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

Pekka Enberg
2012-07-14T13:41:16Z

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

Cc: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
---
arch/x86/mm/init.c | 38 +++++++++++++++++++++-----------------
1 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index bc4e9d8..9eb53c2 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -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));
--
1.7.7.6