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arm64: mark reserved memblock regions explicitly in iomem

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Kdump(kexec-tools) parses /proc/iomem to identify all the memory regions
on the system. Since the current kernel names "nomap" regions, like UEFI
runtime services code/data, as "System RAM," kexec-tools sets up elf core
header to include them in a crash dump file (/proc/vmcore).

Then crash dump kernel parses UEFI memory map again, re-marks those regions
as "nomap" and does not create a memory mapping for them unlike the other
areas of System RAM. In this case, copying /proc/vmcore through
copy_oldmem_page() on crash dump kernel will end up with a kernel abort,
as reported in [1].

This patch names all the "nomap" regions explicitly as "reserved" so that
we can exclude them from a crash dump file. acpi_os_ioremap() must also
be modified because those regions have WB attributes [2].

Apart from kdump, this change also matches x86's use of acpi (and
/proc/iomem).

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-August/448186.html
[2] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-August/450089.html

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: James Morse <james.morse@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
AKASHI Takahiro 2016-08-22 15:55:24 +09:00 committed by Will Deacon
parent 5ebe3a44cc
commit e7cd190385
2 changed files with 13 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
arch/arm64/include/asm/acpi.h
View File

@ -12,7 +12,7 @@
#ifndef _ASM_ACPI_H
#define _ASM_ACPI_H
#include <linux/mm.h>
#include <linux/memblock.h>
#include <linux/psci.h>
#include <asm/cputype.h>
@ -32,7 +32,11 @@
static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys,
acpi_size size)
{
if (!page_is_ram(phys >> PAGE_SHIFT))
/*
* EFI's reserve_regions() call adds memory with the WB attribute
* to memblock via early_init_dt_add_memory_arch().
*/
if (!memblock_is_memory(phys))
return ioremap(phys, size);
return ioremap_cache(phys, size);

9
arch/arm64/kernel/setup.c
View File

@ -206,10 +206,15 @@ static void __init request_standard_resources(void)
for_each_memblock(memory, region) {
res = alloc_bootmem_low(sizeof(*res));
res->name = "System RAM";
if (memblock_is_nomap(region)) {
res->name = "reserved";
res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
} else {
res->name = "System RAM";
res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
}
res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region));
res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1;
res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
request_resource(&iomem_resource, res);