[PATCH] x86: Allow disabling early pci scans with pci=noearly or disallowing conf1
Some buggy systems can machine check when config space accesses
happen for some non existent devices. i386/x86-64 do some early
device scans that might trigger this. Allow pci=noearly to disable
this. Also when type 1 is disabling also don't do any early
accesses which are always type1.
This moves the pci= configuration parsing to be a early parameter.
I don't think this can break anything because it only changes
a single global that is only used by PCI.
Jan Beulich [Tue, 26 Sep 2006 08:52:41 +0000 (10:52 +0200)]
[PATCH] i386/x86-64: Work around gcc bug with noreturn functions in unwinder
Current gcc generates calls not jumps to noreturn functions. When that happens the
return address can point to the next function, which confuses the unwinder.
This patch works around it by marking asynchronous exception
frames in contrast normal call frames in the unwind information. Then teach
the unwinder to decode this.
For normal call frames the unwinder now subtracts one from the address which avoids
this problem. The standard libgcc unwinder uses the same trick.
It doesn't include adjustment of the printed address (i.e. for the original
example, it'd still be kernel_math_error+0 that gets displayed, but the
unwinder wouldn't get confused anymore.
This only works with binutils 2.6.17+ and some versions of H.J.Lu's 2.6.16
unfortunately because earlier binutils don't support .cfi_signal_frame
[AK: added automatic detection of the new binutils and wrote description]
Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de>
[PATCH] Don't synchronize time reading on single core AMD systems
We do some additional CPU synchronization in gettimeofday et.al. to make
sure the time stamps are always monotonic over multiple CPUs. But on
single core systems that is not needed. So don't do it.
Matthew Garrett [Tue, 26 Sep 2006 08:52:41 +0000 (10:52 +0200)]
[PATCH] x86: - restore i8259A eoi status on resume
Got it. i8259A_resume calls init_8259A(0) unconditionally, even if
auto_eoi has been set. Keep track of the current status and restore that
on resume. This fixes it for AMD64 and i386.
Signed-off-by: Matthew Garrett <mjg59@srcf.ucam.org> Signed-off-by: Andi Kleen <ak@suse.de>
Dave Jones [Tue, 26 Sep 2006 08:52:41 +0000 (10:52 +0200)]
[PATCH] i386: Split multi-line printk in oops output.
Sometimes, bug reports come in where we've had an oops, and the
only record we have is what the reporter saw on screen shortly
before the system locked up completely. Unfortunatly, syslog
only prints lines beginning with KERN_EMERG to the console, so
some lines get lost.
An example of this can be seen at https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=203723
Some of this information isn't vital to diagnosis, but some parts
are useful, such as the tainted flag.
Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Andi Kleen <ak@suse.de>
On Sat, Sep 09, 2006 at 04:14:29PM +0200, Andi Kleen wrote:
> [patch] Looks reasonable, but probably not for 2.6.18 because this stuff
> is already too fragile and it is probably too risky to do any big changes now
> since not enough testing time is left. Can you please resubmit
> it with proper description and signed-off-by line? I can queue it for .19 then
>
> -Andi
Patch inserts PCI memory mapped config region(s) into the resource map. This
will allow for the MMCCONFIG regions to be marked as busy in the iomem
address space as well as the regions(s) showing up in /proc/iomem.
Patch inserts the GART region into the iomem resource map. The GART will then
be visible within /proc/iomem. It will also allow for other users
utilizing the GART to subreserve the region (agp or IOMMU).
[PATCH] i386/x86-64: Only do MCFG e820 check when type 1 works
Needs earlier patch to split type 1 probing from use.
This patch should fix the x86 macs where type 1 PCI config space access
doesn't work, but MCFG does. They also don't have a usable e820 table
so the e820 sanity check failed.
Instead assume now that if type 1 doesn't work then MCFG must work
and don't do the e820 check.
