In the current kernel, the function flush_fp_to_thread() is not
dependent on CONFIG_PPC_FPU. So most invocations of this function
is not wrapped by CONFIG_PPC_FPU. Even through we don't really
save the FPRs to the thread struct if CONFIG_PPC_FPU is not enabled,
but there does have some runtime overhead such as the check for
tsk->thread.regs and preempt disable and enable. It really make
no sense to do that. So make it a nop when CONFIG_PPC_FPU is
disabled. Also remove the wrapped #ifdef CONFIG_PPC_FPU
when invoking this function.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

In commit c6e6771b(powerpc: Introduce VSX thread_struct and CONFIG_VSX)
we add a invocation of flush_fp_to_thread() before copying the FPR or
VSR to users. But we already invoke the flush_fp_to_thread() in this
function. So remove one of them.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

We have split the math emulation into two parts. This makes it
possible to just emulate the unimplemented floating point instructions
on these boards.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The only using of function disable_kernel_fp() was already dropped
in the commit 5daf9071 (powerpc: merge align.c).
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

For some SoC (such as the FSL BookE) even though there does have
a hardware FPU, but not all floating point instructions are
implemented. Unfortunately some versions of gcc do use these
unimplemented instructions. Then we have to enable the math emulation
to workaround this issue. It seems a little redundant to have the
support to emulate all the floating point instructions in this case.
So split the math emulation into two parts. One is for the SoC which
doesn't have FPU at all and the other for the SoC which does have the
hardware FPU and only need some special floating point instructions to
be emulated.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

There are two invocations of do_mathemu() in traps.c. And the codes
in these two places are almost the same. Introduce a locale function
to eliminate the duplication. With this change we can also make sure
that in program_check_exception() the PPC_WARN_EMULATED is invoked for
the correctly emulated math instructions.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

By doing this we can make sure that the FPU state is only flushed to
the thread struct when it is really needed.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

I got the following error on my t4240qds board.
  ntpd[2713]: unhandled signal 4 at 0fd5b448 nip 0fd5b448 lr 0fd5b424 code 30001

The root cause is that the float point instruction 'fsqrt' is used.
But this instruction is not implemented on e6500 core. Even this
does seem a gcc bug, I would like to enable the math emulation
in the kernel to workaround this kind of issue.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The Kconfig symbol 8XX_MINIMAL_FPEMU was removed in commit 968219fa
("powerpc/8xx: Remove 8xx specific "minimal FPU emulation""). But that
commit didn't remove all code depending on that symbol. Do so now.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The math.c is only built when CONFIG_MATH_EMULATION is enabled.
So the #ifdef check for CONFIG_MATH_EMULATION in it seems redundant.
Drop all of them.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The math.c is only built when CONFIG_MATH_EMULATION is enabled.
So we would never get into the case that CONFIG_MATH_EMULATION
is not defined in this file.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Legacy UARTs can exist on PowerNV, memory-mapped ones on PCI
or IO based ones on the LPC bus.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Some machines might provide the console via a different mechanism
such as direct access to a UART from Linux, in which case OPAL
might not expose any console. In that case, the code would cause
a NULL dereference.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The udbg_16550 code, which we use for our early consoles and debug
backends was fairly messy. Especially for the debug consoles, it
would re-implement the "high level" getc/putc/poll functions for
each access method. It also had code to configure the UART but only
for the straight MMIO method.

This changes it to instead abstract at the register accessor level,
and have the various functions and configuration routines use these.

