Currently, on 8641D, which doesn't set CONFIG_HAVE_HW_BREAKPOINT
we get the following splat:

BUG: using smp_processor_id() in preemptible [00000000] code: login/1382
caller is set_breakpoint+0x1c/0xa0
CPU: 0 PID: 1382 Comm: login Not tainted 3.15.0-rc3-00041-g2aafe1a4 #1
Call Trace:
[decd5d80] [c0008dc4] show_stack+0x50/0x158 (unreliable)
[decd5dc0] [c03c6fa0] dump_stack+0x7c/0xdc
[decd5de0] [c01f8818] check_preemption_disabled+0xf4/0x104
[decd5e00] [c00086b8] set_breakpoint+0x1c/0xa0
[decd5e10] [c00d4530] flush_old_exec+0x2bc/0x588
[decd5e40] [c011c468] load_elf_binary+0x2ac/0x1164
[decd5ec0] [c00d35f8] search_binary_handler+0xc4/0x1f8
[decd5ef0] [c00d4ee8] do_execve+0x3d8/0x4b8
[decd5f40] [c001185c] ret_from_syscall+0x0/0x38
 --- Exception: c01 at 0xfeee554
    LR = 0xfeee7d4

The call path in this case is:

	flush_thread
	   --> set_debug_reg_defaults
	     --> set_breakpoint
	       --> __get_cpu_var

Since preemption is enabled in the cleanup of flush thread, and
there is no need to disable it, introduce the distinction between
set_breakpoint and __set_breakpoint, leaving only the flush_thread
instance as the current user of set_breakpoint.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

None of the callers check the return value, so it might as
well not have one at all.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The arch/powerpc/include/asm/linkage.h is being unintentionally exported
in the kernel headers since commit e1b5bb6d (consolidate
cond_syscall and SYSCALL_ALIAS declarations) when
arch/powerpc/include/uapi/asm/linkage.h was deleted but the header-y not
removed from the Kbuild file. This happens because Makefile.headersinst
still checks the old asm/ directory if the specified header doesn't
exist in the uapi directory.

The asm/linkage.h shouldn't ever have been exported anyway. No other
arch does and it doesn't contain anything useful to userland, so remove
the header-y line from the Kbuild file which triggers the export.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Commit 7f52a526 ("powerpc/eeh: Allow to disable EEH") caused
following build error with "celleb_defconfig" as being catched
by Mikey on linux-next.

arch/powerpc/kernel/eeh.c: In function 'eeh_init_proc':
arch/powerpc/kernel/eeh.c:1173:37: error: 'powerpc_debugfs_root' \
undeclared (first use in this function)
arch/powerpc/kernel/eeh.c:1173:37: note: each undeclared identifier \
is reported only once for each function it appears in
Reported-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Merge "merge" branch to get two fairly important bug fixes:

powerpc/powernv: Reset root port in firmware
powerpc: irq work racing with timer interrupt can result in timer interrupt

This reverts commit b2b5efcf.

This code was way too board specific, there are quirks as to how
the PERST line is wired on different boards, we'll have to revisit
this using/creating appropriate firmware interfaces.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

I am seeing an issue where a CPU running perf eventually hangs.
Traces show timer interrupts happening every 4 seconds even
when a userspace task is running on the CPU. /proc/timer_list
also shows pending hrtimers have not run in over an hour,
including the scheduler.

Looking closer, decrementers_next_tb is getting set to
0xffffffffffffffff, and at that point we will never take
a timer interrupt again.

In __timer_interrupt() we set decrementers_next_tb to
0xffffffffffffffff and rely on ->event_handler to update it:

        *next_tb = ~(u64)0;
        if (evt->event_handler)
                evt->event_handler(evt);

In this case ->event_handler is hrtimer_interrupt. This will eventually
call back through the clockevents code with the next event to be
programmed:

static int decrementer_set_next_event(unsigned long evt,
                                      struct clock_event_device *dev)
{
        /* Don't adjust the decrementer if some irq work is pending */
        if (test_irq_work_pending())
                return 0;
        __get_cpu_var(decrementers_next_tb) = get_tb_or_rtc() + evt;

If irq work came in between these two points, we will return
before updating decrementers_next_tb and we never process a timer
interrupt again.

