I've noticed some erratic behavior while testing the X86_64 version
of monotonic_clock().
While spinning in a loop reading monotonic clock values (pinned to a
single cpu) I noticed that the difference between subsequent values
occasionally went negative (time going backwards).
I found that in the following code:
this_offset = get_cycles_sync();
/* FIXME: 1000 or 1000000? */
--> offset = (this_offset - last_offset)*1000 / cpu_khz;
}
return base + offset;
the offset sometimes turns out to be 0, even though
this_offset > last_offset.
+Added fix From: Toyo Abe <toyoa@mvista.com>
The x86_64-mm-monotonic-clock.patch in 2.6.18-rc4-mm2 made a change to
the updating of monotonic_base. It now uses cycles_2_ns().
I suggest that a set_cyc2ns_scale() should be done prior to the setup_irq().
Because cycles_2_ns() can be called from the timer ISR right after the irq0
is enabled.
This patch moves the entry.S:error_entry to .kprobes.text section,
since code marked unsafe for kprobes jumps directly to entry.S::error_entry,
that must be marked unsafe as well.
This patch also moves all the ".previous.text" asm directives to ".previous"
for kprobes section.
AK: Following a similar i386 patch from Chuck Ebbert
AK: Also merged Jeremy's fix in.
+From: Jeremy Fitzhardinge <jeremy@goop.org>
KPROBE_ENTRY does a .section .kprobes.text, and expects its users to
do a .previous at the end of the function.
Unfortunately, if any code within the function switches sections, for
example .fixup, then the .previous ends up putting all subsequent code
into .fixup. Worse, any subsequent .fixup code gets intermingled with
the code its supposed to be fixing (which is also in .fixup). It's
surprising this didn't cause more havok.
The fix is to use .pushsection/.popsection, so this stuff nests
properly. A further cleanup would be to get rid of all
.section/.previous pairs, since they're inherently fragile.
+From: Chuck Ebbert <76306.1226@compuserve.com>
Because code marked unsafe for kprobes jumps directly to
entry.S::error_code, that must be marked unsafe as well.
The easiest way to do that is to move the page fault entry
point to just before error_code and let it inherit the same
section.
Also moved all the ".previous" asm directives for kprobes
sections to column 1 and removed ".text" from them.
Dave Jones [Tue, 26 Sep 2006 08:52:34 +0000 (10:52 +0200)]
[PATCH] i386: don't taint UP K7's running SMP kernels.
We have a test that looks for invalid pairings of certain athlon/durons
that weren't designed for SMP, and taint accordingly (with 'S') if we find
such a configuration. However, this test shouldn't fire if there's only
a single CPU present. It's perfectly valid for an SMP kernel to boot on UP
hardware for example.
AK: changed to num_possible_cpus()
Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Andi Kleen <ak@suse.de>
[PATCH] i386: fix dubious segment register clear in cpu_init()
Fix a very dubious piece of code in
arch/i386/kernel/cpu/common.c:cpu_init(). This clears out %fs and
%gs, but clobbers %eax in the process without telling gcc. It turns
out that gcc happens to be not using %eax at that point anyway so it
doesn't matter much, but it looks like a bomb waiting to go off.
This does end up saving an instruction, because gcc wants %eax==0 for
the set_debugreg()s below.
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andi Kleen <ak@suse.de>
Following x86-64 patches. Reuses code from them in fact.
Convert the standard backtracer to do all output using
callbacks. Use the x86-64 stack tracer implementation
that uses these callbacks to implement the stacktrace interface.
This allows to use the new dwarf2 unwinder for stacktrace
and get better backtraces.
This unifies the standard backtracer and the new stacktrace
in memory backtracer. The standard one is converted to use callbacks
and then reimplement stacktrace using new callbacks.
The main advantage is that stacktrace can now use the new dwarf2 unwinder
and avoid false positives in many cases.
I kept it simple to make sure the standard backtracer stays reliable.