Previously exit_idle would be called more often than enter_idle
Now instead of using complicated tests just keep track of it
using the per CPU variable as a flip flop. I moved the idle state into the
PDA to make the access more efficient.
Original bug report and an initial patch from Stephane Eranian,
but redone by AK.
kexec has been marked experimental for a year now and all
of the serious problems have been worked through. So it
is time (if not past time) to remove the experimental mark.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andi Kleen <ak@suse.de>
kexec has been marked experimental for a year now and all
of the serious problems have been worked through. So it
is time (if not past time) to remove the experimental mark.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andi Kleen <ak@suse.de>
[PATCH] Mark per cpu data initialization __initdata again
Before 2.6.16 this was changed to work around code that accessed
CPUs not in the possible map. But that code should be all fixed now,
so mark it __initdata again. Signed-off-by: Andi Kleen <ak@suse.de>
[PATCH] Check return value of copy_to_user in compat_sys_pselect7
Fix
linux/fs/compat.c: In function compat_sys_pselect7
linux/fs/compat.c:1869: warning: ignoring return value of copy_to_user, declared with attribute warn_unused_result
To make it easier to handle I changed to semantics to not try to
write out a timespec if an error occurred. I hope that's ok.
- Don't zero for __copy_from_user_inatomic following i386.
This will prevent spurious zeros for parallel file system writers when
one does a exception
- The string instruction version didn't zero the output on
exception. Oops.
Also I cleaned up the code a bit while I was at it and added a minor
optimization to the string instruction path.
Rusty Russell [Tue, 26 Sep 2006 08:52:39 +0000 (10:52 +0200)]
[PATCH] i386: Allow a kernel not to be in ring 0
We allow for the fact that the guest kernel may not run in ring 0. This
requires some abstraction in a few places when setting %cs or checking
privilege level (user vs kernel).
This is Chris' [RFC PATCH 15/33] move segment checks to subarch, except rather
than using #define USER_MODE_MASK which depends on a config option, we use
Zach's more flexible approach of assuming ring 3 == userspace. I also used
"get_kernel_rpl()" over "get_kernel_cs()" because I think it reads better in
the code...
1) Remove the hardcoded 3 and introduce #define SEGMENT_RPL_MASK 3 2) Add a
get_kernel_rpl() macro, and don't assume it's zero.
And:
Clean up of patch for letting kernel run other than ring 0:
a. Add some comments about the SEGMENT_IS_*_CODE() macros.
b. Add a USER_RPL macro. (Code was comparing a value to a mask
in some places and to the magic number 3 in other places.)
c. Add macros for table indicator field and use them.
d. Change the entry.S tests for LDT stack segment to use the macros
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Andi Kleen <ak@suse.de>
Rusty Russell [Tue, 26 Sep 2006 08:52:39 +0000 (10:52 +0200)]
[PATCH] i386: Abstract sensitive instructions
Abstract sensitive instructions in assembler code, replacing them with macros
(which currently are #defined to the native versions). We use long names:
assembler is case-insensitive, so if something goes wrong and macros do not
expand, it would assemble anyway.
Resulting object files are exactly the same as before.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Andi Kleen <ak@suse.de>
[PATCH] Fix a PDA warning uncovered by the new type checking
Fix
linux/arch/x86_64/kernel/process.c: In function __switch_to:
linux/arch/x86_64/kernel/process.c:626: warning: assignment makes integer from pointer without a cast
I just added type checking for assignments the PDA in the i386 PDA code.
Here's the x86-64 equivalent. (Obviously this doesn't contain the latest
x86-64 PDA change.)
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andi Kleen <ak@suse.de>
Arjan van de Ven [Tue, 26 Sep 2006 08:52:39 +0000 (10:52 +0200)]
[PATCH] Add the -fstack-protector option to the CFLAGS
Add a feature check that checks that the gcc compiler has stack-protector
support and has the bugfix for PR28281 to make this work in kernel mode.