This looks to have been introduced by 0215f7d8 (powerpc: Fix races
with irq_work). Fix it by removing the early exit and relying on
code later on in the function to force an early decrementer:

       /* We may have raced with new irq work */
       if (test_irq_work_pending())
               set_dec(1);
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: stable@vger.kernel.org # 3.14+
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Resetting root port has more stuff to do than that for PCIe switch
ports and we should have resetting root port done in firmware instead
of the kernel itself. The problem was introduced by commit 5b2e198e
("powerpc/powernv: Rework EEH reset").

Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This series adds support for building the powerpc 64-bit
LE kernel using the new ABI v2. We already supported
running ABI v2 userspace programs but this adds support
for building the kernel itself using the new ABI.

In case of extending the eaddr in future, use this macro
PGTABLE_EADDR_SIZE to ease the maintenance of the code.
Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This patch adds an option to enable a work around for an icache bug on
476 that can cause execution of stale instructions when falling
through pages (IBM errata #46). It requires a recent version of
binutils which supports the --ppc476-workaround option.

The work around enables the appropriate linker options and ensures
that all module output sections are aligned to 4K page boundaries. The
work around is only required when building modules.
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The PPC476GTR SoC supports message signalled interrupts (MSI) by writing
to special addresses within the High Speed Transfer Assist (HSTA) module.

This patch adds support for PCI MSI with a new system device. The DMA
window is also updated to allow access to the entire 42-bit address range
to allow PCI devices write access to the HSTA module.
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This patch adds support for the IBM Akebono board.
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The IBM Akebono code uses the same initialisation functions as the
earlier Currituck board. Rather than create a copy of this code for
Akebono we will instead integrate support for it into the same file as
the Currituck code.

This patch just renames the board support file and updates the Makefile.
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

When we never get around to seeing an HEA ethernet adapter, there's
no point in restricting ourselves to 4k IO page size.

This speeds up IO maps when CONFIG_IBMEBUS is disabled.

[ Updated the test to also lift the restriction on arch 2.07
  (Power 8) which cannot have an HEA
 -- BenH ]
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

foo

Unaligned stores take alignment exceptions on POWER7 running in little-endian.
This is a dumb little-endian base memcpy that prevents unaligned stores.
Once booted the feature fixup code switches over to the VMX copy loops
(which are already endian safe).

The question is what we do before that switch over. The base 64bit
memcpy takes alignment exceptions on POWER7 so we can't use it as is.
Fixing the causes of alignment exception would slow it down, because
we'd need to ensure all loads and stores are aligned either through
rotate tricks or bytewise loads and stores. Either would be bad for
all other 64bit platforms.

[ I simplified the loop a bit - Anton ]
Signed-off-by: Philippe Bergheaud <felix@linux.vnet.ibm.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Merge Linus tree to get "cpufreq, powernv: Fix build failure on UP"
to avoid build breakages in some of my test configs.

If we do a treclaim and we are not in TM suspend mode, it results in a TM bad
thing (ie. a 0x700 program check).  Similarly if we do a trechkpt and we have
an active transaction or TEXASR Failure Summary (FS) is not set, we also take a
TM bad thing.

This should never happen, but if it does (ie. a kernel bug), the cause is
almost impossible to debug as the GPR state is mostly userspace and hence we
don't get a call chain.

This adds some checks in these cases case a BUG_ON() (in asm) in case we ever
hit these cases.  It moves the register saving around to preserve r1 till later
also.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

We save r1 to the scratch SPR and restore it from there after the trechkpt so
saving r1 to the paca is not needed.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Implement a method named pnv_get_proc_freq(unsigned int cpu) which
returns the current clock rate on the 'cpu' in Hz to be reported in
/proc/cpuinfo. This method uses the value reported by cpufreq when
such a value is sane. Otherwise it falls back to old way of reporting
the clockrate, i.e. ppc_proc_freq.

Set the ppc_md.get_proc_freq() hook to pnv_get_proc_freq() on the
PowerNV platform.
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Currently, the code in setup-common.c for powerpc assumes that all
clock rates are same in a smp system. This value is cached in the
variable named ppc_proc_freq and is the value that is reported in
/proc/cpuinfo.

However on the PowerNV platform, the clock rate is same only across
the threads of the same core. Hence the value that is reported in
/proc/cpuinfo is incorrect on PowerNV platforms. We need a better way
to query and report the correct value of the processor clock in
/proc/cpuinfo.

