Current kprobe copies the original instruction at the probe point and replaces
it with a breakpoint instruction (int3). When the kernel hits the probe
point, kprobe handler is invoked. And the copied instruction is single-step
executed on the copied buffer (not on the original address) by kprobe. After
that, the kprobe checks registers and modify it (if need) as if the
instructions was executed on the original address.
My proposal is based on the fact there are many instructions which do NOT
require the register modification after the single-step execution. When the
copied instruction is a kind of them, kprobe just jumps back to the next
instruction after single-step execution. If so, why don't we execute those
instructions directly?
With kprobe-booster patch, kprobes will execute a copied instruction directly
and (if need) jump back to original code. This direct execution is executed
when the kprobe don't have both post_handler and break_handler, and the copied
instruction can be executed directly.
I sorted instructions which can be executed directly or not;
- Call instructions are NG(can not be executed directly).
We should correct the return address pushed into top of stack.
- Indirect instructions except for absolute indirect-jumps
are NG. Those instructions changes EIP randomly. We should
check EIP and correct it.
- Instructions that change EIP beyond the range of the
instruction buffer are NG.
- Instructions that change EIP to tail 5 bytes of the
instruction buffer (it is the size of a jump instruction).
We must write a jump instruction which backs to original
kernel code in the instruction buffer.
- Break point instruction is NG. We should not touch EIP and
pass to other handlers.
- Absolute direct/indirect jumps are OK.- Conditional Jumps are NG.
- Halt and software-interruptions are NG. Because it will stay on
the instruction buffer of kprobes.
- Prefixes are NG.
- Unknown/reserved opcode is NG.
- Other 1 byte instructions are OK. But those instructions need a
jump back code.
- 2 bytes instructions are mapped sparsely. So, in this release,
this patch don't boost those instructions.
>From Intel's IA-32 opcode map described in IA-32 Intel Architecture Software
Developer's Manual Vol.2 B, I determined that following opcodes are not
boostable.
- 0FH (2byte escape)
- 70H - 7FH (Jump on condition)
- 9AH (Call) and 9CH (Pushf)
- C0H-C1H (Grp 2: includes reserved opcode)
- C6H-C7H (Grp11: includes reserved opcode)
- CCH-CEH (Software-interrupt)
- D0H-D3H (Grp2: includes reserved opcode)
- D6H (Reserved)
- D8H-DFH (Coprocessor)
- E0H-E3H (loop/conditional jump)
- E8H (Call)
- F0H-F3H (Prefixes and reserved)
- F4H (Halt)
- F6H-F7H (Grp3: includes reserved opcode)
- FEH-FFH(Grp4,5: includes reserved opcode)
Kprobe-booster checks whether target instruction can be boosted (can be
executed directly) at arch_copy_kprobe() function. If the target instruction
can be boosted, it clears "boostable" flag. If not, it sets "boostable" flag
-1. This is disabled status. In resume_execution() function, If "boostable"
flag is cleared, kprobe-booster measures the size of the target instruction
and sets "boostable" flag 1.
In kprobe_handler(), kprobe checks the "boostable" flag. If the flag is 1, it
resets current kprobe and executes instruction buffer directly instead of
single stepping.
When unregistering a boosted kprobe, it calls synchronize_sched()
after "int3" is removed. So we can ensure followings after
the synchronize_sched() called.
- interrupt handlers are finished on all CPUs.
- instruction buffer is not executed on all CPUs.
And we can release the boosted kprobe safely.
And also, on preemptible kernel, the booster is not enabled where the kernel
preemption is enabled. So, there are no preempted threads on the instruction
buffer.
The description of kretprobe-booster:
====================================
In the normal operation, kretprobe make a target function return to trampoline
code. And a kprobe (called trampoline_probe) have been inserted at the
trampoline code. When the kernel hits this kprobe, it calls kretprobe's
handler and it returns to original return address.
Kretprobe-booster patch removes the trampoline_probe. It allows the
trampoline code to call kretprobe's handler directly instead of invoking
kprobe. And tranpoline code returns to original return address.
This new trampoline code stores and restores registers, so the kretprobe
handler is still able to access those registers.
