This is a note to let you know that I've just added the patch titled
x86, mm: Find_early_table_space based on ranges that are actually being
mapped
to the 3.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-mm-find_early_table_space-based-on-ranges-that-are-actually-being-mapped.patch
and it can be found in the queue-3.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 844ab6f993b1d32eb40512503d35ff6ad0c57030 Mon Sep 17 00:00:00 2001
From: Jacob Shin <[email protected]>
Date: Wed, 24 Oct 2012 14:24:44 -0500
Subject: x86, mm: Find_early_table_space based on ranges that are actually
being mapped
From: Jacob Shin <[email protected]>
commit 844ab6f993b1d32eb40512503d35ff6ad0c57030 upstream.
Current logic finds enough space for direct mapping page tables from 0
to end. Instead, we only need to find enough space to cover mr[0].start
to mr[nr_range].end -- the range that is actually being mapped by
init_memory_mapping()
This is needed after 1bbbbe779aabe1f0768c2bf8f8c0a5583679b54a, to address
the panic reported here:
https://lkml.org/lkml/2012/10/20/160
https://lkml.org/lkml/2012/10/21/157
Signed-off-by: Jacob Shin <[email protected]>
Link: http://lkml.kernel.org/r/20121024195311.GB11779@jshin-Toonie
Tested-by: Tom Rini <[email protected]>
Signed-off-by: H. Peter Anvin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/mm/init.c | 70 +++++++++++++++++++++++++++++++----------------------
1 file changed, 41 insertions(+), 29 deletions(-)
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -29,36 +29,54 @@ int direct_gbpages
#endif
;
-static void __init find_early_table_space(unsigned long end, int use_pse,
- int use_gbpages)
+struct map_range {
+ unsigned long start;
+ unsigned long end;
+ unsigned page_size_mask;
+};
+
+/*
+ * First calculate space needed for kernel direct mapping page tables to cover
+ * mr[0].start to mr[nr_range - 1].end, while accounting for possible 2M and
1GB
+ * pages. Then find enough contiguous space for those page tables.
+ */
+static void __init find_early_table_space(struct map_range *mr, int nr_range)
{
- unsigned long puds, pmds, ptes, tables, start = 0, good_end = end;
+ int i;
+ unsigned long puds = 0, pmds = 0, ptes = 0, tables;
+ unsigned long start = 0, good_end;
phys_addr_t base;
- puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
- tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
+ for (i = 0; i < nr_range; i++) {
+ unsigned long range, extra;
- if (use_gbpages) {
- unsigned long extra;
+ range = mr[i].end - mr[i].start;
+ puds += (range + PUD_SIZE - 1) >> PUD_SHIFT;
- extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
- pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT;
- } else
- pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
-
- tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
+ if (mr[i].page_size_mask & (1 << PG_LEVEL_1G)) {
+ extra = range - ((range >> PUD_SHIFT) << PUD_SHIFT);
+ pmds += (extra + PMD_SIZE - 1) >> PMD_SHIFT;
+ } else {
+ pmds += (range + PMD_SIZE - 1) >> PMD_SHIFT;
+ }
- if (use_pse) {
- unsigned long extra;
-
- extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
+ if (mr[i].page_size_mask & (1 << PG_LEVEL_2M)) {
+ extra = range - ((range >> PMD_SHIFT) << PMD_SHIFT);
#ifdef CONFIG_X86_32
- extra += PMD_SIZE;
+ extra += PMD_SIZE;
#endif
- ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
- } else
- ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ /* The first 2/4M doesn't use large pages. */
+ if (mr[i].start < PMD_SIZE)
+ extra += range;
+
+ ptes += (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ } else {
+ ptes += (range + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ }
+ }
+ tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
+ tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
#ifdef CONFIG_X86_32
@@ -76,7 +94,7 @@ static void __init find_early_table_spac
pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT);
printk(KERN_DEBUG "kernel direct mapping tables up to %#lx @ [mem
%#010lx-%#010lx]\n",
- end - 1, pgt_buf_start << PAGE_SHIFT,
+ mr[nr_range - 1].end - 1, pgt_buf_start << PAGE_SHIFT,
(pgt_buf_top << PAGE_SHIFT) - 1);
}
@@ -85,12 +103,6 @@ void __init native_pagetable_reserve(u64
memblock_reserve(start, end - start);
}
-struct map_range {
- unsigned long start;
- unsigned long end;
- unsigned page_size_mask;
-};
-
#ifdef CONFIG_X86_32
#define NR_RANGE_MR 3
#else /* CONFIG_X86_64 */
@@ -263,7 +275,7 @@ unsigned long __init_refok init_memory_m
* nodes are discovered.
*/
if (!after_bootmem)
- find_early_table_space(end, use_pse, use_gbpages);
+ find_early_table_space(mr, nr_range);
for (i = 0; i < nr_range; i++)
ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
Patches currently in stable-queue which might be from [email protected] are
queue-3.6/x86-mm-find_early_table_space-based-on-ranges-that-are-actually-being-mapped.patch
queue-3.6/x86-mm-undo-incorrect-revert-in-arch-x86-mm-init.c.patch
queue-3.6/x86-mm-trim-memory-in-memblock-to-be-page-aligned.patch
--
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