x86_64: Map only usable memory in identity map. All reserved memory maps to a
zero page. This is done later during the boot process, by pruning the
page table setup earlier to remove mappings for the reserved region. Prune
done after mem_init, so we can allocate pages as needed and before APs start.
Signed-off-by: Venkatesh Pallipadi <[EMAIL PROTECTED]>
Signed-off-by: Suresh Siddha <[EMAIL PROTECTED]>
Index: linux-2.6.git/arch/x86/kernel/e820_64.c
===================================================================
--- linux-2.6.git.orig/arch/x86/kernel/e820_64.c 2008-01-08
03:41:30.000000000 -0800
+++ linux-2.6.git/arch/x86/kernel/e820_64.c 2008-01-08 04:00:59.000000000
-0800
@@ -121,6 +121,35 @@
}
EXPORT_SYMBOL_GPL(e820_any_mapped);
+int e820_any_non_reserved(unsigned long start, unsigned long end)
+{
+ int i;
+ for (i = 0; i < e820.nr_map; i++) {
+ struct e820entry *ei = &e820.map[i];
+ if (ei->type == E820_RESERVED)
+ continue;
+ if (ei->addr >= end || ei->addr + ei->size <= start)
+ continue;
+ return 1;
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(e820_any_non_reserved);
+
+int is_memory_any_valid(unsigned long start, unsigned long end)
+{
+ /*
+ * Keep low PCI/ISA area always mapped.
+ * Note: end address is exclusive and start is inclusive here
+ */
+ if (start >= ISA_START_ADDRESS && end <= ISA_END_ADDRESS)
+ return 1;
+
+ /* Switch to efi or e820 in future here */
+ return e820_any_non_reserved(start, end);
+}
+EXPORT_SYMBOL_GPL(is_memory_any_valid);
+
/*
* This function checks if the entire range <start,end> is mapped with type.
*
@@ -156,6 +185,47 @@
return 0;
}
+int e820_all_non_reserved(unsigned long start, unsigned long end)
+{
+ int i;
+ for (i = 0; i < e820.nr_map; i++) {
+ struct e820entry *ei = &e820.map[i];
+ if (ei->type == E820_RESERVED)
+ continue;
+
+ /* is the region (part) in overlap with the current region ?*/
+ if (ei->addr >= end || ei->addr + ei->size <= start)
+ continue;
+
+ /*
+ * if the region is at the beginning of <start,end> we move
+ * start to the end of the region since it's ok until there
+ */
+ if (ei->addr <= start)
+ start = ei->addr + ei->size;
+
+ /* if start is at or beyond end, we're done, full coverage */
+ if (start >= end)
+ return 1; /* we're done */
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(e820_all_non_reserved);
+
+int is_memory_all_valid(unsigned long start, unsigned long end)
+{
+ /*
+ * Keep low PCI/ISA area always mapped.
+ * Note: end address is exclusive and start is inclusive here
+ */
+ if (start >= ISA_START_ADDRESS && end <= ISA_END_ADDRESS)
+ return 1;
+
+ /* Switch to efi or e820 in future here */
+ return e820_all_non_reserved(start, end);
+}
+EXPORT_SYMBOL_GPL(is_memory_all_valid);
+
/*
* Find a free area in a specific range.
*/
Index: linux-2.6.git/arch/x86/mm/init_64.c
===================================================================
--- linux-2.6.git.orig/arch/x86/mm/init_64.c 2008-01-08 03:43:46.000000000
-0800
+++ linux-2.6.git/arch/x86/mm/init_64.c 2008-01-08 03:59:28.000000000 -0800
@@ -215,8 +215,9 @@
int i, pmds;
pmds = ((addr & ~PMD_MASK) + size + ~PMD_MASK) / PMD_SIZE;
- vaddr = __START_KERNEL_map;
- pmd = level2_kernel_pgt;
+ /* Skip PMDs meant for kernel text */
+ vaddr = __START_KERNEL_map + KERNEL_TEXT_SIZE;
+ pmd = level2_kernel_pgt + (KERNEL_TEXT_SIZE / PMD_SIZE);
last_pmd = level2_kernel_pgt + PTRS_PER_PMD - 1;
for (; pmd <= last_pmd; pmd++, vaddr += PMD_SIZE) {
for (i = 0; i < pmds; i++) {
@@ -299,11 +300,6 @@
if (addr >= end)
break;
- if (!after_bootmem && !e820_any_mapped(addr,addr+PUD_SIZE,0)) {
- set_pud(pud, __pud(0));
- continue;
- }
-
if (pud_val(*pud)) {
phys_pmd_update(pud, addr, end);
continue;
@@ -344,6 +340,8 @@
(table_start << PAGE_SHIFT) + tables);
}
+static unsigned long max_addr;
+
/* Setup the direct mapping of the physical memory at PAGE_OFFSET.
This runs before bootmem is initialized and gets pages directly from the
physical memory. To access them they are temporarily mapped. */
@@ -370,10 +368,13 @@
pgd_t *pgd = pgd_offset_k(start);
pud_t *pud;
- if (after_bootmem)
+ if (after_bootmem) {
pud = pud_offset(pgd, start & PGDIR_MASK);
- else
+ } else {
pud = alloc_low_page(&pud_phys);
+ if (end > max_addr)
+ max_addr = end;
+ }
next = start + PGDIR_SIZE;
if (next > end)
@@ -489,6 +490,187 @@
static struct kcore_list kcore_mem, kcore_vmalloc, kcore_kernel, kcore_modules,
kcore_vsyscall;
+
+static unsigned long __init get_res_page(void)
+{
+ static unsigned long res_phys_page;
+ if (!res_phys_page) {
+ pte_t *pte;
+ pte = alloc_low_page(&res_phys_page);
+ unmap_low_page(pte);
+ }
+ return res_phys_page;
+}
+
+static unsigned long __init get_res_ptepage(void)
+{
+ static unsigned long res_phys_ptepage;
+ if (!res_phys_ptepage) {
+ pte_t *pte_page;
+ unsigned long page_phys;
+ unsigned long entry;
+ int i;
+
+ pte_page = alloc_low_page(&res_phys_ptepage);
+
+ page_phys = get_res_page();
+ entry = _PAGE_NX | _KERNPG_TABLE | _PAGE_GLOBAL | page_phys;
+ entry &= __supported_pte_mask;
+ for (i = 0; i < PTRS_PER_PTE; i++) {
+ pte_t *pte = pte_page + i;
+ set_pte(pte, __pte(entry));
+ }
+
+ unmap_low_page(pte_page);
+ }
+ return res_phys_ptepage;
+}
+
+static void __init phys_pte_prune(pte_t *pte_page, unsigned long address,
+ unsigned long end, unsigned long vaddr, unsigned int exec)
+{
+ int i = pte_index(vaddr);
+
+ for (; i < PTRS_PER_PTE; i++, address = (address & PAGE_MASK) +
PAGE_SIZE, vaddr = (vaddr + PAGE_MASK) + PAGE_SIZE) {
+ unsigned long entry;
+ pte_t *pte = pte_page + i;
+
+ if (address >= end)
+ break;
+
+ if (pte_val(*pte))
+ continue;
+
+ /* Nothing to map. Map the null page */
+ if (!(address & (~PAGE_MASK)) &&
+ (address + PAGE_SIZE <= end) &&
+ !is_memory_any_valid(address, address + PAGE_SIZE)) {
+ unsigned long phys_page;
+
+ phys_page = get_res_page();
+ entry = _PAGE_NX | _KERNPG_TABLE | _PAGE_GLOBAL |
+ phys_page;
+
+ entry &= __supported_pte_mask;
+ set_pte(pte, __pte(entry));
+
+ continue;
+ }
+
+ if (exec)
+ entry = _PAGE_NX|_KERNPG_TABLE|_PAGE_GLOBAL|address;
+ else
+ entry = _KERNPG_TABLE|_PAGE_GLOBAL|address;
+ entry &= __supported_pte_mask;
+ set_pte(pte, __pte(entry));
+ }
+}
+
+static void __init phys_pmd_prune(pmd_t *pmd_page, unsigned long address,
+ unsigned long end, unsigned long vaddr, unsigned int exec)
+{
+ int i = pmd_index(vaddr);
+
+ for (; i < PTRS_PER_PMD; i++, address = (address & PMD_MASK) + PMD_SIZE,
+ vaddr = (vaddr & PMD_MASK) + PMD_SIZE) {
+ pmd_t *pmd = pmd_page + i;
+ pte_t *pte;
+ unsigned long pte_phys;
+
+ if (address >= end)
+ break;
+
+ if (!pmd_val(*pmd))
+ continue;
+
+ /* Nothing to map. Map the null page */
+ if (!(address & (~PMD_MASK)) &&
+ (address + PMD_SIZE <= end) &&
+ !is_memory_any_valid(address, address + PMD_SIZE)) {
+
+ pte_phys = get_res_ptepage();
+ set_pmd(pmd, __pmd(pte_phys | _KERNPG_TABLE));
+
+ continue;
+ }
+
+ /* Map with 2M pages */
+ if (is_memory_all_valid(address, address + PUD_SIZE)) {
+ /* Init already done */
+ continue;
+ }
+
+ /* Map with 4k pages */
+ pte = alloc_low_page(&pte_phys);
+ phys_pte_prune(pte, address, address + PMD_SIZE, vaddr, exec);
+ set_pmd(pmd, __pmd(pte_phys | _KERNPG_TABLE));
+ unmap_low_page(pte);
+
+ }
+}
+
+static void __init phys_pud_prune(pud_t *pud_page, unsigned long addr,
+ unsigned long end, unsigned long vaddr, unsigned int exec)
+{
+ int i = pud_index(vaddr);
+
+ for (; i < PTRS_PER_PUD; i++, addr = (addr & PUD_MASK) + PUD_SIZE,
+ vaddr = (vaddr & PUD_MASK) + PUD_SIZE) {
+ pud_t *pud = pud_page + i;
+
+ if (addr >= end)
+ break;
+
+ if (pud_val(*pud)) {
+ pmd_t *pmd = pmd_offset(pud,0);
+ phys_pmd_prune(pmd, addr, end, vaddr, exec);
+ }
+ }
+}
+
+void __init prune_reserved_region_maps(void)
+{
+ unsigned long start, end, next;
+
+ /* Prune physical memory identity map */
