Messages in this thread | | | Date | Thu, 16 Jun 2011 13:07:46 -0500 | From | Larry Finger <> | Subject | Re: Faking MMIO ops? Fooling a driver |
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On 06/16/2011 12:20 PM, Rafał Miłecki wrote: > W dniu 16 czerwca 2011 16:44 użytkownik Rafał Miłecki > <zajec5@gmail.com> napisał: >> I analyze MMIO dumps of closed source driver and found such a place: >> W 2 3855.911536 9 0xb06003fc 0x810 0x0 0 >> R 2 3855.911540 9 0xb06003fe 0x0 0x0 0 >> W 2 3855.911541 9 0xb06003fe 0x0 0x0 0 >> >> After translation: >> phy_read(0x0810) -> 0x0000 >> phy_write(0x0810)<- 0x0000 >> >> So it's quite obvious, the driver is reading PHY register, masking it >> and writing masked value. Unfortunately from just looking at such >> place we can not guess the mask driver uses. >> >> I'd like to fake value read from 0xb06003fe to be 0xFFFF. >> Is there some ready method for doing such a trick? >> >> Dump comes from Kernel hacking → Tracers → MMIO and ndiswrapper. > > I can see values in MMIO trace struct are filled in > arch/x86/mm/mmio-mod.c in "pre" and "post". However still no idea how > to hack the returned value. > > Should I try hacking read[bwl] instead? :|
Probably. I do not see any way to trace and modify the results for a particular address without special code.
FYI, my reference driver for reverse engineering has no instance of a read/modify/write for PHY register 0x810. Is the code in question for a PHY type > 6?
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