The result is simpler and slightly smaller code, and free support
for non-MMIO mapped PIO UARTs, which such as the ones that can be
present on a POWER 8 LPC bus.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This uses the hooks provided by CONFIG_PPC_INDIRECT_PIO to
implement a set of hooks for IO port access to use the LPC
bus via OPAL calls for the first 64K of IO space
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This includes walking the parent nodes if necessary.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Remove the generic PPC_INDIRECT_IO and ensure we only add overhead
to the right accessors. IE. If only CONFIG_PPC_INDIRECT_PIO is set,
we don't add overhead to all MMIO accessors.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The SOFT_DISABLE_INTS seems an odd name for something that updates the
software state to be consistent with interrupts being hard disabled, so
rename SOFT_DISABLE_INTS with RECONCILE_IRQ_STATE to avoid this confusion.
Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The usage of strict_strtoul() is not preferred, because
strict_strtoul() is obsolete. Thus, kstrtoul() should be
used.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

We have a bunch of CONFIG_PPC_EARLY_DEBUG_* options that are intended
for bringup/debug only. They hard wire a machine specific udbg backend
very early on (before we even probe the platform), and use whatever
tricks are available on each machine/cpu to be able to get some kind
of output out there early on.

So far, on powermac with no serial ports, we have CONFIG_PPC_EARLY_DEBUG_BOOTX
to use the low-level btext engine on the screen, but it doesn't do much, at
least on 64-bit. It only really gets enabled after the platform has been
probed and the MMU enabled.

This adds a way to enable it much earlier. From prom_init.c (while still
running with Open Firmware), we grab the screen details and set things up
using the physical address of the frame buffer.

Then btext itself uses the "rm_ci" feature of the 970 processor (Real
Mode Cache Inhibited) to access it while in real mode.

We need to do a little bit of reorg of the btext code to inline things
better, in order to limit how much we touch memory while in this mode as
the consequences might be ... interesting.

This successfully allowed me to debug problems early on with the G5
(related to gold being broken vs. ppc64 kernels).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

pci_read_bridge_bases() already checks if the PCI bus is root
bus or not, so we needn't do same check in pcibios_fixup_bus()
and just remove it.
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

PHB3 doesn't support IO ports and we needn't IO segment map for that.
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The index of one specific PCI controller (struct pci_controller::
global_number) can tell that it's primary one or not. So we needn't
additional variable for that and just remove it.
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

The patch enables fetching bus range from device-tree for the
specific PHB. If we can't get that from device-tree, the default
range [0 255] will be used.
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

We don't free PHB instance (struct pnv_phb) on error to creating
the associated PCI controler (struct pci_controller). The patch
fixes that. Also, the output messages have been cleaned for a bit
so that they looks unified for IODA_1/2 cases.
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Since 2002, the kernel has not saved VRSAVE on exception entry and
restored it on exit; rather, VRSAVE gets context-switched in _switch.
This means that when executing in process context in the kernel, the
userspace VRSAVE value is live in the VRSAVE register.

However, the signal code assumes that current->thread.vrsave holds
the current VRSAVE value, which is incorrect.  Therefore, this
commit changes it to use the actual VRSAVE register instead.  (It
still uses current->thread.vrsave as a temporary location to store
it in, as __get_user and __put_user can only transfer to/from a
variable, not an SPR.)

This also modifies the transactional memory code to save and restore
VRSAVE regardless of whether VMX is enabled in the MSR.  This is
because accesses to VRSAVE are not controlled by the MSR.VEC bit,
but can happen at any time.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Other architectures have a __get_user_pages_fast(), in addition to the
regular get_user_pages_fast(), which doesn't call get_user_pages() on
failure, and thus doesn't attempt to fault pages in or COW them.  The
generic KVM code uses __get_user_pages_fast() to detect whether a page
for which we have only requested read access is actually writable.

This provides an implementation of __get_user_pages_fast() by
splitting the existing get_user_pages_fast() in two.  With this, the
generic KVM code will get the right answer instead of always
considering such pages non-writable.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This commit adds a test of instruction counting using the PMU on powerpc.

Although the bulk of the code is architecture agnostic, the code needs to
run a precisely sized loop which is implemented in assembler.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This commit adds support code used by upcoming powerpc tests.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This commit adds a powerpc subdirectory to tools/testing/selftests,
for tests that are powerpc specific.

On other architectures nothing is built. The makefile supports cross
compilation if the user sets ARCH and CROSS_COMPILE.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

T4, