arm64: kdump: provide /proc/vmcore file
Arch-specific functions are added to allow for implementing a crash dump file interface, /proc/vmcore, which can be viewed as a ELF file. A user space tool, like kexec-tools, is responsible for allocating a separate region for the core's ELF header within crash kdump kernel memory and filling it in when executing kexec_load(). Then, its location will be advertised to crash dump kernel via a new device-tree property, "linux,elfcorehdr", and crash dump kernel preserves the region for later use with reserve_elfcorehdr() at boot time. On crash dump kernel, /proc/vmcore will access the primary kernel's memory with copy_oldmem_page(), which feeds the data page-by-page by ioremap'ing it since it does not reside in linear mapping on crash dump kernel. Meanwhile, elfcorehdr_read() is simple as the region is always mapped. Signed-off-by:AKASHI Takahiro <takahiro.akashi@linaro.org> Reviewed-by:
James Morse <james.morse@arm.com> Acked-by:
Catalin Marinas <catalin.marinas@arm.com> Signed-off-by:
Catalin Marinas <catalin.marinas@arm.com>
parent
20a16624