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authorCarsten Otte <cotte@de.ibm.com>2008-03-25 13:47:10 -0400
committerAvi Kivity <avi@qumranet.com>2008-04-27 05:00:40 -0400
commit402b08622d9ac6e32e25289573272e0f21bb58a7 (patch)
tree40d7386154cef85c9bfd2bd862db025933820776 /include/asm-s390/pgtable.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/asm-s390/pgtable.h')
-rw-r--r--include/asm-s390/pgtable.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/asm-s390/pgtable.h b/include/asm-s390/pgtable.h
index 65154dc9a9e5..8e9a629dc199 100644
--- a/include/asm-s390/pgtable.h
+++ b/include/asm-s390/pgtable.h
@@ -966,6 +966,7 @@ static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
966 966
967extern int add_shared_memory(unsigned long start, unsigned long size); 967extern int add_shared_memory(unsigned long start, unsigned long size);
968extern int remove_shared_memory(unsigned long start, unsigned long size); 968extern int remove_shared_memory(unsigned long start, unsigned long size);
969extern int s390_enable_sie(void);
969 970
970/* 971/*
971 * No page table caches to initialise 972 * No page table caches to initialise