Paul Mackerras
fa28237cfc
[POWERPC] Provide a way to protect 4k subpages when using 64k pages ...
Using 64k pages on 64-bit PowerPC systems makes life difficult for
emulators that are trying to emulate an ISA, such as x86, which use a
smaller page size, since the emulator can no longer use the MMU and
the normal system calls for controlling page protections. Of course,
the emulator can emulate the MMU by checking and possibly remapping
the address for each memory access in software, but that is pretty
slow.
This provides a facility for such programs to control the access
permissions on individual 4k sub-pages of 64k pages. The idea is
that the emulator supplies an array of protection masks to apply to a
specified range of virtual addresses. These masks are applied at the
level where hardware PTEs are inserted into the hardware page table
based on the Linux PTEs, so the Linux PTEs are not affected. Note
that this new mechanism does not allow any access that would otherwise
be prohibited; it can only prohibit accesses that would otherwise be
allowed. This new facility is only available on 64-bit PowerPC and
only when the kernel is configured for 64k pages.
The masks are supplied using a new subpage_prot system call, which
takes a starting virtual address and length, and a pointer to an array
of protection masks in memory. The array has a 32-bit word per 64k
page to be protected; each 32-bit word consists of 16 2-bit fields,
for which 0 allows any access (that is otherwise allowed), 1 prevents
write accesses, and 2 or 3 prevent any access.
Implicit in this is that the regions of the address space that are
protected are switched to use 4k hardware pages rather than 64k
hardware pages (on machines with hardware 64k page support). In fact
the whole process is switched to use 4k hardware pages when the
subpage_prot system call is used, but this could be improved in future
to switch only the affected segments.
The subpage protection bits are stored in a 3 level tree akin to the
page table tree. The top level of this tree is stored in a structure
that is appended to the top level of the page table tree, i.e., the
pgd array. Since it will often only be 32-bit addresses (below 4GB)
that are protected, the pointers to the first four bottom level pages
are also stored in this structure (each bottom level page contains the
protection bits for 1GB of address space), so the protection bits for
addresses below 4GB can be accessed with one fewer loads than those
for higher addresses.
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-01-24 10:06:01 +11:00
genirq: revert lazy irq disable for simple irqs
2007-12-18 18:05:58 +01:00
hibernate: fix lockdep report
2007-11-14 18:45:43 -08:00
clockevents: fix reprogramming decision in oneshot broadcast
2007-12-18 18:05:58 +01:00
sched: fix kernel/acct.c comment
2007-11-26 21:21:49 +01:00
[PATCH] audit: watching subtrees
2007-10-21 02:37:45 -04:00
[PATCH] audit: watching subtrees
2007-10-21 02:37:45 -04:00
[PATCH] audit: watching subtrees
2007-10-21 02:37:45 -04:00
[PATCH] audit: watching subtrees
2007-10-21 02:37:45 -04:00
auditsc: fix kernel-doc param warnings
2007-10-22 19:40:02 -07:00
Uninline find_pid etc set of functions
2007-10-19 11:53:41 -07:00
Improve cgroup printks
2007-11-14 18:45:37 -08:00
Task Control Groups: simple task cgroup debug info subsystem
2007-10-19 11:53:36 -07:00
Merge ssh://master.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrt
2007-10-18 15:12:41 -07:00
use simple_read_from_buffer in kernel/
2007-05-09 12:30:49 -07:00
CPU HOTPLUG: avoid hotadd when proper possible_map isn't specified
2007-10-19 11:53:44 -07:00
hotplug cpu: migrate a task within its cpuset
2007-10-19 11:53:44 -07:00
Add scaled time to taskstats based process accounting
2007-10-18 14:37:28 -07:00
whitespace fixes: DMA channel allocator
2007-10-18 14:37:24 -07:00
whitespace fixes: execution domains
2007-10-18 14:37:26 -07:00
wait_task_stopped(): pass correct exit_code to wait_noreap_copyout()
2007-11-29 09:24:55 -08:00
fix clone(CLONE_NEWPID)
2007-12-05 09:21:18 -08:00
futex: correctly return -EFAULT not -EINVAL
2007-12-05 15:46:09 +01:00
[FUTEX] Fix address computation in compat code.