Current kprobe has about 1.3 usec/probe(*) overhead, and kprobe-booster patch
reduces it to 0.6 usec/probe(*). Also current kretprobe has about 2.0
usec/probe(*) overhead. Kprobe-booster patch reduces it to 1.3 usec/probe(*),
and the combination of both kprobe-booster patch and kretprobe-booster patch
reduces it to 0.9 usec/probe(*).
I expect the combination of both patches can reduce half of a probing
overhead.
Performance numbers strongly depend on the processor model.
Andrew Morton wrote:
> These preempt tricks look rather nasty. Can you please describe what the
> problem is, precisely? And how this code avoids it? Perhaps we can find
> something cleaner.
The problem is how to remove the copied instructions of the
kprobe *safely* on the preemptable kernel (CONFIG_PREEMPT=y).
Kprobes basically executes the following actions;
(1)int3
(2)preempt_disable()
(3)kprobe_prehandler()
(4)copied instructioin(single step)
(5)kprobe_posthandler()
(6)preempt_enable()
(7)return to the original code
During the execution of copied instruction, preemption is
disabled (from step (2) to (6)).
When unregistering the probes, Kprobe waits for RCU
quiescent state by using synchronize_sched() after removing
int3 instruction.
Thus we can ensure the copied instruction is not executed.
On the other hand, kprobe-booster executes the following actions;
(1)int3
(2)preempt_disable()
(3)kprobe_prehandler()
(4)preempt_enable() <-- this one is added by my patch
(5)copied instruction(direct execution)
(6)jmp back to the original code
The problem is that we have no way to prevent preemption on
step (5) or (6). We cannot call preempt_disable() after step (6),
because there are no rooms to do that. Thus, some other
processes may be preempted at step(5) or (6) on preemptable kernel.
And I couldn't find the easy way to ensure that other processes'
stack do *not* have the address of them. (I thought some way
to do that, but those are very costly.)
So currently, I simply boost the kprobe only when the probe
point is already preemption disabled.
> Also, the patch adds a preempt_enable() but I don't see a corresponding
> preempt_disable(). Am I missing something?
It is corresponding to the preempt_disable() in the top of
kprobe_handler().
I copied the code of kprobe_handler() here:
static int __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p;
int ret = 0;
kprobe_opcode_t *addr = NULL;
unsigned long *lp;
struct kprobe_ctlblk *kcb;
/*
* We don't want to be preempted for the entire
* duration of kprobe processing
*/
preempt_disable(); <-- HERE
kcb = get_kprobe_ctlblk();
Signed-off-by: Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add blkcnt_t as the type of inode.i_blocks. This enables you to make the size
of blkcnt_t either 4 bytes or 8 bytes on 32 bits architecture with CONFIG_LSF.
- CONFIG_LSF
Add new configuration parameter.
- blkcnt_t
On h8300, i386, mips, powerpc, s390 and sh that define sector_t,
blkcnt_t is defined as u64 if CONFIG_LSF is enabled; otherwise it is
defined as unsigned long.
On other architectures, it is defined as unsigned long.
- inode.i_blocks
Change the type from sector_t to blkcnt_t.
Signed-off-by: Takashi Sato <sho@tnes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch series fixes the following problems on 32 bits architecture.
o stat64 returns the lower 32 bits of blocks, although userland st_blocks
has 64 bits, because i_blocks has only 32 bits. The ioctl with FIOQSIZE has
the same problem.
o As Dave Kleikamp said, making >2TB file on JFS results in writing an
invalid block number to disk inode. The cause is the same as above too.
o In generic quota code dquot_transfer(), the file usage is calculated from
i_blocks via inode_get_bytes(). If the file is over 2TB, the change of
usage is less than expected. The cause is the same as above too.
o As Trond Myklebust said, statfs64's entries related to blocks are invalid
on statfs64 for a network filesystem which has more than 2^32-1 blocks with
CONFIG_LBD disabled. [PATCH 3/3]
We made patches to fix problems that occur when handling a large filesystem
and a large file. It was discussed on the mails titled "stat64 for over 2TB
file returned invalid st_blocks".
Signed-off-by: Takashi Sato <sho@tnes.nec.co.jp>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There are more and more cases where we need to know DMI information
early to work around bugs. i386 already had early DMI scanning, but
x86-64 didn't. Implement this now.
