Commit Graph

35 Commits

Author SHA1 Message Date
Scott Wood 9d378dfac8 powerpc/booke64: Use SPRG7 for VDSO
Previously SPRG3 was marked for use by both VDSO and critical
interrupts (though critical interrupts were not fully implemented).

In commit 8b64a9dfb0 ("powerpc/booke64:
Use SPRG0/3 scratch for bolted TLB miss & crit int"), Mihai Caraman
made an attempt to resolve this conflict by restoring the VDSO value
early in the critical interrupt, but this has some issues:

 - It's incompatible with EXCEPTION_COMMON which restores r13 from the
   by-then-overwritten scratch (this cost me some debugging time).
 - It forces critical exceptions to be a special case handled
   differently from even machine check and debug level exceptions.
 - It didn't occur to me that it was possible to make this work at all
   (by doing a final "ld r13, PACA_EXCRIT+EX_R13(r13)") until after
   I made (most of) this patch. :-)

It might be worth investigating using a load rather than SPRG on return
from all exceptions (except TLB misses where the scratch never leaves
the SPRG) -- it could save a few cycles.  Until then, let's stick with
SPRG for all exceptions.

Since we cannot use SPRG4-7 for scratch without corrupting the state of
a KVM guest, move VDSO to SPRG7 on book3e.  Since neither SPRG4-7 nor
critical interrupts exist on book3s, SPRG3 is still used for VDSO
there.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: Mihai Caraman <mihai.caraman@freescale.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: kvm-ppc@vger.kernel.org
2014-03-19 19:57:14 -05:00
Anton Blanchard 24b659a138 powerpc: Use unstripped VDSO image for more accurate profiling data
We are seeing a lot of hits in the VDSO that are not resolved by perf.
A while(1) gettimeofday() loop shows the issue:

27.64%  [vdso]  [.] 0x000000000000060c
22.57%  [vdso]  [.] 0x0000000000000628
16.88%  [vdso]  [.] 0x0000000000000610
12.39%  [vdso]  [.] __kernel_gettimeofday
 6.09%  [vdso]  [.] 0x00000000000005f8
 3.58%  test    [.] 00000037.plt_call.gettimeofday@@GLIBC_2.18
 2.94%  [vdso]  [.] __kernel_datapage_offset
 2.90%  test    [.] main

We are using a stripped VDSO image which means only symbols with
relocation info can be resolved. There isn't a lot of point to
stripping the VDSO, the debug info is only about 1kB:

4680 arch/powerpc/kernel/vdso64/vdso64.so
5815 arch/powerpc/kernel/vdso64/vdso64.so.dbg

By using the unstripped image, we can resolve all the symbols in the
VDSO and the perf profile data looks much better:

76.53%  [vdso]  [.] __do_get_tspec
12.20%  [vdso]  [.] __kernel_gettimeofday
 5.05%  [vdso]  [.] __get_datapage
 3.20%  test    [.] main
 2.92%  test    [.] 00000037.plt_call.gettimeofday@@GLIBC_2.18

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-02-17 11:19:37 +11:00
Paul Gortmaker c141611fb1 powerpc: Delete non-required instances of include <linux/init.h>
None of these files are actually using any __init type directives
and hence don't need to include <linux/init.h>.  Most are just a
left over from __devinit and __cpuinit removal, or simply due to
code getting copied from one driver to the next.

The one instance where we add an include for init.h covers off
a case where that file was implicitly getting it from another
header which itself didn't need it.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-01-15 13:46:44 +11:00
Ulrich Weigand 280270828f powerpc: Wrong DWARF CFI in the kernel vdso for little-endian / ELFv2
I've finally tracked down why my CR signal-unwind test case still
fails on little-endian.  The problem turned to be that the kernel
installs a signal trampoline in the vDSO, and provides a DWARF CFI
record for that trampoline.  This CFI describes the save location
for CR:

  rsave (70, 38*RSIZE + (RSIZE - CRSIZE))

which is correct for big-endian, but points to the wrong word on
little-endian.   This is wrong no matter which ABI.

In addition, for the ELFv2 ABI, we should not only provide a CFI
record for register 70 (cr2), but for all CR fields separately.
Strictly speaking, I guess this would mean providing two separate
vDSO images, one for ELFv1 processes and one for ELFv2 processes (or
maybe playing some tricks with conditional DWARF expressions).
However, having CFI records for the other CR fields in ELFv1 is not
actually wrong, they just will be ignored.   So it seems the simplest
fix would be just to always provide CFI for all the fields.

