[PATCH 1/4] s390/mm: recfactor global pgste updates

Dominik Dingel
2014-10-17T14:09:47Z

Replace the s390 specific page table walker for the pgste updates
with a call to the common code walk_page_range function.
There are now two pte modification functions, one for the reset
of the CMMA state and another one for the initialization of the
storage keys.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
arch/s390/include/asm/pgalloc.h | 2 -
arch/s390/include/asm/pgtable.h | 1 +
arch/s390/kvm/kvm-s390.c | 2 +-
arch/s390/mm/pgtable.c | 153 ++++++++++++++--------------------------
4 files changed, 56 insertions(+), 102 deletions(-)

diff --git a/arch/s390/include/asm/pgalloc.h b/arch/s390/include/asm/pgalloc.h
index 9e18a61..120e126 100644
--- a/arch/s390/include/asm/pgalloc.h
+++ b/arch/s390/include/asm/pgalloc.h
@@ -22,8 +22,6 @@ unsigned long *page_table_alloc(struct mm_struct *, unsigned long);
void page_table_free(struct mm_struct *, unsigned long *);
void page_table_free_rcu(struct mmu_gather *, unsigned long *);

-void page_table_reset_pgste(struct mm_struct *, unsigned long, unsigned long,
- bool init_skey);
int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
unsigned long key, bool nq);

diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 5efb2fe..1e991f6a 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1750,6 +1750,7 @@ extern int vmem_add_mapping(unsigned long start, unsigned long size);
extern int vmem_remove_mapping(unsigned long start, unsigned long size);
extern int s390_enable_sie(void);
extern void s390_enable_skey(void);
+extern void s390_reset_cmma(struct mm_struct *mm);

/*
* No page table caches to initialise
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 81b0e11..7a33c11 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -281,7 +281,7 @@ static int kvm_s390_mem_control(struct kvm *kvm, struct kvm_device_attr *attr)
case KVM_S390_VM_MEM_CLR_CMMA:
mutex_lock(&kvm->lock);
idx = srcu_read_lock(&kvm->srcu);
- page_table_reset_pgste(kvm->arch.gmap->mm, 0, TASK_SIZE, false);
+ s390_reset_cmma(kvm->arch.gmap->mm);
srcu_read_unlock(&kvm->srcu, idx);
mutex_unlock(&kvm->lock);
ret = 0;
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 5404a62..ab55ba8 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -885,99 +885,6 @@ static inline void page_table_free_pgste(unsigned long *table)
__free_page(page);
}

-static inline unsigned long page_table_reset_pte(struct mm_struct *mm, pmd_t *pmd,
- unsigned long addr, unsigned long end, bool init_skey)
-{
- pte_t *start_pte, *pte;
- spinlock_t *ptl;
- pgste_t pgste;
-
- start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
- pte = start_pte;
- do {
- pgste = pgste_get_lock(pte);
- pgste_val(pgste) &= ~_PGSTE_GPS_USAGE_MASK;
- if (init_skey) {
- unsigned long address;
-
- pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT |
- PGSTE_GR_BIT | PGSTE_GC_BIT);
-
- /* skip invalid and not writable pages */
- if (pte_val(*pte) & _PAGE_INVALID ||
- !(pte_val(*pte) & _PAGE_WRITE)) {
- pgste_set_unlock(pte, pgste);
- continue;
- }
-
- address = pte_val(*pte) & PAGE_MASK;
- page_set_storage_key(address, PAGE_DEFAULT_KEY, 1);
- }
- pgste_set_unlock(pte, pgste);
- } while (pte++, addr += PAGE_SIZE, addr != end);
- pte_unmap_unlock(start_pte, ptl);
-
- return addr;
-}
-
-static inline unsigned long page_table_reset_pmd(struct mm_struct *mm, pud_t *pud,
- unsigned long addr, unsigned long end, bool init_skey)
-{
- unsigned long next;
- pmd_t *pmd;
-
- pmd = pmd_offset(pud, addr);
- do {
- next = pmd_addr_end(addr, end);
- if (pmd_none_or_clear_bad(pmd))
- continue;
- next = page_table_reset_pte(mm, pmd, addr, next, init_skey);
- } while (pmd++, addr = next, addr != end);
-
- return addr;
-}
-
-static inline unsigned long page_table_reset_pud(struct mm_struct *mm, pgd_t *pgd,
- unsigned long addr, unsigned long end, bool init_skey)
-{
- unsigned long next;
- pud_t *pud;
-
- pud = pud_offset(pgd, addr);
- do {
- next = pud_addr_end(addr, end);
- if (pud_none_or_clear_bad(pud))
- continue;
- next = page_table_reset_pmd(mm, pud, addr, next, init_skey);
- } while (pud++, addr = next, addr != end);
-
- return addr;
-}
-
-void page_table_reset_pgste(struct mm_struct *mm, unsigned long start,
- unsigned long end, bool init_skey)
-{
- unsigned long addr, next;
- pgd_t *pgd;
-
- down_write(&mm->mmap_sem);
- if (init_skey && mm_use_skey(mm))
- goto out_up;
- addr = start;
- pgd = pgd_offset(mm, addr);
- do {
- next = pgd_addr_end(addr, end);
- if (pgd_none_or_clear_bad(pgd))
- continue;
- next = page_table_reset_pud(mm, pgd, addr, next, init_skey);
- } while (pgd++, addr = next, addr != end);
- if (init_skey)
- current->mm->context.use_skey = 1;
-out_up:
- up_write(&mm->mmap_sem);
-}
-EXPORT_SYMBOL(page_table_reset_pgste);
-
int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
unsigned long key, bool nq)
{
@@ -1044,11 +951,6 @@ static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm,
return NULL;
}

