in mm/init.c [109:336]
static void __init setup_bootmem(void)
{
unsigned long mem_max;
#ifndef CONFIG_SPARSEMEM
physmem_range_t pmem_holes[MAX_PHYSMEM_RANGES - 1];
int npmem_holes;
#endif
int i, sysram_resource_count;
disable_sr_hashing(); /* Turn off space register hashing */
/*
* Sort the ranges. Since the number of ranges is typically
* small, and performance is not an issue here, just do
* a simple insertion sort.
*/
for (i = 1; i < npmem_ranges; i++) {
int j;
for (j = i; j > 0; j--) {
if (pmem_ranges[j-1].start_pfn <
pmem_ranges[j].start_pfn) {
break;
}
swap(pmem_ranges[j-1], pmem_ranges[j]);
}
}
#ifndef CONFIG_SPARSEMEM
/*
* Throw out ranges that are too far apart (controlled by
* MAX_GAP).
*/
for (i = 1; i < npmem_ranges; i++) {
if (pmem_ranges[i].start_pfn -
(pmem_ranges[i-1].start_pfn +
pmem_ranges[i-1].pages) > MAX_GAP) {
npmem_ranges = i;
printk("Large gap in memory detected (%ld pages). "
"Consider turning on CONFIG_SPARSEMEM\n",
pmem_ranges[i].start_pfn -
(pmem_ranges[i-1].start_pfn +
pmem_ranges[i-1].pages));
break;
}
}
#endif
/* Print the memory ranges */
pr_info("Memory Ranges:\n");
for (i = 0; i < npmem_ranges; i++) {
struct resource *res = &sysram_resources[i];
unsigned long start;
unsigned long size;
size = (pmem_ranges[i].pages << PAGE_SHIFT);
start = (pmem_ranges[i].start_pfn << PAGE_SHIFT);
pr_info("%2d) Start 0x%016lx End 0x%016lx Size %6ld MB\n",
i, start, start + (size - 1), size >> 20);
/* request memory resource */
res->name = "System RAM";
res->start = start;
res->end = start + size - 1;
res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
request_resource(&iomem_resource, res);
}
sysram_resource_count = npmem_ranges;
/*
* For 32 bit kernels we limit the amount of memory we can
* support, in order to preserve enough kernel address space
* for other purposes. For 64 bit kernels we don't normally
* limit the memory, but this mechanism can be used to
* artificially limit the amount of memory (and it is written
* to work with multiple memory ranges).
*/
mem_limit_func(); /* check for "mem=" argument */
mem_max = 0;
for (i = 0; i < npmem_ranges; i++) {
unsigned long rsize;
rsize = pmem_ranges[i].pages << PAGE_SHIFT;
if ((mem_max + rsize) > mem_limit) {
printk(KERN_WARNING "Memory truncated to %ld MB\n", mem_limit >> 20);
if (mem_max == mem_limit)
npmem_ranges = i;
else {
pmem_ranges[i].pages = (mem_limit >> PAGE_SHIFT)
- (mem_max >> PAGE_SHIFT);
npmem_ranges = i + 1;
mem_max = mem_limit;
}
break;
}
mem_max += rsize;
}
printk(KERN_INFO "Total Memory: %ld MB\n",mem_max >> 20);
#ifndef CONFIG_SPARSEMEM
/* Merge the ranges, keeping track of the holes */
{
unsigned long end_pfn;
unsigned long hole_pages;
npmem_holes = 0;
end_pfn = pmem_ranges[0].start_pfn + pmem_ranges[0].pages;
for (i = 1; i < npmem_ranges; i++) {
hole_pages = pmem_ranges[i].start_pfn - end_pfn;
if (hole_pages) {
pmem_holes[npmem_holes].start_pfn = end_pfn;
pmem_holes[npmem_holes++].pages = hole_pages;
end_pfn += hole_pages;
}
end_pfn += pmem_ranges[i].pages;
}
pmem_ranges[0].pages = end_pfn - pmem_ranges[0].start_pfn;
npmem_ranges = 1;
}
#endif
/*
* Initialize and free the full range of memory in each range.
*/
max_pfn = 0;
for (i = 0; i < npmem_ranges; i++) {
unsigned long start_pfn;
unsigned long npages;
unsigned long start;
unsigned long size;
start_pfn = pmem_ranges[i].start_pfn;
npages = pmem_ranges[i].pages;
start = start_pfn << PAGE_SHIFT;
size = npages << PAGE_SHIFT;
/* add system RAM memblock */
memblock_add(start, size);
if ((start_pfn + npages) > max_pfn)
max_pfn = start_pfn + npages;
}
/*
* We can't use memblock top-down allocations because we only
* created the initial mapping up to KERNEL_INITIAL_SIZE in
* the assembly bootup code.
*/
memblock_set_bottom_up(true);
/* IOMMU is always used to access "high mem" on those boxes
* that can support enough mem that a PCI device couldn't
* directly DMA to any physical addresses.
* ISA DMA support will need to revisit this.
*/
max_low_pfn = max_pfn;
/* reserve PAGE0 pdc memory, kernel text/data/bss & bootmap */
#define PDC_CONSOLE_IO_IODC_SIZE 32768
memblock_reserve(0UL, (unsigned long)(PAGE0->mem_free +
PDC_CONSOLE_IO_IODC_SIZE));
memblock_reserve(__pa(KERNEL_BINARY_TEXT_START),
(unsigned long)(_end - KERNEL_BINARY_TEXT_START));
#ifndef CONFIG_SPARSEMEM
/* reserve the holes */
for (i = 0; i < npmem_holes; i++) {
memblock_reserve((pmem_holes[i].start_pfn << PAGE_SHIFT),
(pmem_holes[i].pages << PAGE_SHIFT));
}
#endif
#ifdef CONFIG_BLK_DEV_INITRD
if (initrd_start) {
printk(KERN_INFO "initrd: %08lx-%08lx\n", initrd_start, initrd_end);
if (__pa(initrd_start) < mem_max) {
unsigned long initrd_reserve;
if (__pa(initrd_end) > mem_max) {
initrd_reserve = mem_max - __pa(initrd_start);
} else {
initrd_reserve = initrd_end - initrd_start;
}
initrd_below_start_ok = 1;
printk(KERN_INFO "initrd: reserving %08lx-%08lx (mem_max %08lx)\n", __pa(initrd_start), __pa(initrd_start) + initrd_reserve, mem_max);
memblock_reserve(__pa(initrd_start), initrd_reserve);
}
}
#endif
data_resource.start = virt_to_phys(&data_start);
data_resource.end = virt_to_phys(_end) - 1;
code_resource.start = virt_to_phys(_text);
code_resource.end = virt_to_phys(&data_start)-1;
/* We don't know which region the kernel will be in, so try
* all of them.
*/
for (i = 0; i < sysram_resource_count; i++) {
struct resource *res = &sysram_resources[i];
request_resource(res, &code_resource);
request_resource(res, &data_resource);
}
request_resource(&sysram_resources[0], &pdcdata_resource);
/* Initialize Page Deallocation Table (PDT) and check for bad memory. */
pdc_pdt_init();
memblock_allow_resize();
memblock_dump_all();
}