Signed-off-by: Ulrich Weigand <Ulrich.Weigand@de.ibm.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-11-21 09:19:23 +11:00
Ian Munsie d72b080171 powerpc: Add ability to build little endian kernels
This patch allows the kbuild system to successfully compile a kernel
for the little endian PowerPC64 architecture. A subsequent patch
will add the CONFIG_CPU_LITTLE_ENDIAN kernel config option which
must be set to build such a kernel.

If cross compiling, CROSS_COMPILE must point to a suitable toolchain
(compiled for the powerpc64le-linux and powerpcle-linux targets).

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-11 16:48:56 +11:00
Adhemerval Zanella fcb41a2030 powerpc: Add VDSO version of time
On 04/18/2013 07:38 PM, Anton Blanchard wrote:
> Since you are only reading one long you shouldn't need to check the
> update count and loop, you will always see a consistent value. The
> system call version of time() just does an unprotected load for example.

Fixed.

> With the above change and with Michael's comments covered (decent
> changelog entry and Signed-off-by):
>
> Acked-by: Anton Blanchard <anton@samba.org>

Thanks for the review, below the updated patch:

From: Adhemerval Zanella <azanella@linux.vnet.ibm.com>

This patch implement the time syscall as vDSO. The performance speedups
are:

Baseline PPC32: 380 nsec
Baseline PPC64: 350 nsec
vdso PPC32:      20 nsec
vsdo PPC64:      20 nsec

Tested on 64 bit build with both 32 bit and 64 bit userland.

Acked-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Adhemerval Zanella <azanella@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-04-23 16:05:05 +10:00
Anton Blanchard 18ad51dd34 powerpc: Add VDSO version of getcpu
We have a request for a fast method of getting CPU and NUMA node IDs
from userspace. This patch implements a getcpu VDSO function,
similar to x86.

Ben suggested we use SPRG3 which is userspace readable. SPRG3 can be
modified by a KVM guest, so we save the SPRG3 value in the paca and
restore it when transitioning from the guest to the host.

I have a glibc patch that implements sched_getcpu on top of this.
Testing on a POWER7:

baseline: 538 cycles
vdso:      30 cycles

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-07-11 14:18:40 +10:00
Lucas De Marchi 25985edced Fix common misspellings
Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 11:26:23 -03:00
matt mooney 4108d9ba90 powerpc/Makefiles: Change to new flag variables
Replace EXTRA_CFLAGS with ccflags-y and EXTRA_AFLAGS with asflags-y.

Signed-off-by: matt mooney <mfm@muteddisk.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-10-13 16:19:22 +11:00
Paul Mackerras 8fd63a9ea7 powerpc: Rework VDSO gettimeofday to prevent time going backwards
Currently it is possible for userspace to see the result of
gettimeofday() going backwards by 1 microsecond, assuming that
userspace is using the gettimeofday() in the VDSO.  The VDSO
gettimeofday() algorithm computes the time in "xsecs", which are
units of 2^-20 seconds, or approximately 0.954 microseconds,
using the algorithm

	now = (timebase - tb_orig_stamp) * tb_to_xs + stamp_xsec

and then converts the time in xsecs to seconds and microseconds.

The kernel updates the tb_orig_stamp and stamp_xsec values every
tick in update_vsyscall().  If the length of the tick is not an
integer number of xsecs, then some precision is lost in converting
the current time to xsecs.  For example, with CONFIG_HZ=1000, the
tick is 1ms long, which is 1048.576 xsecs.  That means that
stamp_xsec will advance by either 1048 or 1049 on each tick.
With the right conditions, it is possible for userspace to get
(timebase - tb_orig_stamp) * tb_to_xs being 1049 if the kernel is
slightly late in updating the vdso_datapage, and then for stamp_xsec
to advance by 1048 when the kernel does update it, and for userspace
to then see (timebase - tb_orig_stamp) * tb_to_xs being zero due to
integer truncation.  The result is that time appears to go backwards
by 1 microsecond.

To fix this we change the VDSO gettimeofday to use a new field in the
VDSO datapage which stores the nanoseconds part of the time as a
fractional number of seconds in a 0.32 binary fraction format.
(Or put another way, as a 32-bit number in units of 0.23283 ns.)
This is convenient because we can use the mulhwu instruction to
convert it to either microseconds or nanoseconds.

