i386: Map only usable memory in identity map. Reserved memory maps to a
zero page.
Signed-off-by: Venkatesh Pallipadi <[EMAIL PROTECTED]>
Signed-off-by: Suresh Siddha <[EMAIL PROTECTED]>
Index: linux-2.6.git/arch/x86/kernel/e820_32.c
===================================================================
--- linux-2.6.git.orig/arch/x86/kernel/e820_32.c 2008-01-08
03:41:30.000000000 -0800
+++ linux-2.6.git/arch/x86/kernel/e820_32.c 2008-01-08 04:05:24.000000000
-0800
@@ -673,14 +673,42 @@
}
EXPORT_SYMBOL_GPL(e820_any_mapped);
+int e820_any_non_reserved(u64 start, u64 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(u64 start, u64 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.
*
* Note: this function only works correct if the e820 table is sorted and
* not-overlapping, which is the case
*/
-int __init
-e820_all_mapped(unsigned long s, unsigned long e, unsigned type)
+int e820_all_mapped(u64 s, u64 e, unsigned type)
{
u64 start = s;
u64 end = e;
@@ -705,6 +733,56 @@
return 0;
}
+int e820_all_non_reserved(u64 start, u64 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(u64 start, u64 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);
+
+int is_memory_all_reserved(u64 start, u64 end)
+{
+ /* Switch to efi or e820 in future here */
+ if (e820_all_mapped(start, end, E820_RESERVED) == 1)
+ return 1;
+ return !is_memory_any_valid(start, end);
+}
+EXPORT_SYMBOL_GPL(is_memory_all_reserved);
+
static int __init parse_memmap(char *arg)
{
if (!arg)
Index: linux-2.6.git/arch/x86/mm/init_32.c
===================================================================
--- linux-2.6.git.orig/arch/x86/mm/init_32.c 2008-01-08 03:41:30.000000000
-0800
+++ linux-2.6.git/arch/x86/mm/init_32.c 2008-01-08 04:20:44.000000000 -0800
@@ -143,6 +143,50 @@
return 0;
}
+static unsigned long __init get_res_page(void)
+{
+ static unsigned long res_phys_page;
+ if (!res_phys_page) {
+
+ res_phys_page = (unsigned long)
+ alloc_bootmem_low_pages(PAGE_SIZE);
+ if (!res_phys_page)
+ BUG();
+
+ memset((char *)res_phys_page, 0xe, PAGE_SIZE);
+ res_phys_page = __pa(res_phys_page);
+ }
+ return res_phys_page;
+}
+
+static unsigned long __init get_res_ptepage(void)
+{
+ static unsigned long res_phys_ptepage;
+ pte_t *pte;
+ int pte_ofs;
+ unsigned long pfn;
+
+ if (!res_phys_ptepage) {
+
+ res_phys_ptepage = (unsigned long)
+ alloc_bootmem_low_pages(PAGE_SIZE);
+ if (!res_phys_ptepage)
+ BUG();
+
+ paravirt_alloc_pt(&init_mm,
+ __pa(res_phys_ptepage) >> PAGE_SHIFT);
+
+ /* Set all PTEs in the range to zero page */
+ pfn = get_res_page() >> PAGE_SHIFT;
+ pte = (pte_t *)res_phys_ptepage;
+ for (pte_ofs = 0; pte_ofs < PTRS_PER_PTE; pte++, pte_ofs++)
+ set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
+
+ res_phys_ptepage = __pa(res_phys_ptepage);
+ }
+ return res_phys_ptepage;
+}
+
/*
* This maps the physical memory to kernel virtual address space, a total
* of max_low_pfn pages, by creating page tables starting from address
@@ -155,6 +199,7 @@
pmd_t *pmd;
pte_t *pte;
int pgd_idx, pmd_idx, pte_ofs;
+ unsigned long temp_pfn;
pgd_idx = pgd_index(PAGE_OFFSET);
pgd = pgd_base + pgd_idx;
@@ -168,15 +213,19 @@
pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn;
pmd++, pmd_idx++) {
unsigned int address = pfn * PAGE_SIZE + PAGE_OFFSET;
+ unsigned int paddr = pfn * PAGE_SIZE;
- /* Map with big pages if possible, otherwise
- create normal page tables. */
- if (cpu_has_pse) {
+ /*
+ * Map with big pages if possible, otherwise create
+ * normal page tables.
