannot set different permissions
>> to the kernel data and text sections, so make sure it is defined before
>> trying to protect the kernel linear mapping.
>>
>> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
> 
> Maybe you should add "Fixes:" tag in commit tag ?

Yes you're right I should have done that. Maybe Palmer will squash it as 
it just entered for-next?

> 
> Otherwise it looks good.
> 
> Reviewed-by: Anup Patel <anup@brainfault.org>

Thank you!

Alex

> 
> Regards,
> Anup
> 
>> ---
>>   arch/riscv/kernel/setup.c | 8 ++++----
>>   1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
>> index 626003bb5fca..ab394d173cd4 100644
>> --- a/arch/riscv/kernel/setup.c
>> +++ b/arch/riscv/kernel/setup.c
>> @@ -264,12 +264,12 @@ void __init setup_arch(char **cmdline_p)
>>
>>          sbi_init();
>>
>> -       if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
>> +       if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) {
>>                  protect_kernel_text_data();
>> -
>> -#if defined(CONFIG_64BIT) && defined(CONFIG_MMU)
>> -       protect_kernel_linear_mapping_text_rodata();
>> +#ifdef CONFIG_64BIT
>> +               protect_kernel_linear_mapping_text_rodata();
>>   #endif
>> +       }
>>
>>   #ifdef CONFIG_SWIOTLB
>>          swiotlb_init(1);
>> --
>> 2.20.1
>>
> 
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