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authorAKASHI Takahiro <takahiro.akashi@linaro.org>2017-04-03 11:24:31 +0900
committerAKASHI Takahiro <takahiro.akashi@linaro.org>2017-06-08 18:39:41 +0900
commit73e7edeb3263c5e5a918927d864da0d2a3459b30 (patch)
treee27f47b467d9f8ec38ec1a011d6fe840b1928aa1
parent0bbb3d8a67d4282e5ccd24430c9f3c8955b7e689 (diff)
downloadlinux-aarch64-73e7edeb3263c5e5a918927d864da0d2a3459b30.tar.gz
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>
-rw-r--r--arch/arm64/mm/init.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 380ebe705093..3c41fd0bbce6 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, &reg);
+ usablemem->size = dt_mem_next_cell(dt_root_size_cells, &reg);
+
+ 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, &reg);
+
+ 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