]> git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blobdiff - arch/arm64/mm/init.c
arm64: limit memory regions based on DT property, usable-memory-range
[mirror_ubuntu-zesty-kernel.git] / arch / arm64 / mm / init.c
index 380ebe70509347f8c9329433a625527b65442aa6..3c41fd0bbce6f2329ce337e2f22a524680707c9d 100644 (file)
@@ -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