x86, mm: Merge alloc_low_page between 64bit and 32bit

They are almost same except 64 bit need to handle after_bootmem case.

Add mm_internal.h to make that alloc_low_page() only to be accessible
from arch/x86/mm/init*.c

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1353123563-3103-25-git-send-email-yinghai@kernel.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 2393d0099e7f..848189229b2d 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -17,10 +17,44 @@
 #include <asm/proto.h>
 #include <asm/dma.h>            /* for MAX_DMA_PFN */
 
+#include "mm_internal.h"
+
 unsigned long __initdata pgt_buf_start;
 unsigned long __meminitdata pgt_buf_end;
 unsigned long __meminitdata pgt_buf_top;
 
+__ref void *alloc_low_page(void)
+{
+        unsigned long pfn;
+        void *adr;
+
+#ifdef CONFIG_X86_64
+        if (after_bootmem) {
+                adr = (void *)get_zeroed_page(GFP_ATOMIC | __GFP_NOTRACK);
+
+                return adr;
+        }
+#endif
+
+        if ((pgt_buf_end + 1) >= pgt_buf_top) {
+                unsigned long ret;
+                if (min_pfn_mapped >= max_pfn_mapped)
+                        panic("alloc_low_page: ran out of memory");
+                ret = memblock_find_in_range(min_pfn_mapped << PAGE_SHIFT,
+                                        max_pfn_mapped << PAGE_SHIFT,
+                                        PAGE_SIZE, PAGE_SIZE);
+                if (!ret)
+                        panic("alloc_low_page: can not alloc memory");
+                memblock_reserve(ret, PAGE_SIZE);
+                pfn = ret >> PAGE_SHIFT;
+        } else
+                pfn = pgt_buf_end++;
+
+        adr = __va(pfn * PAGE_SIZE);
+        clear_page(adr);
+        return adr;
+}
+
 /* need 4 4k for initial PMD_SIZE, 4k for 0-ISA_END_ADDRESS */
 #define INIT_PGT_BUF_SIZE       (5 * PAGE_SIZE)
 RESERVE_BRK(early_pgt_alloc, INIT_PGT_BUF_SIZE);