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-rw-r--r--arch/x86/include/asm/pgtable_types.h1
-rw-r--r--arch/x86/include/asm/x86_init.h12
-rw-r--r--arch/x86/kernel/x86_init.c4
-rw-r--r--arch/x86/mm/init.c24
-rw-r--r--arch/x86/xen/mmu.c15
5 files changed, 54 insertions, 2 deletions
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 7db7723d1f32..d56187c6b838 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -299,6 +299,7 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
/* Install a pte for a particular vaddr in kernel space. */
void set_pte_vaddr(unsigned long vaddr, pte_t pte);
+extern void native_pagetable_reserve(u64 start, u64 end);
#ifdef CONFIG_X86_32
extern void native_pagetable_setup_start(pgd_t *base);
extern void native_pagetable_setup_done(pgd_t *base);
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index 643ebf2e2ad8..d3d859035af9 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -68,6 +68,17 @@ struct x86_init_oem {
};
/**
+ * struct x86_init_mapping - platform specific initial kernel pagetable setup
+ * @pagetable_reserve: reserve a range of addresses for kernel pagetable usage
+ *
+ * For more details on the purpose of this hook, look in
+ * init_memory_mapping and the commit that added it.
+ */
+struct x86_init_mapping {
+ void (*pagetable_reserve)(u64 start, u64 end);
+};
+
+/**
* struct x86_init_paging - platform specific paging functions
* @pagetable_setup_start: platform specific pre paging_init() call
* @pagetable_setup_done: platform specific post paging_init() call
@@ -123,6 +134,7 @@ struct x86_init_ops {
struct x86_init_mpparse mpparse;
struct x86_init_irqs irqs;
struct x86_init_oem oem;
+ struct x86_init_mapping mapping;
struct x86_init_paging paging;
struct x86_init_timers timers;
struct x86_init_iommu iommu;
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index c11514e9128b..75ef4b18e9b7 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -61,6 +61,10 @@ struct x86_init_ops x86_init __initdata = {
.banner = default_banner,
},
+ .mapping = {
+ .pagetable_reserve = native_pagetable_reserve,
+ },
+
.paging = {
.pagetable_setup_start = native_pagetable_setup_start,
.pagetable_setup_done = native_pagetable_setup_done,
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 286d289b039b..722a4c372ce3 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -81,6 +81,11 @@ static void __init find_early_table_space(unsigned long end, int use_pse,
end, pgt_buf_start << PAGE_SHIFT, pgt_buf_top << PAGE_SHIFT);
}
+void native_pagetable_reserve(u64 start, u64 end)
+{
+ memblock_x86_reserve_range(start, end, "PGTABLE");
+}
+
struct map_range {
unsigned long start;
unsigned long end;
@@ -272,9 +277,24 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
__flush_tlb_all();
+ /*
+ * Reserve the kernel pagetable pages we used (pgt_buf_start -
+ * pgt_buf_end) and free the other ones (pgt_buf_end - pgt_buf_top)
+ * so that they can be reused for other purposes.
+ *
+ * On native it just means calling memblock_x86_reserve_range, on Xen it
+ * also means marking RW the pagetable pages that we allocated before
+ * but that haven't been used.
+ *
+ * In fact on xen we mark RO the whole range pgt_buf_start -
+ * pgt_buf_top, because we have to make sure that when
+ * init_memory_mapping reaches the pagetable pages area, it maps
+ * RO all the pagetable pages, including the ones that are beyond
+ * pgt_buf_end at that time.
+ */
if (!after_bootmem && pgt_buf_end > pgt_buf_start)
- memblock_x86_reserve_range(pgt_buf_start << PAGE_SHIFT,
- pgt_buf_end << PAGE_SHIFT, "PGTABLE");
+ x86_init.mapping.pagetable_reserve(PFN_PHYS(pgt_buf_start),
+ PFN_PHYS(pgt_buf_end));
if (!after_bootmem)
early_memtest(start, end);
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index cf4ef61e425b..0684f3c74d53 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1275,6 +1275,20 @@ static __init void xen_pagetable_setup_start(pgd_t *base)
{
}
+static __init void xen_mapping_pagetable_reserve(u64 start, u64 end)
+{
+ /* reserve the range used */
+ native_pagetable_reserve(start, end);
+
+ /* set as RW the rest */
+ printk(KERN_DEBUG "xen: setting RW the range %llx - %llx\n", end,
+ PFN_PHYS(pgt_buf_top));
+ while (end < PFN_PHYS(pgt_buf_top)) {
+ make_lowmem_page_readwrite(__va(end));
+ end += PAGE_SIZE;
+ }
+}
+
static void xen_post_allocator_init(void);
static __init void xen_pagetable_setup_done(pgd_t *base)
@@ -2105,6 +2119,7 @@ static const struct pv_mmu_ops xen_mmu_ops __initdata = {
void __init xen_init_mmu_ops(void)
{
+ x86_init.mapping.pagetable_reserve = xen_mapping_pagetable_reserve;
x86_init.paging.pagetable_setup_start = xen_pagetable_setup_start;
x86_init.paging.pagetable_setup_done = xen_pagetable_setup_done;
pv_mmu_ops = xen_mmu_ops;