[PATCH] Don't access the APIC in safe_smp_processor_id when it is not mapped yet
Lockdep can call the dwarf2 unwinder early, and the dwarf2 code
uses safe_smp_processor_id which tries to access the local APIC page.
But that doesn't work before the APIC code has set up its fixmap.
Check for this case and always return boot cpu then.
tce_cache_blast_stress was useful during bringup to stress the IOMMU's
cache flushing. Now that we quiesce DMAs on every cache flush, using
_stress() brings the machine down to its knees once you put it under
load. Remove this debug / bringup code that isn't useful anymore
completely.
[PATCH] only verify the allocation bitmap if CONFIG_IOMMU_DEBUG is on
Introduce new function verify_bit_range(). Define two versions, one
for CONFIG_IOMMU_DEBUG enabled and one for disabled. Previously we
were checking that the bitmap was consistent every time we allocated
or freed an entry in the TCE table, which is good for debugging but
incurs an unnecessary penalty on non debug builds.
[PATCH] Replace local_save_flags+local_irq_disable with
The combination of "local_save_flags" and "local_irq_disable" seems to be
equivalent to "local_irq_save" (see code snips below). Consequently, replace
occurrences of local_save_flags+local_irq_disable with local_irq_save.
* local_irq_save
#define raw_local_irq_save(flags) \
do { (flags) = __raw_local_irq_save(); } while (0)
static inline unsigned long __raw_local_irq_save(void)
{
unsigned long flags = __raw_local_save_flags();
raw_local_irq_disable();
return flags;
}
* local_save_flags
#define raw_local_save_flags(flags) \
do { (flags) = __raw_local_save_flags(); } while (0)
Signed-off-by: Fernando Vazquez <fernando@intellilink.co.jp> Signed-off-by: Andi Kleen <ak@suse.de>
Requires earlier i386 patchkit, but also fixes i386 early_printk again.
I removed some obsolete really early parameters which didn't do anything useful.
Also made a few parameters that needed it early (mostly oops printing setup)
Also removed one panic check that wasn't visible without
early console anyways (the early console is now initialized after that
panic)
Rusty Russell [Tue, 26 Sep 2006 08:52:32 +0000 (10:52 +0200)]
[PATCH] i386: Replace i386 open-coded cmdline parsing with
This patch replaces the open-coded early commandline parsing
throughout the i386 boot code with the generic mechanism (already used
by ppc, powerpc, ia64 and s390). The code was inconsistent with
whether it deletes the option from the cmdline or not, meaning some of
these will get passed through the environment into init.
This transformation is mainly mechanical, but there are some notable
parts:
1) Grammar: s/linux never set's it up/linux never sets it up/
2) Remove hacked-in earlyprintk= option scanning. When someone
actually implements CONFIG_EARLY_PRINTK, then they can use
early_param().
[AK: actually it is implemented, but I'm adding the early_param it in the next
x86-64 patch]
3) Move declaration of generic_apic_probe() from setup.c into asm/apic.h
4) Various parameters now moved into their appropriate files (thanks Andi).
5) All parse functions which examine arg need to check for NULL,
except one where it has subtle humor value.
AK: readded acpi_sci handling which was completely dropped
AK: moved some more variables into acpi/boot.c
Cc: len.brown@intel.com Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andi Kleen <ak@suse.de>
Rusty Russell [Tue, 26 Sep 2006 08:52:32 +0000 (10:52 +0200)]
[PATCH] Allow early_param and identical __setup to exist
We currently assume that boot parameters which are handled by
early_param() will not overlap boot parameters handled by __setup: if
they do, behaviour is dependent on link order, usually meaning __setup
will not get called.
ACPI wants to use early_param("pci"), and pci uses __setup("pci="), so
we modify the core to let them coexist: "pci=noacpi" will now get
passed to both.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andi Kleen <ak@suse.de>
[PATCH] remove superflous BUG_ON's in nommu and gart
There's no need to check for invalid DMA data direction in nommu and
gart since we do it in dma-mapping.h anyway before calling the
individual dma-ops.