The easiest solution I could find was to have a shell script in scripts/
to do the detection; if needed we can make this fancier in the future
without making the makefile too complex.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andi Kleen <ak@suse.de> CC: Andi Kleen <ak@suse.de> CC: Sam Ravnborg <sam@ravnborg.org>
Arjan van de Ven [Tue, 26 Sep 2006 08:52:38 +0000 (10:52 +0200)]
[PATCH] Add the canary field to the PDA area and the task struct
This patch adds the per thread cookie field to the task struct and the PDA.
Also it makes sure that the PDA value gets the new cookie value at context
switch, and that a new task gets a new cookie at task creation time.
Signed-off-by: Arjan van Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andi Kleen <ak@suse.de> CC: Andi Kleen <ak@suse.de>
Arjan van de Ven [Tue, 26 Sep 2006 08:52:38 +0000 (10:52 +0200)]
[PATCH] Add comments to the PDA structure to annotate offsets
Change the comments in the pda structure to make the first fields to have
their offset documented and to have the comments aligned.
The stack protector series needs a field at offset 40 (gcc ABI); annotate
upto 40 for that reason.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andi Kleen <ak@suse.de> CC: Andi Kleen <ak@suse.de>
Magnus Damm [Tue, 26 Sep 2006 08:52:38 +0000 (10:52 +0200)]
[PATCH] i386: Avoid overwriting the current pgd (V4, i386)
kexec: Avoid overwriting the current pgd (V4, i386)
This patch upgrades the i386-specific kexec code to avoid overwriting the
current pgd. Overwriting the current pgd is bad when CONFIG_CRASH_DUMP is used
to start a secondary kernel that dumps the memory of the previous kernel.
The code introduces a new set of page tables. These tables are used to provide
an executable identity mapping without overwriting the current pgd.
Signed-off-by: Magnus Damm <magnus@valinux.co.jp> Signed-off-by: Andi Kleen <ak@suse.de>
Magnus Damm [Tue, 26 Sep 2006 08:52:38 +0000 (10:52 +0200)]
[PATCH] Avoid overwriting the current pgd (V4, x86_64)
kexec: Avoid overwriting the current pgd (V4, x86_64)
This patch upgrades the x86_64-specific kexec code to avoid overwriting the
current pgd. Overwriting the current pgd is bad when CONFIG_CRASH_DUMP is used
to start a secondary kernel that dumps the memory of the previous kernel.
The code introduces a new set of page tables. These tables are used to provide
an executable identity mapping without overwriting the current pgd.
Signed-off-by: Magnus Damm <magnus@valinux.co.jp> Signed-off-by: Andi Kleen <ak@suse.de>
H. Peter Anvin [Tue, 26 Sep 2006 08:52:38 +0000 (10:52 +0200)]
[PATCH] i386: Fix the EDD code misparsing the command line
The EDD code would scan the command line as a fixed array, without
taking account of either whitespace, null-termination, the old
command-line protocol, late overrides early, or the fact that the
command line may not be reachable from INITSEG.
This should fix those problems, and enable us to use a longer command
line.
Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Andi Kleen <ak@suse.de>
Replace the volatiles and memory clobbers in the PDA access with
telling gcc about access to a proxy PDA structure that doesn't
actually exist. But the dummy accesses give a defined ordering for
read/write accesses.
Also add some memory barriers to the early GS initialization to
make sure no PDA access is moved before it.
Advantage is some .text savings (probably most from better
code for accessing "current"):
Ian Campbell [Tue, 26 Sep 2006 08:52:38 +0000 (10:52 +0200)]
[PATCH] Put .note.* sections into a PT_NOTE segment
This patch updates x86_64 linker script to pack any .note.* sections
into a PT_NOTE segment in the output file.
