Impact: extend prefetch handling on 64-bit
Currently there's an extra is_prefetch() check done in do_sigbus(),
which we only do on 32 bits.
This is a last-ditch check before we terminate a task, so it's worth
giving prefetch instructions another chance - should none of our
existing quirks have caught a prefetch instruction related spurious
fault.
The only risk is if a prefetch causes a real sigbus, in that case
we'll not OOM but try another fault. But this code has been on
32-bit for a long time, so it should be fine in practice.
So do this on 64-bit too - and thus remove one more #ifdef.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Removal of an #ifdef in fault_in_kernel_space(), by making
use of the new TASK_SIZE_MAX symbol which is now available
on 32-bit too.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Rename TASK_SIZE64 to TASK_SIZE_MAX, and provide the
define on 32-bit too. (mapped to TASK_SIZE)
This allows 32-bit code to make use of the (former-) TASK_SIZE64
symbol as well, in a clean way.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
do_page_fault() has this ugly #ifdef in its prototype:
#ifdef CONFIG_X86_64
asmlinkage
#endif
void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
Replace it with 'dotraplinkage' which maps to exactly the above
construct: nothing on 32-bit and asmlinkage on 64-bit.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: add oops-recursion check to 32-bit
Unify the oops state-machine, to the 64-bit version. It is
slightly more careful in that it does a recursion check
in oops_begin(), and is thus more likely to show the relevant
oops.
It also means that 32-bit will print one more line at the
end of pagefault triggered oopses:
printk(KERN_EMERG "CR2: %016lx\n", address);
Which is generally good information to be seen in partial-dump
digital-camera jpegs ;-)
The downside is the somewhat more complex critical path. Both
variants have been tested well meanwhile by kernel developers
crashing their boxes so i dont think this is a practical worry.
This removes 3 ugly #ifdefs from no_context() and makes the
function a lot nicer read.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: refine/extend page fault related oops printing on 64-bit
- honor the pause_on_oops logic on 64-bit too
- print out NX fault warnings on 64-bit as well
- factor out the NX fault message to make it git-greppable and readable
Note that this means that we do the PF_INSTR check on 32-bit non-PAE
as well where it should not occur ... normally. Cannot hurt.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Remove an #ifdef from notify_page_fault(). The function still
compiles to nothing in the !CONFIG_KPROBES case.
Introduce kprobes_built_in() and kprobe_fault_handler() helpers
to allow this - they returns 0 if !CONFIG_KPROBES.
No code changed:
text data bss dec hex filename
4618 32 24 4674 1242 fault.o.before
4618 32 24 4674 1242 fault.o.after
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Remove an #ifdef from kmmio_fault() - we can do this by
providing default implementations for is_kmmio_active()
and kmmio_handler(). The compiler optimizes it all away
in the !CONFIG_MMIOTRACE case.
Also, while at it, clean up mmiotrace.h a bit:
- standard header guards
- standard vertical spaces for structure definitions
No code changed (both with mmiotrace on and off in the config):
text data bss dec hex filename
2947 12 12 2971 b9b fault.o.before
2947 12 12 2971 b9b fault.o.after
Cc: Pekka Paalanen <pq@iki.fi>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: improve page fault handling robustness
The 'PF_RSVD' flag (bit 3) of the page-fault error_code is a
relatively recent addition to x86 CPUs, so the 32-bit do_fault()
implementation never had it. This flag gets set when the CPU
detects nonzero values in any reserved bits of the page directory
entries.
Extend the existing 64-bit check for PF_RSVD in do_page_fault()
to 32-bit too. If we detect such a fault then we print a more
informative oops and the pagetables.
This unifies the code some more, removes an ugly #ifdef and improves
the 32-bit page fault code robustness a bit. It slightly increases
the 32-bit kernel text size.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Instead of an ugly, open-coded, #ifdef-ed vm86 related legacy check
in do_page_fault(), put it into the check_v8086_mode() helper
function and merge it with an existing #ifdef.
Also, simplify the code flow a tiny bit in the helper.
No code changed:
arch/x86/mm/fault.o:
text data bss dec hex filename
2711 12 12 2735 aaf fault.o.before
2711 12 12 2735 aaf fault.o.after
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: no functionality changed
Factor out the opcode checker into a helper inline.
The code got a tiny bit smaller:
text data bss dec hex filename
4632 32 24 4688 1250 fault.o.before
4618 32 24 4674 1242 fault.o.after
And it got cleaner / easier to review as well.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, no code changed
Clean up various small details, which can be correctness checked
automatically:
- tidy up the include file section
- eliminate unnecessary includes
- introduce show_signal_msg() to clean up code flow
- standardize the code flow
- standardize comments and other style details
- more cleanups, pointed out by checkpatch
No code changed on either 32-bit nor 64-bit:
arch/x86/mm/fault.o:
text data bss dec hex filename
4632 32 24 4688 1250 fault.o.before
4632 32 24 4688 1250 fault.o.after
the md5 changed due to a change in a single instruction:
2e8a8241e7f0d69706776a5a26c90bc0 fault.o.before.asm
c5c3d36e725586eb74f0e10692f0193e fault.o.after.asm
Because a __LINE__ reference in a WARN_ONCE() has changed.
