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  1. 14 12月, 2015 2 次提交
  3. 09 4月, 2015 1 次提交
  5. 29 12月, 2014 1 次提交
    • H
      powerpc/kdump: Ignore failure in enabling big endian exception during crash · c1caae3d
      由 Hari Bathini 提交于 
      In LE kernel, we currently have a hack for kexec that resets the exception
endian before starting a new kernel as the kernel that is loaded could be a
big endian or a little endian kernel. In kdump case, resetting exception
endian fails when one or more cpus is disabled. But we can ignore the failure
and still go ahead, as in most cases crashkernel will be of same endianess
as primary kernel and reseting endianess is not even needed in those cases.
This patch adds a new inline function to say if this is kdump path. This
function is used at places where such a check is needed.
Signed-off-by: NHari Bathini <hbathini@linux.vnet.ibm.com>
[mpe: Rename to kdump_in_progress(), use bool, and edit comment]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      c1caae3d
  7. 05 12月, 2014 1 次提交
    • A
      powerpc/mm: don't do tlbie for updatepp request with NO HPTE fault · aefa5688
      由 Aneesh Kumar K.V 提交于 
      upatepp can get called for a nohpte fault when we find from the linux
page table that the translation was hashed before. In that case
we are sure that there is no existing translation, hence we could
avoid doing tlbie.

We could possibly race with a parallel fault filling the TLB. But
that should be ok because updatepp is only ever relaxing permissions.
We also look at linux pte permission bits when filling hash pte
permission bits. We also hold the linux pte busy bits while
inserting/updating a hashpte entry, hence a paralle update of
linux pte is not possible. On the other hand mprotect involves
ptep_modify_prot_start which cause a hpte invalidate and not updatepp.

Performance number:
We use randbox_access_bench written by Anton.

Kernel with THP disabled and smaller hash page table size.

    86.60%  random_access_b  [kernel.kallsyms]                [k] .native_hpte_updatepp
     2.10%  random_access_b  random_access_bench              [.] doit
     1.99%  random_access_b  [kernel.kallsyms]                [k] .do_raw_spin_lock
     1.85%  random_access_b  [kernel.kallsyms]                [k] .native_hpte_insert
     1.26%  random_access_b  [kernel.kallsyms]                [k] .native_flush_hash_range
     1.18%  random_access_b  [kernel.kallsyms]                [k] .__delay
     0.69%  random_access_b  [kernel.kallsyms]                [k] .native_hpte_remove
     0.37%  random_access_b  [kernel.kallsyms]                [k] .clear_user_page
     0.34%  random_access_b  [kernel.kallsyms]                [k] .__hash_page_64K
     0.32%  random_access_b  [kernel.kallsyms]                [k] fast_exception_return
     0.30%  random_access_b  [kernel.kallsyms]                [k] .hash_page_mm

With Fix:

    27.54%  random_access_b  random_access_bench              [.] doit
    22.90%  random_access_b  [kernel.kallsyms]                [k] .native_hpte_insert
     5.76%  random_access_b  [kernel.kallsyms]                [k] .native_hpte_remove
     5.20%  random_access_b  [kernel.kallsyms]                [k] fast_exception_return
     5.12%  random_access_b  [kernel.kallsyms]                [k] .__hash_page_64K
     4.80%  random_access_b  [kernel.kallsyms]                [k] .hash_page_mm
     3.31%  random_access_b  [kernel.kallsyms]                [k] data_access_common
     1.84%  random_access_b  [kernel.kallsyms]                [k] .trace_hardirqs_on_caller
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      aefa5688
  9. 02 12月, 2014 1 次提交
  11. 03 11月, 2014 1 次提交
    • C
      powerpc: Replace __get_cpu_var uses · 69111bac
      由 Christoph Lameter 提交于 
      This still has not been merged and now powerpc is the only arch that does
not have this change. Sorry about missing linuxppc-dev before.

V2->V2
  - Fix up to work against 3.18-rc1

__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x).  This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.

Other use cases are for storing and retrieving data from the current
processors percpu area.  __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.

__get_cpu_var() is defined as :

__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.

this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.

