x86/mm changes for v3.2

Linus,

Please pull the latest x86-mm-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-mm-for-linus

Thanks,

Ingo

------------------>
Stefano Stabellini (5):
x86, mm: Calculate precisely the memory needed by init_memory_mapping Revert "x86,xen: introduce x86_init.mapping.pagetable_reserve" x86, init : Move memblock_x86_reserve_range PGTABLE to find_early_table_space x86-64, mm: Do not assume head_64.S used 4KB pages when !use_pse
x86_32: Calculate additional memory needed by the fixmap

 arch/x86/include/asm/pgtable_types.h |    1 -
 arch/x86/include/asm/x86_init.h      |   12 ---
 arch/x86/kernel/x86_init.c           |    4 -
 arch/x86/mm/init.c                   |  147 +++++++++++++++++++++++++---------
 arch/x86/xen/mmu.c                   |   15 ----
 5 files changed, 109 insertions(+), 70 deletions(-)

arch/x86/include/asm/pgtable_types.h +0 -1

index d56187c..7db7723 100644
@@ -299,7 +299,6 @@ 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);

arch/x86/include/asm/x86_init.h +0 -12

index d3d8590..643ebf2 100644
@@ -68,17 +68,6 @@ 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

@@ -134,7 +123,6 @@ 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;

arch/x86/kernel/x86_init.c +0 -4

index 6f164bd..6eee082 100644
@@ -61,10 +61,6 @@ 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,

arch/x86/mm/init.c +109 -38

index 3032644..a90ccc4 100644
@@ -28,22 +28,110 @@ int direct_gbpages
 #endif
 ;
 
-static void __init find_early_table_space(unsigned long end, int use_pse,
-					  int use_gbpages)
+static unsigned long __init find_early_fixmap_space(void)
 {
-	unsigned long puds, pmds, ptes, tables, start = 0, good_end = end;
+	unsigned long size = 0;
+#ifdef CONFIG_X86_32
+	int kmap_begin_pmd_idx, kmap_end_pmd_idx;
+	int fixmap_begin_pmd_idx, fixmap_end_pmd_idx;
+	int btmap_begin_pmd_idx;
+
+	fixmap_begin_pmd_idx =
+		__fix_to_virt(__end_of_fixed_addresses - 1) >> PMD_SHIFT;
+	/*
+	 * fixmap_end_pmd_idx is the end of the fixmap minus the PMD that
+	 * has been defined in the data section by head_32.S (see
+	 * initial_pg_fixmap).
+	 * Note: This is similar to what early_ioremap_page_table_range_init
+	 * does except that the "end" has PMD_SIZE expunged as per previous
+	 * comment.
+	 */
+	fixmap_end_pmd_idx = (FIXADDR_TOP - 1) >> PMD_SHIFT;
+	btmap_begin_pmd_idx = __fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT;
+	kmap_begin_pmd_idx = __fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
+	kmap_end_pmd_idx = __fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
+
+	size = fixmap_end_pmd_idx - fixmap_begin_pmd_idx;
+	/*
+	 * early_ioremap_init has already allocated a PMD at
+	 * btmap_begin_pmd_idx
+	 */
+	if (btmap_begin_pmd_idx < fixmap_end_pmd_idx)
+		size--;
+
+#ifdef CONFIG_HIGHMEM
+	/*
+	 * see page_table_kmap_check: if the kmap spans multiple PMDs, make
+	 * sure the pte pages are allocated contiguously. It might need up
+	 * to two additional pte pages to replace the page declared by
+	 * head_32.S and the one allocated by early_ioremap_init, if they
+	 * are even partially used for the kmap.
+	 */
+	if (kmap_begin_pmd_idx != kmap_end_pmd_idx) {
+		if (kmap_end_pmd_idx == fixmap_end_pmd_idx)
+			size++;
+		if (btmap_begin_pmd_idx >= kmap_begin_pmd_idx &&
+				btmap_begin_pmd_idx <= kmap_end_pmd_idx)
+			size++;
+	}
+#endif
+#endif
+	return (size * PMD_SIZE + PAGE_SIZE - 1) >> PAGE_SHIFT;
+}
+
+static void __init find_early_table_space(unsigned long start,
+		unsigned long end, int use_pse, int use_gbpages)
+{
+	unsigned long pmds = 0, ptes = 0, tables = 0, good_end = end,
+				  pud_mapped = 0, pmd_mapped = 0, size = end - start;
 	phys_addr_t base;
 
