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Subject[PATCHv2 7/7] x86/mm: isolate the bottom-up style to init_32.c
Date
bottom-up style is useless in x86_64 any longer, isolate it. Later, it may
be removed completely from x86.

Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Chao Fan <fanc.fnst@cn.fujitsu.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: x86@kernel.org
Cc: linux-acpi@vger.kernel.org
Cc: linux-mm@kvack.org
---
arch/x86/mm/init.c | 153 +---------------------------------------------
arch/x86/mm/init_32.c | 147 ++++++++++++++++++++++++++++++++++++++++++++
arch/x86/mm/mm_internal.h | 8 ++-
3 files changed, 155 insertions(+), 153 deletions(-)

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 003ad77..6a853e4 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -502,7 +502,7 @@ unsigned long __ref init_memory_mapping(unsigned long start,
* That range would have hole in the middle or ends, and only ram parts
* will be mapped in init_range_memory_mapping().
*/
-static unsigned long __init init_range_memory_mapping(
+unsigned long __init init_range_memory_mapping(
unsigned long r_start,
unsigned long r_end)
{
@@ -530,157 +530,6 @@ static unsigned long __init init_range_memory_mapping(
return mapped_ram_size;
}

-#ifdef CONFIG_X86_32
-
-static unsigned long min_pfn_mapped;
-
-static unsigned long __init get_new_step_size(unsigned long step_size)
-{
- /*
- * Initial mapped size is PMD_SIZE (2M).
- * We can not set step_size to be PUD_SIZE (1G) yet.
- * In worse case, when we cross the 1G boundary, and
- * PG_LEVEL_2M is not set, we will need 1+1+512 pages (2M + 8k)
- * to map 1G range with PTE. Hence we use one less than the
- * difference of page table level shifts.
- *
- * Don't need to worry about overflow in the top-down case, on 32bit,
- * when step_size is 0, round_down() returns 0 for start, and that
- * turns it into 0x100000000ULL.
- * In the bottom-up case, round_up(x, 0) returns 0 though too, which
- * needs to be taken into consideration by the code below.
- */
- return step_size << (PMD_SHIFT - PAGE_SHIFT - 1);
-}
-
-/**
- * memory_map_top_down - Map [map_start, map_end) top down
- * @map_start: start address of the target memory range
- * @map_end: end address of the target memory range
- *
- * This function will setup direct mapping for memory range
- * [map_start, map_end) in top-down. That said, the page tables
- * will be allocated at the end of the memory, and we map the
- * memory in top-down.
- */
-static void __init memory_map_top_down(unsigned long map_start,
- unsigned long map_end)
-{
- unsigned long real_end, start, last_start;
- unsigned long step_size;
- unsigned long addr;
- unsigned long mapped_ram_size = 0;
-
- /* xen has big range in reserved near end of ram, skip it at first.*/
- addr = memblock_find_in_range(map_start, map_end, PMD_SIZE, PMD_SIZE);
- real_end = addr + PMD_SIZE;
-
- /* step_size need to be small so pgt_buf from BRK could cover it */
- step_size = PMD_SIZE;
- max_pfn_mapped = 0; /* will get exact value next */
- min_pfn_mapped = real_end >> PAGE_SHIFT;
- last_start = start = real_end;
-
- /*
- * We start from the top (end of memory) and go to the bottom.
- * The memblock_find_in_range() gets us a block of RAM from the
- * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
- * for page table.
- */
- while (last_start > map_start) {
- if (last_start > step_size) {
- start = round_down(last_start - 1, step_size);
- if (start < map_start)
- start = map_start;
- } else
- start = map_start;
- mapped_ram_size += init_range_memory_mapping(start,
- last_start);
- set_alloc_range(min_pfn_mapped, max_pfn_mapped);
- last_start = start;
- min_pfn_mapped = last_start >> PAGE_SHIFT;
- if (mapped_ram_size >= step_size)
- step_size = get_new_step_size(step_size);
- }
-
- if (real_end < map_end) {
- init_range_memory_mapping(real_end, map_end);
- set_alloc_range(min_pfn_mapped, max_pfn_mapped);
- }
-}
-
-/**
- * memory_map_bottom_up - Map [map_start, map_end) bottom up
- * @map_start: start address of the target memory range
- * @map_end: end address of the target memory range
- *
- * This function will setup direct mapping for memory range
- * [map_start, map_end) in bottom-up. Since we have limited the
- * bottom-up allocation above the kernel, the page tables will
- * be allocated just above the kernel and we map the memory
- * in [map_start, map_end) in bottom-up.
- */
-static void __init memory_map_bottom_up(unsigned long map_start,
- unsigned long map_end)
-{
- unsigned long next, start;
- unsigned long mapped_ram_size = 0;
- /* step_size need to be small so pgt_buf from BRK could cover it */
- unsigned long step_size = PMD_SIZE;
-
- start = map_start;
- min_pfn_mapped = start >> PAGE_SHIFT;
-
- /*
- * We start from the bottom (@map_start) and go to the top (@map_end).
- * The memblock_find_in_range() gets us a block of RAM from the
- * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
- * for page table.
- */
- while (start < map_end) {
- if (step_size && map_end - start > step_size) {
- next = round_up(start + 1, step_size);
- if (next > map_end)
- next = map_end;
- } else {
- next = map_end;
- }
-
- mapped_ram_size += init_range_memory_mapping(start, next);
- set_alloc_range(min_pfn_mapped, max_pfn_mapped);
- start = next;
-
- if (mapped_ram_size >= step_size)
- step_size = get_new_step_size(step_size);
- }
-}
-
-static unsigned long __init init_range_memory_mapping32(
- unsigned long r_start, unsigned long r_end)
-{
- /*
- * If the allocation is in bottom-up direction, we setup direct mapping
- * in bottom-up, otherwise we setup direct mapping in top-down.
- */
- if (memblock_bottom_up()) {
- unsigned long kernel_end = __pa_symbol(_end);
-
- /*
- * we need two separate calls here. This is because we want to
- * allocate page tables above the kernel. So we first map
- * [kernel_end, end) to make memory above the kernel be mapped
- * as soon as possible. And then use page tables allocated above
- * the kernel to map [ISA_END_ADDRESS, kernel_end).
- */
- memory_map_bottom_up(kernel_end, r_end);
- memory_map_bottom_up(r_start, kernel_end);
- } else {
- memory_map_top_down(r_start, r_end);
- }
-}
-
-#endif
-
void __init init_mem_mapping(void)
{
unsigned long end;
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 49ecf5e..f802678 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -550,6 +550,153 @@ void __init early_ioremap_page_table_range_init(void)
early_ioremap_reset();
}