Since it turns out that computing the time of day using this new field
is simpler than either using stamp_xsec (as gettimeofday does) or
stamp_xtime.tv_nsec (as clock_gettime does), this converts both
gettimeofday and clock_gettime to use the new field.  The existing
__do_get_tspec function is converted to use the new field and take
a parameter in r7 that indicates the desired resolution, 1,000,000
for microseconds or 1,000,000,000 for nanoseconds.  The __do_get_xsec
function is then unused and is deleted.

The new algorithm is

	now = ((timebase - tb_orig_stamp) << 12) * tb_to_xs
		+ (stamp_xtime_seconds << 32) + stamp_sec_fraction

with 'now' in units of 2^-32 seconds.  That is then converted to
seconds and either microseconds or nanoseconds with

	seconds = now >> 32
	partseconds = ((now & 0xffffffff) * resolution) >> 32

The 32-bit VDSO code also makes a further simplification: it ignores
the bottom 32 bits of the tb_to_xs value, which is a 0.64 format binary
fraction.  Doing so gets rid of 4 multiply instructions.  Assuming
a timebase frequency of 1GHz or less and an update interval of no
more than 10ms, the upper 32 bits of tb_to_xs will be at least
4503599, so the error from ignoring the low 32 bits will be at most
2.2ns, which is more than an order of magnitude less than the time
taken to do gettimeofday or clock_gettime on our fastest processors,
so there is no possibility of seeing inconsistent values due to this.

This also moves update_gtod() down next to its only caller, and makes
update_vsyscall use the time passed in via the wall_time argument rather
than accessing xtime directly.  At present, wall_time always points to
xtime, but that could change in future.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-07-09 11:26:16 +10:00
Tim Abbott abe1ee3a22 Use macros for .data.page_aligned section.
This patch changes the remaining direct references to
.data.page_aligned in C and assembly code to use the macros in
include/linux/linkage.h.

Signed-off-by: Tim Abbott <tabbott@ksplice.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-09-21 06:27:08 +02:00
Sam Ravnborg f86fd30660 kbuild: rename ld-option to cc-ldoption
ld-option is misnamed as it test options to gcc, not to ld.
Renamed it to reflect this.

Cc: Andi Kleen <andi@firstfloor.org>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-09-20 12:27:42 +02:00
Michael Ellerman a15098c90d powerpc: Enable GCOV
Make it possible to enable GCOV code coverage measurement on powerpc.

Lightly tested on 64-bit, seems to work as expected.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-08-20 10:29:28 +10:00
Benjamin Herrenschmidt 7c03d653cd powerpc/mm: Introduce MMU features
We're soon running out of CPU features and I need to add some new
ones for various MMU related bits, so this patch separates the MMU
features from the CPU features.  I moved over the 32-bit MMU related
ones, added base features for MMU type families, but didn't move
over any 64-bit only feature yet.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-12-21 14:21:16 +11:00
Paul Mackerras 597bc5c00b powerpc: Improve resolution of VDSO clock_gettime
Currently the clock_gettime implementation in the VDSO produces a
result with microsecond resolution for the cases that are handled
without a system call, i.e. CLOCK_REALTIME and CLOCK_MONOTONIC.  The
nanoseconds field of the result is obtained by computing a
microseconds value and multiplying by 1000.

This changes the code in the VDSO to do the computation for
clock_gettime with nanosecond resolution.  That means that the
resolution of the result will ultimately depend on the timebase
frequency.

Because the timestamp in the VDSO datapage (stamp_xsec, the real time
corresponding to the timebase count in tb_orig_stamp) is in units of
2^-20 seconds, it doesn't have sufficient resolution for computing a
result with nanosecond resolution.  Therefore this adds a copy of
xtime to the VDSO datapage and updates it in update_gtod() along with
the other time-related fields.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-11-06 09:49:22 +11:00
Kumar Gala 2d1b202762 powerpc: Fixup lwsync at runtime
To allow for a single kernel image on e500 v1/v2/mc we need to fixup lwsync
at runtime.  On e500v1/v2 lwsync causes an illop so we need to patch up
the code.  We default to 'sync' since that is always safe and if the cpu
is capable we will replace 'sync' with 'lwsync'.

We introduce CPU_FTR_LWSYNC as a way to determine at runtime if this is
needed.  This flag could be moved elsewhere since we dont really use it
for the normal CPU_FTR purpose.

