Hi Christophe, It testifys problem fixed when we use memcpy_toio() instead of memcpy In our practice, we found everything is ok before the cache_memcpy becomes memcpy in the Patch 0b05e2d671c40cfb57e66e4e402320d6e056b2f8 adopted, it accelerates the memcpy but introduces implicit trouble, our products commonly used memcpy for continuous matainance for a long time , but now those become a big problem for us to check where we use is correct and where is wrong, with respect to cachable_memcpy and memcpy_toio. So, I also want to ask, how can we trustly and unified fill the gap resulted by those changes in memcpy in version mantainance, if you have some tips pls tell me. Tthanks, your Shaobo Wang -----邮件原件----- 发件人: Christophe Leroy [mailto:christophe.leroy@xxxxxx] 发送时间: 2019年10月31日 19:13 收件人: Wangshaobo (bobo) <bobo.shaobowang@xxxxxxxxxx> 抄送: chengjian (D) <cj.chengjian@xxxxxxxxxx>; Libin (Huawei) <huawei.libin@xxxxxxxxxx>; Xiexiuqi <xiexiuqi@xxxxxxxxxx>; zhangyi (F) <yi.zhang@xxxxxxxxxx> 主题: Re: 答复: loop nesting in alignment exception and machine check Hi, Did you try ? Does it work ? Christophe Le 28/10/2019 à 06:57, Wangshaobo (bobo) a écrit : > Hi,Christophe > > Thank you for your quick reply. I will try to use memcpy_toio() instead of memcpy(). > > -----邮件原件----- > 发件人: Christophe Leroy [mailto:christophe.leroy@xxxxxx] > 发送时间: 2019年10月26日 19:20 > 收件人: Wangshaobo (bobo) <bobo.shaobowang@xxxxxxxxxx> > 抄送: linux-arch@xxxxxxxxxxxxxxx; alistair@xxxxxxxxxxxx; chengjian (D) > <cj.chengjian@xxxxxxxxxx>; Xiexiuqi <xiexiuqi@xxxxxxxxxx>; > linux-kernel@xxxxxxxxxxxxxxx; oss@xxxxxxxxxxxx; paulus@xxxxxxxxx; > Libin (Huawei) <huawei.libin@xxxxxxxxxx>; agust@xxxxxxx; > linuxppc-dev@xxxxxxxxxxxxxxxx > 主题: Re: loop nesting in alignment exception and machine check > > Hi, > > Le 26/10/2019 à 09:23, Wangshaobo (bobo) a écrit : >> Hi, >> >> I encountered a problem about a loop nesting occurred in >> manufacturing the alignment exception in machine check, trigger background is : >> >> problem: >> >> machine checkout or critical interrupt ->…->kbox_write[for recording >> last words] -> memcpy(irremap_addr, src,size):_GLOBAL(memcpy)… >> >> when we enter memcpy,a command ‘dcbz r11,r6’ will cause a alignment >> exception, in this situation,r11 loads the ioremap address,which >> leads to the alignment exception, > > You can't use memcpy() on something else than memory. > > For an ioremapped area, you have to use memcpy_toio() > > Christophe > >> >> then the command can not be process successfully,as we still in >> machine check.at the end ,it triggers a new irq machine check in irq >> handler function,a loop nesting begins. >> >> analysis: >> >> We have analysed a lot,but it still can not come to a reasonable >> description,in common,the alignment triggered in machine check >> context can still be collected into the Kbox >> >> after alignment exception be handled by handler function, but how >> does the machine checkout can be triggered in the handler fucntion >> for any causes? We print relevant registers >> >> as follow when first enter machine check and alignment exception >> handler >> function: >> >> MSR:0x2 MSR:0x0 >> >> SRR1:0x2 SRR1:0x21002 >> >> But the manual says SRR1 should be set to MSR(0x2),why >> that happened ? >> >> Then a branch in handler function copy the SRR1 to >> MSR,this enble MSR[ME] and MSR[CE],system collapses. >> >> Conclusion: >> >> 1) why the alignment exception can not be handled in >> machine check ? >> >> 2) besides memcpy,any other function can cause the >> alignment exception ? >> >> We still recurrent it, the line as follows: >> >> Cpu dead lock->watch log->trigger >> fiq->kbox_write->memcpy->alignment exception->print last words. >> >> but for those problems as below,what the kbox printed is empty. >> >> ------------------kbox restart:[ 10.147594]---------------- >> >> kbox verify fs magic fail >> >> kbox mem mabye destroyed, format it >> >> kbox: load OK >> >> lock-task: major[249] minor[0] >> >> -----start show_destroyed_kbox_mem_head---- >> >> 00000000: 00000000 00000000 00000000 00000000 ................ >> >> 00000010: 00000000 00000000 00000000 00000000 ................ >> >> 00000020: 00000000 00000000 00000000 00000000 ................ >> >> 00000030: 00000000 00000000 00000000 00000000 ................ >> >> 00000040: 00000000 00000000 00000000 00000000 ................ >> >> 00000050: 00000000 00000000 00000000 00000000 ................ >> >> 00000060: 00000000 00000000 00000000 00000000 ................ >> >> 00000070: 00000000 00000000 00000000 00000000 ................ >> >> 00000080: 00000000 00000000 00000000 00000000 ................ >> >> 00000090: 00000000 00000000 00000000 00000000 ................ >>
