Re: [Crash-utility] [PATCH v3 0/3] vmalloc translation support for PPC

----- Original Message ----- > On 02/17/2012 12:43 AM, Dave Anderson wrote: >> >> >> ----- Original Message ----- >>> On 02/16/2012 09:52 PM, Dave Anderson wrote: >>>> >>>> >>>> ----- Original Message ----- >>>> ... >>>>>> So just do the same thing -- no verbose expanation is required. >>>>> >>>>> There are two ways to fix this : >>>>> >>>>> 1) Fix dump_mem_map*() to print the header only when there is >>>>> information to dump. >>>>> >>>>> --- a/memory.c >>>>> +++ b/memory.c >>>>> @@ -4637,13 +4637,6 @@ dump_mem_map_SPARSEMEM(struct meminfo >>>>> *mi) >>>>> continue; >>>>> } >>>>> >>>>> - if (print_hdr) { >>>>> - if (!(pc->curcmd_flags& >>>>> HEADER_PRINTED)) >>>>> - fprintf(fp, "%s", hdr); >>>>> - print_hdr = FALSE; >>>>> - pc->curcmd_flags |= HEADER_PRINTED; >>>>> - } >>>>> - >>>>> pp = section_mem_map_addr(section); >>>>> pp = sparse_decode_mem_map(pp, section_nr); >>>>> phys = (physaddr_t) section_nr * >>>>> PAGES_PER_SECTION() >>>>> * PAGESIZE(); >>>>> @@ -4854,6 +4847,13 @@ dump_mem_map_SPARSEMEM(struct meminfo >>>>> *mi) >>>>> } >>>>> >>>>> if (bufferindex> buffersize) { >>>>> + if (print_hdr) { >>>>> + if (!(pc->curcmd_flags& >>>>> HEADER_PRINTED)) >>>>> + fprintf(fp, >>>>> "%s", >>>>> hdr); >>>>> + print_hdr = FALSE; >>>>> + pc->curcmd_flags |= >>>>> HEADER_PRINTED; >>>>> + } >>>>> + >>>>> fprintf(fp, "%s", >>>>> outputbuffer); >>>>> bufferindex = 0; >>>>> } >>>>> @@ -4867,6 +4867,13 @@ dump_mem_map_SPARSEMEM(struct meminfo >>>>> *mi) >>>>> } >>>>> >>>>> if (bufferindex> 0) { >>>>> + if (print_hdr) { >>>>> + if (!(pc->curcmd_flags& >>>>> HEADER_PRINTED)) >>>>> + fprintf(fp, "%s", hdr); >>>>> + print_hdr = FALSE; >>>>> + pc->curcmd_flags |= HEADER_PRINTED; >>>>> + } >>>>> + >>>>> fprintf(fp, "%s", outputbuffer); >>>>> } >>>>> >>>>> Similarly for the dump_mem_map(). >>>>> >>>>> 2) Fix ppc_pgd_vtop() to return FALSE if the paddr> >>>>> machdep->memsize >>>>> >>>>> --- a/ppc.c >>>>> +++ b/ppc.c >>>>> @@ -438,6 +438,10 @@ ppc_pgd_vtop(ulong *pgd, ulong vaddr, >>>>> physaddr_t >>>>> *paddr, int verbose) >>>>> >>>>> *paddr = PAGEBASE(pte) + PAGEOFFSET(vaddr); >>>>> >>>>> + if (*paddr> machdep->memsize) >>>>> + /* We don't have pages above System RAM */ >>>>> + return FALSE; >>>>> + >>>>> return TRUE; >>>>> >>>>> no_page: >>>>> >>>>> I prefer the (1). What do you think ? >>>> >>>> Hi Suzuki, >>>> >>>> Hmmm -- with respect to (1), I suppose that would work, although >>>> given that both x86 and x86_64 pass through >>>> dump_mem_map_SPARSEMEM() >>>> without printing the header in a non-existent-page case, I don't >>>> understand why ppc is different? >>> Yep, I digged into that a little, but not deep enough to debug it >>> with >>> a dump. Nothing was evident from the code :(. >> >> Right -- I tried debugging it from the x86 and x86_64 perspective, >> and couldn't see why ppc would be different! ;-) > Ah, well, I was talking about the x86_64 dump. > I could explain the PPC side of affairs :-). We have page the > following > flags set for the page(with the actual PPC44x page flags support) : > > VIRTUAL PHYSICAL > d1002000 20ec00000 > > PAGE DIRECTORY: c0578000 > PGD: c0579a20 => c784b000 > PMD: c784b000 => c784b010 > PTE: c784b010 => 20ec0051b > PAGE: 20ec00000 > > PTE PHYSICAL FLAGS > 20ec0051b 20ec00000 (PRESENT|RW|GUARDED|NO_CACHE|DIRTY|ACCESSED) > > > So the page is 'present', but there is no page descriptor associated > with it. > Hence dump_mem_map() would still be called and hence the problem. > > Why doesn't it get called in x86_64 case even when the flags indicate > page 'PRESENT' ? I don't know -- that's what I was asking!

>> if ((pc->flags & DEVMEM) && (paddr >= VTOP(vt->high_memory))) <<

in all cases with the patch to do_vtop().