This required some cleanup in the i386 code.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Implement the half-closed devices notifiation, by adding a new POLLRDHUP
(and its alias EPOLLRDHUP) bit to the existing poll/select sets. Since the
existing POLLHUP handling, that does not report correctly half-closed
devices, was feared to be changed, this implementation leaves the current
POLLHUP reporting unchanged and simply add a new bit that is set in the few
places where it makes sense. The same thing was discussed and conceptually
agreed quite some time ago:
http://lkml.org/lkml/2003/7/12/116
Since this new event bit is added to the existing Linux poll infrastruture,
even the existing poll/select system calls will be able to use it. As far
as the existing POLLHUP handling, the patch leaves it as is. The
pollrdhup-2.6.16.rc5-0.10.diff defines the POLLRDHUP for all the existing
archs and sets the bit in the six relevant files. The other attached diff
is the simple change required to sys/epoll.h to add the EPOLLRDHUP
definition.
There is "a stupid program" to test POLLRDHUP delivery here:
http://www.xmailserver.org/pollrdhup-test.c
It tests poll(2), but since the delivery is same epoll(2) will work equally.
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
include/linux/platform.h contained nothing that was actually used except
the default_idle() prototype, and is therefore removed by this patch.
This patch does the following with the platform specific default_idle()
functions on different architectures:
- remove the unused function:
- parisc
- sparc64
- make the needlessly global function static:
- arm
- h8300
- m68k
- m68knommu
- s390
- v850
- x86_64
- add a prototype in asm/system.h:
- cris
- i386
- ia64
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Patrick Mochel <mochel@digitalimplant.org>
Acked-by: Kyle McMartin <kyle@parisc-linux.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
unused isa_...() helpers removed.
Adrian Bunk:
The asm-sh part was rediffed due to unrelated changes.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Without branch hints, the very unlikely chance of the loop repeating due to
cmpxchg failure is unrolled with gcc-4 that I have tested.
Improve this for architectures with a native cas/cmpxchg. llsc archs
should try to implement this natively.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Seems like needless clutter having a bunch of #if defined(CONFIG_$ARCH) in
include/linux/cache.h. Move the per architecture section definition to
asm/cache.h, and keep the if-not-defined dummy case in linux/cache.h to
catch architectures which don't implement the section.
Verified that symbols still go in .data.read_mostly on parisc,
and the compile doesn't break.
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Gcc reserves %ebx when compiling position-independent-code on i386. This
means, the _syscallX() macros in include/asm-i386/unistd.h will not
compile. This patch is changes the existing macros to take special care to
preserve %ebx.
The bug can be tracked at http://bugzilla.kernel.org/show_bug.cgi?id=6204
Signed-off-by: Markus Gutschke <markus@google.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
_raw_spin_lock_flags() is entered with interrupts disabled. If it cannot
obtain a spinlock, it checks the flags that were passed and re-enables
interrupts before spinning if that's how the flags are set. When the
spinlock might be available, it disables interrupts (even if they are
already disabled) before trying to get the lock. Change that so interrupts
are only disabled if they have been enabled. This costs nine bytes of
duplicated spinloop code.
Fastpath before patch:
jle <keep looping> not-taken conditional jump
cli disable interrupts
jmp <try for lock> unconditional jump
Fastpath after patch, if interrupts were not enabled:
jg <try for lock> taken conditional branch
Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
arch/i386/kernel/cpu/centaur.c: In function `centaur_mcr_insert':
arch/i386/kernel/cpu/centaur.c:33: warning: implicit declaration of function `mtrr_centaur_report_mcr'
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
>commit 76381fee7e
>Author: Vincent Hanquez <vincent.hanquez@cl.cam.ac.uk>
>Date: Thu Jun 23 00:08:46 2005 -0700
>
> [PATCH] xen: x86_64: use more usermode macro
>
> Make use of the user_mode macro where it's possible. This is useful for Xen
> because it will need only to redefine only the macro to a hypervisor call.
