releases/4.8.16/arm64-mark-reserved-memblock-regions-explicitly-in-iomem.patch

   1 From e7cd190385d17790cc3eb3821b1094b00aacf325 Mon Sep 17 00:00:00 2001
   2 From: AKASHI Takahiro <takahiro.akashi@linaro.org>
   3 Date: Mon, 22 Aug 2016 15:55:24 +0900
   4 Subject: arm64: mark reserved memblock regions explicitly in iomem
   5
   6 From: AKASHI Takahiro <takahiro.akashi@linaro.org>
   7
   8 commit e7cd190385d17790cc3eb3821b1094b00aacf325 upstream.
   9
  10 Kdump(kexec-tools) parses /proc/iomem to identify all the memory regions
  11 on the system. Since the current kernel names "nomap" regions, like UEFI
  12 runtime services code/data, as "System RAM," kexec-tools sets up elf core
  13 header to include them in a crash dump file (/proc/vmcore).
  14
  15 Then crash dump kernel parses UEFI memory map again, re-marks those regions
  16 as "nomap" and does not create a memory mapping for them unlike the other
  17 areas of System RAM. In this case, copying /proc/vmcore through
  18 copy_oldmem_page() on crash dump kernel will end up with a kernel abort,
  19 as reported in [1].
  20
  21 This patch names all the "nomap" regions explicitly as "reserved" so that
  22 we can exclude them from a crash dump file. acpi_os_ioremap() must also
  23 be modified because those regions have WB attributes [2].
  24
  25 Apart from kdump, this change also matches x86's use of acpi (and
  26 /proc/iomem).
  27
  28 [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-August/448186.html
  29 [2] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-August/450089.html
  30
  31 Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
  32 Tested-by: James Morse <james.morse@arm.com>
  33 Reviewed-by: James Morse <james.morse@arm.com>
  34 Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
  35 Signed-off-by: Will Deacon <will.deacon@arm.com>
  36 Cc: Matthias Brugger <mbrugger@suse.com>
  37 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  38
  39 ---
  40  arch/arm64/include/asm/acpi.h |    8 ++++++--
  41  arch/arm64/kernel/setup.c     |    9 +++++++--
  42  2 files changed, 13 insertions(+), 4 deletions(-)
  43
  44 --- a/arch/arm64/include/asm/acpi.h
  45 +++ b/arch/arm64/include/asm/acpi.h
  46 @@ -12,7 +12,7 @@
  47  #ifndef _ASM_ACPI_H
  48  #define _ASM_ACPI_H
  49
  50 -#include <linux/mm.h>
  51 +#include <linux/memblock.h>
  52  #include <linux/psci.h>
  53
  54  #include <asm/cputype.h>
  55 @@ -32,7 +32,11 @@
  56  static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys,
  57                                             acpi_size size)
  58  {
  59 -       if (!page_is_ram(phys >> PAGE_SHIFT))
  60 +       /*
  61 +        * EFI's reserve_regions() call adds memory with the WB attribute
  62 +        * to memblock via early_init_dt_add_memory_arch().
  63 +        */
  64 +       if (!memblock_is_memory(phys))
  65                 return ioremap(phys, size);
  66
  67         return ioremap_cache(phys, size);
  68 --- a/arch/arm64/kernel/setup.c
  69 +++ b/arch/arm64/kernel/setup.c
  70 @@ -206,10 +206,15 @@ static void __init request_standard_reso
  71
  72         for_each_memblock(memory, region) {
  73                 res = alloc_bootmem_low(sizeof(*res));
  74 -               res->name  = "System RAM";
  75 +               if (memblock_is_nomap(region)) {
  76 +                       res->name  = "reserved";
  77 +                       res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
  78 +               } else {
  79 +                       res->name  = "System RAM";
  80 +                       res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
  81 +               }
  82                 res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region));
  83                 res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1;
  84 -               res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
  85
  86                 request_resource(&iomem_resource, res);
  87