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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 12:00:40 +0300 |
| commit | 402b08622d9ac6e32e25289573272e0f21bb58a7 (patch) | |
| tree | 40d7386154cef85c9bfd2bd862db025933820776 /arch/s390/kernel/setup.c | |
| parent | 37817f2982d0f559f90cecc66e150dd9d2c2df05 (diff) | |
| download | blackbird-op-linux-402b08622d9ac6e32e25289573272e0f21bb58a7.tar.gz blackbird-op-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 'arch/s390/kernel/setup.c')
| -rw-r--r-- | arch/s390/kernel/setup.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index 7141147e6b63..2f35133ebc18 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -316,7 +316,11 @@ static int __init early_parse_ipldelay(char *p) early_param("ipldelay", early_parse_ipldelay); #ifdef CONFIG_S390_SWITCH_AMODE +#ifdef CONFIG_PGSTE +unsigned int switch_amode = 1; +#else unsigned int switch_amode = 0; +#endif EXPORT_SYMBOL_GPL(switch_amode); static void set_amode_and_uaccess(unsigned long user_amode, |