On 32-bit a few stack offsets changed - no code size difference
nor any functionality difference.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: future-proof the split_large_page() function
Linus noticed that split_large_page() is not safe wrt. the
PAT bit: it is bit 12 on the 1GB and 2MB page table level
(_PAGE_BIT_PAT_LARGE), and it is bit 7 on the 4K page
table level (_PAGE_BIT_PAT).
Currently it is not a problem because we never set
_PAGE_BIT_PAT_LARGE on any of the large-page mappings - but
should this happen in the future the split_large_page() would
silently lift bit 12 into the lowlevel 4K pte and would start
corrupting the physical page frame offset. Not fun.
So add a debug warning, to make sure if something ever sets
the PAT bit then this function gets updated too.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix to prevent hard lockup on bad PMD permissions
If the PMD does not have the correct permissions for a page access,
but the PTE does, the spurious fault handler will mistake the fault
as a lazy TLB transaction. This will result in an infinite loop of:
fault -> spurious_fault check (pass) -> return to code -> fault
This patch adds a check and a warn on if the PTE passes the permissions
but the PMD does not.
[ Updated: Ingo Molnar suggested using WARN_ONCE with some text ]
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Steven Rostedt found a bug in where in his modified kernel
ftrace was unable to modify the kernel text, due to the PMD
itself having been marked read-only as well in
split_large_page().
The fix, suggested by Linus, is to not try to 'clone' the
reference protection of a huge-page, but to use the standard
(and permissive) page protection bits of KERNPG_TABLE.
The 'cloning' makes sense for the ptes but it's a confused and
incorrect concept at the page table level - because the
pagetable entry is a set of all ptes and hence cannot
'clone' any single protection attribute - the ptes can be any
mixture of protections.
With the permissive KERNPG_TABLE, even if the pte protections
get changed after this point (due to ftrace doing code-patching
or other similar activities like kprobes), the resulting combined
protections will still be correct and the pte's restrictive
(or permissive) protections will control it.
Also update the comment.
This bug was there for a long time but has not caused visible
problems before as it needs a rather large read-only area to
trigger. Steve possibly hacked his kernel with some really
large arrays or so. Anyway, the bug is definitely worth fixing.
[ Huang Ying also experienced problems in this area when writing
the EFI code, but the real bug in split_large_page() was not
realized back then. ]
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Reported-by: Huang Ying <ying.huang@intel.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
What's happening is that the assertion in mm/page_alloc.c:move_freepages()
is triggering:
BUG_ON(page_zone(start_page) != page_zone(end_page));
Once I knew this is what was happening, I added some annotations:
if (unlikely(page_zone(start_page) != page_zone(end_page))) {
printk(KERN_ERR "move_freepages: Bogus zones: "
"start_page[%p] end_page[%p] zone[%p]\n",
start_page, end_page, zone);
printk(KERN_ERR "move_freepages: "
"start_zone[%p] end_zone[%p]\n",
page_zone(start_page), page_zone(end_page));
printk(KERN_ERR "move_freepages: "
"start_pfn[0x%lx] end_pfn[0x%lx]\n",
page_to_pfn(start_page), page_to_pfn(end_page));
printk(KERN_ERR "move_freepages: "
"start_nid[%d] end_nid[%d]\n",
page_to_nid(start_page), page_to_nid(end_page));
...
And here's what I got:
move_freepages: Bogus zones: start_page[2207d0000] end_page[2207dffc0] zone[fffff8103effcb00]
move_freepages: start_zone[fffff8103effcb00] end_zone[fffff8003fffeb00]
move_freepages: start_pfn[0x81f600] end_pfn[0x81f7ff]
move_freepages: start_nid[1] end_nid[0]
My memory layout on this box is:
[ 0.000000] Zone PFN ranges:
[ 0.000000] Normal 0x00000000 -> 0x0081ff5d
[ 0.000000] Movable zone start PFN for each node
[ 0.000000] early_node_map[8] active PFN ranges
[ 0.000000] 0: 0x00000000 -> 0x00020000
[ 0.000000] 1: 0x00800000 -> 0x0081f7ff
[ 0.000000] 1: 0x0081f800 -> 0x0081fe50
[ 0.000000] 1: 0x0081fed1 -> 0x0081fed8
[ 0.000000] 1: 0x0081feda -> 0x0081fedb
[ 0.000000] 1: 0x0081fedd -> 0x0081fee5
[ 0.000000] 1: 0x0081fee7 -> 0x0081ff51
[ 0.000000] 1: 0x0081ff59 -> 0x0081ff5d
So it's a block move in that 0x81f600-->0x81f7ff region which triggers
the problem.
This patch:
Declaration of early_pfn_to_nid() is scattered over per-arch include
files, and it seems it's complicated to know when the declaration is used.
I think it makes fix-for-memmap-init not easy.
