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| author | Carsten Otte <cotte@de.ibm.com> | 2008-03-25 18:47:10 +0100 |
|---|---|---|
| committer | Avi Kivity <avi@qumranet.com> | 2008-04-27 11:00:40 +0200 |
| commit | 402b08622d9ac6e32e25289573272e0f21bb58a7 (patch) | |
| tree | 40d7386154cef85c9bfd2bd862db025933820776 /include/asm-s390 | |
| parent | KVM: x86: hardware task switching support (diff) | |
| download | linux-402b08622d9ac6e32e25289573272e0f21bb58a7.tar.xz linux-402b08622d9ac6e32e25289573272e0f21bb58a7.zip | |
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')
| -rw-r--r-- | include/asm-s390/mmu.h | 1 | ||||
| -rw-r--r-- | include/asm-s390/mmu_context.h | 8 | ||||
| -rw-r--r-- | include/asm-s390/pgtable.h | 1 |
3 files changed, 9 insertions, 1 deletions
diff --git a/include/asm-s390/mmu.h b/include/asm-s390/mmu.h index 1698e29c5b20..5dd5e7b3476f 100644 --- a/include/asm-s390/mmu.h +++ b/include/asm-s390/mmu.h @@ -7,6 +7,7 @@ typedef struct { unsigned long asce_bits; unsigned long asce_limit; int noexec; + int pgstes; } mm_context_t; #endif diff --git a/include/asm-s390/mmu_context.h b/include/asm-s390/mmu_context.h index b5a34c6f91a9..4c2fbf48c9c4 100644 --- a/include/asm-s390/mmu_context.h +++ b/include/asm-s390/mmu_context.h @@ -20,7 +20,13 @@ static inline int init_new_context(struct task_struct *tsk, #ifdef CONFIG_64BIT mm->context.asce_bits |= _ASCE_TYPE_REGION3; #endif - mm->context.noexec = s390_noexec; + if (current->mm->context.pgstes) { + mm->context.noexec = 0; + mm->context.pgstes = 1; + } else { + mm->context.noexec = s390_noexec; + mm->context.pgstes = 0; + } mm->context.asce_limit = STACK_TOP_MAX; crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm)); return 0; 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) extern int add_shared_memory(unsigned long start, unsigned long size); extern int remove_shared_memory(unsigned long start, unsigned long size); +extern int s390_enable_sie(void); /* * No page table caches to initialise |