-	puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
-	tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
+	pud_mapped = DIV_ROUND_UP(PFN_PHYS(max_pfn_mapped),
+			(PUD_SIZE * PTRS_PER_PUD));
+	pud_mapped *= (PUD_SIZE * PTRS_PER_PUD);
+	pmd_mapped = DIV_ROUND_UP(PFN_PHYS(max_pfn_mapped),
+			(PMD_SIZE * PTRS_PER_PMD));
+	pmd_mapped *= (PMD_SIZE * PTRS_PER_PMD);
+
+	/*
+	 * On x86_64 do not limit the size we need to cover with 4KB pages
+	 * depending on the initial allocation because head_64.S always uses
+	 * 2MB pages.
+	 */
+#ifdef CONFIG_X86_32
+	if (start < PFN_PHYS(max_pfn_mapped)) {
+		if (PFN_PHYS(max_pfn_mapped) < end)
+			size -= PFN_PHYS(max_pfn_mapped) - start;
+		else
+			size = 0;
+	}
+#endif
+
+#ifndef __PAGETABLE_PUD_FOLDED
+	if (end > pud_mapped) {
+		unsigned long puds;
+		if (start < pud_mapped)
+			puds = (end - pud_mapped + PUD_SIZE - 1) >> PUD_SHIFT;
+		else
+			puds = (end - start + PUD_SIZE - 1) >> PUD_SHIFT;
+		tables += roundup(puds * sizeof(pud_t), PAGE_SIZE);
+	}
+#endif
 
 	if (use_gbpages) {
 		unsigned long extra;
 
 		extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
 		pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT;
-	} else
-		pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
+	}
+#ifndef __PAGETABLE_PMD_FOLDED
+	else if (end > pmd_mapped) {
+		if (start < pmd_mapped)
+			pmds = (end - pmd_mapped + PMD_SIZE - 1) >> PMD_SHIFT;
+		else
+			pmds = (end - start + PMD_SIZE - 1) >> PMD_SHIFT;
+	}
+#endif
 
 	tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
 

@@ -51,23 +139,22 @@ static void __init find_early_table_space(unsigned long end, int use_pse,
 		unsigned long extra;
 
 		extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
-#ifdef CONFIG_X86_32
-		extra += PMD_SIZE;
-#endif
 		ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	} else
-		ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
+		ptes = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
+	ptes += find_early_fixmap_space();
 
 	tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
 
-#ifdef CONFIG_X86_32
-	/* for fixmap */
-	tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE);
+	if (!tables)
+		return;
 
+#ifdef CONFIG_X86_32
 	good_end = max_pfn_mapped << PAGE_SHIFT;
 #endif
 
-	base = memblock_find_in_range(start, good_end, tables, PAGE_SIZE);
+	base = memblock_find_in_range(0x00, good_end, tables, PAGE_SIZE);
 	if (base == MEMBLOCK_ERROR)
 		panic("Cannot find space for the kernel page tables");
 

@@ -77,11 +164,10 @@ static void __init find_early_table_space(unsigned long end, int use_pse,
 
 	printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
 		end, pgt_buf_start << PAGE_SHIFT, pgt_buf_top << PAGE_SHIFT);
-}
 
-void __init native_pagetable_reserve(u64 start, u64 end)
-{
-	memblock_x86_reserve_range(start, end, "PGTABLE");
+	if (pgt_buf_top > pgt_buf_start)
+		memblock_x86_reserve_range(pgt_buf_start << PAGE_SHIFT,
+				 pgt_buf_top << PAGE_SHIFT, "PGTABLE");
 }
 
 struct map_range {

@@ -261,7 +347,7 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
 	 * nodes are discovered.
 	 */
 	if (!after_bootmem)
-		find_early_table_space(end, use_pse, use_gbpages);
+		find_early_table_space(start, end, use_pse, use_gbpages);
 
 	for (i = 0; i < nr_range; i++)
 		ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,

