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x86: make 32-bit init_memory_mapping range change more like 64-bit

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Impact: cleanup

make code more readable and more like 64-bit

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <49AE48B4.8010907@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Yinghai Lu 2009-03-04 01:24:04 -08:00 committed by Ingo Molnar
parent a71edd1f46
commit b68adb16f2
1 changed files with 94 additions and 32 deletions
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120
arch/x86/mm/init_32.c
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@ -885,29 +885,55 @@ static void __init find_early_table_space(unsigned long end, int use_pse)
(table_start << PAGE_SHIFT) + tables);
}
struct map_range {
unsigned long start;
unsigned long end;
unsigned page_size_mask;
};
#define NR_RANGE_MR 3
static int save_mr(struct map_range *mr, int nr_range,
unsigned long start_pfn, unsigned long end_pfn,
unsigned long page_size_mask)
{
if (start_pfn < end_pfn) {
if (nr_range >= NR_RANGE_MR)
panic("run out of range for init_memory_mapping\n");
mr[nr_range].start = start_pfn<<PAGE_SHIFT;
mr[nr_range].end = end_pfn<<PAGE_SHIFT;
mr[nr_range].page_size_mask = page_size_mask;
nr_range++;
}
return nr_range;
}
unsigned long __init_refok init_memory_mapping(unsigned long start,
unsigned long end)
{
pgd_t *pgd_base = swapper_pg_dir;
unsigned long page_size_mask = 0;
unsigned long start_pfn, end_pfn;
unsigned long big_page_start;
unsigned long pos;
struct map_range mr[NR_RANGE_MR];
int nr_range, i;
int use_pse;
printk(KERN_INFO "init_memory_mapping: %08lx-%08lx\n", start, end);
#ifdef CONFIG_DEBUG_PAGEALLOC
/*
* For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
* This will simplify cpa(), which otherwise needs to support splitting
* large pages into small in interrupt context, etc.
*/
int use_pse = 0;
use_pse = 0;
#else
int use_pse = cpu_has_pse;
use_pse = cpu_has_pse;
#endif
/*
* Find space for the kernel direct mapping tables.
*/
if (!after_init_bootmem)
find_early_table_space(end, use_pse);
#ifdef CONFIG_X86_PAE
set_nx();
if (nx_enabled)
@ -924,45 +950,81 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
__supported_pte_mask |= _PAGE_GLOBAL;
}
memset(mr, 0, sizeof(mr));
nr_range = 0;
if (use_pse)
page_size_mask |= 1 << PG_LEVEL_2M;
/*
* Don't use a large page for the first 2/4MB of memory
* because there are often fixed size MTRRs in there
* and overlapping MTRRs into large pages can cause
* slowdowns.
*/
big_page_start = PMD_SIZE;
if (start < big_page_start) {
/* head could not be big page alignment ? */
start_pfn = start >> PAGE_SHIFT;
end_pfn = min(big_page_start>>PAGE_SHIFT, end>>PAGE_SHIFT);
} else {
/* head is not big page alignment ? */
start_pfn = start >> PAGE_SHIFT;
end_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
pos = start_pfn << PAGE_SHIFT;
if (pos == 0)
end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT);
else
end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
<< (PMD_SHIFT - PAGE_SHIFT);
if (end_pfn > (end>>PAGE_SHIFT))
end_pfn = end>>PAGE_SHIFT;
if (start_pfn < end_pfn) {
nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
pos = end_pfn << PAGE_SHIFT;
}
if (start_pfn < end_pfn)
kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn, 0);
/* big page range */
start_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
<< (PMD_SHIFT - PAGE_SHIFT);
if (start_pfn < (big_page_start >> PAGE_SHIFT))
start_pfn = big_page_start >> PAGE_SHIFT;
end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
if (start_pfn < end_pfn)
kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn,
use_pse);
if (start_pfn < end_pfn) {
nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
page_size_mask & (1<<PG_LEVEL_2M));
pos = end_pfn << PAGE_SHIFT;
}
/* tail is not big page alignment ? */
start_pfn = end_pfn;
if (start_pfn > (big_page_start>>PAGE_SHIFT)) {
start_pfn = pos>>PAGE_SHIFT;
end_pfn = end>>PAGE_SHIFT;
if (start_pfn < end_pfn)
kernel_physical_mapping_init(pgd_base, start_pfn,
end_pfn, 0);
nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
/* try to merge same page size and continuous */
for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
unsigned long old_start;
if (mr[i].end != mr[i+1].start ||
mr[i].page_size_mask != mr[i+1].page_size_mask)
continue;
/* move it */
old_start = mr[i].start;
memmove(&mr[i], &mr[i+1],
(nr_range - 1 - i) * sizeof(struct map_range));
mr[i--].start = old_start;
nr_range--;
}
for (i = 0; i < nr_range; i++)
printk(KERN_DEBUG " %08lx - %08lx page %s\n",
mr[i].start, mr[i].end,
(mr[i].page_size_mask & (1<<PG_LEVEL_2M)) ?
"big page" : "4k");
/*
* Find space for the kernel direct mapping tables.
*/
if (!after_init_bootmem)
find_early_table_space(end, use_pse);
for (i = 0; i < nr_range; i++)
kernel_physical_mapping_init(pgd_base,
mr[i].start >> PAGE_SHIFT,
mr[i].end >> PAGE_SHIFT,
mr[i].page_size_mask == (1<<PG_LEVEL_2M));
early_ioremap_page_table_range_init(pgd_base);
load_cr3(swapper_pg_dir);