- Inline spinlock strings into their inline functions
- Convert macros to typesafe inlines
- Replace some leftover __asm__ __volatile__s with asm volatile
- Inline spinlock strings into their inline functions
- Convert macros to typesafe inlines
- Replace some leftover __asm__ __volatile__s with asm volatile
[PATCH] Calgary IOMMU: fix reference counting of Calgary PCI devices
The pci_get_device() API decrements the reference count on the 'from'
parameter when it continues searching. Therefore, take a ref count on
Calgary bus when we initialize them in either translated or
non-translated mode.
[PATCH] Calgary IOMMU: consolidate per bus data structures
Move the tce_table_kva array, disabled bitmap and bus_to_phb array
into a new per bus 'struct calgary_bus_info'. Also slightly reorganize
build_tce_table and tce_table_setparms to avoid exporting bus_info to
tce.c.
Jan Beulich [Tue, 26 Sep 2006 08:52:31 +0000 (10:52 +0200)]
[PATCH] i386: initialize end-of-memory variables as early as possible
Move initialization of all memory end variables to as early as
possible, so that dependent code doesn't need to check whether these
variables have already been set.
Change the range check in kunmap_atomic to actually make use of this
so that the no-mapping-estabished path (under CONFIG_DEBUG_HIGHMEM)
gets used only when the address is inside the lowmem area (and BUG()
otherwise).
Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de>
Jan Beulich [Tue, 26 Sep 2006 08:52:31 +0000 (10:52 +0200)]
[PATCH] initialize end of memory variables as early as possible
While an earlier patch already did a small step into that direction,
this patch moves initialization of all memory end variables to as
early as possible, so that dependent code doesn't need to check
whether these variables have already been set.
Also, remove a misleading (perhaps just outdated) comment, and make
static a variable only used in a single file.
Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de>
[PATCH] x86: Detect CFI support in the assembler at runtime
... instead of using a CONFIG option. The config option still controls
if the resulting executable actually has unwind information.
This is useful to prevent compilation errors when users select
CONFIG_STACK_UNWIND on old binutils and also allows to use
CFI in the future for non kernel debugging applications.
The MPS table specification says that the operating system should
renumber the IO-APICs following the table as needed. However in
ACPI this is not allowed or neeeded and all x86-64 systems are ACPI
compliant.
The code was already disabled on some systems because it caused
problems there. Remove it completely now.
Diego Calleja [Tue, 26 Sep 2006 08:52:30 +0000 (10:52 +0200)]
[PATCH] x86: AUX_DEVICE_INFO is one byte long, use 'movb'
Bugzilla #6552 says:
"In arch/i386/boot/setup.S, movw is used instead of movb for PS/2 mouse
information, although it is unsigned char. This does not harm, because
the jmp instruction overwritten by movw is used before executing movw,
and never be used again"
I've no idea if this is a real bug or how it gets fixed, so I'm submitting
it for review instead of letting it die of boredom in bugzilla. Aditionally
to i386, I've changed x86-64, which mirrors the same code.
Credits to Yoshinori K. Okuji, who found the problem and suggested a fix.
Signed-off-by: Diego Calleja <diegocg@gmail.com> Signed-off-by: Andi Kleen <ak@suse.de>
- Convert CR* accesses to dedicated inline functions and rewrite
the rest as C inlines
- Don't do a double flush for global flushes (pointed out by Zach Amsden)
This was a bug workaround for old CPUs that don't do 64bit and is obsolete.
- Add a proper memory clobber to invlpg
- Remove an unused extern
[PATCH] i386: Redo semaphore and rwlock assembly helpers
- Move them to a pure assembly file. Previously they were in
a C file that only consisted of inline assembly. Doing it in pure
assembler is much nicer.
- Add a frame.i include with FRAME/ENDFRAME macros to easily
add frame pointers to assembly functions
- Add dwarf2 annotation to them so that the new dwarf2 unwinder
doesn't get stuck on them
- Random cleanups
Includes feedback from Jan Beulich and a UML build fix from Andrew
Morton.