@@ -275,24 +361,9 @@ 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)
-		x86_init.mapping.pagetable_reserve(PFN_PHYS(pgt_buf_start),
-				PFN_PHYS(pgt_buf_end));
+	if (pgt_buf_end != pgt_buf_top)
+		printk(KERN_DEBUG "initial kernel pagetable allocation wasted %lx"
+				" pages\n", pgt_buf_top - pgt_buf_end);
 
 	if (!after_bootmem)
 		early_memtest(start, end);

arch/x86/xen/mmu.c +0 -16

index dc708dc..2004f1e 100644
@@ -1153,20 +1153,6 @@ static void __init 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 void __init xen_pagetable_setup_done(pgd_t *base)

@@ -1997,7 +1983,6 @@ static const struct pv_mmu_ops xen_mmu_ops __initconst = {
 
 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;
--

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Quoted 5 lines · Ingo Molnar

Linus,

Please pull the latest x86-mm-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git

x86-mm-for-linus

Quoted 1 line

Hey Ingo,

When I spoke to hpa (LinuxCon in Canada) he mentioned that you guys decided
against this patchset and just stick with the

"x86,xen: introduce x86_init.mapping.pagetable_reserve"?

Maybe I am misremembering the conversation - there was a fair amount of beer
involved.

Quoted 7 lines

Thanks,

Ingo

------------------>
Stefano Stabellini (5):
x86, mm: Calculate precisely the memory needed by

init_memory_mapping

Quoted 2 lines

Revert "x86,xen: introduce x86_init.mapping.pagetable_reserve" x86, init : Move memblock_x86_reserve_range PGTABLE to

find_early_table_space

Quoted 1 line

x86-64, mm: Do not assume head_64.S used 4KB pages when

!use_pse

Quoted 7 lines

x86_32: Calculate additional memory needed by the fixmap

 arch/x86/include/asm/pgtable_types.h |    1 -
 arch/x86/include/asm/x86_init.h      |   12 ---
 arch/x86/kernel/x86_init.c           |    4 -
 arch/x86/mm/init.c                   |  147

+++++++++++++++++++++++++---------

Review

Quoted 4 lines

 arch/x86/xen/mmu.c                   |   15 ----
 5 files changed, 109 insertions(+), 70 deletions(-)

(quoted diff) +0 -0

b/arch/x86/include/asm/pgtable_types.h

arch/x86/include/asm/pgtable_types.h int phys_mem_access_prot_allowed(struct file

Quoted 4 lines

index d56187c..7db7723 100644

arch/x86/include/asm/pgtable_types.h +0 -0

@@ -299,7 +299,6 @@ int phys_mem_access_prot_allowed(struct file

*file, unsigned long pfn,

Review

Quoted 8 lines

arch/x86/include/asm/pgtable_types.h +0 -1

 /* 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);

(quoted diff) +0 -0

b/arch/x86/include/asm/x86_init.h

arch/x86/include/asm/x86_init.h struct x86_init_oem { · line 71

Quoted 8 lines

index d3d8590..643ebf2 100644

arch/x86/include/asm/x86_init.h +0 -1

@@ -68,17 +68,6 @@ struct x86_init_oem {
 };
 
 /**
- * struct x86_init_mapping - platform specific initial kernel

pagetable setup

arch/x86/include/asm/x86_init.h struct x86_init_oem { · line 72

Quoted 1 line

arch/x86/include/asm/x86_init.h +0 -1

- * @pagetable_reserve:	reserve a range of addresses for kernel

pagetable usage

Quoted 40 lines

arch/x86/include/asm/x86_init.h +0 -10

- *
- * 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

@@ -134,7 +123,6 @@ 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;

arch/x86/kernel/x86_init.c +0 -4

index 6f164bd..6eee082 100644
@@ -61,10 +61,6 @@ 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,

arch/x86/mm/init.c +0 -0

index 3032644..a90ccc4 100644

arch/x86/mm/init.c int direct_gbpages · line 31

Quoted 4 lines

arch/x86/mm/init.c +0 -1

@@ -28,22 +28,110 @@ int direct_gbpages
 #endif
 ;
 
