Commit graph

61 commits

Author SHA1 Message Date
David S. Miller
7e0b1e6186 sparc64: Fix sparse warnings in visemul.c
1) edge8 tables should be static
2) add vis_emul() extern decl. to asm/visasm.h

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-11 23:46:40 -07:00
David S. Miller
41660e9ac6 sparc64: Allow chmc to be built as a module.
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-24 22:17:29 -07:00
David S. Miller
881d021ab0 sparc64: Add generic interface for registering a dimm printing handler.
The way to do this varies by platform type and the exact memory
controller the cpu uses.

For Spitfire cpus we currently just use prom_getunumber() and hope
that works.

For Cheetah cpus we have a memory controller driver that can
compute this information.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-24 22:08:34 -07:00
David S. Miller
4f70f7a91b sparc64: Implement IRQ stacks.
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-12 18:33:56 -07:00
David S. Miller
dbf3e95067 sparc64: Kill __show_regs().
The story is that what we used to do when we actually used
smp_report_regs() is that if you specifically only wanted to have the
current cpu's registers dumped you would call "__show_regs()"
otherwise you would call show_regs() which also invoked
smp_report_regs().

Now that we killed off smp_report_regs() there is no longer any
reason to have these two routines, just show_regs() is sufficient.

Also kill off a stray declaration of show_regs() in sparc64_ksym.c

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-31 20:33:43 -07:00
David S. Miller
9c636e30a3 sparc64: Kill smp_report_regs().
All the call sites are #if 0'd out and we have a much more
useful global cpu dumping facility these days.  smp_report_regs()
is way too verbose to be usable.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-31 01:06:02 -07:00
Johannes Berg
184b6c7682 remove CONFIG_KMOD from sparc64
One place is just a comment, the other a conditional, unused
inclusion of linux/kmod.h.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-07-22 19:24:30 +10:00
David S. Miller
4fe3ebec12 sparc: Use new '%pS' infrastructure to print symbols.
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-17 22:11:32 -07:00
David S. Miller
14d2c68baa sparc64: Fix stack tracing through trap frames.
The offset to the pt_regs area was wrong, so we weren't
looking at the right location for the magic cookie.

A trap frame is composed of a "struct sparc_stackf" then
a "struct pt_regs", the code was using "struct reg_window"
instead of "struct sparc_stackf".

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-05-21 18:15:53 -07:00
David S. Miller
77c664fa58 [SPARC64]: Detect trap frames in stack backtraces.
Now that we have a magic cookie in the pt_regs, we can
properly detect trap frames in stack bactraces.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-24 03:28:52 -07:00
David S. Miller
99cd220133 [SPARC64]: Fix sparse errors in arch/sparc64/kernel/traps.c
Add 'UL' markers to DCU_* macros.

Declare C functions called from assembler in entry.h

Declare C functions called from within the sparc64 arch
code in include/asm-sparc64/*.h headers as appropriate.

Remove unused routines in traps.c

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-26 00:19:43 -07:00
David S. Miller
3ac1da338b [SPARC64]: Fix sparse warnings wrt. __show_regs().
arch/sparc64/kernel/process.c:219:6: warning: symbol '__show_regs' was not declared. Should it be static?

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-02-19 20:48:58 -08:00
David S. Miller
6320bcebc0 [SPARC64]: Fix hypervisor TLB operation error reporting.
1) Trap level wasn't being passed down properly, we need to
   move it from %l4 into the correct outgoing arg register.

2) Although the TPC often provides the most direct clue, we
   have the caller PC so we should provide that as well.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-17 06:26:55 -08:00
David S. Miller
d979f1792d [SPARC64]: __inline__ --> inline
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-27 00:13:04 -07:00
Alexey Dobriyan
19c5870c0e Use helpers to obtain task pid in printks (arch code)
One of the easiest things to isolate is the pid printed in kernel log.
There was a patch, that made this for arch-independent code, this one makes
so for arch/xxx files.

