1 files changed, 34 insertions, 5 deletions

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index f28c56e6bf94..e6b742d2a3f5 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -114,6 +114,9 @@
 
 unsigned int boot_cpu_id __read_mostly;
 
+static __initdata unsigned long _brk_start = (unsigned long)__brk_base;
+unsigned long _brk_end = (unsigned long)__brk_base;
+
 #ifdef CONFIG_X86_64
 int default_cpu_present_to_apicid(int mps_cpu)
 {
@@ -337,6 +340,34 @@ static void __init relocate_initrd(void)
 }
 #endif
 
+void * __init extend_brk(size_t size, size_t align)
+{
+        size_t mask = align - 1;
+        void *ret;
+
+        BUG_ON(_brk_start == 0);
+        BUG_ON(align & mask);
+
+        _brk_end = (_brk_end + mask) & ~mask;
+        BUG_ON((char *)(_brk_end + size) > __brk_limit);
+
+        ret = (void *)_brk_end;
+        _brk_end += size;
+
+        memset(ret, 0, size);
+
+        return ret;
+}
+
+static void __init reserve_brk(void)
+{
+        if (_brk_end > _brk_start)
+                reserve_early(__pa(_brk_start), __pa(_brk_end), "BRK");
+
+        /* Mark brk area as locked down and no longer taking any new allocations */
+        _brk_start = 0;
+}
+
 static void __init reserve_initrd(void)
 {
         u64 ramdisk_image = boot_params.hdr.ramdisk_image;
@@ -717,11 +748,7 @@ void __init setup_arch(char **cmdline_p)
         init_mm.start_code = (unsigned long) _text;
         init_mm.end_code = (unsigned long) _etext;
         init_mm.end_data = (unsigned long) _edata;
-#ifdef CONFIG_X86_32
-        init_mm.brk = init_pg_tables_end + PAGE_OFFSET;
-#else
-        init_mm.brk = (unsigned long) &_end;
-#endif
+        init_mm.brk = _brk_end;
 
         code_resource.start = virt_to_phys(_text);
         code_resource.end = virt_to_phys(_etext)-1;
@@ -842,6 +869,8 @@ void __init setup_arch(char **cmdline_p)
         setup_bios_corruption_check();
 #endif
 
+        reserve_brk();
+
         /* max_pfn_mapped is updated here */
         max_low_pfn_mapped = init_memory_mapping(0, max_low_pfn<<PAGE_SHIFT);
         max_pfn_mapped = max_low_pfn_mapped;