-static void __init find_early_table_space(unsigned long end, int

use_pse,

Quoted 7 lines

arch/x86/mm/init.c +4 -2

-					  int use_gbpages)
+static unsigned long __init find_early_fixmap_space(void)
 {
-	unsigned long puds, pmds, ptes, tables, start = 0, good_end = end;
+	unsigned long size = 0;
+#ifdef CONFIG_X86_32
+	int kmap_begin_pmd_idx, kmap_end_pmd_idx;

arch/x86/mm/init.c int direct_gbpages

Quoted 10 lines

arch/x86/mm/init.c +10 -0

+	int fixmap_begin_pmd_idx, fixmap_end_pmd_idx;
+	int btmap_begin_pmd_idx;
+
+	fixmap_begin_pmd_idx =
+		__fix_to_virt(__end_of_fixed_addresses - 1) >> PMD_SHIFT;
+	/*
+	 * fixmap_end_pmd_idx is the end of the fixmap minus the PMD that
+	 * has been defined in the data section by head_32.S (see
+	 * initial_pg_fixmap).
+	 * Note: This is similar to what

early_ioremap_page_table_range_init

Quoted 45 lines

arch/x86/mm/init.c +41 -2

+	 * does except that the "end" has PMD_SIZE expunged as per previous
+	 * comment.
+	 */
+	fixmap_end_pmd_idx = (FIXADDR_TOP - 1) >> PMD_SHIFT;
+	btmap_begin_pmd_idx = __fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT;
+	kmap_begin_pmd_idx = __fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
+	kmap_end_pmd_idx = __fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
+
+	size = fixmap_end_pmd_idx - fixmap_begin_pmd_idx;
+	/*
+	 * early_ioremap_init has already allocated a PMD at
+	 * btmap_begin_pmd_idx
+	 */
+	if (btmap_begin_pmd_idx < fixmap_end_pmd_idx)
+		size--;
+
+#ifdef CONFIG_HIGHMEM
+	/*
+	 * see page_table_kmap_check: if the kmap spans multiple PMDs, make
+	 * sure the pte pages are allocated contiguously. It might need up
+	 * to two additional pte pages to replace the page declared by
+	 * head_32.S and the one allocated by early_ioremap_init, if they
+	 * are even partially used for the kmap.
+	 */
+	if (kmap_begin_pmd_idx != kmap_end_pmd_idx) {
+		if (kmap_end_pmd_idx == fixmap_end_pmd_idx)
+			size++;
+		if (btmap_begin_pmd_idx >= kmap_begin_pmd_idx &&
+				btmap_begin_pmd_idx <= kmap_end_pmd_idx)
+			size++;
+	}
+#endif
+#endif
+	return (size * PMD_SIZE + PAGE_SIZE - 1) >> PAGE_SHIFT;
+}
+
+static void __init find_early_table_space(unsigned long start,
+		unsigned long end, int use_pse, int use_gbpages)
+{
+	unsigned long pmds = 0, ptes = 0, tables = 0, good_end = end,
+				  pud_mapped = 0, pmd_mapped = 0, size = end - start;
 	phys_addr_t base;
 