+ start = (unsigned long)__va(0);
+ end = max_addr;
+ for (; start < end; start = next) {
+ pgd_t *pgd = pgd_offset_k(start);
+ pud_t *pud;
+
+ pud = pud_offset(pgd, start & PGDIR_MASK);
+
+ next = start + PGDIR_SIZE;
+ if (next > end)
+ next = end;
+
+ phys_pud_prune(pud, __pa(start), __pa(next), start, 0);
+ }
+
+ /* Prune kernel text region */
+ start = (unsigned long)KERNEL_TEXT_START;
+ end = start + (unsigned long)KERNEL_TEXT_SIZE;
+ for (; start < end; start = next) {
+ pgd_t *pgd = pgd_offset_k(start);
+ pud_t *pud;
+
+ pud = pud_offset(pgd, start & PGDIR_MASK);
+
+ next = (start & PGDIR_MASK) + (unsigned long)PGDIR_SIZE;
+ if (!next || next > end)
+ next = end;
+
+ phys_pud_prune(pud,
+ start - (unsigned long)KERNEL_TEXT_START,
+ next - (unsigned long)KERNEL_TEXT_START,
+ start,
+ 1);
+ }
+
+ __flush_tlb();
+}
+
void __init mem_init(void)
{
long codesize, reservedpages, datasize, initsize;
@@ -538,6 +720,8 @@
reservedpages << (PAGE_SHIFT-10),
datasize >> 10,
initsize >> 10);
+
+ prune_reserved_region_maps();
}
void free_init_pages(char *what, unsigned long begin, unsigned long end)
Index: linux-2.6.git/arch/x86/mm/ioremap_64.c
===================================================================
--- linux-2.6.git.orig/arch/x86/mm/ioremap_64.c 2008-01-08 03:41:30.000000000
-0800
+++ linux-2.6.git/arch/x86/mm/ioremap_64.c 2008-01-08 03:59:28.000000000
-0800
@@ -19,6 +19,7 @@
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>
#include <asm/proto.h>
+#include <asm/e820.h>
unsigned long __phys_addr(unsigned long x)
{
@@ -28,9 +29,6 @@
}
EXPORT_SYMBOL(__phys_addr);
-#define ISA_START_ADDRESS 0xa0000
-#define ISA_END_ADDRESS 0x100000
-
/*
* Fix up the linear direct mapping of the kernel to avoid cache attribute
* conflicts.
Index: linux-2.6.git/arch/x86/mm/pageattr_64.c
===================================================================
--- linux-2.6.git.orig/arch/x86/mm/pageattr_64.c 2008-01-08
03:41:30.000000000 -0800
+++ linux-2.6.git/arch/x86/mm/pageattr_64.c 2008-01-08 04:03:33.000000000
-0800
@@ -53,9 +53,11 @@
/*
* page_private is used to track the number of entries in
* the page table page have non standard attributes.
+ * Count of 1 indicates page split by split_large_page(),
+ * additional count indicates the number of pages with non-std attr.
*/
SetPagePrivate(base);
- page_private(base) = 0;
+ page_private(base) = 1;
address = __pa(address);
addr = address & LARGE_PAGE_MASK;
@@ -176,11 +178,8 @@
BUG();
}
- /* on x86-64 the direct mapping set at boot is not using 4k pages */
- BUG_ON(PageReserved(kpte_page));
-
save_page(kpte_page);
- if (page_private(kpte_page) == 0)
+ if (page_private(kpte_page) == 1)
revert_page(address, ref_prot);
return 0;
}
Index: linux-2.6.git/include/asm-x86/e820_64.h
===================================================================
--- linux-2.6.git.orig/include/asm-x86/e820_64.h 2008-01-08
03:41:30.000000000 -0800
+++ linux-2.6.git/include/asm-x86/e820_64.h 2008-01-08 03:59:28.000000000
-0800
@@ -26,6 +26,10 @@
extern void e820_mark_nosave_regions(void);
extern int e820_any_mapped(unsigned long start, unsigned long end, unsigned
type);
extern int e820_all_mapped(unsigned long start, unsigned long end, unsigned
type);
+extern int e820_any_non_reserved(unsigned long start, unsigned long end);
+extern int is_memory_any_valid(unsigned long start, unsigned long end);
+extern int e820_all_non_reserved(unsigned long start, unsigned long end);
+extern int is_memory_all_valid(unsigned long start, unsigned long end);
extern unsigned long e820_hole_size(unsigned long start, unsigned long end);
extern void e820_setup_gap(void);
@@ -38,6 +42,10 @@
extern unsigned ebda_addr, ebda_size;
extern unsigned long nodemap_addr, nodemap_size;
+
+#define ISA_START_ADDRESS 0xa0000
+#define ISA_END_ADDRESS 0x100000
+
#endif/*!__ASSEMBLY__*/
#endif/*__E820_HEADER*/
--
--
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