From f481bfafd36e621d6cbc62d4b25f74811410aef7 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Wed, 18 Mar 2009 13:27:36 +0100 Subject: [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 --- arch/s390/mm/mmap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/s390/mm/mmap.c') diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c index 5932a824547a..346dd0c5cbde 100644 --- a/arch/s390/mm/mmap.c +++ b/arch/s390/mm/mmap.c @@ -35,7 +35,7 @@ * Leave an at least ~128 MB hole. */ #define MIN_GAP (128*1024*1024) -#define MAX_GAP (TASK_SIZE/6*5) +#define MAX_GAP (STACK_TOP/6*5) static inline unsigned long mmap_base(void) { @@ -46,7 +46,7 @@ static inline unsigned long mmap_base(void) else if (gap > MAX_GAP) gap = MAX_GAP; - return TASK_SIZE - (gap & PAGE_MASK); + return STACK_TOP - (gap & PAGE_MASK); } static inline int mmap_is_legacy(void) -- cgit v1.2.2 From 0fb1d9bcbcf701a45835aa150c57ca54ea685bfa Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Wed, 18 Mar 2009 13:27:37 +0100 Subject: [S390] make page table upgrade work again After TASK_SIZE now gives the current size of the address space the upgrade of a 64 bit process from 3 to 4 levels of page table needs to use the arch_mmap_check hook to catch large mmap lengths. The get_unmapped_area* functions need to check for -ENOMEM from the arch_get_unmapped_area*, upgrade the page table and retry. Signed-off-by: Martin Schwidefsky --- arch/s390/mm/mmap.c | 44 ++++++++++++++++++++++++++++++-------------- 1 file changed, 30 insertions(+), 14 deletions(-) (limited to 'arch/s390/mm/mmap.c') diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c index 346dd0c5cbde..e008d236cc15 100644 --- a/arch/s390/mm/mmap.c +++ b/arch/s390/mm/mmap.c @@ -89,42 +89,58 @@ EXPORT_SYMBOL_GPL(arch_pick_mmap_layout); #else +int s390_mmap_check(unsigned long addr, unsigned long len) +{ + if (!test_thread_flag(TIF_31BIT) && + len >= TASK_SIZE && TASK_SIZE < (1UL << 53)) + return crst_table_upgrade(current->mm, 1UL << 53); + return 0; +} + static unsigned long s390_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { struct mm_struct *mm = current->mm; + unsigned long area; int rc; - addr = arch_get_unmapped_area(filp, addr, len, pgoff, flags); - if (addr & ~PAGE_MASK) - return addr; - if (unlikely(mm->context.asce_limit < addr + len)) { - rc = crst_table_upgrade(mm, addr + len); + area = arch_get_unmapped_area(filp, addr, len, pgoff, flags); + if (!(area & ~PAGE_MASK)) + return area; + if (area == -ENOMEM && + !test_thread_flag(TIF_31BIT) && TASK_SIZE < (1UL << 53)) { + /* Upgrade the page table to 4 levels and retry. */ + rc = crst_table_upgrade(mm, 1UL << 53); if (rc) return (unsigned long) rc; + area = arch_get_unmapped_area(filp, addr, len, pgoff, flags); } - return addr; + return area; } static unsigned long -s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, +s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr, const unsigned long len, const unsigned long pgoff, const unsigned long flags) { struct mm_struct *mm = current->mm; - unsigned long addr = addr0; + unsigned long area; int rc; - addr = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags); - if (addr & ~PAGE_MASK) - return addr; - if (unlikely(mm->context.asce_limit < addr + len)) { - rc = crst_table_upgrade(mm, addr + len); + area = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags); + if (!(area & ~PAGE_MASK)) + return area; + if (area == -ENOMEM && + !test_thread_flag(TIF_31BIT) && TASK_SIZE < (1UL << 53)) { + /* Upgrade the page table to 4 levels and retry. */ + rc = crst_table_upgrade(mm, 1UL << 53); if (rc) return (unsigned long) rc; + area = arch_get_unmapped_area_topdown(filp, addr, len, + pgoff, flags); } - return addr; + return area; } /* * This function, called very early during the creation of a new -- cgit v1.2.2