I am of the opinion that the above changeset is incomplete, i.e. it missed
converting some previous uses of user_mode to user_mode_vm. While most of
them could be considered just cosmetical, at least the one in die_nmi
doesn't appear to be.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Vincent Hanquez <vincent.hanquez@cl.cam.ac.uk>
Cc: Zachary Amsden <zach@vmware.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Registering a callback handler through register_die_notifier() is obviously
primarily intended for use by modules. However, the way these currently
get called it is basically impossible for them to actually be used by
modules, as there is, on non-PAE configurationes, a good chance (the larger
the module, the better) for the system to crash as a result.
This is because the callback gets invoked
(a) in the page fault path before the top level page table propagation
gets carried out (hence a fault to propagate the top level page table
entry/entries mapping to module's code/data would nest infinitly) and
(b) in the NMI path, where nested faults must absolutely not happen,
since otherwise the IRET from the nested fault re-enables NMIs,
potentially resulting in nested NMI occurences.
Besides the modular aspect, similar problems would even arise for in-
kernel consumers of the API if they touched ioremap()ed or vmalloc()ed
memory inside their handlers.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The history is that -mm kernels do not work for me for a few months
already. The things started from crashing somewhere after starting init,
and for the last month - no boot at all, just "Uncompressing... OK,
booting kernel", and silence. Early console didn't work too. With the
latest releases this degraded into an infinite stream of the "Unknown
interrupt or fault" messages. So today my patience ran out and I started
to think how can I collect at least some info for the bug-report. Attached
is the patch that allows to gather some valueable debug info on the problem
by making an early console more useable. I can't properly test the patch,
as the kernel still doesn't boot, so I'll explain it in details in a hope
someone else can justify the intrusive changes.
arch_hooks.h: added prototypes for setup_early_printk() and early_printk().
setup.c: killed wrong setup_early_printk() prototype. Moved
setup_early_printk() a bit earlier, as it was not "early enough" to cover
the bug I was fighting with.
early_printk.c: made it to start printing from the bottom of the screen,
otherwise the messages interfere with the ones of the boot-loader, so you
can't read them.
Signed-off-by: Stas Sergeev <stsp@aknet.ru>
Cc: Andi Kleen <ak@muc.de>
Cc: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
ES7000 platform code clean up for compilation errors and a warning.
Ifdef'd the ACPI related parts in the ES7000 platform code. They were
causing compile errors in certain configuration (without ACPI defined). I
think this approach would be best (as opposed to Kconfig changes) since it
only touches the subarch...
Signed-off-by: <Natalie.Protasevich@unisys.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In some code I am developing I had occasion to change the type of a
variable. This made the value put_user was putting to user space wrong.
But the code continued to build cleanly without errors.
Introducing a temporary fixes this problem and at least with gcc-3.3.5 does
not cause gcc any problems with optimizing out the temporary. gcc-4.x
using SSA internally ought to be even better at optimizing out temporaries,
so I don't expect a temporary to become a problem. Especially because in
all correct cases the types on both sides of the assignment to the
temporary are the same.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Implement SMP alternatives, i.e. switching at runtime between different
code versions for UP and SMP. The code can patch both SMP->UP and UP->SMP.
The UP->SMP case is useful for CPU hotplug.
With CONFIG_CPU_HOTPLUG enabled the code switches to UP at boot time and
when the number of CPUs goes down to 1, and switches to SMP when the number
of CPUs goes up to 2.
Without CONFIG_CPU_HOTPLUG or on non-SMP-capable systems the code is
patched once at boot time (if needed) and the tables are released
afterwards.
The changes in detail:
* The current alternatives bits are moved to a separate file,
the SMP alternatives code is added there.
* The patch adds some new elf sections to the kernel:
.smp_altinstructions
like .altinstructions, also contains a list
of alt_instr structs.
.smp_altinstr_replacement
like .altinstr_replacement, but also has some space to
save original instruction before replaving it.
.smp_locks
list of pointers to lock prefixes which can be nop'ed
out on UP.
The first two are used to replace more complex instruction
sequences such as spinlocks and semaphores. It would be possible
to deal with the lock prefixes with that as well, but by handling
them as special case the table sizes become much smaller.
* The sections are page-aligned and padded up to page size, so they
can be free if they are not needed.
* Splitted the code to release init pages to a separate function and
use it to release the elf sections if they are unused.
Signed-off-by: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2.6.16-rc3 uses hugetlb on-demand paging, but it doesn_t support hugetlb
mprotect.
