lkml.org 
[lkml]   [2015]   [Nov]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[PATCH] mtd: phram: error handling
Date

Brian Norris wrote:
> Well, today you're in luck! You're touching a driver that requires no
> special hardware, so you should be able to test it.

> I think you can try using the mem= kernel parameter (see
> Documentation/kernel-parameters.txt) to restrict your system memory, and
> then try using that unreachable portions of memory for phram. You can
> try this driver as either a module or built-in. For the former, you can
> specify the parameters during modprobe time, or later by writing to
> /sys/module/phram/parameters/phram. For the latter, you can specify on
> the kernel command line or in /sys/module/phram/parameters/phram.

> Let me know if you have any more questions about testing your patch.


Hi Brian,

As you have suggested I have restricted my laptop's memory to 1GB and tried to access unreachable portion of memory(2GB).
It seems to be successfully registered(this is OK right ?).

I have also tested below error scenarios; all exiting gracefully
- parameter too long
- too many arguments
- not enough arguments
- invalid start adddress
- invalid device length


This is my first interaction with phram device so I request you to verify my testing.
Below are the commands and output I did for this testing.

-----------------------------------------------------
<restricting memory of my machine to 1 GB>
saurabh@saurabh:~/little/Task02/linux$ cat /proc/meminfo | grep Mem
MemTotal: 1016588 kB
MemFree: 126016 kB
MemAvailable: 295508 kB
saurabh@saurabh:~/little/Task02/linux$ cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-4.3.0-10333-gdfe4330-dirty mem=1024M root=UUID=2b66d4b2-ac21-4554-bf3b-64bc973e1dad ro quiet splash vt.handoff=7

<accessing unreachable portions of memory>
saurabh@saurabh:~/little/Task02/linux$ sudo insmod drivers/mtd/devices/phram.ko phram=ram,2048Mi,1ki
saurabh@saurabh:~/little/Task02/linux$ sudo dmesg -c
[ 634.748495] phram: ram device: 0x400 at 0x80000000

<parameter too long>
saurabh@saurabh:~/little/Task02/linux$ sudo insmod drivers/mtd/devices/phram.ko phram=abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz,256Mi,1Mi
insmod: ERROR: could not insert module drivers/mtd/devices/phram.ko: Invalid parameters
saurabh@saurabh:~/little/Task02/linux$ sudo dmesg -c
[ 1469.763787] phram: parameter too long
[ 1469.763797] phram: `abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz,256Mi,1Mi' invalid for parameter `phram'


<too many arguments>
saurabh@saurabh:~/little/Task02/linux$ sudo insmod drivers/mtd/devices/phram.ko phram=swap,256Mi,1Mi,extra_parameter
insmod: ERROR: could not insert module drivers/mtd/devices/phram.ko: Invalid parameters
saurabh@saurabh:~/little/Task02/linux$ sudo dmesg -c
[ 1650.081694] phram: too many arguments
[ 1650.081703] phram: `swap,256Mi,1Mi,extra_parameter' invalid for parameter `phram'

<not enough arguments>
saurabh@saurabh:~/little/Task02/linux$ sudo insmod drivers/mtd/devices/phram.ko phram=swap,256Mi
insmod: ERROR: could not insert module drivers/mtd/devices/phram.ko: Invalid parameters
saurabh@saurabh:~/little/Task02/linux$ sudo dmesg -c
[ 1707.437130] phram: not enough arguments
[ 1707.437138] phram: `swap,256Mi' invalid for parameter `phram'


<invalid start address>
saurabh@saurabh:~/little/Task02/linux$ sudo insmod drivers/mtd/devices/phram.ko phram=swap,256xyz,1Mi
insmod: ERROR: could not insert module drivers/mtd/devices/phram.ko: Invalid parameters
saurabh@saurabh:~/little/Task02/linux$ sudo dmesg -c
[ 1783.014351] phram: invalid start address
[ 1783.014359] phram: `swap,256xyz,1Mi' invalid for parameter `phram'

<invalid device length>
saurabh@saurabh:~/little/Task02/linux$ sudo insmod drivers/mtd/devices/phram.ko phram=swap,256Mi,1xyz
insmod: ERROR: could not insert module drivers/mtd/devices/phram.ko: Invalid parameters
saurabh@saurabh:~/little/Task02/linux$ sudo dmesg -c
[ 1831.746108] phram: invalid device length
[ 1831.746117] phram: `swap,256Mi,1xyz' invalid for parameter `phram'
-------------------------------------------


\
 
 \ /
  Last update: 2015-11-11 09:41    [W:0.088 / U:0.048 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site