Date: Mon, 25 Jan 2010 12:51:29 -0800 From: Randall Stewart <rrs@lakerest.net> To: Neelkanth Natu <neelnatu@yahoo.com> Cc: freebsd-mips@freebsd.org Subject: Re: AR71XX RTC Message-ID: <5D3E417C-FE51-49A7-B8CC-564932BF0D3E@lakerest.net> In-Reply-To: <832529.2466.qm@web34404.mail.mud.yahoo.com> References: <832529.2466.qm@web34404.mail.mud.yahoo.com>
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Neil: Thanks for the patch.. it does look good since the old code was tromping part of the old threads PCB which is definitely not right ;-0 .. I do have a question for you.. forgive my ignorance.. What exactly are we trying to switch here. It seems that cpu_switch(...) is now being called with oldtd, newtd and mtx... I see that the thread structure has a struct mutex *td_lock as its first member. But what is this supposed to be pointing to? And when we switch are we trying to take the oldtd->td_lock and place it into the newtd->td_lock Or? What... I guess I just don't have any context for whats going on.. R On Jan 25, 2010, at 12:41 PM, Neelkanth Natu wrote: > Hi Warner, > > The patch looks good. Please commit it. > > The reason we started seeing this recently is because of this: > http://svn.freebsd.org/viewvc/base/head/sys/kern/sched_4bsd.c?r1=202889&r2=202888&pathrev=202889 > > In particular the call to thread_block_lock() will point 'td_lock' to > 'blocked_lock' and if we don't switch it back in cpu_switch() then > anybody trying to call thread_lock() on the thread will panic. > > best > Neel > > --- On Mon, 1/25/10, M. Warner Losh <imp@bsdimp.com> wrote: > >> From: M. Warner Losh <imp@bsdimp.com> >> Subject: Re: AR71XX RTC >> To: neelnatu@yahoo.com >> Cc: gonzo@bluezbox.com, smeagle@bsdler.de, freebsd-mips@FreeBSD.org >> Date: Monday, January 25, 2010, 8:31 AM >> In message: <434364.57659.qm@web34405.mail.mud.yahoo.com> >> Neelkanth Natu >> <neelnatu@yahoo.com> >> writes: >> : Hi Flo, >> : >> : Can you try the following patch and see if it helps with >> the >> : hang-followed-by-trap problem? >> : >> : I am seeing a similar problem on the Sibyte and this >> patch gets me >> : past it. >> : >> : best >> : Neel >> : >> : Index: swtch.S >> : >> =================================================================== >> : --- swtch.S (revision 202961) >> : +++ swtch.S (working copy) >> : @@ -323,7 +323,7 @@ >> : * to be saved with >> the other registers do so here. >> : */ >> : >> : - sw a3, >> TD_LOCK(a0) >> # Switchout td_lock >> : + sw a2, >> TD_LOCK(a3) >> # Switchout td_lock >> : >> : mips_sw1: >> : #if defined(SMP) && defined(SCHED_ULE) >> >> I really like this patch. For the OCTEON I went from >> having all kinds >> of head-scratcher problems on boot that I was about to look >> at >> instruction traces in the simulator to try to track down to >> an >> immediate mountroot> prompt. So after reading the >> code, my first >> reaction is "how the heck did the old code work as well as >> it did?" >> and my second reaction is "This is obviously the right fix >> since a3 is >> a saved copy of a0, and a0 points to the pcb at this point, >> not the >> old thread." >> >> I've touched up the comments a bit. Maybe the >> register assignments is >> a bit of overkill, but this is a complicated function >> that's very >> tricky. What do you think of this patch: >> >> Index: sys/mips/mips/swtch.S >> =================================================================== >> --- sys/mips/mips/swtch.S (revision >> 202867) >> +++ sys/mips/mips/swtch.S (working copy) >> @@ -282,9 +282,10 @@ >> END(mips_cpu_throw) >> >> /* >> - *XXX Fixme: should be written to new >> interface that requires lock >> - * storage. We >> fake it for now. >> - * cpu_switch(struct thread *old, struct thread *new); >> + * cpu_switch(struct thread *old, struct thread *new, >> struct mutex *mtx); >> + * a0 - old >> + * a1 - new >> + * a2 - mtx >> * Find the highest priority process and resume it. >> */ >> NON_LEAF(cpu_switch, STAND_FRAME_SIZE, ra) >> @@ -323,7 +324,7 @@ >> * to be saved with the other >> registers do so here. >> */ >> >> - sw a3, >> TD_LOCK(a0) >> # Switchout td_lock >> + sw a2, >> TD_LOCK(a3) >> # Switchout td_lock >> >> mips_sw1: >> #if defined(SMP) && defined(SCHED_ULE) >> >> >> Thanks for saving me hours of debugging. :) >> >> Warner >> >> >> : --- On Sun, 1/24/10, Florian Kruegl <smeagle@bsdler.de> >> wrote: >> : >> : > From: Florian Kruegl <smeagle@bsdler.de> >> : > Subject: Re: AR71XX RTC >> : > To: "Oleksandr Tymoshenko" <gonzo@bluezbox.com> >> : > Cc: freebsd-mips@freebsd.org >> : > Date: Sunday, January 24, 2010, 8:52 AM >> : > Hi, >> : > >> : > On Sun, 2010-01-24 at 02:41 +0100, Florian Kruegl >> wrote: >> : > > On Sat, 2010-01-23 at 16:53 -0800, Oleksandr >> : > Tymoshenko wrote: >> : > > > On 2010-01-23, at 4:44 PM, Florian Kruegl >> wrote: >> : > > > >> : > > > > Hi, >> : > > > > >> : > > > > On Sat, 2010-01-23 at 16:21 -0800, >> Oleksandr >> : > Tymoshenko wrote: >> : > > > >> On 2010-01-23, at 4:00 PM, >> Florian >> : > Kruegl wrote: >> : > > > >> >> : > > > >>> Hi, >> : > > > >>> >> : > > > >>> anyone working on pfc2123 >> driver for >> : > RouterStation Pro? >> : > > > >>> Seems quite well documented, >> one >> : > issue might be CS hack, but the rest >> : > > > >>> should be straight. >> : > > > >> Driver was commited >> : > yesterday: >> : > > > >> http://svn.freebsd.org/viewvc/base?view=revision&revision=202839 >> : > > > >> >> : > > > >> And yes, CS hack is the problem. >> I'm >> : > trying to figure out how to fit it into FreeBSD >> : > > > >> SPI framework. >> : > > > > >> : > > > > sounds good, will do an update as >> soon as i >> : > removed me work from code. >> : > > > > My CS "solution" was more than crude, >> but >> : > the frames simply didn't >> : > > > > fit... so I am looking forward for a >> : > different one :) >> : > > > >> : > > > Yeah, my CS solution was >> : > dirty hack too. If for "didn't fit" you mean missing >> last >> : > > > byte of frame then this problem was solved >> to. >> : > Bug was in AR71XX SPI code: falling >> : > > > edge was not provided for last byte in >> transfer >> : > in time and RTC chip acts of falling edge. >> : > > > Fix was committed before driver. >> : > > > >> : > > > >> : > > > >> : > > >> : > > code looks similar, can't tell much about >> result as >> : > kernel hangs for a >> : > > while before getting this: >> : > > >> : > >> <<<<<<<<<<<<<<<<<<<<<<<<<<< >> : > schnipp >> : > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >> : > > Trap cause = 2 (TLB miss (load or instr. fetch) >> - >> : > kernel mode) >> : > > [thread pid 4 tid 100009 ] >> : > > Stopped at >> : > _thread_lock_flags+0x150: >> : > lw v0,60(a3) >> : > > db> bt >> : > > Tracing pid 4 tid 100009 td 0xc0c47270 >> : > > db_trace_thread+30 (?,?,?,?) ra 800a6c10 sz 24 >> : > > 800a6af4+11c (0,?,ffffffff,?) ra 800a6604 sz >> 32 >> : > > 800a6270+394 (?,?,?,?) ra 800a6794 sz 168 >> : > > db_command_loop+78 (?,?,?,?) ra 800a8e68 sz 24 >> : > > 800a8d60+108 (?,?,?,?) ra 80215ff8 sz 424 >> : > > kdb_trap+f8 (?,?,?,?) ra 80474350 sz 32 >> : > > trap+134c (?,?,?,?) ra 8046b7fc sz 176 >> : > > MipsKernGenException+100 >> (b,173,804d5de8,deadc0d8) ra >> : > 801c593c sz 200 >> : > > _thread_lock_flags+130 (?,?,?,?) ra 80221f18 sz >> 56 >> : > > sleepq_broadcast+ac (?,?,?,?) ra 801e5f20 sz >> 40 >> : > > wakeup+2c (?,?,?,?) ra 8016de18 sz 32 >> : > > g_io_deliver+198 (?,?,?,?) ra 8016bbd4 sz 80 >> : > > 8016b590+644 (?,?,?,?) ra 8016e184 sz 104 >> : > > g_io_schedule_down+2ec (?,?,?,?) ra 8016eb94 sz >> 64 >> : > > 8016eb18+7c (?,?,?,?) ra 801a331c sz 24 >> : > > fork_exit+a0 (?,?,?,?) ra 80478f10 sz 48 >> : > > fork_trampoline+10 (?,?,?,?) ra 0 sz 0 >> : > > pid 4 >> : > > >> : > >> <<<<<<<<<<<<<<<<<<<<<<<<<<< >> : > schnapp >> : > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >> : > > >> : > > will use AR71XX as config file tomorrow, mine >> has many >> : > additional devs >> : > > configured for booting from usb devices. >> : > > >> : > [...] >> : > >> : > seems to make no difference. removed all mini pci >> : > devs and most code >> : > changes. kernel hangs during bootup for a while. >> then gets >> : > a trap. >> : > >> : > Source Info: >> : > >> : > -------------------------- schnipp >> : > -------------------------- >> : > brain:head> svn info >> : > Path: . >> : > URL: svn://svn.freebsd.org/base/head >> : > Repository Root: svn://svn.freebsd.org/base >> : > Repository UUID: >> ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f >> : > Revision: 202904 >> : > Node Kind: directory >> : > Schedule: normal >> : > Last Changed Author: marcel >> : > Last Changed Rev: 202904 >> : > Last Changed Date: 2010-01-24 00:16:50 +0100 (Sun, >> 24 Jan >> : > 2010) >> : > -------------------------- schnapp >> : > -------------------------- >> : > >> : > -------------------------- schnipp >> : > -------------------------- >> : > brain:head> svn stat >> : > ? GRTAGS >> : > ? GSYMS >> : > ? GTAGS >> : > ? GPATH >> : > M sys/kern/vfs_mount.c >> : > M sys/mips/conf/AR71XX >> : > ? sys/dev/pfc2123 >> : > -------------------------- schnapp >> : > -------------------------- >> : > >> : > - vfs_mount should be far away. >> : > - sys/dev/pfc2123 is no longer used. >> : > - sys/mips/conf/AR71XX altered to include >> pfc2123_rtc >> : > >> : > >> : > -------------------------- schnipp >> : > -------------------------- >> : > FreeBSD 9.0-CURRENT #1: Sun Jan 24 15:58:37 UTC >> 2010 >> : > >> : > root@pinky.lan.terror.local:/home/smeagle/obj/mips/mips/home/ >> smeagle/src/freebsd/head/sys/AR71XX >> : > mips >> : > real memory = 134217728 (131072K bytes) >> : > avail memory = 125689856 (119MB) >> : > nexus0: <MIPS32 root nexus> >> : > clock0: <Generic MIPS32 ticker> on nexus0 >> : > clock0: [FILTER] >> : > apb0 at irq 4 on nexus0 >> : > apb0: [FILTER] >> : > uart0: <16550 or compatible> on apb0 >> : > uart0: [FILTER] >> : > uart0: console (115200,n,8,1) >> : > pcib0 at irq 0 on nexus0 >> : > pcib0: [FILTER] >> : > pci0: <PCI bus> on pcib0 >> : > pci0: <old, non-VGA display device> at device >> 0.0 (no >> : > driver attached) >> : > pci0: <processor> at device 17.0 (no