Finally we only store the relative offset in the fixup section to keep it
as small as possible rather than using a full fixup_entry.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-07-03 16:58:10 +10:00
Michael Ellerman fac23fe4be powerpc: Introduce infrastructure for feature sections with alternatives
The current feature section logic only supports nop'ing out code, this means
if you want to choose at runtime between instruction sequences, one or both
cases will have to execute the nop'ed out contents of the other section, eg:

BEGIN_FTR_SECTION
	or	1,1,1
END_FTR_SECTION_IFSET(FOO)
BEGIN_FTR_SECTION
	or	2,2,2
END_FTR_SECTION_IFCLR(FOO)

and the resulting code will be either,

	or	1,1,1
	nop

or,
	nop
	or	2,2,2

For small code segments this is fine, but for larger code blocks and in
performance criticial code segments, it would be nice to avoid the nops.
This commit starts to implement logic to allow the following:

BEGIN_FTR_SECTION
	or	1,1,1
FTR_SECTION_ELSE
	or	2,2,2
ALT_FTR_SECTION_END_IFSET(FOO)

and the resulting code will be:

	or	1,1,1
or,
	or	2,2,2

We achieve this by extending the existing FTR macros. The current feature
section semantic just becomes a special case, ie. if the else case is empty
we nop out the default case.

The key limitation is that the size of the else case must be less than or
equal to the size of the default case. If the else case is smaller the
remainder of the section is nop'ed.

We let the linker put the else case code in with the rest of the text,
so that relative branches from the else case are more likley to link,
this has the disadvantage that we can't free the unused else cases.

This commit introduces the required macro and linker script changes, but
does not enable the patching of the alternative sections.

We also need to update two hand-made section entries in reg.h and timex.h

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-07-01 11:28:28 +10:00
Roland McGrath 2ca7633dc7 [POWERPC] Tweak VDSO linker script to avoid upsetting old binutils
This works around bugs in older binutils' objcopy.
The placement of these sections does not really matter,
but it confused the buggy old BFD libraries.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-05-23 15:27:23 +10:00
Olof Johansson fbe481756d [POWERPC] vdso: Fixes for cache block sizes
The current VDSO implementation is hardcoded to 128 byte cache blocks,
which are only used on IBM's 64-bit processors.

Convert it to get the cache block sizes out of vdso_data instead,
similar to how the ppc64 in-kernel cache flush does it.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-11-20 13:56:31 +11:00
Benjamin Herrenschmidt 081c11a5d0 [POWERPC] Fix 64 bits vDSO DWARF info for CR register
The current DWARF info for CR are incorrect, causing the gcc unwinder to
go to lunch if we take a segfault in the vdso.  This fixes it.

Problem identified by Andrew Haley, and fix provided by Jakub Jelinek
(thanks !).

Unfortunately, a bug in gcc cause it to not quite work either, but that
is being fixed separately with something around the lines of:

linux-unwind.h:

     fs->regs.reg[R_CR2].loc.offset = (long) &regs->ccr - new_cfa;
+    /* CR? regs are just 32-bit and PPC is big-endian.  */
+    fs->regs.reg[R_CR2].loc.offset += sizeof (long) - 4;

(According to Jakub)

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-10-17 22:30:09 +10:00
Roland McGrath 558da7561e powerpc64 vDSO: linker script indentation
This cleans up the formatting in the vDSO linker script, mostly just the
use of whitespace.  It's intended to approximate the kernel standard
conventions for indenting C, treating elements of the linker script about
like initialized variable definitions.

Signed-off-by: Roland McGrath <roland@redhat.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 10:01:50 -07:00
Kumar Gala 6039680705 [POWERPC] Update .gitignore for new vdso generated files
We now generate vdso[32,64].so.dbg as part of the build so
add them to .gitignore

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-10-08 08:38:12 -05:00
Roland McGrath 8150caad02 [POWERPC] powerpc vDSO: install unstripped copies on disk
This keeps an unstripped copy of the vDSO images built before they are
stripped and embedded in the kernel.  The unstripped copies get installed in
$(MODLIB)/vdso/ by "make install".  These files can be useful when they
contain source-level debugging information.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-10-03 12:02:43 +10:00
Will Schmidt fde937d826 Fix VDSO gettimeofday() when called with NULL struct timeval.
The vdso64 portion of patch 74609f4536 for
fixing problems with NULL gettimeofday input mistakenly checks for a
null tz field twice, when it should be checking for null tz once, and
null tv once; by way of a r10/r11 typo.