-void page_table_reset_pgste(struct mm_struct *mm, unsigned long start,
- unsigned long end, bool init_skey)
-{
-}
-
static inline void page_table_free_pgste(unsigned long *table)
{
}
@@ -1400,13 +1302,66 @@ EXPORT_SYMBOL_GPL(s390_enable_sie);
* Enable storage key handling from now on and initialize the storage
* keys with the default key.
*/
+static int __s390_enable_skey(pte_t *pte, unsigned long addr,
+ unsigned long next, struct mm_walk *walk)
+{
+ unsigned long ptev;
+ pgste_t pgste;
+
+ pgste = pgste_get_lock(pte);
+ /* Clear storage key */
+ pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT |
+ PGSTE_GR_BIT | PGSTE_GC_BIT);
+ ptev = pte_val(*pte);
+ if (!(ptev & _PAGE_INVALID) && (ptev & _PAGE_WRITE))
+ page_set_storage_key(ptev & PAGE_MASK, PAGE_DEFAULT_KEY, 1);
+ pgste_set_unlock(pte, pgste);
+ return 0;
+}
+
void s390_enable_skey(void)
{
- page_table_reset_pgste(current->mm, 0, TASK_SIZE, true);
+ struct mm_walk walk = { .pte_entry = __s390_enable_skey };
+ struct mm_struct *mm = current->mm;
+
+ down_write(&mm->mmap_sem);
+ if (mm_use_skey(mm))
+ goto out_up;
+ walk.mm = mm;
+ walk_page_range(0, TASK_SIZE, &walk);
+ mm->context.use_skey = 1;
+
+out_up:
+ up_write(&mm->mmap_sem);
}
EXPORT_SYMBOL_GPL(s390_enable_skey);

/*
+ * Reset CMMA state, make all pages stable again.
+ */
+static int __s390_reset_cmma(pte_t *pte, unsigned long addr,
+ unsigned long next, struct mm_walk *walk)
+{
+ pgste_t pgste;
+
+ pgste = pgste_get_lock(pte);
+ pgste_val(pgste) &= ~_PGSTE_GPS_USAGE_MASK;
+ pgste_set_unlock(pte, pgste);
+ return 0;
+}
+
+void s390_reset_cmma(struct mm_struct *mm)
+{
+ struct mm_walk walk = { .pte_entry = __s390_reset_cmma };
+
+ down_write(&mm->mmap_sem);
+ walk.mm = mm;
+ walk_page_range(0, TASK_SIZE, &walk);
+ up_write(&mm->mmap_sem);
+}
+EXPORT_SYMBOL_GPL(s390_reset_cmma);
+
+/*
* Test and reset if a guest page is dirty
*/
bool gmap_test_and_clear_dirty(unsigned long address, struct gmap *gmap)
--
1.8.5.5