9 files changed, 65 insertions, 12 deletions

diff --git a/arch/x86/include/asm/sections.h b/arch/x86/include/asm/sections.h
index 2b8c5160388..1b7ee5d673c 100644
--- a/arch/x86/include/asm/sections.h
+++ b/arch/x86/include/asm/sections.h
@@ -1 +1,8 @@
+#ifndef _ASM_X86_SECTIONS_H
+#define _ASM_X86_SECTIONS_H
+
 #include <asm-generic/sections.h>
+
+extern char __brk_base[], __brk_limit[];
+
+#endif  /* _ASM_X86_SECTIONS_H */
diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index 05c6f6b11fd..45454f3fa12 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -100,6 +100,10 @@ extern struct boot_params boot_params;
  */
 #define LOWMEMSIZE()    (0x9f000)
 
+/* exceedingly early brk-like allocator */
+extern unsigned long _brk_end;
+void *extend_brk(size_t size, size_t align);
+
 #ifdef __i386__
 
 void __init i386_start_kernel(void);
diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index ac108d1fe18..29f1095b084 100644
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -18,7 +18,7 @@ void __init i386_start_kernel(void)
 {
         reserve_trampoline_memory();
 
-        reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");
+        reserve_early(__pa_symbol(&_text), __pa_symbol(&__bss_stop), "TEXT DATA BSS");
 
 #ifdef CONFIG_BLK_DEV_INITRD
         /* Reserve INITRD */
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index f5b27224769..70eaa852c73 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -100,7 +100,7 @@ void __init x86_64_start_reservations(char *real_mode_data)
 
         reserve_trampoline_memory();
 
-        reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");
+        reserve_early(__pa_symbol(&_text), __pa_symbol(&__bss_stop), "TEXT DATA BSS");
 
 #ifdef CONFIG_BLK_DEV_INITRD
         /* Reserve INITRD */
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index f28c56e6bf9..e6b742d2a3f 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;
diff --git a/arch/x86/kernel/vmlinux_32.lds.S b/arch/x86/kernel/vmlinux_32.lds.S
index 0d860963f26..27e44aa2158 100644
--- a/arch/x86/kernel/vmlinux_32.lds.S
+++ b/arch/x86/kernel/vmlinux_32.lds.S
@@ -189,7 +189,14 @@ SECTIONS
         *(.bss)
         . = ALIGN(4);
         __bss_stop = .;
+
+        . = ALIGN(PAGE_SIZE);
+        __brk_base = . ;
+        . += 1024 * 1024 ;
+        __brk_limit = . ;
+
         _end = . ;
+
         /* This is where the kernel creates the early boot page tables */
         . = ALIGN(PAGE_SIZE);
         pg0 = . ;
diff --git a/arch/x86/kernel/vmlinux_64.lds.S b/arch/x86/kernel/vmlinux_64.lds.S
index fe5d21ce724..ff373423138 100644
--- a/arch/x86/kernel/vmlinux_64.lds.S
+++ b/arch/x86/kernel/vmlinux_64.lds.S
@@ -247,6 +247,11 @@ SECTIONS
         *(.bss.page_aligned)
         *(.bss)
         __bss_stop = .;
+
+        . = ALIGN(PAGE_SIZE);
+        __brk_base = . ;
+        . += 1024 * 1024 ;
+        __brk_limit = . ;
   }
 
   _end = . ;
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 9c4294986af..1280565670e 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -16,6 +16,7 @@
 #include <asm/processor.h>
 #include <asm/tlbflush.h>
 #include <asm/sections.h>
+#include <asm/setup.h>
 #include <asm/uaccess.h>
 #include <asm/pgalloc.h>
 #include <asm/proto.h>
@@ -95,7 +96,7 @@ static inline unsigned long highmap_start_pfn(void)
 
 static inline unsigned long highmap_end_pfn(void)
 {
-        return __pa(roundup((unsigned long)_end, PMD_SIZE)) >> PAGE_SHIFT;
+        return __pa(roundup(_brk_end, PMD_SIZE)) >> PAGE_SHIFT;
 }
 
 #endif
@@ -711,7 +712,7 @@ static int cpa_process_alias(struct cpa_data *cpa)
          * No need to redo, when the primary call touched the high
          * mapping already:
          */
-        if (within(vaddr, (unsigned long) _text, (unsigned long) _end))
+        if (within(vaddr, (unsigned long) _text, _brk_end))
                 return 0;
 
         /*
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index cb6afa4ec95..72f6a76dbfb 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1723,9 +1723,9 @@ __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd,
 {
         pmd_t *kernel_pmd;
 
-        init_pg_tables_start = __pa(pgd);
-        init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE;
-        max_pfn_mapped = PFN_DOWN(init_pg_tables_end + 512*1024);
+        max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
+                                  xen_start_info->nr_pt_frames * PAGE_SIZE +
+                                  512*1024);
 
         kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
         memcpy(level2_kernel_pgt, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);