Date: Sat, 04 Aug 2018 09:25:47 -0600 From: Ian Lepore <ian@freebsd.org> To: Konstantin Belousov <kostikbel@gmail.com>, Kyle Evans <kevans@freebsd.org> Cc: freebsd-current Current <freebsd-current@freebsd.org>, Eitan Adler <eadler@freebsd.org> Subject: Re: panic: mutex pmap not owned at ... efirt_machdep.c:255 Message-ID: <1533396347.9860.11.camel@freebsd.org> In-Reply-To: <20180804152225.GP6049@kib.kiev.ua> References: <CAF6rxg=4OnHEJa1OnJerMeEKD66nZg3j-H-XZ-9YAA1TE_NoDQ@mail.gmail.com> <CACNAnaFv9Gj%2BM2Gb8FbwY5q56dnTR6OgjZ5qth9gjr8LreHeow@mail.gmail.com> <20180804083720.GJ6049@kib.kiev.ua> <CACNAnaGZJxm=_oM_f0xinUe2NZ=tZn3w%2BnLTE62_r9EAm0UuTA@mail.gmail.com> <20180804131352.GL6049@kib.kiev.ua> <CACNAnaFUto6gSaDx3vrgnSykRfBhV_Mgx4OLaXJgENvgqjgSHg@mail.gmail.com> <1533394281.9860.5.camel@freebsd.org> <CACNAnaF9vqxrKsOUDTjMhHOyTX==0irDbrHrmLbHUZ_kqH1MSg@mail.gmail.com> <20180804152225.GP6049@kib.kiev.ua>
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On Sat, 2018-08-04 at 18:22 +0300, Konstantin Belousov wrote: > On Sat, Aug 04, 2018 at 09:58:43AM -0500, Kyle Evans wrote: > > > > On Sat, Aug 4, 2018 at 9:51 AM, Ian Lepore <ian@freebsd.org> wrote: > > > > > > On Sat, 2018-08-04 at 08:56 -0500, Kyle Evans wrote: > > > > > > > > On Sat, Aug 4, 2018 at 8:13 AM, Konstantin Belousov <kostikbel@ > > > > gmail. > > > > com> wrote: > > > > > > > > > > > > > > > On Sat, Aug 04, 2018 at 08:05:24AM -0500, Kyle Evans wrote: > > > > > > > > > > > > > > > > > > On Sat, Aug 4, 2018 at 3:37 AM, Konstantin Belousov <kostik > > > > > > bel@gm > > > > > > ail.com> wrote: > > > > > > > > > > > > > > > > > > > > > On Fri, Aug 03, 2018 at 11:27:02PM -0500, Kyle Evans > > > > > > > wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > This seems odd- pmap lock is acquired at [1], then > > > > > > > > asserted > > > > > > > > shortly > > > > > > > > later at [2]... I avoid some of this stuff as well as I > > > > > > > > can, > > > > > > > > but is it > > > > > > > > actually possible for PCPU_GET(...) acquired curpmap to > > > > > > > > not > > > > > > > > match > > > > > > > > curthread->td_proc->p_vmspace->vm_pmap in this context? > > > > > > > > > > > > > > > > [1] https://svnweb.freebsd.org/base/head/sys/dev/efidev > > > > > > > > /efirt > > > > > > > > .c?view=markup#l260 > > > > > > > > [2] https://svnweb.freebsd.org/base/head/sys/amd64/amd6 > > > > > > > > 4/efir > > > > > > > > t_machdep.c?view=markup#l254 > > > > > > > There could be that curpcpu not yet synced with proc0 > > > > > > > pmap. It > > > > > > > could be > > > > > > > fixed. > > > > > > > > > > > > > > But it is not clear to me why efi_arch_enter() is called > > > > > > > there. I see > > > > > > > the check for GetTime belonging to the range described by > > > > > > > a map > > > > > > > descriptor. > > > > > > > I do not see why do you need an enter into the EFI > > > > > > > context for > > > > > > > comparing > > > > > > > integers. > > > > > > This probably could have been documented better, but > > > > > > efi_runtime > > > > > > pointer may (always?) point into runtime service memory > > > > > > that > > > > > > isn't > > > > > > valid/available at that point, so we get a fault and panic > > > > > > when > > > > > > dereferencing it to grab rt_gettime address. We ran into > > > > > > this > > > > > > wall > > > > > > when adding the check originally. > > > > > Wouldn't it be enough to access it by translating physical > > > > > address > > > > > into > > > > > DMAP ? > > > > Ah, sure, sure. [1] is proper form, yeah? > > > > > > > > [1] https://people.freebsd.org/~kevans/efi-dmap.diff > > > What do we do on 32-bit arm that has no dmap but may have efi > > > runtime > > > support? > > > > > This should probably just be compiled out for !arm64 && !x86 - its > > sole purpose was to compensate for outdated loader.efi that hasn't > > done the SetVirtualAddressMap. EFI on 32-bit ARM is "new" enough > > that > > it shouldn't have this problem. > Does EFI on 32bit arm have RT support ? I suspect the uboot implementation doesn't, but I can't think of any reason why other implementations are not possible/available. In particular, even 32bit arm supports virtualization and such an environment could provide rt support. -- Ian
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