[PATCH] csky: Add setup_initrd check code

[guoren]

From: Guo Ren <ren_...@c-sky.com>

We should give some necessary check for initrd just like other
architectures and it seems that setup_initrd() could be a common
code for all architectures.

Signed-off-by: Guo Ren <ren_...@c-sky.com>
---
 arch/csky/kernel/setup.c |  3 ---
 arch/csky/mm/init.c      | 44 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/arch/csky/kernel/setup.c b/arch/csky/kernel/setup.c
index 23ee604..a00f8a0 100644
--- a/arch/csky/kernel/setup.c
+++ b/arch/csky/kernel/setup.c
@@ -47,9 +47,6 @@ static void __init csky_memblock_init(void)
        signed long size;
 
        memblock_reserve(__pa(_stext), _end - _stext);
-#ifdef CONFIG_BLK_DEV_INITRD
-       memblock_reserve(__pa(initrd_start), initrd_end - initrd_start);
-#endif
 
        early_init_fdt_reserve_self();
        early_init_fdt_scan_reserved_mem();
diff --git a/arch/csky/mm/init.c b/arch/csky/mm/init.c
index d4c2292..48f791d 100644
--- a/arch/csky/mm/init.c
+++ b/arch/csky/mm/init.c
@@ -35,6 +35,45 @@ unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned 
long)]
                                                __page_aligned_bss;
 EXPORT_SYMBOL(empty_zero_page);
 
+#ifdef CONFIG_BLK_DEV_INITRD
+static void __init setup_initrd(void)
+{
+       unsigned long size;
+
+       if (initrd_start >= initrd_end) {
+               pr_err("initrd not found or empty");
+               goto disable;
+       }
+
+       if (__pa(initrd_end) > PFN_PHYS(max_low_pfn)) {
+               pr_err("initrd extends beyond end of memory");
+               goto disable;
+       }
+
+       size = initrd_end - initrd_start;
+
+       if (memblock_is_region_reserved(__pa(initrd_start), size)) {
+               pr_err("INITRD: 0x%08lx+0x%08lx overlaps in-use memory region",
+                      __pa(initrd_start), size);
+               goto disable;
+       }
+
+       memblock_reserve(__pa(initrd_start), size);
+
+       pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",
+               (void *)(initrd_start), size);
+
+       initrd_below_start_ok = 1;
+
+       return;
+
+disable:
+       initrd_start = initrd_end = 0;
+
+       pr_err(" - disabling initrd\n");
+}
+#endif
+
 void __init mem_init(void)
 {
 #ifdef CONFIG_HIGHMEM
@@ -57,6 +96,11 @@ void __init mem_init(void)
                        free_highmem_page(page);
        }
 #endif
+
+#ifdef CONFIG_BLK_DEV_INITRD
+       setup_initrd();
+#endif
+
        mem_init_print_info(NULL);
 }
 
-- 
2.7.4