This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset.  Thereby address calculations are avoided and less registers
are used when code is generated.

At the end of the patch set all uses of __get_cpu_var have been removed so
the macro is removed too.

The patch set includes passes over all arches as well. Once these operations
are used throughout then specialized macros can be defined in non -x86
arches as well in order to optimize per cpu access by f.e.  using a global
register that may be set to the per cpu base.

Transformations done to __get_cpu_var()

1. Determine the address of the percpu instance of the current processor.

	DEFINE_PER_CPU(int, y);
	int *x = &__get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(&y);

2. Same as #1 but this time an array structure is involved.

	DEFINE_PER_CPU(int, y[20]);
	int *x = __get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(y);

3. Retrieve the content of the current processors instance of a per cpu
variable.

	DEFINE_PER_CPU(int, y);
	int x = __get_cpu_var(y)

   Converts to

	int x = __this_cpu_read(y);

4. Retrieve the content of a percpu struct

	DEFINE_PER_CPU(struct mystruct, y);
	struct mystruct x = __get_cpu_var(y);

   Converts to

	memcpy(&x, this_cpu_ptr(&y), sizeof(x));

5. Assignment to a per cpu variable

	DEFINE_PER_CPU(int, y)
	__get_cpu_var(y) = x;

   Converts to

	__this_cpu_write(y, x);

6. Increment/Decrement etc of a per cpu variable

	DEFINE_PER_CPU(int, y);
	__get_cpu_var(y)++

   Converts to

	__this_cpu_inc(y)

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
Signed-off-by: NChristoph Lameter <cl@linux.com>
[mpe: Fix build errors caused by set/or_softirq_pending(), and rework
      assignment in __set_breakpoint() to use memcpy().]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      69111bac
  13. 30 10月, 2014 1 次提交
    • H
      powerpc/fadump: Fix endianess issues in firmware assisted dump handling · 408cddd9
      由 Hari Bathini 提交于 
      Firmware-assisted dump (fadump) kernel code is not endian safe. The
below patch fixes this issue. Tested this patch with upstream kernel.
Below output shows crash tool successfully opening LE fadump vmcore.

    # crash vmlinux vmcore
    GNU gdb (GDB) 7.6
    This GDB was configured as "powerpc64le-unknown-linux-gnu"...

          KERNEL: vmlinux
        DUMPFILE: vmcore
    	CPUS: 16
    	DATE: Wed Dec 31 19:00:00 1969
          UPTIME: 00:03:28
    LOAD AVERAGE: 0.46, 0.86, 0.41
           TASKS: 268
        NODENAME: linux-dhr2
         RELEASE: 3.17.0-rc5-7-default
         VERSION: #6 SMP Tue Sep 30 01:06:34 EDT 2014
         MACHINE: ppc64le  (4116 Mhz)
          MEMORY: 40 GB
           PANIC: "Oops: Kernel access of bad area, sig: 11 [#1]" (check log for details)
    	 PID: 6223
         COMMAND: "bash"
    	TASK: c0000009661b2500  [THREAD_INFO: c000000967ac0000]
    	 CPU: 2
           STATE: TASK_RUNNING (PANIC)
Signed-off-by: NHari Bathini <hbathini@linux.vnet.ibm.com>
[mpe: Make the comment in pSeries_lpar_hptab_clear() clearer]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
      408cddd9
  15. 25 9月, 2014 2 次提交
  17. 27 8月, 2014 2 次提交
    • T
      Revert "powerpc: Replace __get_cpu_var uses" · 23f66e2d
      由 Tejun Heo 提交于 
      This reverts commit 5828f666 due to
build failure after merging with pending powerpc changes.

Link: http://lkml.kernel.org/g/20140827142243.6277eaff@canb.auug.org.auSigned-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      23f66e2d
    • C
      powerpc: Replace __get_cpu_var uses · 5828f666
      由 Christoph Lameter 提交于 
      __get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x).  This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.

Other use cases are for storing and retrieving data from the current
processors percpu area.  __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.

__get_cpu_var() is defined as :

#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))

__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.

this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.

This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset.  Thereby address calculations are avoided and less registers
are used when code is generated.