2007-11-09 16:13:08 -08:00
hrtimers: avoid overflow for large relative timeouts
2007-12-07 19:16:17 +01:00
whitespace fixes: interval timers
2007-10-18 14:37:26 -07:00
FRV: fix the extern declaration of kallsyms_num_syms
2007-11-29 09:24:54 -08:00
[PATCH] HZ: 300Hz support
2006-12-07 08:39:36 -08:00
Tiny clean-up of OPROFILE/KPROBES configuration
2007-12-06 09:41:12 -08:00
Move PREEMPT_NOTIFIERS into an always-included Kconfig
2007-10-17 08:42:55 -07:00
Extended crashkernel command line
2007-10-19 11:53:49 -07:00
is_power_of_2: kernel/kfifo.c
2007-07-16 09:05:50 -07:00
Restore call_usermodehelper_pipe() behaviour
2007-09-11 17:21:20 -07:00
kprobes: support kretprobe blacklist
2007-10-16 09:43:10 -07:00
add-vmcore: cleanup the coding style according to Andrew's comments
2007-10-17 08:42:54 -07:00
kthread: silence bogus section mismatch warning
2007-07-31 15:39:42 -07:00
[PATCH] severing module.h->sched.h
2006-12-04 02:00:22 -05:00
lockdep: make cli/sti annotation warnings clearer
2007-12-07 19:02:47 +01:00
[PATCH] lockdep: more chains
2006-12-07 08:39:43 -08:00
lockdep: Avoid /proc/lockdep & lock_stat infinite output
2007-10-11 22:11:11 +02:00
revert "Task Control Groups: example CPU accounting subsystem"
2007-11-14 18:45:40 -08:00
Linux Kernel Markers: fix marker mutex not taken upon module load
2007-11-14 18:45:40 -08:00
module: fix and elaborate comments
2007-11-19 11:20:43 +11:00
[PATCH] remove many unneeded #includes of sched.h
2007-02-14 08:09:54 -08:00
lockdep: fixup mutex annotations
2007-10-11 22:11:12 +02:00
Add kernel/notifier.c
2007-10-19 11:53:34 -07:00
cgroups: implement namespace tracking subsystem
2007-10-19 11:53:37 -07:00
pid namespaces: allow cloning of new namespace
2007-10-19 11:53:39 -07:00
debug: add end-of-oops marker
2007-12-20 15:01:17 +01:00
fix param_sysfs_builtin name length check
2007-11-14 18:45:42 -08:00
pidns: Place under CONFIG_EXPERIMENTAL
2007-11-14 18:45:43 -08:00
Isolate some explicit usage of task->tgid
2007-10-19 11:53:40 -07:00
Isolate some explicit usage of task->tgid
2007-10-19 11:53:40 -07:00
serial: turn serial console suspend a boot rather than compile time option
2007-10-18 14:37:19 -07:00
sched: document profile=sleep requiring CONFIG_SCHEDSTATS
2007-10-24 18:23:50 +02:00
Isolate some explicit usage of task->tgid
2007-10-19 11:53:40 -07:00
Clean up duplicate includes in kernel/
2007-10-17 08:42:48 -07:00
Make rcutorture RNG use temporal entropy
2007-10-17 08:42:53 -07:00
whitespace fixes: relayfs
2007-10-18 14:37:24 -07:00
Add IORESOUCE_BUSY flag for System RAM
2007-11-14 18:45:39 -08:00
Use helpers to obtain task pid in printks
2007-10-19 11:53:43 -07:00
Freezer: make kernel threads nonfreezable by default
2007-07-17 10:23:02 -07:00
Use helpers to obtain task pid in printks
2007-10-19 11:53:43 -07:00
FUTEX: Tidy up the code
2007-07-16 09:05:49 -07:00
sched: mark rwsem functions as __sched for wchan/profiling
2007-12-18 15:21:13 +01:00
sched: touch softlockup watchdog after idling
2007-12-18 15:21:13 +01:00
sched: clean up overlong line in kernel/sched_debug.c
2007-11-28 15:52:56 +01:00
sched: do not hurt SCHED_BATCH on wakeup
2007-12-18 15:21:13 +01:00
sched: isolate SMP balancing code a bit more
2007-10-24 18:23:51 +02:00
sched: rt: account the cpu time during the tick
2007-12-20 15:01:17 +01:00
sched: clean up kernel/sched_stat.h
2007-11-28 15:52:56 +01:00
make seccomp zerocost in schedule
2007-07-16 09:05:50 -07:00
sigwait eats blocked default-ignore signals
2007-11-12 16:05:23 -08:00
[KERNEL]: Unexport raise_softirq_irqoff
2007-10-10 16:49:18 -07:00
Use helpers to obtain task pid in printks
2007-10-19 11:53:43 -07:00
lockstat: hook into spinlock_t, rwlock_t, rwsem and mutex
2007-07-19 10:04:49 -07:00
[PATCH] SRCU: report out-of-memory errors
2006-10-04 07:55:30 -07:00
Fix stop_machine_run problem with naughty real time process
2007-07-16 09:05:41 -07:00
x86: ignore the sys_getcpu() tcache parameter
2007-11-17 16:27:00 +01:00
[POWERPC] Provide a way to protect 4k subpages when using 64k pages
2008-01-24 10:06:01 +11:00
sched: sysctl, proc_dointvec_minmax() expects int values for
2007-12-18 15:21:13 +01:00
sysctl: fix ax25 checks
2007-12-17 19:28:17 -08:00
kernel/taskstats.c: fix bogus nlmsg_free()
2007-11-14 18:45:44 -08:00
whitespace fixes: time syscalls
2007-10-18 14:37:24 -07:00
timer: kernel/timer.c section fixes
2007-12-18 18:05:58 +01:00
Add scaled time to taskstats based process accounting
2007-10-18 14:37:28 -07:00
header cleaning: don't include smp_lock.h when not used
2007-05-08 11:15:07 -07:00
sched: don't forget to unlock uids_mutex on error paths
2007-11-26 21:21:49 +01:00
Fix user namespace exiting OOPs
2007-09-19 11:24:18 -07:00
Fix UTS corruption during clone(CLONE_NEWUTS)
2007-09-19 11:24:17 -07:00
Isolate the UTS namespace's domainname and hostname back
2007-11-29 09:24:53 -08:00
Fix occurrences of "the the "
2007-05-09 08:57:56 +02:00
Use helpers to obtain task pid in printks
2007-10-19 11:53:43 -07:00
fa28237cfc