This patch moves all declaration to include/linux/mm.h
After this,
if !CONFIG_NODES_POPULATES_NODE_MAP && !CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
-> Use static definition in include/linux/mm.h
else if !CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
-> Use generic definition in mm/page_alloc.c
else
-> per-arch back end function will be called.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reported-by: David Miller <davem@davemlloft.net>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: <stable@kernel.org> [2.6.25.x, 2.6.26.x, 2.6.27.x, 2.6.28.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, vm86: fix preemption bug
x86, olpc: fix model detection without OFW
x86, hpet: fix for LS21 + HPET = boot hang
x86: CPA avoid repeated lazy mmu flush
x86: warn if arch_flush_lazy_mmu_cpu is called in preemptible context
x86/paravirt: make arch_flush_lazy_mmu/cpu disable preemption
x86, pat: fix warn_on_once() while mapping 0-1MB range with /dev/mem
x86/cpa: make sure cpa is safe to call in lazy mmu mode
x86, ptrace, mm: fix double-free on race
Impact: Flush the lazy MMU only once
Pending mmu updates only need to be flushed once to bring the
in-memory pagetable state up to date.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Impact: cleanup
Make the max_low_pfn logic a bit more standard between
lowmem_pfn_init() and highmem_pfn_init().
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Split find_low_pfn_range() into two functions:
- lowmem_pfn_init()
- highmem_pfn_init()
The former gets called if all of RAM fits into lowmem,
otherwise we call highmem_pfn_init().
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Jeff Mahoney reported:
> With Suse's hwinfo tool, on -tip:
> WARNING: at arch/x86/mm/pat.c:637 reserve_pfn_range+0x5b/0x26d()
reserve_pfn_range() is not tracking the memory range below 1MB
as non-RAM and as such is inconsistent with similar checks in
reserve_memtype() and free_memtype()
Rename the pagerange_is_ram() to pat_pagerange_is_ram() and add the
"track legacy 1MB region as non RAM" condition.
And also, fix reserve_pfn_range() to return -EINVAL, when the pfn
range is RAM. This is to be consistent with this API design.
Reported-and-tested-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix race leading to crash under KVM and Xen
The CPA code may be called while we're in lazy mmu update mode - for
example, when using DEBUG_PAGE_ALLOC and doing a slab allocation
in an interrupt handler which interrupted a lazy mmu update. In this
case, the in-memory pagetable state may be out of date due to pending
queued updates. We need to flush any pending updates before inspecting
the page table. Similarly, we must explicitly flush any modifications
CPA may have made (which comes down to flushing queued operations when
flushing the TLB).
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Stable Kernel <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/mm/init_32.c: In function ‘find_low_pfn_range’:
arch/x86/mm/init_32.c:696: warning: format ‘%u’ expects type ‘unsigned int’, but
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* commit 'remotes/tip/x86/paravirt': (175 commits)
xen: use direct ops on 64-bit
xen: make direct versions of irq_enable/disable/save/restore to common code
xen: setup percpu data pointers
xen: fix 32-bit build resulting from mmu move
x86/paravirt: return full 64-bit result
x86, percpu: fix kexec with vmlinux
x86/vmi: fix interrupt enable/disable/save/restore calling convention.
x86/paravirt: don't restore second return reg
xen: setup percpu data pointers
x86: split loading percpu segments from loading gdt
x86: pass in cpu number to switch_to_new_gdt()
x86: UV fix uv_flush_send_and_wait()
x86/paravirt: fix missing callee-save call on pud_val
x86/paravirt: use callee-saved convention for pte_val/make_pte/etc
x86/paravirt: implement PVOP_CALL macros for callee-save functions
x86/paravirt: add register-saving thunks to reduce caller register pressure
x86/paravirt: selectively save/restore regs around pvops calls
x86: fix paravirt clobber in entry_64.S
x86/pvops: add a paravirt_ident functions to allow special patching
xen: move remaining mmu-related stuff into mmu.c
...
Conflicts:
arch/x86/mach-voyager/voyager_smp.c
arch/x86/mm/fault.c
Impact: bug fix
Don't use per_cpu_offset() to determine if it valid to access a
per-cpu variable for a given cpu number. It is not a valid assumption
on x86-64 anymore. Use cpu_possible() instead.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Prevent kprobes from catching spurious faults which will cause infinite
recursive page-fault and memory corruption by stack overflow.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: <stable@kernel.org> [2.6.28.x]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Impact: cleanup
Introduce helper function fault_in_kernel_address() to make editors happy.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Impact: widen debug checks
VirtualBox calls do_page_fault() from an atomic context but runs into a
might_sleep() way pas this point, cure that.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The x86/Voyager subarch used to have this distinction between
'x86 SMP support' and 'Voyager SMP support':
config X86_SMP
bool
depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
This is a pointless distinction - Voyager can (and already does) use
smp_ops to implement various SMP quirks it has - and it can be extended
more to cover all the specialities of Voyager.
So remove this complication in the Kconfig space.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Our send_IPI_*() methods and definitions are a twisted mess: the same
symbol is defined to different things depending on .config details,
in a non-transparent way.
- spread out the quirks into separately named per apic driver methods
- prefix the standard PC methods with default_
- get rid of wrapper macro obfuscation
- clean up various details
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Ingo Molnar