At the end of the patch set all uses of __get_cpu_var have been removed so
the macro is removed too.

The patch set includes passes over all arches as well. Once these operations
are used throughout then specialized macros can be defined in non -x86
arches as well in order to optimize per cpu access by f.e.  using a global
register that may be set to the per cpu base.

Transformations done to __get_cpu_var()

1. Determine the address of the percpu instance of the current processor.

	DEFINE_PER_CPU(int, y);
	int *x = &__get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(&y);

2. Same as #1 but this time an array structure is involved.

	DEFINE_PER_CPU(int, y[20]);
	int *x = __get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(y);

3. Retrieve the content of the current processors instance of a per cpu
variable.

	DEFINE_PER_CPU(int, y);
	int x = __get_cpu_var(y)

   Converts to

	int x = __this_cpu_read(y);

4. Retrieve the content of a percpu struct

	DEFINE_PER_CPU(struct mystruct, y);
	struct mystruct x = __get_cpu_var(y);

   Converts to

	memcpy(&x, this_cpu_ptr(&y), sizeof(x));

5. Assignment to a per cpu variable

	DEFINE_PER_CPU(int, y)
	__get_cpu_var(y) = x;

   Converts to

	__this_cpu_write(y, x);

6. Increment/Decrement etc of a per cpu variable

	DEFINE_PER_CPU(int, y);
	__get_cpu_var(y)++

   Converts to

	__this_cpu_inc(y)

tj: Folded a fix patch.
    http://lkml.kernel.org/g/alpine.DEB.2.11.1408172143020.9652@gentwo.org

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
Signed-off-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      5828f666
  19. 13 8月, 2014 1 次提交
  21. 11 7月, 2014 1 次提交
    • A
      powerpc/pseries: Use jump labels for hcall tracepoints · cc1adb5f
      由 Anton Blanchard 提交于 
      hcall tracepoints add quite a few instructions to our hcall path:

plpar_hcall:
	mr      r2,r2
	mfcr    r0
	stw     r0,8(r1)
	b       164		<---- start
	ld      r12,0(r2)
	std     r12,32(r1)
	cmpdi   r12,0
	beq     164		<---- end
...

We have an unconditional branch that gets noped out during boot and
a load/compare/branch. We also store the tracepoint value to the
stack for the hcall_exit path to use.

By using jump labels we can simplify this to just a single nop that
gets replaced with a branch when the tracepoint is enabled:

plpar_hcall:
	mr      r2,r2
	mfcr    r0
	stw     r0,8(r1)
	nop			<----
...

If jump labels are not enabled, we fall back to the old method.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      cc1adb5f
  23. 09 12月, 2013 2 次提交
  25. 21 11月, 2013 1 次提交
  27. 27 8月, 2013 2 次提交
  29. 14 8月, 2013 2 次提交
  31. 24 7月, 2013 1 次提交
  33. 01 7月, 2013 1 次提交
  35. 21 6月, 2013 2 次提交
  37. 30 4月, 2013 2 次提交
  39. 08 4月, 2013 1 次提交
  41. 17 9月, 2012 1 次提交
  43. 05 9月, 2012 1 次提交
  45. 21 3月, 2012 1 次提交
  47. 11 1月, 2012 1 次提交
    • A
      powerpc: Fix RCU idle and hcall tracing · a5ccfee0
      由 Anton Blanchard 提交于 
      Tracepoints should not be called inside an rcu_idle_enter/rcu_idle_exit
region. Since pSeries calls H_CEDE in the idle loop, we were violating
this rule.

commit a7b152d5 (powerpc: Tell RCU about idle after hcall tracing)
tried to work around it by delaying the rcu_idle_enter until after we
called the hcall tracepoint, but there are a number of issues with it.

The hcall tracepoint trampoline code is called conditionally when the
tracepoint is enabled. If the tracepoint is not enabled we never call
rcu_idle_enter. The idle_uses_rcu check was also done at compile time
which breaks multiplatform builds.

The simple fix is to avoid tracing H_CEDE and rely on other tracepoints
and the hypervisor dispatch trace log to work out if we called H_CEDE.