+ */
+ if (cpu_has_pse &&
+ is_memory_all_valid(paddr, paddr + PMD_SIZE)) {
unsigned int address2;
pgprot_t prot = PAGE_KERNEL_LARGE;
- address2 = (pfn + PTRS_PER_PTE - 1) * PAGE_SIZE
+
- PAGE_OFFSET + PAGE_SIZE-1;
+ address2 = (pfn + PTRS_PER_PTE) * PAGE_SIZE +
+ PAGE_OFFSET - 1;
if (is_kernel_text(address) ||
is_kernel_text(address2))
@@ -185,19 +234,42 @@
set_pmd(pmd, pfn_pmd(pfn, prot));
pfn += PTRS_PER_PTE;
- } else {
- pte = one_page_table_init(pmd);
-
- for (pte_ofs = 0;
- pte_ofs < PTRS_PER_PTE && pfn <
max_low_pfn;
- pte++, pfn++, pte_ofs++, address +=
PAGE_SIZE) {
- pgprot_t prot = PAGE_KERNEL;
+ continue;
+ }
+ if (cpu_has_pse &&
+ !is_memory_any_valid(paddr, paddr + PMD_SIZE)) {
- if (is_kernel_text(address))
- prot = PAGE_KERNEL_EXEC;
+ temp_pfn = get_res_ptepage();
+ set_pmd(pmd, __pmd(temp_pfn | _PAGE_TABLE));
+ pfn += PTRS_PER_PTE;
+ continue;
+ }
- set_pte(pte, pfn_pte(pfn, prot));
+ /*
+ * Either !cpu_has_pse or we have some reserved holes
+ * in the memory region
+ */
+ pte = one_page_table_init(pmd);
+
+ for (pte_ofs = 0;
+ pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn;
+ pte++, pfn++, pte_ofs++,
+ address += PAGE_SIZE, paddr += PAGE_SIZE) {
+ pgprot_t prot = PAGE_KERNEL;
+
+ if (!is_memory_any_valid(paddr,
+ paddr + PAGE_SIZE)) {
+
+ temp_pfn = get_res_page() >> PAGE_SHIFT;
+ set_pte(pte,
+ pfn_pte(temp_pfn, PAGE_KERNEL));
+ continue;
}
+
+ if (is_kernel_text(address))
+ prot = PAGE_KERNEL_EXEC;
+
+ set_pte(pte, pfn_pte(pfn, prot));
}
}
}
@@ -713,6 +785,8 @@
if (boot_cpu_data.wp_works_ok < 0)
test_wp_bit();
+ printk("Prune to be done here. max_low_pfn %lu\n", max_low_pfn);
+ //prune_kernel_identity_map();
/*
* Subtle. SMP is doing it's boot stuff late (because it has to
* fork idle threads) - but it also needs low mappings for the
Index: linux-2.6.git/include/asm-x86/e820_32.h
===================================================================
--- linux-2.6.git.orig/include/asm-x86/e820_32.h 2008-01-08
03:41:30.000000000 -0800
+++ linux-2.6.git/include/asm-x86/e820_32.h 2008-01-08 04:05:24.000000000
-0800
@@ -20,9 +20,13 @@
extern struct e820map e820;
-extern int e820_all_mapped(unsigned long start, unsigned long end,
- unsigned type);
+extern int e820_all_mapped(u64 start, u64 end, unsigned type);
extern int e820_any_mapped(u64 start, u64 end, unsigned type);
+extern int e820_any_non_reserved(u64 start, u64 end);
+extern int is_memory_any_valid(u64 start, u64 end);
+extern int e820_all_non_reserved(u64 start, u64 end);
+extern int is_memory_all_valid(u64 start, u64 end);
+extern int is_memory_all_reserved(u64 start, u64 end);
extern void find_max_pfn(void);
extern void register_bootmem_low_pages(unsigned long max_low_pfn);
extern void e820_register_memory(void);
@@ -41,5 +45,8 @@
#endif
+#define ISA_START_ADDRESS 0xa0000
+#define ISA_END_ADDRESS 0x100000
+
#endif/*!__ASSEMBLY__*/
#endif/*__E820_HEADER*/
Index: linux-2.6.git/arch/x86/mm/pageattr_32.c
===================================================================
--- linux-2.6.git.orig/arch/x86/mm/pageattr_32.c 2008-01-08
03:41:30.000000000 -0800
+++ linux-2.6.git/arch/x86/mm/pageattr_32.c 2008-01-08 04:05:24.000000000
-0800
@@ -55,9 +55,11 @@
/*
* page_private is used to track the number of entries in
* the page table page that 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;
@@ -203,7 +205,7 @@
save_page(kpte_page);
if (!PageReserved(kpte_page)) {
- if (cpu_has_pse && (page_private(kpte_page) == 0)) {
+ if (cpu_has_pse && (page_private(kpte_page) == 1)) {
paravirt_release_pt(page_to_pfn(kpte_page));
revert_page(kpte_page, address);
}
--
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