Any application calling gettimeofday(&tv,NULL) will "fail".

This corrects that typo, and makes my G5 happy.

Tested on G5.

Signed-off-by: Will Schmidt <will_schmidt@vnet.ibm.com>
Cc: Tony Breeds <tony@bakeyournoodle.com>
Forwarded-by: Ben Herrenschmidt <benh@kernel.crashing.org>

[ Ben says: "I checked the 32 bits part of the change is correct.  You
  can probably blame me for originally writing the 2 versions with
  inversed usage of r10 and r11, thus confusing Tony :-)"

  Ben duly blamed.   - Linus ]

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-29 21:27:00 -07:00
Tony Breeds 74609f4536 [POWERPC] Fix VDSO gettimeofday() when called with NULL struct timeval
Consider the prototype for gettimeofday():
	int gettimofday(struct timeval *tv, struct timezone *tz);

Although it is valid to call with /either/ tv or tz being NULL, and
the C version of sys_gettimeofday() supports this, the current version
of gettimeofday() in the VDSO will SEGV if called with a NULL tv.

This adds a check for tv being NULL so that it doesn't SEGV.

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-06-26 14:41:19 +10:00
Benjamin Herrenschmidt 859deea949 [POWERPC] Cell timebase bug workaround
The Cell CPU timebase has an erratum. When reading the entire 64 bits
of the timebase with one mftb instruction, there is a handful of cycles
window during which one might read a value with the low order 32 bits
already reset to 0x00000000 but the high order bits not yet incremeted
by one. This fixes it by reading the timebase again until the low order
32 bits is no longer 0. That might introduce occasional latencies if
hitting mftb just at the wrong time, but no more than 70ns on a cell
blade, and that was considered acceptable.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-10-25 11:54:18 +10:00
Benjamin Herrenschmidt 0909c8c2d5 [POWERPC] Support feature fixups in vdso's
This patch reworks the feature fixup mecanism so vdso's can be fixed up.
The main issue was that the construct:

        .long   label  (or .llong on 64 bits)

will not work in the case of a shared library like the vdso. It will
generate an empty placeholder in the fixup table along with a reloc,
which is not something we can deal with in the vdso.

The idea here (thanks Alan Modra !) is to instead use something like:

1:
        .long   label - 1b

That is, the feature fixup tables no longer contain addresses of bits of
code to patch, but offsets of such code from the fixup table entry
itself. That is properly resolved by ld when building the .so's. I've
modified the fixup mecanism generically to use that method for the rest
of the kernel as well.

Another trick is that the 32 bits vDSO included in the 64 bits kernel
need to have a table in the 64 bits format. However, gas does not
support 32 bits code with a statement of the form:

        .llong  label - 1b  (Or even just .llong label)

That is, it cannot emit the right fixup/relocation for the linker to use
to assign a 32 bits address to an .llong field. Thus, in the specific
case of the 32 bits vdso built as part of the 64 bits kernel, we are
using a modified macro that generates:

        .long   0xffffffff
        .llong  label - 1b

Note that is assumes that the value is negative which is enforced by
the .lds (those offsets are always negative as the .text is always
before the fixup table and gas doesn't support emiting the reloc the
other way around).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-10-25 11:54:07 +10:00
Roland McGrath 0b0bf7a3cc [PATCH] vDSO hash-style fix
The latest toolchains can produce a new ELF section in DSOs and
dynamically-linked executables.  The new section ".gnu.hash" replaces
".hash", and allows for more efficient runtime symbol lookups by the
dynamic linker.  The new ld option --hash-style={sysv|gnu|both} controls
whether to produce the old ".hash", the new ".gnu.hash", or both.  In some
new systems such as Fedora Core 6, gcc by default passes --hash-style=gnu
to the linker, so that a standard invocation of "gcc -shared" results in
producing a DSO with only ".gnu.hash".  The new ".gnu.hash" sections need
to be dealt with the same way as ".hash" sections in all respects; only the
dynamic linker cares about their contents.  To work with older dynamic
linkers (i.e.  preexisting releases of glibc), a binary must have the old
".hash" section.  The --hash-style=both option produces binaries that a new
dynamic linker can use more efficiently, but an old dynamic linker can
still handle.