This fixes a hang during boot on pSeries.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      a5ccfee0
  49. 03 1月, 2012 1 次提交
  51. 12 12月, 2011 1 次提交
    • P
      powerpc: Tell RCU about idle after hcall tracing · a7b152d5
      由 Paul E. McKenney 提交于 
      The PowerPC pSeries platform (CONFIG_PPC_PSERIES=y) enables
hypervisor-call tracing for CONFIG_TRACEPOINTS=y kernels.  One of the
hypervisor calls that is traced is the H_CEDE call in the idle loop
that tells the hypervisor that this OS instance no longer needs the
current CPU.  However, tracing uses RCU, so this combination of kernel
configuration variables needs to avoid telling RCU about the current CPU's
idleness until after the H_CEDE-entry tracing completes on the one hand,
and must tell RCU that the the current CPU is no longer idle before the
H_CEDE-exit tracing starts.

In all other cases, it suffices to inform RCU of CPU idleness upon
idle-loop entry and exit.

This commit makes the required adjustments.
Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
      a7b152d5
  53. 01 11月, 2011 1 次提交
  55. 05 8月, 2011 2 次提交
  57. 29 6月, 2011 2 次提交
    • B
      powerpc/pseries: Re-implement HVSI as part of hvc_vio · 4d2bb3f5
      由 Benjamin Herrenschmidt 提交于 
      On pseries machines, consoles are provided by the hypervisor using
a low level get_chars/put_chars type interface. However, this is
really just a transport to the service processor which implements
them either as "raw" console (networked consoles, HMC, ...) or as
"hvsi" serial ports.

The later is a simple packet protocol on top of the raw character
interface that is supposed to convey additional "serial port" style
semantics. In practice however, all it does is provide a way to
read the CD line and set/clear our DTR line, that's it.

We currently implement the "raw" protocol as an hvc console backend
(/dev/hvcN) and the "hvsi" protocol using a separate tty driver
(/dev/hvsi0).

However this is quite impractical. The arbitrary difference between
the two type of devices has been a major source of user (and distro)
confusion. Additionally, there's an additional mini -hvsi implementation
in the pseries platform code for our low level debug console and early
boot kernel messages, which means code duplication, though that low
level variant is impractical as it's incapable of doing the initial
protocol negociation to establish the link to the FSP.

This essentially replaces the dedicated hvsi driver and the platform
udbg code completely by extending the existing hvc_vio backend used
in "raw" mode so that:

 - It now supports HVSI as well
 - We add support for hvc backend providing tiocm{get,set}
 - It also provides a udbg interface for early debug and boot console

This is overall less code, though this will only be obvious once we
remove the old "hvsi" driver, which is still available for now. When
the old driver is enabled, the new code still kicks in for the low
level udbg console, replacing the old mini implementation in the platform
code, it just doesn't provide the higher level "hvc" interface.

In addition to producing generally simler code, this has several benefits
over our current situation:

 - The user/distro only has to deal with /dev/hvcN for the hypervisor
console, avoiding all sort of confusion that has plagued us in the past

 - The tty, kernel and low level debug console all use the same code
base which supports the full protocol establishment process, thus the
console is now available much earlier than it used to be with the
old HVSI driver. The kernel console works much earlier and udbg is
available much earlier too. Hackers can enable a hard coded very-early
debug console as well that works with HVSI (previously that was only
supported for the "raw" mode).

I've tried to keep the same semantics as hvsi relative to how I react
to things like CD changes, with some subtle differences though:

 - I clear DTR on close if HUPCL is set

 - Current hvsi triggers a hangup if it detects a up->down transition
   on CD (you can still open a console with CD down). My new implementation
   triggers a hangup if the link to the FSP is severed, and severs it upon
   detecting a up->down transition on CD.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      4d2bb3f5
    • B
      powerpc/udbg: Register udbg console generically · dd2e356a
      由 Benjamin Herrenschmidt 提交于 
      When CONFIG_PPC_EARLY_DEBUG is set, call register_early_udbg_console()
early from generic code.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      dd2e356a
  59. 04 5月, 2011 1 次提交