diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index d37f29376b0ce455ae3907051a58779f4b995a25..9b5f7d7049d044c78f017f1f33377ac5db4caed7 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -194,11 +194,30 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
- unsigned pages_2m = 0, pages_4k = 0;
+ unsigned pages_2m, pages_4k;
+ int mapping_iter;
+
+ /*
+ * First iteration will setup identity mapping using large/small pages
+ * based on use_pse, with other attributes same as set by
+ * the early code in head_32.S
+ *
+ * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
+ * as desired for the kernel identity mapping.
+ *
+ * This two pass mechanism conforms to the TLB app note which says:
+ *
+ * "Software should not write to a paging-structure entry in a way
+ * that would change, for any linear address, both the page size
+ * and either the page frame or attributes."
+ */
+ mapping_iter = 1;
if (!cpu_has_pse)
use_pse = 0;
+repeat:
+ pages_2m = pages_4k = 0;
pfn = start_pfn;
pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
pgd = pgd_base + pgd_idx;
@@ -224,6 +243,13 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
if (use_pse) {
unsigned int addr2;
pgprot_t prot = PAGE_KERNEL_LARGE;
+ /*
+ * first pass will use the same initial
+ * identity mapping attribute + _PAGE_PSE.
+ */
+ pgprot_t init_prot =
+ __pgprot(PTE_IDENT_ATTR |
+ _PAGE_PSE);
addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
PAGE_OFFSET + PAGE_SIZE-1;
@@ -233,7 +259,10 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
prot = PAGE_KERNEL_LARGE_EXEC;
pages_2m++;
- set_pmd(pmd, pfn_pmd(pfn, prot));
+ if (mapping_iter == 1)
+ set_pmd(pmd, pfn_pmd(pfn, init_prot));
+ else
+ set_pmd(pmd, pfn_pmd(pfn, prot));
pfn += PTRS_PER_PTE;
continue;
@@ -245,17 +274,43 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
pgprot_t prot = PAGE_KERNEL;
+ /*
+ * first pass will use the same initial
+ * identity mapping attribute.
+ */
+ pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
if (is_kernel_text(addr))
prot = PAGE_KERNEL_EXEC;
pages_4k++;
- set_pte(pte, pfn_pte(pfn, prot));
+ if (mapping_iter == 1)
+ set_pte(pte, pfn_pte(pfn, init_prot));
+ else
+ set_pte(pte, pfn_pte(pfn, prot));
}
}
}
- update_page_count(PG_LEVEL_2M, pages_2m);
- update_page_count(PG_LEVEL_4K, pages_4k);
+ if (mapping_iter == 1) {
+ /*
+ * update direct mapping page count only in the first
+ * iteration.
+ */
+ update_page_count(PG_LEVEL_2M, pages_2m);
+ update_page_count(PG_LEVEL_4K, pages_4k);
+
+ /*
+ * local global flush tlb, which will flush the previous
+ * mappings present in both small and large page TLB's.
+ */
+ __flush_tlb_all();
+
+ /*
+ * Second iteration will set the actual desired PTE attributes.
+ */
+ mapping_iter = 2;
+ goto repeat;
+ }
}
/*
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index d3746efb060d1602a9de63d3be955522f0cd2a5d..1ba945eb6282b29c99c7adc598711e91263fcaf4 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -270,6 +270,8 @@ static __ref void unmap_low_page(void *adr)
early_iounmap(adr, PAGE_SIZE);
}
+static int physical_mapping_iter;
+
static unsigned long __meminit
phys_pte_init(pte_t *pte_page, unsigned long addr, unsigned long end)
{
@@ -290,16 +292,19 @@ phys_pte_init(pte_t *pte_page, unsigned long addr, unsigned long end)
}
if (pte_val(*pte))
- continue;
+ goto repeat_set_pte;
if (0)
printk(" pte=%p addr=%lx pte=%016lx\n",
pte, addr, pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL).pte);
+ pages++;
+repeat_set_pte:
set_pte(pte, pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL));
last_map_addr = (addr & PAGE_MASK) + PAGE_SIZE;
- pages++;
}
- update_page_count(PG_LEVEL_4K, pages);
+
+ if (physical_mapping_iter == 1)
+ update_page_count(PG_LEVEL_4K, pages);
return last_map_addr;
}
@@ -318,7 +323,6 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end,
{
unsigned long pages = 0;
unsigned long last_map_addr = end;
- unsigned long start = address;
int i = pmd_index(address);
@@ -341,15 +345,14 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end,
last_map_addr = phys_pte_update(pmd, address,
end);
spin_unlock(&init_mm.page_table_lock);
