4.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx> commit e7cd190385d17790cc3eb3821b1094b00aacf325 upstream. 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@xxxxxxx> Tested-by: James Morse <james.morse@xxxxxxx> Reviewed-by: James Morse <james.morse@xxxxxxx> Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx> Signed-off-by: Will Deacon <will.deacon@xxxxxxx> Cc: Matthias Brugger <mbrugger@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/arm64/include/asm/acpi.h | 8 ++++++-- arch/arm64/kernel/setup.c | 9 +++++++-- 2 files changed, 13 insertions(+), 4 deletions(-) --- a/arch/arm64/include/asm/acpi.h +++ b/arch/arm64/include/asm/acpi.h @@ -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); --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -206,10 +206,15 @@ static void __init request_standard_reso 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); -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html