The patch achieves this by creating a machdep_call named
get_proc_freq() which is expected to returns the frequency in Hz. The
code in show_cpuinfo() can invoke this method to display the correct
clock rate on platforms that have implemented this method. On the
other powerpc platforms it can use the value cached in ppc_proc_freq.
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Firmware update on PowerNV platform takes several minutes. During
this time one CPU is stuck in FW and the kernel complains about "soft
lockups".

This patch returns all secondary CPUs to firmware before starting
firmware update process.

[ Reworked a bit and cleaned up -- BenH ]
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This patch updates the implementation of pci_process_bridge_OF_ranges to use
the of_pci_range_parser helpers.
Signed-off-by: Andrew Murray <amurray@embedded-bits.co.uk>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This patch adds support to legacy serial for
UARTS with shifted registers.

The MVME5100 Single Board Computer is a PowerPC platform
that has 16550 style UARTS with register addresses that are
16 bytes apart (shifted by 4).

Commit 	30925748
"powerpc: Cleanup udbg_16550 and add support for LPC PIO-only UARTs"
added support to udbg_16550 for shifted registers by adding a "stride"
parameter to the initialisation operations for Programmed IO and
Memory Mapped IO.

As a consequence it is now possible to use the services of legacy serial
to provide early serial console messages for the MVME5100.

An added benefit of this is that the serial console will always be
"ttyS0" irrespective of whether the computer is fitted with extra
PCI 8250 interface boards or not.

I have tested this patch using the four PowerPC platforms available to me:

	MVME5100 - shifted registers,
	SAM440EP - unshifted registers,
	MPC8349 - unshifted registers,
	MVME4100 - unshifted registers.
Signed-off-by: Stephen Chivers <schivers@csc.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The code is only slightly modified : entry points now use the
FIXUP_ENDIAN trampoline to switch endian order. The 32bit wrapper
is kept for big endian kernels and 64bit is enforced for little
endian kernels with a PPC64_BOOT_WRAPPER config option.

The linker script is generated using the kernel preprocessor flags
to make use of the CONFIG_* definitions and the wrapper script is
modified to take into account the new elf64ppc format.

Finally, the zImage file is compiled as a position independent
executable (-pie) which makes it loadable at any address by the
firmware.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

When entering the boot wrapper in little endian, we will need to fix
the endian order using a fixup trampoline like in the kernel. This
patch overrides the _zimage_start entry point for this purpose.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This patch adds support a 64bit wrapper entry point. As in 32bit, the
entry point does its own relocation and can be loaded at any address
by the firmware.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This patch defines a 'prom' routine similar to 'enter_prom' in the
kernel.

The difference is in the MSR which is built before entering prom. Big
endian order is enforced as in the kernel but 32bit mode is not. It
prepares ground for the next patches which will introduce Little endian
order.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

It could certainly be improved using Elf macros and byteswapping
routines, but the initial version of the code is organised to be a
single file program with limited dependencies. yaboot is the same.

Please scream if you want a total rewrite.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

These are not the most efficient versions of swab but the wrapper does
not do much byte swapping. On a big endian cpu, these routines are
a no-op.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/boot/oflib.c:211:9: warning: cast to pointer from integer of \
		  different size [-Wint-to-pointer-cast]
  return (phandle) of_call_prom("finddevice", 1, 1, name);

This is a work around. The definite solution would be to define the
phandle typedef as a u32, as in the kernel, but this would break the
device tree ops API.

Let it be for the moment.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This makes ihandle 64bit friendly.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This patch fixes 64bit compile warnings and updates the wrapper code
to converge the kernel code in prom_init.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This is mostly useful to make to the boot wrapper code closer with
the kernel code in prom_init.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Values will need to be byte-swapped when calling prom (big endian) from
a little endian boot wrapper.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This patch updates the wrapper code to converge with the kernel code in
prom_init.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This patch fixes warnings when the wrapper is compiled in 64bit and
updates the boot wrapper code related to prom to converge with the
kernel code in prom_init. This should make the review of changes easier.

The kernel has a different number of possible arguments (10) when
entering prom. There does not seem to be any good reason to have
12 in the wrapper, so the patch changes this value to args[10] in
the prom_args struct.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

When the boot wrapper is compiled in 64bit, there is no need to
use __div64_32.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>