It took some time to cross-compile it, but hopefully these are all the
printks in arch code.

Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:43 -07:00
David S. Miller
eb2d8d6032 [SPARC64]: Access ivector_table[] using physical addresses.
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-13 21:53:15 -07:00
David S. Miller
c1f193a7ae [SPARC64]: Fix show_stack() when stack argument is NULL.
It didn't handle that case at all, and now dump_stack()
can be implemented directly as show_stack(current, NULL)

Signed-off-by: David S. Miller <davem@davemloft.net>
2007-07-30 00:27:38 -07:00
Pavel Emelianov
bcdcd8e725 Report that kernel is tainted if there was an OOPS
If the kernel OOPSed or BUGed then it probably should be considered as
tainted.  Thus, all subsequent OOPSes and SysRq dumps will report the
tainted kernel.  This saves a lot of time explaining oddities in the
calltraces.

Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ Added parisc patch from Matthew Wilson  -Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 10:23:02 -07:00
David S. Miller
5cbc307373 [SPARC64]: Use machine description and OBP properly for cpu probing.
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-05-29 02:49:41 -07:00
Fernando Luis Vazquez Cao
2f4dfe206a Remove hardcoding of hard_smp_processor_id on UP systems
With the advent of kdump, the assumption that the boot CPU when booting an UP
kernel is always the CPU with a particular hardware ID (often 0) (usually
referred to as BSP on some architectures) is not valid anymore.  The reason
being that the dump capture kernel boots on the crashed CPU (the CPU that
invoked crash_kexec), which may be or may not be that particular CPU.

Move definition of hard_smp_processor_id for the UP case to
architecture-specific code ("asm/smp.h") where it belongs, so that each
architecture can provide its own implementation.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Cc: "Luck, Tony" <tony.luck@intel.com>
Acked-by: Andi Kleen <ak@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:48 -07:00
Randy Dunlap
e63340ae6b header cleaning: don't include smp_lock.h when not used
Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.

Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:07 -07:00
Christoph Hellwig
1eeb66a1bb move die notifier handling to common code
This patch moves the die notifier handling to common code.  Previous
various architectures had exactly the same code for it.  Note that the new
code is compiled unconditionally, this should be understood as an appel to
the other architecture maintainer to implement support for it aswell (aka
sprinkling a notify_die or two in the proper place)

arm had a notifiy_die that did something totally different, I renamed it to
arm_notify_die as part of the patch and made it static to the file it's
declared and used at.  avr32 used to pass slightly less information through
this interface and I brought it into line with the other architectures.

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix vmalloc_sync_all bustage]
[bryan.wu@analog.com: fix vmalloc_sync_all in nommu]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: <linux-arch@vger.kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:04 -07:00
David S. Miller
a2c1e064c4 [SPARC64]: Run ctrl-alt-del action for sun4v powerdown request.
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 02:39:51 -08:00
David S. Miller
6e7726e16f [SPARC64]: Call do_mathemu on illegal instruction traps too.
To add this logic, put the VIS instruction check at the
vis_emul() call site instead of inside of vis_emul().

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-10 02:39:32 -08:00
David S. Miller
5af47db796 [SPARC64]: Add some missing print_symbol() calls.
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-10-30 19:33:33 -08:00
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
David S. Miller
07f8e5f358 [SPARC64]: Convert cpu_find_by_*() interface to in-kernel PROM device tree.
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-23 23:15:17 -07:00
David S. Miller
fd0504c321 [SPARC64]: Send all device interrupts via one PIL.
This is the first in a series of cleanups that will hopefully
allow a seamless attempt at using the generic IRQ handling
infrastructure in the Linux kernel.

Define PIL_DEVICE_IRQ and vector all device interrupts through
there.

Get rid of the ugly pil0_dummy_{bucket,desc}, instead vector
the timer interrupt directly to a specific handler since the
timer interrupt is the only event that will be signaled on
PIL 14.