From: David Gibson <david@gibson.dropbear.id.au>
Remove a test from the mprotect() path which checks that the mprotect()ed
range on a hugepage VMA is hugepage aligned (yes, really, the sense of
is_aligned_hugepage_range() is the opposite of what you'd guess :-/).
In fact, we don't need this test. If the given addresses match the
beginning/end of a hugepage VMA they must already be suitably aligned. If
they don't, then mprotect_fixup() will attempt to split the VMA. The very
first test in split_vma() will check for a badly aligned address on a
hugepage VMA and return -EINVAL if necessary.
From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
On i386 and x86-64, pte flag _PAGE_PSE collides with _PAGE_PROTNONE. The
identify of hugetlb pte is lost when changing page protection via mprotect.
A page fault occurs later will trigger a bug check in huge_pte_alloc().
The fix is to always make new pte a hugetlb pte and also to clean up
legacy code where _PAGE_PRESENT is forced on in the pre-faulting day.
Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
check_acpi_pci() is called from arch/i386/kernel/setup.c even if
CONFIG_ACPI is not defined, but the code in include/asm/acpi.h doesn't
provide it in this case.
Signed-off-by: Herbert Pötzl <herbert@13thfloor.at>
Cc: "Brown, Len" <len.brown@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
ATI chipsets tend to generate double timer interrupts for the local APIC
timer when both the 8254 and the IO-APIC timer pins are enabled. This is
because they route it to both and the result is anded together and the CPU
ends up processing it twice.
This patch changes check_timer to disable the 8254 routing for interrupt 0.
I think it would be safe on all chipsets actually (i tested it on a couple
and it worked everywhere) and Windows seems to do it in a similar way, but
to be conservative this patch only enables this mode on ATI (and adds
options to enable/disable too)
Ported over from a similar x86-64 change.
I reused the ACPI earlyquirk infrastructure for the ATI bridge check, but
tweaked it a bit to work even without ACPI.
Inspired by a patch from Chuck Ebbert, but redone.
Cc: Chuck Ebbert <76306.1226@compuserve.com>
Cc: "Brown, Len" <len.brown@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Recent GDT changes broke the SMP boot sequence if the booting CPU is
numbered anything other than zero. There's also a subtle source of error
in that the boot time CPU now uses cpu_gdt_table (which is actually the GDT
for booting CPUs in head.S). This patch fixes both problems by making GDT
descriptors themselves allocated from a per_cpu area and switching to them
in cpu_init(), which now means that cpu_gdt_table is exclusively used for
booting CPUs again.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Matt Tolentino <metolent@snoqualmie.dp.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix a problem seen on i686 machine with NX support where the instruction
could not be single stepped because of NX bit set on the memory pages
allocated by kprobes module. This patch provides allocation of instruction
solt so that the processor can execute the instruction from that location
similar to x86_64 architecture. Thanks to Bibo and Masami for testing this
patch.
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Do not mask TIF_SINGLESTEP bit in _TIF_WORK_MASK. Masking this stopped
do_notify_resume() from being called when it should have been.
Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make new MADV_REMOVE, MADV_DONTFORK, MADV_DOFORK consistent across all
arches. The idea is to make it possible to use them portably even before
distros include them in libc headers.
Move common flags to asm-generic/mman.h
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Cc: Roland Dreier <rolandd@cisco.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently, copy-on-write may change the physical address of a page even if the
user requested that the page is pinned in memory (either by mlock or by
get_user_pages). This happens if the process forks meanwhile, and the parent
writes to that page. As a result, the page is orphaned: in case of
get_user_pages, the application will never see any data hardware DMA's into
this page after the COW. In case of mlock'd memory, the parent is not getting
the realtime/security benefits of mlock.
In particular, this affects the Infiniband modules which do DMA from and into
user pages all the time.
This patch adds madvise options to control whether memory range is inherited
across fork. Useful e.g. for when hardware is doing DMA from/into these
pages. Could also be useful to an application wanting to speed up its forks
by cutting large areas out of consideration.
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Acked-by: Hugh Dickins <hugh@veritas.com>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The correct way to export hyperthreading based functions is to predicate
them on CONFIG_X86_HT. Without this, the topology exporting patch breaks
the build on all non-PC x86 subarchitectures.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The *at patches introduced fstatat and, due to inusfficient research, I
used the newfstat functions generally as the guideline. The result is that
on 32-bit platforms we don't have all the information needed to implement
fstatat64.
