diff options
| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2012-07-26 08:53:06 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-08-09 08:31:31 -0700 |
| commit | cd1af8b7d386e6b3991252650c16b3e9d5a03b65 (patch) | |
| tree | 93fc53558ab9ad563fb4d58b5f3b7f6a62e85215 /arch/s390/mm | |
| parent | 554c9a0c6f72a8a5c44962b82f495d95e547b4b3 (diff) | |
s390/mm: downgrade page table after fork of a 31 bit process
commit 0f6f281b731d20bfe75c13f85d33f3f05b440222 upstream.
The downgrade of the 4 level page table created by init_new_context is
currently done only in start_thread31. If a 31 bit process forks the
new mm uses a 4 level page table, including the task size of 2<<42
that goes along with it. This is incorrect as now a 31 bit process
can map memory beyond 2GB. Define arch_dup_mmap to do the downgrade
after fork.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/s390/mm')
| -rw-r--r-- | arch/s390/mm/mmap.c | 12 | ||||
| -rw-r--r-- | arch/s390/mm/pgtable.c | 5 |
2 files changed, 10 insertions, 7 deletions
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c index 2857c48486ea..a64fe53c7202 100644 --- a/arch/s390/mm/mmap.c +++ b/arch/s390/mm/mmap.c @@ -105,9 +105,15 @@ void arch_pick_mmap_layout(struct mm_struct *mm) int s390_mmap_check(unsigned long addr, unsigned long len) { + int rc; + if (!is_compat_task() && - len >= TASK_SIZE && TASK_SIZE < (1UL << 53)) - return crst_table_upgrade(current->mm, 1UL << 53); + len >= TASK_SIZE && TASK_SIZE < (1UL << 53)) { + rc = crst_table_upgrade(current->mm, 1UL << 53); + if (rc) + return rc; + update_mm(current->mm, current); + } return 0; } @@ -127,6 +133,7 @@ s390_get_unmapped_area(struct file *filp, unsigned long addr, rc = crst_table_upgrade(mm, 1UL << 53); if (rc) return (unsigned long) rc; + update_mm(mm, current); area = arch_get_unmapped_area(filp, addr, len, pgoff, flags); } return area; @@ -149,6 +156,7 @@ s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr, rc = crst_table_upgrade(mm, 1UL << 53); if (rc) return (unsigned long) rc; + update_mm(mm, current); area = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags); } diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 6e765bf00670..87f0efd0e77c 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -85,7 +85,6 @@ repeat: crst_table_free(mm, table); if (mm->context.asce_limit < limit) goto repeat; - update_mm(mm, current); return 0; } @@ -93,9 +92,6 @@ void crst_table_downgrade(struct mm_struct *mm, unsigned long limit) { pgd_t *pgd; - if (mm->context.asce_limit <= limit) - return; - __tlb_flush_mm(mm); while (mm->context.asce_limit > limit) { pgd = mm->pgd; switch (pgd_val(*pgd) & _REGION_ENTRY_TYPE_MASK) { @@ -118,7 +114,6 @@ void crst_table_downgrade(struct mm_struct *mm, unsigned long limit) mm->task_size = mm->context.asce_limit; crst_table_free(mm, (unsigned long *) pgd); } - update_mm(mm, current); } #endif |