Provides kernel modules a way to register custom page fault handlers.
On every page fault this will call a list of registered functions. The
functions may handle the fault and force do_page_fault() to return
immediately.
This functionality is similar to the now removed page fault notifiers.
Custom page fault handlers are used by debugging and reverse engineering
tools. Mmiotrace is one such tool and a patch to add it into the tree
will follow.
The custom page fault handlers are called earlier in do_page_fault()
than the page fault notifiers were.
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
So Ingo finally did figure out why UML broke with this option: UML
passes gcc the -fno-unit-at-a-time flag, and apparently that wreaks
havoc with gcc's inlining.
We could turn off -fno-unit-at-a-time for UML for gcc4+ (which is what
x86 does), but there's bad blood about this whole option, and it does
show that the thing is just fragile as heck.
So let tempers cool, and disable the thing, and we can revisit the
decision later.
Cc: Adrian Bunk <bunk@kernel.org>
Cc: David Miller <davem@davemloft.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Switch back to 8K stacks as the safer default. Out-of-memory
situations are less problematic than silent and hard to debug
stack corruption.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Andrew noticed that OPTIMIZE_INLINING appeared in the toplevel
menu - fix it.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
add CONFIG_OPTIMIZE_INLINING=y.
allow gcc to optimize the kernel image's size by uninlining
functions that have been marked 'inline'. Previously gcc was
forced by Linux to always-inline these functions via a gcc
attribute:
#define inline inline __attribute__((always_inline))
Especially when the user has already selected
CONFIG_OPTIMIZE_FOR_SIZE=y this can make a huge difference in
kernel image size (using a standard Fedora .config):
text data bss dec hex filename
5613924 562708 3854336 10030968 990f78 vmlinux.before
5486689 562708 3854336 9903733 971e75 vmlinux.after
that's a 2.3% text size reduction (!).
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch introduces a restriction on /dev/mem: Only non-memory can be
read or written unless the newly introduced config option is set.
The X server needs access to /dev/mem for the PCI space, but it doesn't need
access to memory; both the file permissions and SELinux permissions of /dev/mem
just make X effectively super-super powerful. With the exception of the
BIOS area, there's just no valid app that uses /dev/mem on actual memory.
Other popular users of /dev/mem are rootkits and the like.
(note: mmap access of memory via /dev/mem was already not allowed since
a really long time)
People who want to use /dev/mem for kernel debugging can enable the config
option.
The restrictions of this patch have been in the Fedora and RHEL kernels for
at least 4 years without any problems.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
These new controls toggle experimental support for a new CPU feature,
the straightforward extension of largepages from the pmd level to the
pud level, which allows 1GB (kernel) TLBs instead of 2MB TLBs.
Turn it off by default, as this code has not been tested well enough yet.
Use the CONFIG_DIRECT_GBPAGES=y .config option or gbpages on the
boot line can be used to enable it. If enabled in the .config then
nogbpages boot option disables it.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Clean up the page table dumper (fix boundary conditions, table driven
address ranges, some formatting changes since it is no longer using
the kernel log but a separate virtual file), and generalize to 32
bits.
[ mingo@elte.hu: x86: fix the pagetable dumper ]
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This patch adds code to the kernel to have an (optional)
/proc/kernel_page_tables debug file that basically dumps the kernel
pagetables; this allows us kernel developers to verify that nothing fishy is
going on and that the various mappings are set up correctly. This was quite
useful in finding various change_page_attr() bugs, and is very likely to be
useful in the future as well.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: mingo@elte.hu
Cc: tglx@tglx.de
Cc: hpa@zytor.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
change back the IO delay to 0x80.
Alan says that 0xed is known to break some older boxes, and given that
the get-rid-of-outb-APIs efforts are well underway we should just let
them be finished.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Now, that the page pool is in place we can enable DEBUG_PAGEALLOC on
64bit.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
delay the CPA self-test so that any impact (corruption) of
user-space pagetables can be triggered. Repeat the test
every 30 seconds.
this would have prevented the bug fixed by 8cb2a7c1e9,
at its source.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
make CONFIG_DEBUG_PAGEALLOC universally available.
CONFIG_HIBERNATION and CONFIG_HUGETLBFS was disabling it, for no
particular reason.
If there are any unfixed bugs here we'll fix it, but do not disable
vital debugging facilities like that ..
