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author | AKASHI Takahiro <takahiro.akashi@linaro.org> | 2017-04-03 02:24:31 (GMT) |
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committer | AKASHI Takahiro <takahiro.akashi@linaro.org> | 2017-06-08 09:39:41 (GMT) |
commit | 73e7edeb3263c5e5a918927d864da0d2a3459b30 (patch) | |
tree | e27f47b467d9f8ec38ec1a011d6fe840b1928aa1 /arch/arm64/mm | |
parent | 0bbb3d8a67d4282e5ccd24430c9f3c8955b7e689 (diff) | |
download | linux-73e7edeb3263c5e5a918927d864da0d2a3459b30.tar.xz |
arm64: limit memory regions based on DT property, usable-memory-range
Crash dump kernel uses only a limited range of available memory as System
RAM. On arm64 kdump, This memory range is advertised to crash dump kernel
via a device-tree property under /chosen,
linux,usable-memory-range = <BASE SIZE>
Crash dump kernel reads this property at boot time and calls
memblock_cap_memory_range() to limit usable memory which are listed either
in UEFI memory map table or "memory" nodes of a device tree blob.
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Geoff Levand <geoff@infradead.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/mm')
-rw-r--r-- | arch/arm64/mm/init.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 380ebe7..3c41fd0 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -187,10 +187,45 @@ static int __init early_mem(char *p) } early_param("mem", early_mem); +static int __init early_init_dt_scan_usablemem(unsigned long node, + const char *uname, int depth, void *data) +{ + struct memblock_region *usablemem = data; + const __be32 *reg; + int len; + + if (depth != 1 || strcmp(uname, "chosen") != 0) + return 0; + + reg = of_get_flat_dt_prop(node, "linux,usable-memory-range", &len); + if (!reg || (len < (dt_root_addr_cells + dt_root_size_cells))) + return 1; + + usablemem->base = dt_mem_next_cell(dt_root_addr_cells, ®); + usablemem->size = dt_mem_next_cell(dt_root_size_cells, ®); + + return 1; +} + +static void __init fdt_enforce_memory_region(void) +{ + struct memblock_region reg = { + .size = 0, + }; + + of_scan_flat_dt(early_init_dt_scan_usablemem, ®); + + if (reg.size) + memblock_cap_memory_range(reg.base, reg.size); +} + void __init arm64_memblock_init(void) { const s64 linear_region_size = -(s64)PAGE_OFFSET; + /* Handle linux,usable-memory-range property */ + fdt_enforce_memory_region(); + /* * Ensure that the linear region takes up exactly half of the kernel * virtual address space. This way, we can distinguish a linear address |