[PATCH] i386: add alternative-asm.h to allow LOCK_PREFIX replacement in .S files
LOCK_PREFIX is replaced by nops on UP systems, so it has to be a special
macro. Previously this was only possible from C. Allow it for pure
assembly files too. Similar to earlier x86-64 patch. Signed-off-by: Andi Kleen <ak@suse.de>
- Move the slow path fallbacks to their own assembly files
This makes them much easier to read and is needed for the next change.
- Add CFI annotations for unwinding (XXX need review)
- Remove constant case which can never happen with out of line spinlocks
- Use patchable LOCK prefixes
- Don't use lock sections anymore for inline code because they can't
be expressed by the unwinder (this adds one taken jump to the lock
fast path)
[PATCH] i386: Account spinlocks to the caller during profiling for !FP kernels
This ports the algorithm from x86-64 (with improvements) to i386.
Previously this only worked for frame pointer enabled kernels.
But spinlocks have a very simple stack frame that can be manually
analyzed. Do this.
Adam Henley [Tue, 26 Sep 2006 08:52:28 +0000 (10:52 +0200)]
[PATCH] A few trivial spelling and grammar fixes
A few trivial spelling and grammar mistakes picked up in
"arch/x86_64/aperture.c", "arch/x86_64/crash.c" and
"arch/x86_64/apic.c". I think all are correct fixes but am ever aware
of my fallibility :o) This is my first patch submission so all
feedback is appreciated, esp. WRT CCing to Linus, Andi and
trivial@kernel.org, is this correct? And which is the most appropriate
kernel version to diff against? If any.
Should apply cleanly to 2.6.18-rc1
Signed-off-by: Adam Henley <adamazing@gmail.com> Signed-off-by: Andi Kleen <ak@suse.de>
- adam
[PATCH] x86-64 TIF flags for debug regs and io bitmap in ctxsw
Hello,
Following my discussion with Andi. Here is a patch that introduces
two new TIF flags to simplify the context switch code in __switch_to().
The idea is to minimize the number of cache lines accessed in the common
case, i.e., when neither the debug registers nor the I/O bitmap are used.
This patch covers the x86-64 modifications. A patch for i386 follows.
Changelog:
- add TIF_DEBUG to track when debug registers are active
- add TIF_IO_BITMAP to track when I/O bitmap is used
- modify __switch_to() to use the new TIF flags
For NUMA optimization and some other algorithms it is useful to have a fast
to get the current CPU and node numbers in user space.
x86-64 added a fast way to do this in a vsyscall. This adds a generic
syscall for other architectures to make it a generic portable facility.
I expect some of them will also implement it as a faster vsyscall.
The cache is an optimization for the x86-64 vsyscall optimization. Since
what the syscall returns is an approximation anyways and user space
often wants very fast results it can be cached for some time. The norma
methods to get this information in user space are relatively slow
The vsyscall is in a better position to manage the cache because it has direct
access to a fast time stamp (jiffies). For the generic syscall optimization
it doesn't help much, but enforce a valid argument to keep programs
portable
I only added an i386 syscall entry for now. Other architectures can follow
as needed.
This patch adds a vgetcpu vsyscall, which depending on the CPU RDTSCP
capability uses either the RDTSCP or CPUID to obtain a CPU and node
numbers and pass them to the program.
AK: Lots of changes over Vojtech's original code:
Better prototype for vgetcpu()
It's better to pass the cpu / node numbers as separate arguments
to avoid mistakes when going from SMP to NUMA.
Also add a fast time stamp based cache using a user supplied
argument to speed things more up.
Use fast method from Chuck Ebbert to retrieve node/cpu from
GDT limit instead of CPUID
Made sure RDTSCP init is always executed after node is known.
Drop printk
[PATCH] Add initalization of the RDTSCP auxilliary values
This patch adds initalization of the RDTSCP auxilliary values to CPU numbers
to time.c. If RDTSCP is available, the MSRs are written with the respective
values. It can be later used to initalize per-cpu timekeeping variables.
AK: Some cleanups. Move externs into headers and fix CPU hotplug.
projects / linux-2.6 / log