W dniu 16 czerwca 2011 21:34 uÅytkownik Pekka Paalanen <pq@xxxxxx> napisaÅ: > On Thu, 16 Jun 2011 21:19:04 +0200 > RafaÅ MiÅecki <zajec5@xxxxxxxxx> wrote: > >> W dniu 16 czerwca 2011 20:07 uÅytkownik Larry Finger >> <Larry.Finger@xxxxxxxxxxxx> napisaÅ: >> > On 06/16/2011 12:20 PM, RafaÅ MiÅecki wrote: >> >> >> >> W dniu 16 czerwca 2011 16:44 uÅytkownik RafaÅ MiÅecki >> >> <zajec5@xxxxxxxxx> ÂnapisaÅ: >> >>> >> >>> 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: >> >>> Âphy_read(0x0810) -> Â0x0000 >> >>> 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 â Tracers â 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. > > If you want to do it that way, the idea is to overwrite > the right CPU register in mmio-mod.c:post(). You would test for > the address you want to mess with, and then "invert" > get_ins_reg_val() to overwrite the register with your own value. Good, idea thanks! >> >> 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. >> >> Did you success with writing some special code? Following patch >> does not seem to work for me: >> >> >> diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h >> index e0ffa3d..448e4ff 100644 >> --- a/include/asm-generic/io.h >> +++ b/include/asm-generic/io.h >> @@ -23,6 +23,8 @@ >> Â#define mmiowb() do {} while (0) >> Â#endif >> >> +static int zajec = 0; >> + >> Â/*****************************************************************************/ >> Â/* >> Â * readX/writeX() are used to access memory mapped devices. On >> some @@ -40,6 +42,11 @@ static inline u8 __raw_readb(const >> volatile void __iomem *addr) >> Â#ifndef __raw_readw >> Âstatic inline u16 __raw_readw(const volatile void __iomem *addr) >> Â{ >> + Â Â if (zajec++ < 10) >> + Â Â Â Â Â Â printk(KERN_INFO "[ZAJEC] %d\n", *addr); >> + Â Â if (*addr == 0xfaafc000) >> + Â Â Â Â Â Â printk(KERN_INFO "[ZAJEC] Bingo!\n"); >> + Â Â //0x1381a8d8 >> Â Â Â return *(const volatile u16 __force *) addr; >> Â} >> Â#endif >> >> Should I modify different readw? Path include/asm-generic/io.h >> sounds sane to me, so I modified this one. > > Are you sure that code is ever used on your arch? > For instance, it seems that arch/x86/include/asm/io.h > defines a different __raw_readw. You're right, I was using wrong file. Anyway it's too low level stuff to use printk here. So thank you for the other suggested method! -- RafaÅ -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html