To do this, we tell ld that we need a PT_NOTE segment. This requires
us to start explicitly mapping sections to segments, so we also need
to explicitly create PT_LOAD segments for text and data, and map the
sections to them appropriately. Fortunately, each section will
default to its previous section's segment, so it doesn't take many
changes to vmlinux.lds.S.
The corresponding change is already made for i386 in -mm and I'd like
this patch to join it. The section to segment mappings do change as do
the segment flags so some time in -mm would be good for that reason as
well, just in case.
In particular .data and .bss move from the text segment to the data
segment and .data.cacheline_aligned .data.read_mostly are put in the
data segment instead of a separate one.
I think that it would be possible to exactly match the existing section
to segment mapping and flags but it would be a more intrusive change and
I'm not sure there is a reason for the existing layout other than it is
what you get by default if you don't explicitly specify something else.
If there is a reason for the existing layout then I will of course make
the more intrusive change. If there is no reason we could probably drop
the executable or writable flags from some segments but I don't know how
much attention is paid to them anyway so it might not be worth the
effort.
The vsyscall related sections need to go in a different segment to the
normal data segment and so I invented a "user" segment to contain them.
I believe this should appear to be another data segment as far as the
kernel is concerned so the flags are setup accordingly.
The notes will be used in the Xen paravirt_ops backend to provide
additional information to the domain builder. I am in the process of
converting the xen-unstable kernels and tools over to this scheme at the
moment to support this in the future.
It has been suggested to me that the notes segment should have flags 0
(i.e. not readable) since it is only used by the loader and is not used
at runtime. For now I went with a readable segment since that is what
the i386 patch uses.
AK: dropped NOTES addition right now because the needed infrastructure
for that is not merged yet
Signed-off-by: Ian Campbell <ian.campbell@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de>
In long mode the %cs is largely a relic. However there are a few cases
like iret where it matters that we have a valid value. Without this
patch it is possible to enter the kernel in startup_64 without setting
%cs to a valid value. With this patch we don't care what %cs value
we enter the kernel with, so long as the cs shadow register indicates
it is a privileged code segment.
Thanks to Magnus Damm for finding this problem and posting the
first workable patch. I have moved the jump to set %cs down a
few instructions so we don't need to take an extra jump. Which
keeps the code simpler.
Signed-of-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andi Kleen <ak@suse.de>
Based on patch from David Rientjes <rientjes@google.com>, but
changed by AK.
Optimizes the 64-bit hamming weight for x86_64 processors assuming they
have fast multiplication. Uses five fewer bitops than the generic
hweight64. Benchmark on one EMT64 showed ~25% speedup with 2^24
consecutive calls.
Define a new ARCH_HAS_FAST_MULTIPLIER that can be set by other
architectures that can also multiply fast.
When compiling a 64-bit kernel on an Ubuntu 6.06 32bit system (whose GCC is also
a cross-compiler for x86_64) I've seen that head.o is compiled as a 64-bit file
(while it should not) and ld complaining about this during linking:
[AK: it happens on all systems with new binutils]
ld: warning: i386:x86-64 architecture of input file
`arch/x86_64/boot/compressed/head.o' is incompatible with i386 output
I've verified that removing -m64 from compilation flags to turn
"-m64 -traditional -m32" into "-traditional -m32" fixes the issue.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andi Kleen <ak@suse.de>
[PATCH] Remove some cruft in apic id checking during processor setup
- Remove a define that was used only once
- Remove the too large APIC ID check because we always support
the full 8bit range of APICs.
- Restructure code a bit to be simpler.
ACPI went to great trouble to get the APIC version and CPU capabilities
of different CPUs before passing them to the mpparser. But all
that data was used was to print it out. Actually it even faked some data
based on the boot cpu, not on the actual CPU being booted.
[PATCH] Fix pte_exec/mkexec and use it in change_page_attr()
Fix the pte_exec/mkexec page table accessor functions to really
use the NX bit. Previously they only checked the USER bit, but
weren't actually used for anything.