+static unsigned long min_pfn_mapped;
+
+static unsigned long __init get_new_step_size(unsigned long step_size)
+{
+ /*
+ * Initial mapped size is PMD_SIZE (2M).
+ * We can not set step_size to be PUD_SIZE (1G) yet.
+ * In worse case, when we cross the 1G boundary, and
+ * PG_LEVEL_2M is not set, we will need 1+1+512 pages (2M + 8k)
+ * to map 1G range with PTE. Hence we use one less than the
+ * difference of page table level shifts.
+ *
+ * Don't need to worry about overflow in the top-down case, on 32bit,
+ * when step_size is 0, round_down() returns 0 for start, and that
+ * turns it into 0x100000000ULL.
+ * In the bottom-up case, round_up(x, 0) returns 0 though too, which
+ * needs to be taken into consideration by the code below.
+ */
+ return step_size << (PMD_SHIFT - PAGE_SHIFT - 1);
+}
+
+/**
+ * memory_map_top_down - Map [map_start, map_end) top down
+ * @map_start: start address of the target memory range
+ * @map_end: end address of the target memory range
+ *
+ * This function will setup direct mapping for memory range
+ * [map_start, map_end) in top-down. That said, the page tables
+ * will be allocated at the end of the memory, and we map the
+ * memory in top-down.
+ */
+static void __init memory_map_top_down(unsigned long map_start,
+ unsigned long map_end)
+{
+ unsigned long real_end, start, last_start;
+ unsigned long step_size;
+ unsigned long addr;
+ unsigned long mapped_ram_size = 0;
+
+ /* xen has big range in reserved near end of ram, skip it at first.*/
+ addr = memblock_find_in_range(map_start, map_end, PMD_SIZE, PMD_SIZE);
+ real_end = addr + PMD_SIZE;
+
+ /* step_size need to be small so pgt_buf from BRK could cover it */
+ step_size = PMD_SIZE;
+ max_pfn_mapped = 0; /* will get exact value next */
+ min_pfn_mapped = real_end >> PAGE_SHIFT;
+ last_start = start = real_end;
+
+ /*
+ * We start from the top (end of memory) and go to the bottom.
+ * The memblock_find_in_range() gets us a block of RAM from the
+ * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
+ * for page table.
+ */
+ while (last_start > map_start) {
+ if (last_start > step_size) {
+ start = round_down(last_start - 1, step_size);
+ if (start < map_start)
+ start = map_start;
+ } else
+ start = map_start;
+ mapped_ram_size += init_range_memory_mapping(start,
+ last_start);
+ set_alloc_range(min_pfn_mapped, max_pfn_mapped);
+ last_start = start;
+ min_pfn_mapped = last_start >> PAGE_SHIFT;
+ if (mapped_ram_size >= step_size)
+ step_size = get_new_step_size(step_size);
+ }
+
+ if (real_end < map_end) {
+ init_range_memory_mapping(real_end, map_end);
+ set_alloc_range(min_pfn_mapped, max_pfn_mapped);
+ }
+}
+
+/**
+ * memory_map_bottom_up - Map [map_start, map_end) bottom up
+ * @map_start: start address of the target memory range
+ * @map_end: end address of the target memory range
+ *
+ * This function will setup direct mapping for memory range
+ * [map_start, map_end) in bottom-up. Since we have limited the
+ * bottom-up allocation above the kernel, the page tables will
+ * be allocated just above the kernel and we map the memory
+ * in [map_start, map_end) in bottom-up.
+ */
+static void __init memory_map_bottom_up(unsigned long map_start,
+ unsigned long map_end)
+{
+ unsigned long next, start;
+ unsigned long mapped_ram_size = 0;
+ /* step_size need to be small so pgt_buf from BRK could cover it */
+ unsigned long step_size = PMD_SIZE;
+
+ start = map_start;
+ min_pfn_mapped = start >> PAGE_SHIFT;
+
+ /*
+ * We start from the bottom (@map_start) and go to the top (@map_end).
+ * The memblock_find_in_range() gets us a block of RAM from the
+ * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
+ * for page table.
+ */
+ while (start < map_end) {
+ if (step_size && map_end - start > step_size) {
+ next = round_up(start + 1, step_size);
+ if (next > map_end)
+ next = map_end;
+ } else {
+ next = map_end;
+ }
+
+ mapped_ram_size += init_range_memory_mapping(start, next);
+ set_alloc_range(min_pfn_mapped, max_pfn_mapped);
+ start = next;
+
+ if (mapped_ram_size >= step_size)
+ step_size = get_new_step_size(step_size);
+ }
+}
+
+void __init init_range_memory_mapping32(
+ unsigned long r_start, unsigned long r_end)
+{
+ /*
+ * If the allocation is in bottom-up direction, we setup direct mapping
+ * in bottom-up, otherwise we setup direct mapping in top-down.
+ */
+ if (memblock_bottom_up()) {
+ unsigned long kernel_end = __pa_symbol(_end);
+
+ /*
+ * we need two separate calls here. This is because we want to
+ * allocate page tables above the kernel. So we first map
+ * [kernel_end, end) to make memory above the kernel be mapped
+ * as soon as possible. And then use page tables allocated above
+ * the kernel to map [ISA_END_ADDRESS, kernel_end).
+ */
+ memory_map_bottom_up(kernel_end, r_end);
+ memory_map_bottom_up(r_start, kernel_end);
+ } else {
+ memory_map_top_down(r_start, r_end);
+ }
+}
+
static void __init pagetable_init(void)
{
pgd_t *pgd_base = swapper_pg_dir;
diff --git a/arch/x86/mm/mm_internal.h b/arch/x86/mm/mm_internal.h
index 4e1f6e1..5ab133c 100644
--- a/arch/x86/mm/mm_internal.h
+++ b/arch/x86/mm/mm_internal.h
@@ -9,7 +9,13 @@ static inline void *alloc_low_page(void)
}

void early_ioremap_page_table_range_init(void);
-
+void init_range_memory_mapping32(
+ unsigned long r_start,
+ unsigned long r_end);
+void set_alloc_range(unsigned long low, unsigned long high);
+unsigned long __init init_range_memory_mapping(
+ unsigned long r_start,
+ unsigned long r_end);
unsigned long kernel_physical_mapping_init(unsigned long start,
unsigned long end,
unsigned long page_size_mask);
--
2.7.4
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