The irq_worklist is now in the per-cpu trap_block[].

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-20 01:20:00 -07:00
David S. Miller
5224e6cc3a [SPARC64]: Dump local cpu registers in sun4v_log_error()
This makes the debugging information more usable.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-09 12:03:49 -07:00
David S. Miller
955c054f79 [SPARC64]: Print out return PC in cheetah_log_errors().
This makes debugging things a little bit easier.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-04-09 22:56:37 -07:00
Alan Stern
e041c68341 [PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe.  There is no
protection against entries being added to or removed from a chain while the
chain is in use.  The issues were discussed in this thread:

    http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2

We noticed that notifier chains in the kernel fall into two basic usage
classes:

	"Blocking" chains are always called from a process context
	and the callout routines are allowed to sleep;

	"Atomic" chains can be called from an atomic context and
	the callout routines are not allowed to sleep.

We decided to codify this distinction and make it part of the API.  Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name).  New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain.  The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.

With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed.  For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections.  (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)

There are some limitations, which should not be too hard to live with.  For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem.  Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain.  (This did happen in a couple of places and the code
had to be changed to avoid it.)

Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization.  Instead we use RCU.  The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.

Here is the list of chains that we adjusted and their classifications.  None
of them use the raw API, so for the moment it is only a placeholder.

  ATOMIC CHAINS
  -------------
arch/i386/kernel/traps.c:		i386die_chain
arch/ia64/kernel/traps.c:		ia64die_chain
arch/powerpc/kernel/traps.c:		powerpc_die_chain
arch/sparc64/kernel/traps.c:		sparc64die_chain
arch/x86_64/kernel/traps.c:		die_chain
drivers/char/ipmi/ipmi_si_intf.c:	xaction_notifier_list
kernel/panic.c:				panic_notifier_list
kernel/profile.c:			task_free_notifier
net/bluetooth/hci_core.c:		hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c:	ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c:	ip_conntrack_expect_chain
net/ipv6/addrconf.c:			inet6addr_chain
net/netfilter/nf_conntrack_core.c:	nf_conntrack_chain
net/netfilter/nf_conntrack_core.c:	nf_conntrack_expect_chain
net/netlink/af_netlink.c:		netlink_chain

  BLOCKING CHAINS
  ---------------
arch/powerpc/platforms/pseries/reconfig.c:	pSeries_reconfig_chain
arch/s390/kernel/process.c:		idle_chain
arch/x86_64/kernel/process.c		idle_notifier
drivers/base/memory.c:			memory_chain
drivers/cpufreq/cpufreq.c		cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c		cpufreq_transition_notifier_list
drivers/macintosh/adb.c:		adb_client_list
drivers/macintosh/via-pmu.c		sleep_notifier_list
drivers/macintosh/via-pmu68k.c		sleep_notifier_list
drivers/macintosh/windfarm_core.c	wf_client_list
drivers/usb/core/notify.c		usb_notifier_list
drivers/video/fbmem.c			fb_notifier_list
kernel/cpu.c				cpu_chain
kernel/module.c				module_notify_list
kernel/profile.c			munmap_notifier
kernel/profile.c			task_exit_notifier
kernel/sys.c				reboot_notifier_list
net/core/dev.c				netdev_chain
net/decnet/dn_dev.c:			dnaddr_chain
net/ipv4/devinet.c:			inetaddr_chain

It's possible that some of these classifications are wrong.  If they are,
please let us know or submit a patch to fix them.  Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)

The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.

[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 08:44:50 -08:00
David S. Miller
dcc1e8dd88 [SPARC64]: Add a secondary TSB for hugepage mappings.
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-22 01:15:14 -08:00
David S. Miller
0c51ed93ca [SPARC64]: First cut at VIS simulator for Niagara.
Niagara does not implement some of the VIS instructions in
hardware, so we have to emulate them.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:14:26 -08:00
David S. Miller
2a3a5f5ddb [SPARC64]: Bulletproof hypervisor TLB flushing.
Check TLB flush hypervisor calls for errors and report them.