-	puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
-	tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);

arch/x86/mm/init.c int direct_gbpages

Quoted 10 lines

arch/x86/mm/init.c +10 -0

+	pud_mapped = DIV_ROUND_UP(PFN_PHYS(max_pfn_mapped),
+			(PUD_SIZE * PTRS_PER_PUD));
+	pud_mapped *= (PUD_SIZE * PTRS_PER_PUD);
+	pmd_mapped = DIV_ROUND_UP(PFN_PHYS(max_pfn_mapped),
+			(PMD_SIZE * PTRS_PER_PMD));
+	pmd_mapped *= (PMD_SIZE * PTRS_PER_PMD);
+
+	/*
+	 * On x86_64 do not limit the size we need to cover with 4KB pages
+	 * depending on the initial allocation because head_64.S always

uses

arch/x86/mm/init.c static void __init

Quoted 42 lines

arch/x86/mm/init.c +30 -2

+	 * 2MB pages.
+	 */
+#ifdef CONFIG_X86_32
+	if (start < PFN_PHYS(max_pfn_mapped)) {
+		if (PFN_PHYS(max_pfn_mapped) < end)
+			size -= PFN_PHYS(max_pfn_mapped) - start;
+		else
+			size = 0;
+	}
+#endif
+
+#ifndef __PAGETABLE_PUD_FOLDED
+	if (end > pud_mapped) {
+		unsigned long puds;
+		if (start < pud_mapped)
+			puds = (end - pud_mapped + PUD_SIZE - 1) >> PUD_SHIFT;
+		else
+			puds = (end - start + PUD_SIZE - 1) >> PUD_SHIFT;
+		tables += roundup(puds * sizeof(pud_t), PAGE_SIZE);
+	}
+#endif
 
 	if (use_gbpages) {
 		unsigned long extra;
 
 		extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
 		pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT;
-	} else
-		pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
+	}
+#ifndef __PAGETABLE_PMD_FOLDED
+	else if (end > pmd_mapped) {
+		if (start < pmd_mapped)
+			pmds = (end - pmd_mapped + PMD_SIZE - 1) >> PMD_SHIFT;
+		else
+			pmds = (end - start + PMD_SIZE - 1) >> PMD_SHIFT;
+	}
+#endif
 
 	tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
 

@@ -51,23 +139,22 @@ static void __init

find_early_table_space(unsigned long end, int use_pse,

Quoted 8 lines

arch/x86/mm/init.c +0 -3

 		unsigned long extra;
 
 		extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
-#ifdef CONFIG_X86_32
-		extra += PMD_SIZE;
-#endif
 		ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	} else

arch/x86/mm/init.c static void __init find_early_table_space(unsigned long end, int use_pse,

Quoted 10 lines

arch/x86/mm/init.c +3 -4

-		ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
+		ptes = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
+	ptes += find_early_fixmap_space();
 
 	tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
 
-#ifdef CONFIG_X86_32
-	/* for fixmap */
-	tables += roundup(__end_of_fixed_addresses * sizeof(pte_t),

PAGE_SIZE);

arch/x86/mm/init.c static void __init

Quoted 13 lines

arch/x86/mm/init.c +4 -1

+	if (!tables)
+		return;
 
+#ifdef CONFIG_X86_32
 	good_end = max_pfn_mapped << PAGE_SHIFT;
 #endif
 
-	base = memblock_find_in_range(start, good_end, tables, PAGE_SIZE);
+	base = memblock_find_in_range(0x00, good_end, tables, PAGE_SIZE);
 	if (base == MEMBLOCK_ERROR)
 		panic("Cannot find space for the kernel page tables");
 

@@ -77,11 +164,10 @@ static void __init

find_early_table_space(unsigned long end, int use_pse,

arch/x86/mm/init.c static void __init · line 164

Quoted 2 lines

arch/x86/mm/init.c +0 -0

 	printk(KERN_DEBUG "kernel direct mapping tables up to %lx @

%lx-%lx\n",

arch/x86/mm/init.c unsigned long __init_refok

Quoted 13 lines

arch/x86/mm/init.c +3 -4

 		end, pgt_buf_start << PAGE_SHIFT, pgt_buf_top << PAGE_SHIFT);
-}
 
-void __init native_pagetable_reserve(u64 start, u64 end)
-{
-	memblock_x86_reserve_range(start, end, "PGTABLE");
+	if (pgt_buf_top > pgt_buf_start)
+		memblock_x86_reserve_range(pgt_buf_start << PAGE_SHIFT,
+				 pgt_buf_top << PAGE_SHIFT, "PGTABLE");
 }
 
 struct map_range {

@@ -261,7 +347,7 @@ unsigned long __init_refok

init_memory_mapping(unsigned long start,

arch/x86/mm/init.c unsigned long __init_refok

Quoted 9 lines

arch/x86/mm/init.c +1 -1

 	 * nodes are discovered.
 	 */
 	if (!after_bootmem)
-		find_early_table_space(end, use_pse, use_gbpages);
+		find_early_table_space(start, end, use_pse, use_gbpages);
 
 	for (i = 0; i < nr_range; i++)
 		ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,

