1.1 --- a/extras/mini-os/arch/x86/mm.c	Fri Dec 05 13:03:44 2008 +0000
     1.2 +++ b/extras/mini-os/arch/x86/mm.c	Fri Dec 05 13:06:57 2008 +0000
     1.3 @@ -420,7 +420,9 @@ static unsigned long demand_map_area_sta
     1.4  #define DEMAND_MAP_PAGES ((2ULL << 30) / PAGE_SIZE)
     1.5  #endif
     1.6  
     1.7 -#ifdef HAVE_LIBC
     1.8 +#ifndef HAVE_LIBC
     1.9 +#define HEAP_PAGES 0
    1.10 +#else
    1.11  unsigned long heap, brk, heap_mapped, heap_end;
    1.12  #ifdef __x86_64__
    1.13  #define HEAP_PAGES ((128ULL << 30) / PAGE_SIZE)
    1.14 @@ -591,7 +593,7 @@ void arch_init_p2m(unsigned long max_pfn
    1.15  void arch_init_mm(unsigned long* start_pfn_p, unsigned long* max_pfn_p)
    1.16  {
    1.17  
    1.18 -    unsigned long start_pfn, max_pfn;
    1.19 +    unsigned long start_pfn, max_pfn, virt_pfns;
    1.20  
    1.21      printk("  _text:        %p\n", &_text);
    1.22      printk("  _etext:       %p\n", &_etext);
    1.23 @@ -604,7 +606,12 @@ void arch_init_mm(unsigned long* start_p
    1.24      start_pfn = PFN_UP(to_phys(start_info.pt_base)) + 
    1.25                  start_info.nr_pt_frames + 3;
    1.26      max_pfn = start_info.nr_pages;
    1.27 -   
    1.28 +
    1.29 +    /* We need room for demand mapping and heap, clip available memory */
    1.30 +    virt_pfns = DEMAND_MAP_PAGES + HEAP_PAGES;
    1.31 +    if (max_pfn + virt_pfns + 1 < max_pfn)
    1.32 +        max_pfn = -(virt_pfns + 1);
    1.33 +
    1.34      printk("  start_pfn:    %lx\n", start_pfn);
    1.35      printk("  max_pfn:      %lx\n", max_pfn);
    1.36