Then use them in change_page_attr() to manipulate the NX bit
properly.
And replace all users with ordinary smp_processor_id. The function
was originally added to get some basic oops information out even
if the GS register was corrupted. However that didn't
work for some anymore because printk is needed to print the oops
and it uses smp_processor_id() already. Also GS register corruptions
are not particularly common anymore.
This also helps the Xen port which would otherwise need to
do this in a special way because it can't access the local APIC.
Cc: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andi Kleen <ak@suse.de>
Detect the situations in which the time after a resume from disk would
be earlier than the time before the suspend and prevent them from
happening on x86_64.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Andi Kleen <ak@suse.de>
[PATCH] i386: annotate FIX_STACK() and the rest of nmi()
In i386's entry.S, FIX_STACK() needs annotation because it
replaces the stack pointer. And the rest of nmi() needs
annotation in order to compile with these new annotations.
A kprobe executes IRET early and that could cause NMI recursion and stack
corruption.
Note: This problem was originally spotted and solved by Andi Kleen in the
x86_64 architecture. This patch is an adaption of his patch for i386.
AK: Merged with current code which was a bit different.
AK: Removed printk in nmi handler that shouldn't be there in the first time
AK: Added missing include.
AK: added KPROBES_END
Signed-off-by: Fernando Vazquez <fernando@intellilink.co.jp> Signed-off-by: Andi Kleen <ak@suse.de>
A kprobe executes IRET early and that could cause NMI recursion and stack
corruption.
Note: This problem was originally spotted by Andi Kleen. This patch
adds fixes not included in his original patch.
[AK: Jan Beulich originally discovered these classes of bugs]
Signed-off-by: Fernando Vazquez <fernando@intellilink.co.jp> Signed-off-by: Andi Kleen <ak@suse.de>
Magnus Damm [Tue, 26 Sep 2006 08:52:36 +0000 (10:52 +0200)]
[PATCH] i386: mark cpu cache functions as __cpuinit
Mark i386-specific cpu cache functions as __cpuinit. They are all
only called from arch/i386/common.c:display_cache_info() that already is
marked as __cpuinit.
Signed-off-by: Magnus Damm <magnus@valinux.co.jp> Signed-off-by: Andi Kleen <ak@suse.de>
Magnus Damm [Tue, 26 Sep 2006 08:52:36 +0000 (10:52 +0200)]
[PATCH] i386: mark cpu identify functions as __cpuinit
Mark i386-specific cpu identification functions as __cpuinit. They are all
only called from arch/i386/common.c:identify_cpu() that already is marked as
__cpuinit.
Signed-off-by: Magnus Damm <magnus@valinux.co.jp> Signed-off-by: Andi Kleen <ak@suse.de>
Magnus Damm [Tue, 26 Sep 2006 08:52:36 +0000 (10:52 +0200)]
[PATCH] i386: mark cpu init functions as __cpuinit, data as __cpuinitdata
Mark i386-specific cpu init functions as __cpuinit. They are all
only called from arch/i386/common.c:identify_cpu() that already is marked as
__cpuinit. This patch also removes the empty function init_umc().
Signed-off-by: Magnus Damm <magnus@valinux.co.jp> Signed-off-by: Andi Kleen <ak@suse.de>
Magnus Damm [Tue, 26 Sep 2006 08:52:36 +0000 (10:52 +0200)]
[PATCH] i386: mark cpu_dev structures as __cpuinitdata
The different cpu_dev structures are all used from __cpuinit callers what
I can tell. So mark them as __cpuinitdata instead of __initdata. I am a
little bit unsure about arch/i386/common.c:default_cpu, especially when it
comes to the purpose of this_cpu.
