From 917db484dc6a69969d317b3e57add4208a8d9d42 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 21 Sep 2016 12:50:45 -0700 Subject: [PATCH] x86/boot: Fix kdump, cleanup aborted E820_PRAM max_pfn manipulation 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 However, that approach was abandoned when Christoph ported the patches [1], and that functionality has since been replaced by devm_memremap_pages().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. [1]: https://lists.01.org/pipermail/linux-nvdimm/2015-March/000348.html [2]: https://bugzilla.redhat.com/show_bug.cgi?id=1351098 So fix it. Reported-by: Zhang Yi Reported-by: Jeff Moyer Tested-by: Zhang Yi Signed-off-by: Dan Williams Reviewed-by: Jeff Moyer Cc: # v4.1 and later kernels Cc: Andrew Morton Cc: Boaz Harrosh Cc: Christoph Hellwig Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Ross Zwisler Cc: Thomas Gleixner Cc: linux-nvdimm@lists.01.org Fixes: ec776ef6bbe1 ("x86/mm: Add support for the non-standard protected e820 type") Link: http://lkml.kernel.org/r/147448744538.34910.11287693517367139607.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/e820.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index bb8c690..b85fe5f 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -350,7 +350,7 @@ 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; @@ -783,7 +783,7 @@ 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; @@ -794,11 +794,7 @@ 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; @@ -823,12 +819,12 @@ 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 __init early_panic(char *msg) -- 2.7.4