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x86/mm: Simplify memory mapping PFN calculation

PATCH New Pekka Enberg 1 participant 3 messages Jul 15, 2012

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x86 x86 MM
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Pekka Enberg

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#0 lore raw

PATCH v2 1/3 x86/mm: Simplify memory mapping PFN calculation

Introduce two new helper functions, addr_to_pmd_pfn() and addr_to_pud_pfn(), to simplify init_memory_mapping() code flow.

Cc Joe Perces <[email protected]>
Cc Tejun Heo <[email protected]>
Acked-by Yinghai Lu <[email protected]>
Signed-off-by Pekka Enberg <[email protected]>
---
 arch/x86/mm/init.c |   38 +++++++++++++++++++++-----------------
 1 files changed, 21 insertions(+), 17 deletions(-)
arch/x86/mm/init.c +21 -17
index bc4e9d8..9eb53c2 100644
@@ -117,6 +117,16 @@ static int __meminit save_mr(struct map_range *mr, int nr_range,
 	return nr_range;
 }
 
+static unsigned long addr_to_pmd_pfn(unsigned long addr)
+{
+	return (addr >> PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
+}
+
+static unsigned long addr_to_pud_pfn(unsigned long addr)
+{
+	return (addr >> PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT);
+}
+
 /*
  * Setup the direct mapping of the physical memory at PAGE_OFFSET.
  * This runs before bootmem is initialized and gets pages directly from

@@ -180,11 +190,9 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
 	if (pos == 0)
 		end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT);
 	else
-		end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
-				 << (PMD_SHIFT - PAGE_SHIFT);
+		end_pfn = addr_to_pmd_pfn(pos + (PMD_SIZE - 1));
 #else /* CONFIG_X86_64 */
-	end_pfn = ((pos + (PMD_SIZE - 1)) >> PMD_SHIFT)
-			<< (PMD_SHIFT - PAGE_SHIFT);
+	end_pfn = addr_to_pmd_pfn(pos + (PMD_SIZE - 1));
 #endif
 	if (end_pfn > (end >> PAGE_SHIFT))
 		end_pfn = end >> PAGE_SHIFT;

@@ -194,15 +202,13 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
 	}
 
 	/* big page (2M) range */
-	start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
-			 << (PMD_SHIFT - PAGE_SHIFT);
+	start_pfn = addr_to_pmd_pfn(pos + (PMD_SIZE - 1));
 #ifdef CONFIG_X86_32
-	end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
+	end_pfn = addr_to_pmd_pfn(end);
 #else /* CONFIG_X86_64 */
-	end_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
-			 << (PUD_SHIFT - PAGE_SHIFT);
-	if (end_pfn > ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT)))
-		end_pfn = ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT));
+	end_pfn = addr_to_pud_pfn(pos + (PUD_SIZE - 1));
+	if (end_pfn > addr_to_pmd_pfn(end))
+		end_pfn = addr_to_pmd_pfn(end);
 #endif
 
 	if (start_pfn < end_pfn) {

@@ -213,9 +219,8 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
 
 #ifdef CONFIG_X86_64
 	/* big page (1G) range */
-	start_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
-			 << (PUD_SHIFT - PAGE_SHIFT);
-	end_pfn = (end >> PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT);
+	start_pfn = addr_to_pud_pfn(pos + (PUD_SIZE - 1));
+	end_pfn = addr_to_pud_pfn(end);
 	if (start_pfn < end_pfn) {
 		nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 				page_size_mask &

@@ -224,9 +229,8 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
 	}
 
 	/* tail is not big page (1G) alignment */
-	start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
-			 << (PMD_SHIFT - PAGE_SHIFT);
-	end_pfn = (end >> PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
+	start_pfn = addr_to_pmd_pfn(pos + (PMD_SIZE - 1));
+	end_pfn = addr_to_pmd_pfn(end);
 	if (start_pfn < end_pfn) {
 		nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 				page_size_mask & (1<<PG_LEVEL_2M));
Signature · 1 line
1.7.7.6
author
#1 lore raw

PATCH v2 2/3 x86/mm: Simplify free_init_pages()

As a cleanup, separate the #ifdef'd code in a new helper function and move initial "addr" assignment to the for-loop construct.

Cc Joe Perches <[email protected]>
Cc Tejun Heo <[email protected]>
Cc Yinghai Lu <[email protected]>
Signed-off-by Pekka Enberg <[email protected]>
---
 arch/x86/mm/init.c |   44 ++++++++++++++++++++++++--------------------
 1 files changed, 24 insertions(+), 20 deletions(-)
arch/x86/mm/init.c +24 -20
index 9eb53c2..4f863cc 100644
@@ -332,35 +332,20 @@ int devmem_is_allowed(unsigned long pagenr)
 	return 0;
 }
 
