Blackfin arch: fix bug kernel not to boot up with mtd filesystems

Revert this patch:
move the init sections to the end of memory, so that after they
are free, run time memory is all continugous - this should help decrease
memory fragementation. When doing this, we also pack some of the other
sections a little closer together, to make sure we don't waste memory.
To make this happen, we need to rename the .data.init_task section to
.init_task.data, so it doesn't get picked up by the linker script glob.

Since it causes the kernel not to boot up with mtd filesystems.

Signed-off-by: Bernd Schmidt <bernd.schmidt@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

arch/blackfin/kernel/init_task.c

@@ -57,5 +57,5 @@ EXPORT_SYMBOL(init_task);
  * "init_task" linker map entry.
  */
 union thread_union init_thread_union
-    __attribute__ ((__section__(".init_task.data"))) = {
+    __attribute__ ((__section__(".data.init_task"))) = {
 INIT_THREAD_INFO(init_task)};

arch/blackfin/kernel/setup.c

@@ -237,7 +237,7 @@ void __init setup_arch(char **cmdline_p)
 	/* by now the stack is part of the init task */
 	memory_end = _ramend - DMA_UNCACHED_REGION;
 
-	_ramstart = (unsigned long)_end;
+	_ramstart = (unsigned long)__bss_stop;
 	memory_start = PAGE_ALIGN(_ramstart);
 
 #if defined(CONFIG_MTD_UCLINUX)
@@ -286,7 +286,7 @@ void __init setup_arch(char **cmdline_p)
 	}
 
 	/* Relocate MTD image to the top of memory after the uncached memory area */
-	dma_memcpy((char *)memory_end, _end, mtd_size);
+	dma_memcpy((char *)memory_end, __bss_stop, mtd_size);
 
 	memory_mtd_start = memory_end;
 	_ebss = memory_mtd_start;	/* define _ebss for compatible */
@@ -358,10 +358,10 @@ void __init setup_arch(char **cmdline_p)
 	printk(KERN_INFO "Memory map:\n"
 	       KERN_INFO "  text      = 0x%p-0x%p\n"
 	       KERN_INFO "  rodata    = 0x%p-0x%p\n"
-	       KERN_INFO "  bss       = 0x%p-0x%p\n"
 	       KERN_INFO "  data      = 0x%p-0x%p\n"
 	       KERN_INFO "    stack   = 0x%p-0x%p\n"
 	       KERN_INFO "  init      = 0x%p-0x%p\n"
+	       KERN_INFO "  bss       = 0x%p-0x%p\n"
 	       KERN_INFO "  available = 0x%p-0x%p\n"
 #ifdef CONFIG_MTD_UCLINUX
 	       KERN_INFO "  rootfs    = 0x%p-0x%p\n"
@@ -371,10 +371,10 @@ void __init setup_arch(char **cmdline_p)
 #endif
 	       , _stext, _etext,
 	       __start_rodata, __end_rodata,
-	       __bss_start, __bss_stop,
 	       _sdata, _edata,
 	       (void *)&init_thread_union, (void *)((int)(&init_thread_union) + 0x2000),
 	       __init_begin, __init_end,
+	       __bss_start, __bss_stop,
 	       (void *)_ramstart, (void *)memory_end
 #ifdef CONFIG_MTD_UCLINUX
 	       , (void *)memory_mtd_start, (void *)(memory_mtd_start + mtd_size)

arch/blackfin/kernel/vmlinux.lds.S

@@ -41,9 +41,6 @@ _jiffies = _jiffies_64;
 SECTIONS
 {
 	. = CONFIG_BOOT_LOAD;
-	/* Neither the text, ro_data or bss section need to be aligned
-	 * So pack them back to back
-	 */
 	.text :
 	{
 		__text = .;
@@ -61,25 +58,22 @@ SECTIONS
 		*(__ex_table)
 		___stop___ex_table = .;
 
+		. = ALIGN(4);
 		__etext = .;
 	}
 
-	/* Just in case the first read only is a 32-bit access */
+	RO_DATA(PAGE_SIZE)
-	RO_DATA(4)
-
-	.bss :
-	{
-		. = ALIGN(4);
-		___bss_start = .;
-		*(.bss .bss.*)
-		*(COMMON)
-		___bss_stop = .;
-	}
 
 	.data :
 	{
+		/* make sure the init_task is aligned to the
+		 * kernel thread size so we can locate the kernel
+		 * stack properly and quickly.
+		 */
 		__sdata = .;
-		/* This gets done first, so the glob doesn't suck it in */
+		. = ALIGN(THREAD_SIZE);
+		*(.data.init_task)
+
 		. = ALIGN(32);
 		*(.data.cacheline_aligned)
 
@@ -87,22 +81,10 @@ SECTIONS
 		*(.data.*)
 		CONSTRUCTORS
 
-		/* make sure the init_task is aligned to the
-		 * kernel thread size so we can locate the kernel
-		 * stack properly and quickly.
-		 */
 		. = ALIGN(THREAD_SIZE);
-		*(.init_task.data)
-
 		__edata = .;
 	}
 
-	/* The init section should be last, so when we free it, it goes into
-	 * the general memory pool, and (hopefully) will decrease fragmentation
-	 * a tiny bit. The init section has a _requirement_ that it be
-	 * PAGE_SIZE aligned
-	 */
-	. = ALIGN(PAGE_SIZE);
 	___init_begin = .;
 
 	.init.text :
@@ -197,7 +179,16 @@ SECTIONS
 	. = ALIGN(PAGE_SIZE);
 	___init_end = .;
 
-	__end =.;
+	.bss :
+	{
+		. = ALIGN(4);
+		___bss_start = .;
+		*(.bss .bss.*)
+		*(COMMON)
+		. = ALIGN(4);
+		___bss_stop = .;
+		__end = .;
+	}
 
 	STABS_DEBUG