Pass HV_MMU_ALL always for now, we can add back the optimization
to avoid the I-TLB flush later.

Always explicitly page align the virtual address arguments.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:14:05 -08:00
David S. Miller
55555633bd [SPARC64]: Typo in sun4v_data_access_exception log message.
Should be "Dax" not "Iax".

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:13:46 -08:00
David S. Miller
39334a4b2c [SPARC64]: Fix typo in dump_tl1_traplog()
Actually make use of the 'limit' we compute.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:13:43 -08:00
David S. Miller
37133c006c [SPARC64]: Disable smp_report_regs() for now.
It's extremely noisy and causes much grief on slow
consoles with large numbers of cpus.

We'll have to provide this some saner way in order
to re-enable this.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:13:42 -08:00
David S. Miller
04d74758eb [SPARC64]: Use KERN_EMERG in dump_tl1_traplog() and sun4v TLB errors.
We're about to seriously die in these cases so it is important
that the messages make it to the console.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:13:40 -08:00
David S. Miller
6c8927c963 [SPARC64]: Fix some SUN4V TLB handling bugs.
1) Add error return checking for TLB load hypervisor
   calls.

2) Don't fallthru to dtlb tsb miss handler from itlb tsb
   miss handler, oops.

3) On window fixups, propagate fault information to fixup
   handler correctly.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:13:32 -08:00
David S. Miller
72aff53f1f [SPARC64]: Get SUN4V SMP working.
The sibling cpu bringup is extremely fragile.  We can only
perform the most basic calls until we take over the trap
table from the firmware/hypervisor on the new cpu.

This means no accesses to %g4, %g5, %g6 since those can't be
TLB translated without our trap handlers.

In order to achieve this:

1) Change sun4v_init_mondo_queues() so that it can operate in
   several modes.

   It can allocate the queues, or install them in the current
   processor, or both.

   The boot cpu does both in it's call early on.

   Later, the boot cpu allocates the sibling cpu queue, starts
   the sibling cpu, then the sibling cpu loads them in.

2) init_cur_cpu_trap() is changed to take the current_thread_info()
   as an argument instead of reading %g6 directly on the current
   cpu.

3) Create a trampoline stack for the sibling cpus.  We do our basic
   kernel calls using this stack, which is locked into the kernel
   image, then go to our proper thread stack after taking over the
   trap table.

4) While we are in this delicate startup state, we put 0xdeadbeef
   into %g4/%g5/%g6 in order to catch accidental accesses.

5) On the final prom_set_trap_table*() call, we put &init_thread_union
   into %g6.  This is a hack to make prom_world(0) work.  All that
   wants to do is restore the %asi register using
   get_thread_current_ds().

Longer term we should just do the OBP calls to set the trap table by
hand just like we do for everything else.  This would avoid that silly
prom_world(0) issue, then we can remove the init_thread_union hack.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:13:22 -08:00
David S. Miller
3d6395cb77 [SPARC64]: Fix tl1 trap state capture/dump on SUN4V.
No trap levels above 2 in privileged mode on SUN4V.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:13:12 -08:00
David S. Miller
9f8a5b843f [SPARC64]: Fix C-function name called by sun4v_mna trap code.
The trap code was calling itself :-)

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:12:56 -08:00
David S. Miller
ed6b0b4543 [SPARC64]: SUN4V memory exception trap handlers.
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:12:07 -08:00
David S. Miller
1d2f1f90a1 [SPARC64]: Sun4v cross-call sending support.
Technically the hypervisor call supports sending in a list
of all cpus to get the cross-call, but I only pass in one
cpu at a time for now.