Signed-off-by: Magnus Damm <magnus@valinux.co.jp> Signed-off-by: Andi Kleen <ak@suse.de>
Magnus Damm [Tue, 26 Sep 2006 08:52:36 +0000 (10:52 +0200)]
[PATCH] i386: remove redundant generic_identify() calls when identifying cpus
cpu_dev->c_identify is only called from arch/i386/common.c:identify_cpu(), and
this after generic_identify() already has been called. There is no need to call
this function twice and hook it in c_identify - but I may be wrong, please
double check before applying.
This patch also removes generic_identify() from cpu.h to avoid unnecessary
future nesting.
Signed-off-by: Magnus Damm <magnus@valinux.co.jp> Signed-off-by: Andi Kleen <ak@suse.de>
Keith Mannthey [Tue, 26 Sep 2006 08:52:36 +0000 (10:52 +0200)]
[PATCH] x86_64 kernel mapping fix
Fix for the x86_64 kernel mapping code. Without this patch the update path
only inits one pmd_page worth of memory and tramples any entries on it. now
the calling convention to phys_pmd_init and phys_init is to always pass a
[pmd/pud] page not an offset within a page.
Signed-off-by: Keith Mannthey<kmannth@us.ibm.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@osdl.org>
Arjan van de Ven [Tue, 26 Sep 2006 08:52:36 +0000 (10:52 +0200)]
[PATCH] non lazy "sleazy" fpu implementation
Right now the kernel on x86-64 has a 100% lazy fpu behavior: after *every*
context switch a trap is taken for the first FPU use to restore the FPU
context lazily. This is of course great for applications that have very
sporadic or no FPU use (since then you avoid doing the expensive
save/restore all the time). However for very frequent FPU users... you
take an extra trap every context switch.
The patch below adds a simple heuristic to this code: After 5 consecutive
context switches of FPU use, the lazy behavior is disabled and the context
gets restored every context switch. If the app indeed uses the FPU, the
trap is avoided. (the chance of the 6th time slice using FPU after the
previous 5 having done so are quite high obviously).
After 256 switches, this is reset and lazy behavior is returned (until
there are 5 consecutive ones again). The reason for this is to give apps
that do longer bursts of FPU use still the lazy behavior back after some
time.
[akpm@osdl.org: place new task_struct field next to jit_keyring to save space] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org>
[PATCH] i386: Support physical cpu hotplug for x86_64
This patch enables ACPI based physical CPU hotplug support for x86_64.
Implements acpi_map_lsapic() and acpi_unmap_lsapic() to support physical cpu
hotplug.
Now for a completely different but trivial approach.
I just boot tested it with 255 CPUS and everything worked.
Currently everything (except module data) we place in
the per cpu area we know about at compile time. So
instead of allocating a fixed size for the per_cpu area
allocate the number of bytes we need plus a fixed constant
for to be used for modules.
It isn't perfect but it is much less of a pain to
work with than what we are doing now.
AK: fixed warning
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andi Kleen <ak@suse.de>
Rusty Russell [Tue, 26 Sep 2006 08:52:35 +0000 (10:52 +0200)]
[PATCH] i386: Descriptor and trap table cleanups.
The implementation comes from Zach's [RFC, PATCH 10/24] i386 Vmi
descriptor changes:
Descriptor and trap table cleanups. Add cleanly written accessors for
IDT and GDT gates so the subarch may override them. Note that this
allows the hypervisor to transparently tweak the DPL of the descriptors
as well as the RPL of segments in those descriptors, with no unnecessary
kernel code modification. It also allows the hypervisor implementation
of the VMI to tweak the gates, allowing for custom exception frames or
extra layers of indirection above the guest fault / IRQ handlers.
[PATCH] i386: move kernel_thread_helper into entry.S
And add proper CFI annotation to it which was previously
impossible. This prevents "stuck" messages by the dwarf2 unwinder
when reaching the top of a kernel stack.
linux/arch/i386/kernel/mpparse.c: In function #MP_bus_info#:
linux/arch/i386/kernel/mpparse.c:232: warning: comparison is always false due to limited range of data type
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>
projects / linux-beck.git / log