The new section runs afoul of the custom linker scripts used to build vDSO
images for the kernel.  On ia64, the failure mode for this is a boot-time
panic because the vDSO's PT_IA_64_UNWIND segment winds up ill-formed.

This patch addresses the problem in two ways.

First, it mentions ".gnu.hash" in all the linker scripts alongside ".hash".
 This produces correct vDSO images with --hash-style=sysv (or old tools),
with --hash-style=gnu, or with --hash-style=both.

Second, it passes the --hash-style=sysv option when building the vDSO
images, so that ".gnu.hash" is not actually produced.  This is the most
conservative choice for compatibility with any old userland.  There is some
concern that some ancient glibc builds (though not any known old production
system) might choke on --hash-style=both binaries.  The optimizations
provided by the new style of hash section do not really matter for a DSO
with a tiny number of symbols, as the vDSO has.  If someone wants to use
=gnu or =both for their vDSO builds and worry less about that
compatibility, just change the option and the linker script changes will
make any choice work fine.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-31 13:28:43 -07:00
Jörn Engel 6ab3d5624e Remove obsolete #include <linux/config.h>
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-30 19:25:36 +02:00
Jakub Jelinek da2e9e1ff4 [PATCH] Mark unwind info for signal trampolines in vDSOs
Mark unwind info for signal trampolines using the new S augmentation flag
introduced in: http://gcc.gnu.org/PR26208.

GCC 4.2 (or patched earlier GCC) will be able to special case unwinding
through frames right above signal trampolines.  As the augmentations start
with z flag and S is at the very end of the augmentation string, older GCCs
will just skip the S flag as unknown (that's why an augmentation flag was
chosen over say a new CFA opcode).

Signed-off-by: Jakub Jelinek <jakub@redhat.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-31 12:18:52 -08:00
Benjamin Herrenschmidt 634473db86 [PATCH] powerpc: vdso 64bits gettimeofday bug
A bug in the assembly code of the vdso can cause gettimeofday() to hang
or to return incorrect results. The wrong register was used to test for
pending updates of the calibration variables and to create a dependency
for subsequent loads. This fixes it.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-02-28 16:25:54 +11:00
Kumar Gala 0e5e39bfd8 [PATCH] powerpc: Add some missing .gitignore's
ignore generated files under arch/powerpc

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-01-11 15:35:35 +11:00
Benjamin Herrenschmidt 5d66da3d71 [PATCH] powerpc: Make the vDSO functions set error code (#2)
The vDSO functions should have the same calling convention as a syscall.
Unfortunately, they currently don't set the cr0.so bit which is used to
indicate an error. This patch makes them clear this bit unconditionally
since all functions currently succeed. The syscall fallback done by some
of them will eventually override this if the syscall fails.

This also changes the symbol version of all vdso exports to make sure
glibc can differenciate between old and fixed calls for existing ones
like __kernel_gettimeofday.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-16 14:05:11 +11:00
Benjamin Herrenschmidt 0c37ec2aa8 [PATCH] powerpc: vdso fixes (take #2)
This fixes various errors in the new functions added in the vDSO's,
I've now verified all functions on both 32 and 64 bits vDSOs. It also
fix a sign extension bug getting the initial time of day at boot that
could cause the monotonic clock value to be completely on bogus for
64 bits applications (with either the vDSO or the syscall) on
powermacs.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-14 16:35:58 +11:00
Benjamin Herrenschmidt a7f290dad3 [PATCH] powerpc: Merge vdso's and add vdso support to 32 bits kernel
This patch moves the vdso's to arch/powerpc, adds support for the 32
bits vdso to the 32 bits kernel, rename systemcfg (finally !), and adds
some new (still untested) routines to both vdso's: clock_gettime() with
support for CLOCK_REALTIME and CLOCK_MONOTONIC, clock_getres() (same
clocks) and get_tbfreq() for glibc to retreive the timebase frequency.

Tom,Steve: The implementation of get_tbfreq() I've done for 32 bits
returns a long long (r3, r4) not a long. This is such that if we ever
add support for >4Ghz timebases on ppc32, the userland interface won't
have to change.

I have tested gettimeofday() using some glibc patches in both ppc32 and
ppc64 kernels using 32 bits userland (I haven't had a chance to test a
64 bits userland yet, but the implementation didn't change and was
tested earlier). I haven't tested yet the new functions.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-11 22:25:39 +11:00