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Commit f481bfafd36e621d6cbc62d4b25f74811410aef7

Authored by Martin Schwidefsky
1 parent 2887fc5aa6
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

[S390] make page table walking more robust 

Make page table walking on s390 more robust. The current code requires
that the pgd/pud/pmd/pte loop is only done for address ranges that are
below the end address of the last vma of the address space. But this
is not always true, e.g. the generic page table walker does not guarantee
this. Change TASK_SIZE/TASK_SIZE_OF to reflect the current size of the
address space. This makes the generic page table walker happy but it
breaks the upgrade of a 3 level page table to a 4 level page table.
To make the upgrade work again another fix is required.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

Showing 3 changed files with 6 additions and 5 deletions Side-by-side Diff

arch/s390/include/asm/processor.h
Diff comments   View file @ f481bfa
... ... @@ -61,7 +61,7 @@
61 61 extern int get_cpu_capability(unsigned int *);
62 62  
63 63 /*
64   - * User space process size: 2GB for 31 bit, 4TB for 64 bit.
  64 + * User space process size: 2GB for 31 bit, 4TB or 8PT for 64 bit.
65 65 */
66 66 #ifndef __s390x__
67 67  
... ... @@ -70,8 +70,7 @@
70 70  
71 71 #else /* __s390x__ */
72 72  
73   -#define TASK_SIZE_OF(tsk) (test_tsk_thread_flag(tsk,TIF_31BIT) ? \
74   - (1UL << 31) : (1UL << 53))
  73 +#define TASK_SIZE_OF(tsk) ((tsk)->mm->context.asce_limit)
75 74 #define TASK_UNMAPPED_BASE (test_thread_flag(TIF_31BIT) ? \
76 75 (1UL << 30) : (1UL << 41))
77 76 #define TASK_SIZE TASK_SIZE_OF(current)
... ... @@ -35,7 +35,7 @@
35 35 * Leave an at least ~128 MB hole.
36 36 */
37 37 #define MIN_GAP (128*1024*1024)
38   -#define MAX_GAP (TASK_SIZE/6*5)
  38 +#define MAX_GAP (STACK_TOP/6*5)
39 39  
40 40 static inline unsigned long mmap_base(void)
41 41 {
... ... @@ -46,7 +46,7 @@
46 46 else if (gap > MAX_GAP)
47 47 gap = MAX_GAP;
48 48  
49   - return TASK_SIZE - (gap & PAGE_MASK);
  49 + return STACK_TOP - (gap & PAGE_MASK);
50 50 }
51 51  
52 52 static inline int mmap_is_legacy(void)
arch/s390/mm/pgtable.c
Diff comments   View file @ f481bfa
... ... @@ -117,6 +117,7 @@
117 117 crst_table_init(table, entry);
118 118 pgd_populate(mm, (pgd_t *) table, (pud_t *) pgd);
119 119 mm->pgd = (pgd_t *) table;
  120 + mm->task_size = mm->context.asce_limit;
120 121 table = NULL;
121 122 }
122 123 spin_unlock(&mm->page_table_lock);
... ... @@ -154,6 +155,7 @@
154 155 BUG();
155 156 }
156 157 mm->pgd = (pgd_t *) (pgd_val(*pgd) & _REGION_ENTRY_ORIGIN);
  158 + mm->task_size = mm->context.asce_limit;
157 159 crst_table_free(mm, (unsigned long *) pgd);
158 160 }
159 161 update_mm(mm, current);