FEX-Emu/linux
1
0
Fork 0
mirror of https://github.com/FEX-Emu/linux.git synced 2024-11-28 01:52:08 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity
dad4e5b390
linux/arch/x86
History
Mike Rapoport bde9cfa3af x86/setup: don't remove E820_TYPE_RAM for pfn 0 
Patch series "mm: fix initialization of struct page for holes in  memory layout", v3.

Commit 73a6e474cb ("mm: memmap_init: iterate over memblock regions
rather that check each PFN") exposed several issues with the memory map
initialization and these patches fix those issues.

Initially there were crashes during compaction that Qian Cai reported
back in April [1].  It seemed back then that the problem was fixed, but
a few weeks ago Andrea Arcangeli hit the same bug [2] and there was an
additional discussion at [3].

[1] https://lore.kernel.org/lkml/8C537EB7-85EE-4DCF-943E-3CC0ED0DF56D@lca.pw
[2] https://lore.kernel.org/lkml/20201121194506.13464-1-aarcange@redhat.com
[3] https://lore.kernel.org/mm-commits/20201206005401.qKuAVgOXr%akpm@linux-foundation.org

This patch (of 2):

The first 4Kb of memory is a BIOS owned area and to avoid its allocation
for the kernel it was not listed in e820 tables as memory.  As the result,
pfn 0 was never recognised by the generic memory management and it is not
a part of neither node 0 nor ZONE_DMA.

If set_pfnblock_flags_mask() would be ever called for the pageblock
corresponding to the first 2Mbytes of memory, having pfn 0 outside of
ZONE_DMA would trigger

	VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);

Along with reserving the first 4Kb in e820 tables, several first pages are
reserved with memblock in several places during setup_arch().  These
reservations are enough to ensure the kernel does not touch the BIOS area
and it is not necessary to remove E820_TYPE_RAM for pfn 0.

Remove the update of e820 table that changes the type of pfn 0 and move
the comment describing why it was done to trim_low_memory_range() that
reserves the beginning of the memory.

Link: https://lkml.kernel.org/r/20210111194017.22696-2-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-24 09:20:52 -08:00
..
boot EFI updates collected by Ard Biesheuvel: 2020-12-24 12:40:07 -08:00
configs * A defconfig fix, from Daniel Díaz. 2020-09-20 15:06:43 -07:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-12-14 12:18:19 -08:00
entry epoll: wire up syscall epoll_pwait2 2020-12-19 11:18:38 -08:00
events Perf updates: 2020-12-14 17:34:12 -08:00
hyperv x86/hyperv: Initialize clockevents after LAPIC is initialized 2021-01-17 15:20:50 +00:00
ia32 x86/ia32_signal: Propagate __user annotation properly 2020-12-11 19:44:31 +01:00
include hyperv-fixes for 5.11-rc4 2021-01-11 11:28:58 -08:00
kernel x86/setup: don't remove E820_TYPE_RAM for pfn 0 2021-01-24 09:20:52 -08:00
kvm x86: 2021-01-08 15:06:02 -08:00
lib Scheduler updates: 2020-12-14 18:29:11 -08:00
math-emu
mm x86/mm: Fix leak of pmd ptlock 2021-01-05 11:40:23 +01:00
net bpf: x64: Do not emit sub/add 0, %rsp when !stack_depth 2020-09-29 16:47:39 -07:00
oprofile x86/oprofile: Avoid TIF_IA32 when checking 64bit mode 2020-10-26 13:46:46 +01:00
pci ARM: SoC drivers for v5.11 2020-12-16 16:38:41 -08:00
platform Yet another large set of x86 interrupt management updates: 2020-12-14 18:59:53 -08:00
power
purgatory crypto: sha - split sha.h into sha1.h and sha2.h 2020-11-20 14:45:33 +11:00
ras
realmode x86/head/64: Don't call verify_cpu() on starting APs 2020-09-09 11:33:20 +02:00
tools x86/insn: Make inat-tables.c suitable for pre-decompression code 2020-09-07 19:45:24 +02:00
um arch/um: partially revert the conversion to __section() macro 2020-10-26 15:39:37 -07:00
video
xen xen: branch for v5.11-rc5 2021-01-20 11:46:38 -08:00
.gitignore
Kbuild
Kconfig fanotify: Fix sys_fanotify_mark() on native x86-32 2020-12-28 11:58:59 +01:00
Kconfig.assembler
Kconfig.cpu
Kconfig.debug x86, libnvdimm/test: Remove COPY_MC_TEST 2020-10-26 18:08:35 +01:00
Makefile - Fix the vmlinux size check on 64-bit along with adding useful clarifications on the topic 2020-12-14 13:54:50 -08:00
Makefile_32.cpu
Makefile.um