driver >> : > attached) >> : > arge0: <Atheros AR71xx built-in ethernet >> interface> >> : > at mem >> : > 0x19000000-0x19000fff irq 2 on nexus0 >> : > miibus0: <MII bus> on arge0 >> : > ukphy0: <Generic IEEE 802.3u media interface> >> PHY 4 >> : > on miibus0 >> : > ukphy0: 10baseT, 10baseT-FDX, 100baseTX, >> : > 100baseTX-FDX, 1000baseT-FDX, >> : > auto >> : > arge0: Ethernet address: 00:00:00:00:46:61 >> : > arge0: [FILTER+ITHREAD] >> : > arge1: <Atheros AR71xx built-in ethernet >> interface> >> : > at mem >> : > 0x1a000000-0x1a000fff irq 3 on nexus0 >> : > arge1: Ethernet address: 00:00:00:00:46:62 >> : > arge1: [FILTER+ITHREAD] >> : > spi0: <AR71XX SPI> at mem >> 0x1f000000-0x1f00000f on >> : > nexus0 >> : > spibus0: <spibus bus> on spi0 >> : > mx25l0: <M25Pxx Flash Family> at cs 0 on >> spibus0 >> : > mx25l0: mx25ll128, sector 65536 bytes, 256 sectors >> : > ar71xx_wdog0: <Atheros AR71XX watchdog timer> >> on >> : > nexus0 >> : > Timecounter "MIPS32" frequency 360000000 Hz quality >> 800 >> : > Timecounters tick every 1.000 msec >> : > bootpc_init: wired to interface 'arge0' >> : > Sending DHCP Discover packet from interface arge0 >> : > (00:00:00:00:46:61) >> : > arge0: link state changed to DOWN >> : > Trap cause = 2 (TLB miss (load or instr. fetch) - >> kernel >> : > mode) >> : > [thread pid 4 tid 100008 ] >> : > Stopped at >> : > _thread_lock_flags+0x150: >> : > lw v0,60(a3) >> : > db> bt >> : > Tracing pid 4 tid 100008 td 0xc0c414e0 >> : > db_trace_thread+30 (?,?,?,?) ra 80055900 sz 24 >> : > 800557e4+11c (0,?,ffffffff,?) ra 800552f4 sz 32 >> : > 80054f60+394 (?,?,?,?) ra 80055484 sz 168 >> : > db_command_loop+78 (?,?,?,?) ra 80057b58 sz 24 >> : > 80057a50+108 (?,?,?,?) ra 8017b7d8 sz 424 >> : > kdb_trap+f8 (?,?,?,?) ra 8035ab40 sz 32 >> : > trap+134c (?,?,?,?) ra 80351fec sz 176 >> : > MipsKernGenException+100 (b,173,8039ce74,deadc0d8) >> ra >> : > 8012c92c sz 200 >> : > _thread_lock_flags+130 (?,?,?,?) ra 801876f8 sz 56 >> : > sleepq_broadcast+ac (?,?,?,?) ra 8014b700 sz 40 >> : > wakeup+2c (?,?,?,?) ra 800d6ba8 sz 32 >> : > g_io_deliver+198 (?,?,?,?) ra 800d4964 sz 80 >> : > 800d4320+644 (?,?,?,?) ra 800d6f14 sz 104 >> : > g_io_schedule_down+2ec (?,?,?,?) ra 800d7924 sz 64 >> : > 800d78a8+7c (?,?,?,?) ra 8010c0ac sz 24 >> : > fork_exit+a0 (?,?,?,?) ra 8035f700 sz 48 >> : > fork_trampoline+10 (?,?,?,?) ra 0 sz 0 >> : > pid 4 >> : > -------------------------- schnapp >> : > -------------------------- >> : > >> : > >> : > >> : > >> : > Flo >> : > >> : > _______________________________________________ >> : > freebsd-mips@freebsd.org >> : > mailing list >> : > http://lists.freebsd.org/mailman/listinfo/freebsd-mips >> : > To unsubscribe, send any mail to "freebsd-mips-unsubscribe@freebsd.org >> " >> : > >> : >> : >> : >> : _______________________________________________ >> : freebsd-mips@freebsd.org >> mailing list >> : http://lists.freebsd.org/mailman/listinfo/freebsd-mips >> : To unsubscribe, send any mail to "freebsd-mips-unsubscribe@freebsd.org >> " >> : >> : >> > > > > _______________________________________________ > freebsd-mips@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-mips > To unsubscribe, send any mail to "freebsd-mips- > unsubscribe@freebsd.org" > ------------------------------ Randall Stewart 803-317-4952 (cell) 803-345-0391(direct)
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