-void free_init_pages(char *what, unsigned long begin, unsigned long end)
+static void __free_init_pages(char *what, unsigned long begin, unsigned long end)
 {
-	unsigned long addr;
-	unsigned long begin_aligned, end_aligned;
-
-	/* Make sure boundaries are page aligned */
-	begin_aligned = PAGE_ALIGN(begin);
-	end_aligned   = end & PAGE_MASK;
-
-	if (WARN_ON(begin_aligned != begin || end_aligned != end)) {
-		begin = begin_aligned;
-		end   = end_aligned;
-	}
-
-	if (begin >= end)
-		return;
-
-	addr = begin;
-
+#ifdef CONFIG_DEBUG_PAGEALLOC
 	/*
 	 * If debugging page accesses then do not free this memory but
 	 * mark them not present - any buggy init-section access will
 	 * create a kernel page fault:
 	 */
-#ifdef CONFIG_DEBUG_PAGEALLOC
 	printk(KERN_INFO "debug: unmapping init [mem %#010lx-%#010lx]\n",
 		begin, end - 1);
 	set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
 #else
+	unsigned long addr;
+
 	/*
 	 * We just marked the kernel text read only above, now that
 	 * we are going to free part of that, we need to make that

@@ -371,7 +356,7 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end)
 
 	printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
 
-	for (; addr < end; addr += PAGE_SIZE) {
+	for (addr = begin; addr < end; addr += PAGE_SIZE) {
 		ClearPageReserved(virt_to_page(addr));
 		init_page_count(virt_to_page(addr));
 		memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);

@@ -381,6 +366,25 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end)
 #endif
 }
 
+void free_init_pages(char *what, unsigned long begin, unsigned long end)
+{
+	unsigned long begin_aligned, end_aligned;
+
+	/* Make sure boundaries are page aligned */
+	begin_aligned = PAGE_ALIGN(begin);
+	end_aligned   = end & PAGE_MASK;
+
+	if (WARN_ON(begin_aligned != begin || end_aligned != end)) {
+		begin = begin_aligned;
+		end   = end_aligned;
+	}
+
+	if (begin >= end)
+		return;
+
+	__free_init_pages(what, begin, end);
+}
+
 void free_initmem(void)
 {
 	free_init_pages("unused kernel memory",
Signature · 1 line
1.7.7.6
author
#2 lore raw

PATCH v2 3/3 x86/mm: Separate paging setup from memory mapping

In reply to Pekka Enberg

Move PSE and PGE bit twiddling from init_memory_mapping() to a new setup_paging() function to simplify the former function. The init_memory_mapping() function is called later in the boot process by gart_iommu_init(), efi_ioremap(), and arch_add_memory() which have no business whatsover updating the CR4 register.

Cc Joe Perches <[email protected]>
Cc Tejun Heo <[email protected]>
Cc Yinghai Lu <[email protected]>
Signed-off-by Pekka Enberg <[email protected]>
---
 arch/x86/include/asm/page_types.h |    2 ++
 arch/x86/kernel/setup.c           |    2 ++
 arch/x86/mm/init.c                |   23 +++++++++++++----------
 3 files changed, 17 insertions(+), 10 deletions(-)
arch/x86/include/asm/page_types.h +2 -0
index e21fdd1..529905e 100644
@@ -51,6 +51,8 @@ static inline phys_addr_t get_max_mapped(void)
 	return (phys_addr_t)max_pfn_mapped << PAGE_SHIFT;
 }
 
+extern void setup_paging(void);
+
 extern unsigned long init_memory_mapping(unsigned long start,
 					 unsigned long end);
arch/x86/kernel/setup.c +2 -0
index 16be6dc..a883978 100644
@@ -913,6 +913,8 @@ void __init setup_arch(char **cmdline_p)
 
 	init_gbpages();
 
+	setup_paging();
+
 	/* max_pfn_mapped is updated here */
 	max_low_pfn_mapped = init_memory_mapping(0, max_low_pfn<<PAGE_SHIFT);
 	max_pfn_mapped = max_low_pfn_mapped;
arch/x86/mm/init.c +13 -10
index 4f863cc..a972325 100644
@@ -127,6 +127,19 @@ static unsigned long addr_to_pud_pfn(unsigned long addr)
 	return (addr >> PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT);
 }
 
+void setup_paging(void)
+{
+	/* Enable PSE if available */
+	if (cpu_has_pse)
+		set_in_cr4(X86_CR4_PSE);
+
+	/* Enable PGE if available */
+	if (cpu_has_pge) {
+		set_in_cr4(X86_CR4_PGE);
+		__supported_pte_mask |= _PAGE_GLOBAL;
+	}
+}
+
 /*
  * Setup the direct mapping of the physical memory at PAGE_OFFSET.
  * This runs before bootmem is initialized and gets pages directly from

@@ -159,16 +172,6 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
 	use_gbpages = direct_gbpages;
 #endif
 
-	/* Enable PSE if available */
-	if (cpu_has_pse)
-		set_in_cr4(X86_CR4_PSE);
-
-	/* Enable PGE if available */
-	if (cpu_has_pge) {
-		set_in_cr4(X86_CR4_PGE);
-		__supported_pte_mask |= _PAGE_GLOBAL;
-	}
-
 	if (use_gbpages)
 		page_size_mask |= 1 << PG_LEVEL_1G;
 	if (use_pse)
Signature · 1 line
1.7.7.6