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authorCarsten Otte <cotte@de.ibm.com>2008-03-25 18:47:10 +0100
committerAvi Kivity <avi@qumranet.com>2008-04-27 12:00:40 +0300
commit402b08622d9ac6e32e25289573272e0f21bb58a7 (patch)
tree40d7386154cef85c9bfd2bd862db025933820776 /include/linux/sched.h
parent37817f2982d0f559f90cecc66e150dd9d2c2df05 (diff)
s390: KVM preparation: provide hook to enable pgstes in user pagetable
The SIE instruction on s390 uses the 2nd half of the page table page to virtualize the storage keys of a guest. This patch offers the s390_enable_sie function, which reorganizes the page tables of a single-threaded process to reserve space in the page table: s390_enable_sie makes sure that the process is single threaded and then uses dup_mm to create a new mm with reorganized page tables. The old mm is freed and the process has now a page status extended field after every page table. Code that wants to exploit pgstes should SELECT CONFIG_PGSTE. This patch has a small common code hit, namely making dup_mm non-static. Edit (Carsten): I've modified Martin's patch, following Jeremy Fitzhardinge's review feedback. Now we do have the prototype for dup_mm in include/linux/sched.h. Following Martin's suggestion, s390_enable_sie() does now call task_lock() to prevent race against ptrace modification of mm_users. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'include/linux/sched.h')
-rw-r--r--include/linux/sched.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index d0bd97044abd..9a4f3e63e3bf 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1798,6 +1798,8 @@ extern void mmput(struct mm_struct *);
extern struct mm_struct *get_task_mm(struct task_struct *task);
/* Remove the current tasks stale references to the old mm_struct */
extern void mm_release(struct task_struct *, struct mm_struct *);
+/* Allocate a new mm structure and copy contents from tsk->mm */
+extern struct mm_struct *dup_mm(struct task_struct *tsk);
extern int copy_thread(int, unsigned long, unsigned long, unsigned long, struct task_struct *, struct pt_regs *);
extern void flush_thread(void);