@@ -275,24 +361,9 @@ unsigned long __init_refok

init_memory_mapping(unsigned long start,

arch/x86/mm/init.c unsigned long __init_refok init_memory_mapping(unsigned long start,

Quoted 9 lines

arch/x86/mm/init.c +0 -6

 	__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

arch/x86/mm/init.c unsigned long __init_refok · line 283

Quoted 1 line

arch/x86/mm/init.c +0 -1

-	 * also means marking RW the pagetable pages that we allocated

before

arch/x86/xen/mmu.c static void __init

Quoted 22 lines

arch/x86/mm/init.c +3 -11

-	 * 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)
-		x86_init.mapping.pagetable_reserve(PFN_PHYS(pgt_buf_start),
-				PFN_PHYS(pgt_buf_end));
+	if (pgt_buf_end != pgt_buf_top)
+		printk(KERN_DEBUG "initial kernel pagetable allocation wasted %lx"
+				" pages\n", pgt_buf_top - pgt_buf_end);
 
 	if (!after_bootmem)
 		early_memtest(start, end);

arch/x86/xen/mmu.c +0 -0

index dc708dc..2004f1e 100644
@@ -1153,20 +1153,6 @@ static void __init

xen_pagetable_setup_start(pgd_t *base)

arch/x86/xen/mmu.c static const struct pv_mmu_ops xen_mmu_ops

Quoted 21 lines

arch/x86/xen/mmu.c +0 -14

 {
 }
 
-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 void __init xen_pagetable_setup_done(pgd_t *base)

@@ -1997,7 +1983,6 @@ static const struct pv_mmu_ops xen_mmu_ops

__initconst = {

Quoted 9 lines

arch/x86/xen/mmu.c +0 -2

 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;
--

To unsubscribe from this list: send the line "unsubscribe

linux-kernel" in

Quoted 3 lines

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/

Yes... I thought we had agreed that as ugly as the hook it is better than the fragility of second-guessing other code. I would like to see something automatically correct by construction, but that seems to be really difficult for reasons I don't remember, possibly having to do with bad Xen setup APIs.

Okay.

Linus, please ignore this pull request.

Peter, once you get some time please sort out which of these commits we want to keep:

b17a5f97d413: x86_32: Calculate additional memory needed by the fixmap 2e9fbad5955f: x86-64, mm: Do not assume head_64.S used 4KB pages when !use_pse 1938931a20da: x86, init : Move memblock_x86_reserve_range PGTABLE to find_early_table_space
d8ca7b16cfc1: Revert "x86,xen: introduce x86_init.mapping.pagetable_reserve" 8e7f9f8d4076: x86, mm: Calculate precisely the memory needed by init_memory_mapping

for example 2e9fbad5955f looks independent.

Quoted 14 lines · Ingo Molnar

Okay.

Linus, please ignore this pull request.

Peter, once you get some time please sort out which of these commits we want to keep:

b17a5f97d413: x86_32: Calculate additional memory needed by the fixmap 2e9fbad5955f: x86-64, mm: Do not assume head_64.S used 4KB pages when !use_pse 1938931a20da: x86, init : Move memblock_x86_reserve_range PGTABLE to find_early_table_space
d8ca7b16cfc1: Revert "x86,xen: introduce x86_init.mapping.pagetable_reserve" 8e7f9f8d4076: x86, mm: Calculate precisely the memory needed by init_memory_mapping

Quoted 2 lines

for example 2e9fbad5955f looks independent.

I'll take a look as soon as I can.