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
When CONFIG_DEBUG_RODATA is enabled undo the ro mapping and redo it again.
This gives some simple testing for change_page_attr().
Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
fix kconfig text and make DEBUG_RODATA default.
this helps debugging quite a bit.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Provide a means to trap usages of per_cpu map variables before
they are setup. Define CONFIG_DEBUG_PER_CPU_MAPS to activate.
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This patch export the boot parameters via debugfs for debugging.
The files added are as follow:
boot_params/data : binary file for struct boot_params
boot_params/version : boot protocol version
This patch is based on 2.6.24-rc5-mm1 and has been tested on i386 and
x86_64 platform.
This patch is based on the Peter Anvin's proposal.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Combine the 32 and 64 bit specific Makefiles in one file.
While doing so link order was (almost) preserved on 32 bit
but on 64 bit link order changed a lot.
Patch was checked with defconfig + allyesconfig builds.
The same .o files were linked in these configurations.
To keep readability of the Makefiles a few Kconfig
symbols was added/modified and it was checked that
they were not used anywhere else.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
make io_delay=0xed the default. This frees up port 0x80 which is
a debug port on some machines and locks up certain laptops.
Testing only for now. Try the io_delay=0x80 boot option if this does not
work for you.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
various changes to the in_p/out_p delay details:
- add the io_delay=none method
- make each method selectable from the kernel config
- simplify the delay code a bit by getting rid of an indirect function call
- add the /proc/sys/kernel/io_delay_type sysctl
- change 'io_delay=standard|alternate' to io_delay=0x80 and io_delay=0xed
- make the io delay config not depend on CONFIG_DEBUG_KERNEL
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: "David P. Reed" <dpreed@reed.com>
x86: provide a DMI based port 0x80 I/O delay override.
Certain (HP) laptops experience trouble from our port 0x80 I/O delay
writes. This patch provides for a DMI based switch to the "alternate
diagnostic port" 0xed (as used by some BIOSes as well) for these.
David P. Reed confirmed that port 0xed works for him and provides a
proper delay. The symptoms of _not_ working are a hanging machine,
with "hwclock" use being a direct trigger.
Earlier versions of this attempted to simply use udelay(2), with the
2 being a value tested to be a nicely conservative upper-bound with
help from many on the linux-kernel mailinglist but that approach has
two problems.
First, pre-loops_per_jiffy calibration (which is post PIT init while
some implementations of the PIT are actually one of the historically
problematic devices that need the delay) udelay() isn't particularly
well-defined. We could initialise loops_per_jiffy conservatively (and
based on CPU family so as to not unduly delay old machines) which
would sort of work, but...
Second, delaying isn't the only effect that a write to port 0x80 has.
It's also a PCI posting barrier which some devices may be explicitly
or implicitly relying on. Alan Cox did a survey and found evidence
that additionally some drivers may be racy on SMP without the bus
locking outb.
Switching to an inb() makes the timing too unpredictable and as such,
this DMI based switch should be the safest approach for now. Any more
invasive changes should get more rigid testing first. It's moreover
only very few machines with the problem and a DMI based hack seems
to fit that situation.
This also introduces a command-line parameter "io_delay" to override
the DMI based choice again:
io_delay=<standard|alternate>
where "standard" means using the standard port 0x80 and "alternate"
port 0xed.
This retains the udelay method as a config (CONFIG_UDELAY_IO_DELAY) and
command-line ("io_delay=udelay") choice for testing purposes as well.
This does not change the io_delay() in the boot code which is using
the same port 0x80 I/O delay but those do not appear to be a problem
as David P. Reed reported the problem was already gone after using the
udelay version. He moreover reported that booting with "acpi=off" also
fixed things and seeing as how ACPI isn't touched until after this DMI
based I/O port switch I believe it's safe to leave the ones in the boot
code be.
The DMI strings from David's HP Pavilion dv9000z are in there already
and we need to get/verify the DMI info from other machines with the
problem, notably the HP Pavilion dv6000z.
This patch is partly based on earlier patches from Pavel Machek and
David P. Reed.
Signed-off-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This patch renames the IOMMU config option to GART_IOMMU because in fact it
means the GART and not general support for an IOMMU on x86.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Acked-by: Muli Ben-Yehuda <muli@il.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Adding proper dependencies so the two Kconfig.debug files
are now identical and move the result file to x86.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
