| Message ID | 147448744538.34910.11287693517367139607.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Dan Williams <dan.j.williams@intel.com> writes: > In commit ec776ef6bbe1 "x86/mm: Add support for the non-standard > protected e820 type" Christoph references the original patch I wrote > implementing pmem support. The intent of the 'max_pfn' changes in that > commit were to enable persistent memory ranges to be covered by the > struct page memmap by default. However, that approach was abandoned > when Christoph ported the patches [1], and that functionality has since > been replaced by devm_memremap_pages(). > > In the meantime, this max_pfn manipulation is confusing kdump [2] that > assumes that everything covered by the max_pfn is "System RAM". This > results in kdump hanging or crashing. That was my assumption, I'm not certain that the kdump code is assuming the pmem region is usable as RAM. The end result is a hung kdump kernel. > [1]: https://lists.01.org/pipermail/linux-nvdimm/2015-March/000348.html > [2]: https://bugzilla.redhat.com/show_bug.cgi?id=1351098 > > Cc: Christoph Hellwig <hch@lst.de> > Cc: Ross Zwisler <ross.zwisler@linux.intel.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Boaz Harrosh <boaz@plexistor.com> > Cc: H. Peter Anvin <hpa@zytor.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@kernel.org> > Reported-by: Zhang Yi <yizhan@redhat.com> > Reported-by: Jeff Moyer <jmoyer@redhat.com> > Tested-by: Zhang Yi <yizhan@redhat.com> I actually did the testing. You can leave that line as is, though, as I'm sure Yi will also test it. :) > Fixes: ec776ef6bbe1 ("x86/mm: Add support for the non-standard protected e820 type") > Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Thanks, Dan! -Jeff
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index 621b501f8935..8a90f1517837 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -348,7 +348,7 @@ int __init sanitize_e820_map(struct e820entry *biosmap, int max_nr_map, * continue building up new bios map based on this * information */ - if (current_type != last_type || current_type == E820_PRAM) { + if (current_type != last_type) { if (last_type != 0) { new_bios[new_bios_entry].size = change_point[chgidx]->addr - last_addr; @@ -754,7 +754,7 @@ u64 __init early_reserve_e820(u64 size, u64 align) /* * Find the highest page frame number we have available */ -static unsigned long __init e820_end_pfn(unsigned long limit_pfn) +static unsigned long __init e820_end_pfn(unsigned long limit_pfn, unsigned type) { int i; unsigned long last_pfn = 0; @@ -765,11 +765,7 @@ static unsigned long __init e820_end_pfn(unsigned long limit_pfn) unsigned long start_pfn; unsigned long end_pfn; - /* - * Persistent memory is accounted as ram for purposes of - * establishing max_pfn and mem_map. - */ - if (ei->type != E820_RAM && ei->type != E820_PRAM) + if (ei->type != type) continue; start_pfn = ei->addr >> PAGE_SHIFT; @@ -794,12 +790,12 @@ static unsigned long __init e820_end_pfn(unsigned long limit_pfn) } unsigned long __init e820_end_of_ram_pfn(void) { - return e820_end_pfn(MAX_ARCH_PFN); + return e820_end_pfn(MAX_ARCH_PFN, E820_RAM); } unsigned long __init e820_end_of_low_ram_pfn(void) { - return e820_end_pfn(1UL << (32-PAGE_SHIFT)); + return e820_end_pfn(1UL << (32 - PAGE_SHIFT), E820_RAM); } static void early_panic(char *msg)