This patch modifies the code to pass up 64-bit information if
__ARCH_WANT_STAT64 is defined. I renamed the syscall entry point to make
this clear. Other archs will continue to use the existing code. On x86-64
the compat code is implemented using a new sys32_ function. this is what
is done for the other stat syscalls as well.
This patch might break some other archs (those which define
__ARCH_WANT_STAT64 and which already wired up the syscall). Yet others
might need changes to accomodate the compatibility mode. I really don't
want to do that work because all this stat handling is a mess (more so in
glibc, but the kernel is also affected). It should be done by the arch
maintainers. I'll provide some stand-alone test shortly. Those who are
eager could compile glibc and run 'make check' (no installation needed).
The patch below has been tested on x86 and x86-64.
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Registers system call for the i386 architecture.
Signed-off-by: Janak Desai <janak@us.ibm.com>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Cc: Andi Kleen <ak@muc.de>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix gcc4.1 compile warnings "value computed is not used" with
set_current_state() and set_task_state() on i386/SMP and x86-64.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The patch implements cpu topology exportation by sysfs.
Items (attributes) are similar to /proc/cpuinfo.
1) /sys/devices/system/cpu/cpuX/topology/physical_package_id:
represent the physical package id of cpu X;
2) /sys/devices/system/cpu/cpuX/topology/core_id:
represent the cpu core id to cpu X;
3) /sys/devices/system/cpu/cpuX/topology/thread_siblings:
represent the thread siblings to cpu X in the same core;
4) /sys/devices/system/cpu/cpuX/topology/core_siblings:
represent the thread siblings to cpu X in the same physical package;
To implement it in an architecture-neutral way, a new source file,
driver/base/topology.c, is to export the 5 attributes.
If one architecture wants to support this feature, it just needs to
implement 4 defines, typically in file include/asm-XXX/topology.h.
The 4 defines are:
#define topology_physical_package_id(cpu)
#define topology_core_id(cpu)
#define topology_thread_siblings(cpu)
#define topology_core_siblings(cpu)
The type of **_id is int.
The type of siblings is cpumask_t.
To be consistent on all architectures, the 4 attributes should have
deafult values if their values are unavailable. Below is the rule.
1) physical_package_id: If cpu has no physical package id, -1 is the
default value.
2) core_id: If cpu doesn't support multi-core, its core id is 0.
3) thread_siblings: Just include itself, if the cpu doesn't support
HT/multi-thread.
4) core_siblings: Just include itself, if the cpu doesn't support
multi-core and HT/Multi-thread.
So be careful when declaring the 4 defines in include/asm-XXX/topology.h.
If an attribute isn't defined on an architecture, it won't be exported.
Thank Nathan, Greg, Andi, Paul and Venki.
The patch provides defines for i386/x86_64/ia64.
Signed-off-by: Zhang, Yanmin <yanmin.zhang@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Enable selection of different user/kernel VM splits for i386, including an
optimized mode for 1GB physical RAM, which gives the kernel a direct (non
HIGHMEM) mapping to the entire 1GB rather than just the first 896MB.
There is a similarly a similarly optimized mode for machines with exactly 2GB
of physical RAM.
This can speed up the kernel by avoiding having to create/destroy temporary
HIGHMEM mappings, and by not having to include HIGHMEM support at all on such
machines. The flip side is that there's less virtual addressing left for
userspace in these alternatives, and some binary-only kernel modules may
misbehave unless rebuilt with the same VMSPLIT option as the main kernel
image.
Original idea/patch from Jens Axboe, modified based on suggestions from Linus
et al.
Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is a subset of the bluesmoke project core code, stripped of the NMI work
which isn't ready to merge and some of the "interesting" proc functionality
that needs reworking or just has no place in kernel. It requires no core
kernel changes except the added scrub functions already posted.
The goal is to merge further functionality only after the core code is
accepted and proven in the base kernel, and only at the point the upstream
extras are really ready to merge.
