Initial import of modified Linux 2.6.28 tree

Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y

1 files changed, 90 insertions, 0 deletions

diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
new file mode 100644
index 0000000..28ec870
--- /dev/null
+++ b/arch/s390/include/asm/mmu_context.h
@@ -0,0 +1,90 @@
+/*
+ *  include/asm-s390/mmu_context.h
+ *
+ *  S390 version
+ *
+ *  Derived from "include/asm-i386/mmu_context.h"
+ */
+
+#ifndef __S390_MMU_CONTEXT_H
+#define __S390_MMU_CONTEXT_H
+
+#include <asm/pgalloc.h>
+#include <asm/uaccess.h>
+#include <asm-generic/mm_hooks.h>
+
+static inline int init_new_context(struct task_struct *tsk,
+				   struct mm_struct *mm)
+{
+	mm->context.asce_bits = _ASCE_TABLE_LENGTH | _ASCE_USER_BITS;
+#ifdef CONFIG_64BIT
+	mm->context.asce_bits |= _ASCE_TYPE_REGION3;
+#endif
+	if (current->mm->context.alloc_pgste) {
+		/*
+		 * alloc_pgste indicates, that any NEW context will be created
+		 * with extended page tables. The old context is unchanged. The
+		 * page table allocation and the page table operations will
+		 * look at has_pgste to distinguish normal and extended page
+		 * tables. The only way to create extended page tables is to
+		 * set alloc_pgste and then create a new context (e.g. dup_mm).
+		 * The page table allocation is called after init_new_context
+		 * and if has_pgste is set, it will create extended page
+		 * tables.
+		 */
+		mm->context.noexec = 0;
+		mm->context.has_pgste = 1;
+		mm->context.alloc_pgste = 1;
+	} else {
+		mm->context.noexec = s390_noexec;
+		mm->context.has_pgste = 0;
+		mm->context.alloc_pgste = 0;
+	}
+	mm->context.asce_limit = STACK_TOP_MAX;
+	crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
+	return 0;
+}
+
+#define destroy_context(mm)             do { } while (0)
+
+#ifndef __s390x__
+#define LCTL_OPCODE "lctl"
+#else
+#define LCTL_OPCODE "lctlg"
+#endif
+
+static inline void update_mm(struct mm_struct *mm, struct task_struct *tsk)
+{
+	pgd_t *pgd = mm->pgd;
+
+	S390_lowcore.user_asce = mm->context.asce_bits | __pa(pgd);
+	if (switch_amode) {
+		/* Load primary space page table origin. */
+		pgd = mm->context.noexec ? get_shadow_table(pgd) : pgd;
+		S390_lowcore.user_exec_asce = mm->context.asce_bits | __pa(pgd);
+		asm volatile(LCTL_OPCODE" 1,1,%0\n"
+			     : : "m" (S390_lowcore.user_exec_asce) );
+	} else
+		/* Load home space page table origin. */
+		asm volatile(LCTL_OPCODE" 13,13,%0"
+			     : : "m" (S390_lowcore.user_asce) );
+	set_fs(current->thread.mm_segment);
+}
+
+static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+			     struct task_struct *tsk)
+{
+	cpu_set(smp_processor_id(), next->cpu_vm_mask);
+	update_mm(next, tsk);
+}
+
+#define enter_lazy_tlb(mm,tsk)	do { } while (0)
+#define deactivate_mm(tsk,mm)	do { } while (0)
+
+static inline void activate_mm(struct mm_struct *prev,
+                               struct mm_struct *next)
+{
+        switch_mm(prev, next, current);
+}
+
+#endif /* __S390_MMU_CONTEXT_H */