Introduce flags for reserve_bootmem()

This patchset adds a flags variable to reserve_bootmem() and uses the
BOOTMEM_EXCLUSIVE flag in crashkernel reservation code to detect collisions
between crashkernel area and already used memory.

This patch:

Change the reserve_bootmem() function to accept a new flag BOOTMEM_EXCLUSIVE.
If that flag is set, the function returns with -EBUSY if the memory already
has been reserved in the past.  This is to avoid conflicts.

Because that code runs before SMP initialisation, there's no race condition
inside reserve_bootmem_core().

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix powerpc build]
Signed-off-by: Bernhard Walle <bwalle@suse.de>
Cc: <linux-arch@vger.kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/frv/kernel/setup.c b/arch/frv/kernel/setup.c
index b38ae1f..6c01464 100644
--- a/arch/frv/kernel/setup.c
+++ b/arch/frv/kernel/setup.c
@@ -925,13 +925,15 @@
 #endif
 
 	/* take back the memory occupied by the kernel image and the bootmem alloc map */
-	reserve_bootmem(kstart, kend - kstart + bootmap_size);
+	reserve_bootmem(kstart, kend - kstart + bootmap_size,
+			BOOTMEM_DEFAULT);
 
 	/* reserve the memory occupied by the initial ramdisk */
 #ifdef CONFIG_BLK_DEV_INITRD
 	if (LOADER_TYPE && INITRD_START) {
 		if (INITRD_START + INITRD_SIZE <= (low_top_pfn << PAGE_SHIFT)) {
-			reserve_bootmem(INITRD_START, INITRD_SIZE);
+			reserve_bootmem(INITRD_START, INITRD_SIZE,
+					BOOTMEM_DEFAULT);
 			initrd_start = INITRD_START + PAGE_OFFSET;
 			initrd_end = initrd_start + INITRD_SIZE;
 		}
@@ -986,9 +988,10 @@
 
 	/* now take back the bits the core kernel is occupying */
 #ifndef CONFIG_PROTECT_KERNEL
-	reserve_bootmem(kend, bootmap_size);
+	reserve_bootmem(kend, bootmap_size, BOOTMEM_DEFAULT);
 	reserve_bootmem((unsigned long) &__kernel_image_start,
-			kend - (unsigned long) &__kernel_image_start);
+			kend - (unsigned long) &__kernel_image_start,
+			BOOTMEM_DEFAULT);
 
 #else
 	dampr = __get_DAMPR(0);
@@ -996,14 +999,15 @@
 	dampr = (dampr >> 4) + 17;
 	dampr = 1 << dampr;
 
-	reserve_bootmem(__get_DAMPR(0) & xAMPRx_PPFN, dampr);
+	reserve_bootmem(__get_DAMPR(0) & xAMPRx_PPFN, dampr, BOOTMEM_DEFAULT);
 #endif
 
 	/* reserve some memory to do uncached DMA through if requested */
 #ifdef CONFIG_RESERVE_DMA_COHERENT
 	if (dma_coherent_mem_start)
 		reserve_bootmem(dma_coherent_mem_start,
-				dma_coherent_mem_end - dma_coherent_mem_start);
+				dma_coherent_mem_end - dma_coherent_mem_start,
+				BOOTMEM_DEFAULT);
 #endif
 
 } /* end setup_uclinux_memory() */