From: doug thompson <norsk5@xmission.com>
This converts EDAC to sysfs and is the final chunk neccessary before EDAC
has a stable user space API and can be considered for submission into the
base kernel.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: doug thompson <norsk5@xmission.com>
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
EDAC requires a way to scrub memory if an ECC error is found and the chipset
does not do the work automatically. That means rewriting memory locations
atomically with respect to all CPUs _and_ bus masters. That means we can't
use atomic_add(foo, 0) as it gets optimised for non-SMP
This adds a function to include/asm-foo/atomic.h for the platforms currently
supported which implements a scrub of a mapped block.
It also adjusts a few other files include order where atomic.h is included
before types.h as this now causes an error as atomic_scrub uses u32.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add the sys_pselect6() and sys_poll() calls to the i386 syscall table.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Handle TIF_RESTORE_SIGMASK as added by David Woodhouse's patch entitled:
[PATCH] 2/3 Add TIF_RESTORE_SIGMASK support for arch/powerpc
[PATCH] 3/3 Generic sys_rt_sigsuspend
It does the following:
(1) Declares TIF_RESTORE_SIGMASK for i386.
(2) Invokes it over to do_signal() when TIF_RESTORE_SIGMASK is set.
(3) Makes do_signal() support TIF_RESTORE_SIGMASK, using the signal mask saved
in current->saved_sigmask.
(4) Discards sys_rt_sigsuspend() from the arch, using the generic one instead.
(5) Makes sys_sigsuspend() save the signal mask and set TIF_RESTORE_SIGMASK
rather than attempting to fudge the return registers.
(6) Makes sys_sigsuspend() return -ERESTARTNOHAND rather than looping
intrinsically.
(7) Makes setup_frame(), setup_rt_frame() and handle_signal() return 0 or
-EFAULT rather than true/false to be consistent with the rest of the
kernel.
Due to the fact do_signal() is then only called from one place:
(8) Makes do_signal() no longer have a return value is it was just being
ignored; force_sig() takes care of this.
(9) Discards the old sigmask argument to do_signal() as it's no longer
necessary.
(10) Makes do_signal() static.
(11) Marks the second argument to do_notify_resume() as unused. The unused
argument should remain in the middle as the arguments are passed in as
registers, and the ordering is specific in entry.S
Given the way do_signal() is now no longer called from sys_{,rt_}sigsuspend(),
they no longer need access to the exception frame, and so can just take
arguments normally.
This patch depends on sys_rt_sigsuspend patch.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Wire up the x86 syscalls
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I added this line to share this file with UML, but now it's no longer
shared so remove this useless leftover.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Arjan van de Ven <arjan@infradead.org>
Mark a number of functions as 'must inline'. The functions affected by this
patch need to be inlined because they use knowledge that their arguments are
constant so that most of the function optimizes away. At this point this
patch does not change behavior, it's for documentation only (and for future
patches in the inline series)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
{get,put}_thread_info() were introduced in 2.5.4 and never
had been called by anything in the tree.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
)
From: Al Viro <viro@ftp.linux.org.uk>
task_pt_regs() needs the same offset-by-8 to match copy_thread()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
)
From: Ingo Molnar <mingo@elte.hu>
This is the latest version of the scheduler cache-hot-auto-tune patch.
The first problem was that detection time scaled with O(N^2), which is
unacceptable on larger SMP and NUMA systems. To solve this:
- I've added a 'domain distance' function, which is used to cache
measurement results. Each distance is only measured once. This means
that e.g. on NUMA distances of 0, 1 and 2 might be measured, on HT
distances 0 and 1, and on SMP distance 0 is measured. The code walks
the domain tree to determine the distance, so it automatically follows
whatever hierarchy an architecture sets up. This cuts down on the boot
time significantly and removes the O(N^2) limit. The only assumption
is that migration costs can be expressed as a function of domain
distance - this covers the overwhelming majority of existing systems,
and is a good guess even for more assymetric systems.
