[MIPS] setup.c: clean up initrd related code

Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 48 insertions, 27 deletions

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index b52cc9763763..89440a0d8528 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -145,13 +145,12 @@ static int __init rd_start_early(char *p)
         unsigned long start = memparse(p, &p);
 
 #ifdef CONFIG_64BIT
-        /* HACK: Guess if the sign extension was forgotten */
-        if (start > 0x0000000080000000 && start < 0x00000000ffffffff)
-                start |= 0xffffffff00000000UL;
+        /* Guess if the sign extension was forgotten by bootloader */
+        if (start < XKPHYS)
+                start = (int)start;
 #endif
         initrd_start = start;
         initrd_end += start;
-
         return 0;
 }
 early_param("rd_start", rd_start_early);
@@ -159,41 +158,64 @@ early_param("rd_start", rd_start_early);
 static int __init rd_size_early(char *p)
 {
         initrd_end += memparse(p, &p);
-
         return 0;
 }
 early_param("rd_size", rd_size_early);
 
+/* it returns the next free pfn after initrd */
 static unsigned long __init init_initrd(void)
 {
-        unsigned long tmp, end, size;
+        unsigned long end;
         u32 *initrd_header;
 
-        ROOT_DEV = Root_RAM0;
-
         /*
          * Board specific code or command line parser should have
          * already set up initrd_start and initrd_end. In these cases
          * perfom sanity checks and use them if all looks good.
          */
-        size = initrd_end - initrd_start;
-        if (initrd_end == 0 || size == 0) {
-                initrd_start = 0;
-                initrd_end = 0;
-        } else
-                return initrd_end;
-
-        end = (unsigned long)&_end;
-        tmp = PAGE_ALIGN(end) - sizeof(u32) * 2;
-        if (tmp < end)
-                tmp += PAGE_SIZE;
-
-        initrd_header = (u32 *)tmp;
-        if (initrd_header[0] == 0x494E5244) {
-                initrd_start = (unsigned long)&initrd_header[2];
-                initrd_end = initrd_start + initrd_header[1];
+        if (initrd_start && initrd_end > initrd_start)
+                goto sanitize;
+
+        /*
+         * See if initrd has been added to the kernel image by
+         * arch/mips/boot/addinitrd.c. In that case a header is
+         * prepended to initrd and is made up by 8 bytes. The fisrt
+         * word is a magic number and the second one is the size of
+         * initrd.  Initrd start must be page aligned in any cases.
+         */
+        initrd_header = __va(PAGE_ALIGN(__pa_symbol(&_end) + 8)) - 8;
+        if (initrd_header[0] != 0x494E5244)
+                goto disable;
+        initrd_start = (unsigned long)(initrd_header + 2);
+        initrd_end = initrd_start + initrd_header[1];
+
+sanitize:
+        if (initrd_start & ~PAGE_MASK) {
+                printk(KERN_ERR "initrd start must be page aligned\n");
+                goto disable;
         }
-        return initrd_end;
+        if (initrd_start < PAGE_OFFSET) {
+                printk(KERN_ERR "initrd start < PAGE_OFFSET\n");
+                goto disable;
+        }
+
+        /*
+         * Sanitize initrd addresses. For example firmware
+         * can't guess if they need to pass them through
+         * 64-bits values if the kernel has been built in pure
+         * 32-bit. We need also to switch from KSEG0 to XKPHYS
+         * addresses now, so the code can now safely use __pa().
+         */
+        end = __pa(initrd_end);
+        initrd_end = (unsigned long)__va(end);
+        initrd_start = (unsigned long)__va(__pa(initrd_start));
+
+        ROOT_DEV = Root_RAM0;
+        return PFN_UP(end);
+disable:
+        initrd_start = 0;
+        initrd_end = 0;
+        return 0;
 }
 
 static void __init finalize_initrd(void)
@@ -259,8 +281,7 @@ static void __init bootmem_init(void)
          * not selected. Once that done we can determine the low bound
          * of usable memory.
          */
-        reserved_end = init_initrd();
-        reserved_end = PFN_UP(max(__pa(reserved_end), __pa_symbol(&_end)));
+        reserved_end = max(init_initrd(), PFN_UP(__pa_symbol(&_end)));
 
         /*
          * Find the highest page frame number we have available.