Re: [PATCH 2/2] arm: apply more __ro_after_init

From	Kees Cook <keescook@chromium.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 2/2] arm: apply more __ro_after_init
Date	2016-08-10 22:10 +0200
Message-ID	<s4HFM-12V-31@gated-at.bofh.it> (permalink)
References	<rG2kq-6QU-9@gated-at.bofh.it> <rG2kq-6QU-7@gated-at.bofh.it> <s4G70-8uN-47@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On Wed, Aug 10, 2016 at 2:43 AM, Russell King - ARM Linux
<linux@armlinux.org.uk> wrote:
> On Fri, Jun 03, 2016 at 11:40:24AM -0700, Kees Cook wrote:
>> @@ -1309,16 +1309,11 @@ void __init arm_mm_memblock_reserve(void)
>>   * Any other function or debugging method which may touch any device _will_
>>   * crash the kernel.
>>   */
>> +static char vectors[PAGE_SIZE * 2] __ro_after_init __aligned(PAGE_SIZE);
>>  static void __init devicemaps_init(const struct machine_desc *mdesc)
>>  {
>>       struct map_desc map;
>>       unsigned long addr;
>> -     void *vectors;
>> -
>> -     /*
>> -      * Allocate the vector page early.
>> -      */
>> -     vectors = early_alloc(PAGE_SIZE * 2);
>
> This one is not appropriate.  We _do_ write to these pages after init
> for FIQ handler updates.  See set_fiq_handler().

Ah, interesting. I guess none of that hardware is being tested on
linux-next. I'll drop that chunk and resubmit.

Thanks!

-Kees

-- 
Kees Cook
Nexus Security

Thread

Re: [PATCH 2/2] arm: apply more __ro_after_init Russell King - ARM Linux <linux@armlinux.org.uk> - 2016-08-10 20:30 +0200
  Re: [PATCH 2/2] arm: apply more __ro_after_init Arnd Bergmann <arnd@arndb.de> - 2016-08-10 21:50 +0200
    Re: [PATCH 2/2] arm: apply more __ro_after_init Kees Cook <keescook@chromium.org> - 2016-08-10 23:50 +0200
    Re: [PATCH 2/2] arm: apply more __ro_after_init Russell King - ARM Linux <linux@armlinux.org.uk> - 2016-08-11 01:10 +0200
      Re: [PATCH 2/2] arm: apply more __ro_after_init Arnd Bergmann <arnd@arndb.de> - 2016-08-11 18:00 +0200
        Re: [PATCH 2/2] arm: apply more __ro_after_init Kees Cook <keescook@chromium.org> - 2016-08-12 00:20 +0200
        Re: [PATCH 2/2] arm: apply more __ro_after_init Russell King - ARM Linux <linux@armlinux.org.uk> - 2016-08-12 18:30 +0200
  Re: [PATCH 2/2] arm: apply more __ro_after_init Kees Cook <keescook@chromium.org> - 2016-08-10 22:10 +0200
  Re: [PATCH 2/2] arm: apply more __ro_after_init Russell King - ARM Linux <linux@armlinux.org.uk> - 2016-08-10 22:30 +0200
  Re: [PATCH 2/2] arm: apply more __ro_after_init Arnd Bergmann <arnd@arndb.de> - 2016-08-10 23:50 +0200

csiph-web