The multi-cpu support is there, just ifdef'd out so it's easy to
enable or delete it later.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:12:02 -08:00
David S. Miller
5b0c0572fc [SPARC64]: Sun4v interrupt handling.
Sun4v has 4 interrupt queues: cpu, device, resumable errors,
and non-resumable errors.  A set of head/tail offset pointers
help maintain a work queue in physical memory.  The entries
are 64-bytes in size.

Each queue is allocated then registered with the hypervisor
as we bring cpus up.

The two error queues each get a kernel side buffer that we
use to quickly empty the main interrupt queue before we
call up to C code to log the event and possibly take evasive
action.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:12:01 -08:00
David S. Miller
e088ad7ca3 [SPARC64]: Verify all trap_per_cpu assembler offsets in trap_init()
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:11:59 -08:00
David S. Miller
92704a1c63 [SPARC64]: Refine code sequences to get the cpu id.
On uniprocessor, it's always zero for optimize that.

On SMP, the jmpl to the stub kills the return address stack in the cpu
branch prediction logic, so expand the code sequence inline and use a
code patching section to fix things up.  This also always better and
explicit register selection, which will be taken advantage of in a
future changeset.

The hard_smp_processor_id() function is big, so do not inline it.

Fix up tests for Jalapeno to also test for Serrano chips too.  These
tests want "jbus Ultra-IIIi" cases to match, so that is what we should
test for.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:11:35 -08:00
David S. Miller
7bec08e38a [SPARC64]: Correctable ECC errors cannot occur at trap level > 0.
The are distrupting, which by the sparc v9 definition means they
can only occur when interrupts are enabled in the %pstate register.
This never occurs in any of the trap handling code running at
trap levels > 0.

So just mark it as an unexpected trap.

This allows us to kill off the cee_stuff member of struct thread_info.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:11:33 -08:00
David S. Miller
56fb4df6da [SPARC64]: Elminate all usage of hard-coded trap globals.
UltraSPARC has special sets of global registers which are switched to
for certain trap types.  There is one set for MMU related traps, one
set of Interrupt Vector processing, and another set (called the
Alternate globals) for all other trap types.

For what seems like forever we've hard coded the values in some of
these trap registers.  Some examples include:

1) Interrupt Vector global %g6 holds current processors interrupt
   work struct where received interrupts are managed for IRQ handler
   dispatch.

2) MMU global %g7 holds the base of the page tables of the currently
   active address space.

3) Alternate global %g6 held the current_thread_info() value.

Such hardcoding has resulted in some serious issues in many areas.
There are some code sequences where having another register available
would help clean up the implementation.  Taking traps such as
cross-calls from the OBP firmware requires some trick code sequences
wherein we have to save away and restore all of the special sets of
global registers when we enter/exit OBP.

We were also using the IMMU TSB register on SMP to hold the per-cpu
area base address, which doesn't work any longer now that we actually
use the TSB facility of the cpu.

The implementation is pretty straight forward.  One tricky bit is
getting the current processor ID as that is different on different cpu
variants.  We use a stub with a fancy calling convention which we
patch at boot time.  The calling convention is that the stub is
branched to and the (PC - 4) to return to is in register %g1.  The cpu
number is left in %g6.  This stub can be invoked by using the
__GET_CPUID macro.

We use an array of per-cpu trap state to store the current thread and
physical address of the current address space's page tables.  The
TRAP_LOAD_THREAD_REG loads %g6 with the current thread from this
table, it uses __GET_CPUID and also clobbers %g1.

TRAP_LOAD_IRQ_WORK is used by the interrupt vector processing to load
the current processor's IRQ software state into %g6.  It also uses
__GET_CPUID and clobbers %g1.

Finally, TRAP_LOAD_PGD_PHYS loads the physical address base of the
current address space's page tables into %g7, it clobbers %g1 and uses
__GET_CPUID.

Many refinements are possible, as well as some tuning, with this stuff
in place.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:11:16 -08:00
Al Viro
ee3eea165e [PATCH] sparc64: task_stack_page()
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>
2006-01-12 09:08:52 -08:00