[ People hacking systems that have assymetries that break this
assumption (e.g. different CPU speeds) should experiment a bit with
the cpu_distance() function. Adding a ->migration_distance factor to
the domain structure would be one possible solution - but lets first
see the problem systems, if they exist at all. Lets not overdesign. ]
Another problem was that only a single cache-size was used for measuring
the cost of migration, and most architectures didnt set that variable
up. Furthermore, a single cache-size does not fit NUMA hierarchies with
L3 caches and does not fit HT setups, where different CPUs will often
have different 'effective cache sizes'. To solve this problem:
- Instead of relying on a single cache-size provided by the platform and
sticking to it, the code now auto-detects the 'effective migration
cost' between two measured CPUs, via iterating through a wide range of
cachesizes. The code searches for the maximum migration cost, which
occurs when the working set of the test-workload falls just below the
'effective cache size'. I.e. real-life optimized search is done for
the maximum migration cost, between two real CPUs.
This, amongst other things, has the positive effect hat if e.g. two
CPUs share a L2/L3 cache, a different (and accurate) migration cost
will be found than between two CPUs on the same system that dont share
any caches.
(The reliable measurement of migration costs is tricky - see the source
for details.)
Furthermore i've added various boot-time options to override/tune
migration behavior.
Firstly, there's a blanket override for autodetection:
migration_cost=1000,2000,3000
will override the depth 0/1/2 values with 1msec/2msec/3msec values.
Secondly, there's a global factor that can be used to increase (or
decrease) the autodetected values:
migration_factor=120
will increase the autodetected values by 20%. This option is useful to
tune things in a workload-dependent way - e.g. if a workload is
cache-insensitive then CPU utilization can be maximized by specifying
migration_factor=0.
I've tested the autodetection code quite extensively on x86, on 3
P3/Xeon/2MB, and the autodetected values look pretty good:
Dual Celeron (128K L2 cache):
---------------------
migration cost matrix (max_cache_size: 131072, cpu: 467 MHz):
---------------------
[00] [01]
[00]: - 1.7(1)
[01]: 1.7(1) -
---------------------
cacheflush times [2]: 0.0 (0) 1.7 (1784008)
---------------------
Here the slow memory subsystem dominates system performance, and even
though caches are small, the migration cost is 1.7 msecs.
Dual HT P4 (512K L2 cache):
---------------------
migration cost matrix (max_cache_size: 524288, cpu: 2379 MHz):
---------------------
[00] [01] [02] [03]
[00]: - 0.4(1) 0.0(0) 0.4(1)
[01]: 0.4(1) - 0.4(1) 0.0(0)
[02]: 0.0(0) 0.4(1) - 0.4(1)
[03]: 0.4(1) 0.0(0) 0.4(1) -
---------------------
cacheflush times [2]: 0.0 (33900) 0.4 (448514)
---------------------
Here it can be seen that there is no migration cost between two HT
siblings (CPU#0/2 and CPU#1/3 are separate physical CPUs). A fast memory
system makes inter-physical-CPU migration pretty cheap: 0.4 msecs.
8-way P3/Xeon [2MB L2 cache]:
---------------------
migration cost matrix (max_cache_size: 2097152, cpu: 700 MHz):
---------------------
[00] [01] [02] [03] [04] [05] [06] [07]
[00]: - 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1)
[01]: 19.2(1) - 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1)
[02]: 19.2(1) 19.2(1) - 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1)
[03]: 19.2(1) 19.2(1) 19.2(1) - 19.2(1) 19.2(1) 19.2(1) 19.2(1)
[04]: 19.2(1) 19.2(1) 19.2(1) 19.2(1) - 19.2(1) 19.2(1) 19.2(1)
[05]: 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1) - 19.2(1) 19.2(1)
[06]: 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1) - 19.2(1)
[07]: 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1) 19.2(1) -
---------------------
cacheflush times [2]: 0.0 (0) 19.2 (19281756)
---------------------
This one has huge caches and a relatively slow memory subsystem - so the
migration cost is 19 msecs.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Cc: <wilder@us.ibm.com>
Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add per-arch sched_cacheflush() which is a write-back cacheflush used by
the migration-cost calibration code at bootup time.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Passing random input values in eax to cpuid is not a good idea
because the CPU will GPF for unknown ones.
Use the correct x86-64 version that exists for a longer time too.
This also adds a memory barrier to prevent the optimizer from
reordering.
Cc: tigran@veritas.com
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
As suggested by Linus.
This catches driver bugs that could cause corruption on IOMMU architectures.
Also I converted the BUGs to out_of_line_bug()s to save a bit
of text space.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
