diff options
| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2012-07-26 08:53:06 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2012-08-10 00:24:54 +0100 |
| commit | f22027d0e8398e377a42a62241137b77a35eda97 (patch) | |
| tree | 691aacb8ce4a0fb9a72e95744c54fb00e2767d59 /arch/s390/mm | |
| parent | 60ed9e385606f27c787710bba0dfdb7ff467bdf7 (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>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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 a0155c02e32..c70b3d8dea0 100644 --- a/arch/s390/mm/mmap.c +++ b/arch/s390/mm/mmap.c @@ -106,9 +106,15 @@ EXPORT_SYMBOL_GPL(arch_pick_mmap_layout); 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; } @@ -128,6 +134,7 @@ 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; @@ -150,6 +157,7 @@ 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 f8ceac48cf3..f8e92f831ef 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -97,7 +97,6 @@ repeat: crst_table_free(mm, table); if (mm->context.asce_limit < limit) goto repeat; - update_mm(mm, current); return 0; } @@ -105,9 +104,6 @@ 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) { @@ -130,7 +126,6 @@ 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 |