+ continue;
}
- /* Count entries we're using from level2_ident_pgt */
- if (start == 0)
- pages++;
- continue;
+ goto repeat_set_pte;
}
if (page_size_mask & (1<<PG_LEVEL_2M)) {
pages++;
+repeat_set_pte:
spin_lock(&init_mm.page_table_lock);
set_pte((pte_t *)pmd,
pfn_pte(address >> PAGE_SHIFT, PAGE_KERNEL_LARGE));
@@ -366,7 +369,8 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end,
pmd_populate_kernel(&init_mm, pmd, __va(pte_phys));
spin_unlock(&init_mm.page_table_lock);
}
- update_page_count(PG_LEVEL_2M, pages);
+ if (physical_mapping_iter == 1)
+ update_page_count(PG_LEVEL_2M, pages);
return last_map_addr;
}
@@ -405,14 +409,18 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end,
}
if (pud_val(*pud)) {
- if (!pud_large(*pud))
+ if (!pud_large(*pud)) {
last_map_addr = phys_pmd_update(pud, addr, end,
page_size_mask);
- continue;
+ continue;
+ }
+
+ goto repeat_set_pte;
}
if (page_size_mask & (1<<PG_LEVEL_1G)) {
pages++;
+repeat_set_pte:
spin_lock(&init_mm.page_table_lock);
set_pte((pte_t *)pud,
pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL_LARGE));
@@ -430,7 +438,9 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end,
spin_unlock(&init_mm.page_table_lock);
}
__flush_tlb_all();
- update_page_count(PG_LEVEL_1G, pages);
+
+ if (physical_mapping_iter == 1)
+ update_page_count(PG_LEVEL_1G, pages);
return last_map_addr;
}
@@ -494,15 +504,54 @@ static void __init init_gbpages(void)
direct_gbpages = 0;
}
+static int is_kernel(unsigned long pfn)
+{
+ unsigned long pg_addresss = pfn << PAGE_SHIFT;
+
+ if (pg_addresss >= (unsigned long) __pa(_text) &&
+ pg_addresss <= (unsigned long) __pa(_end))
+ return 1;
+
+ return 0;
+}
+
static unsigned long __init kernel_physical_mapping_init(unsigned long start,
unsigned long end,
unsigned long page_size_mask)
{
- unsigned long next, last_map_addr = end;
+ unsigned long next, last_map_addr;
+ u64 cached_supported_pte_mask = __supported_pte_mask;
+ unsigned long cache_start = start;
+ unsigned long cache_end = end;
+
+ /*
+ * First iteration will setup identity mapping using large/small pages
+ * based on page_size_mask, with other attributes same as set by
+ * the early code in head_64.S
+ *
+ * Second iteration will setup the appropriate attributes
+ * as desired for the kernel identity mapping.
+ *
+ * This two pass mechanism conforms to the TLB app note which says:
+ *
+ * "Software should not write to a paging-structure entry in a way
+ * that would change, for any linear address, both the page size
+ * and either the page frame or attributes."
+ *
+ * For now, only difference between very early PTE attributes used in
+ * head_64.S and here is _PAGE_NX.
+ */
+ BUILD_BUG_ON((__PAGE_KERNEL_LARGE & ~__PAGE_KERNEL_IDENT_LARGE_EXEC)
+ != _PAGE_NX);
+ __supported_pte_mask &= ~(_PAGE_NX);
+ physical_mapping_iter = 1;
- start = (unsigned long)__va(start);
- end = (unsigned long)__va(end);
+repeat:
+ last_map_addr = cache_end;
+
+ start = (unsigned long)__va(cache_start);
+ end = (unsigned long)__va(cache_end);
for (; start < end; start = next) {
pgd_t *pgd = pgd_offset_k(start);
@@ -514,11 +563,21 @@ static unsigned long __init kernel_physical_mapping_init(unsigned long start,
next = end;
if (pgd_val(*pgd)) {
+ /*
+ * Static identity mappings will be overwritten
+ * with run-time mappings. For example, this allows
+ * the static 0-1GB identity mapping to be mapped
+ * non-executable with this.
+ */
+ if (is_kernel(pte_pfn(*((pte_t *) pgd))))
+ goto realloc;
+
last_map_addr = phys_pud_update(pgd, __pa(start),
__pa(end), page_size_mask);
continue;
}
+realloc:
pud = alloc_low_page(&pud_phys);
last_map_addr = phys_pud_init(pud, __pa(start), __pa(next),
page_size_mask);
@@ -528,6 +587,16 @@ static unsigned long __init kernel_physical_mapping_init(unsigned long start,
pgd_populate(&init_mm, pgd, __va(pud_phys));
spin_unlock(&init_mm.page_table_lock);
}
+ __flush_tlb_all();
+
+ if (physical_mapping_iter == 1) {
+ physical_mapping_iter = 2;
+ /*
+ * Second iteration will set the actual desired PTE attributes.
+ */
+ __supported_pte_mask = cached_supported_pte_mask;
+ goto repeat;
+ }
return last_map_addr;
}