Hi Saurabh, On Wed, Nov 11, 2015 at 01:53:58PM +0530, Saurabh Sengar wrote: > 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 ?).
Seems OK. > 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 Nice! Glad to see you've tested quite a few good scenarios. > 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' > ------------------------------------------- This all looks very good. For the successful cases, it might be nice to make sure you can still read and write the "device". (Try dd on /dev/mtd0, or see mtd-utils for tools like flash_erase.) But you're not touching the actual I/O behavior, so this isn't so important. More importantly, it's good to test these cases too: * phram is built-in (not a module), with and without a phram= line on the commandline * writing to /sys/module/phram/parameters/phram (for both the module and built-in cases) Thanks, Brian -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
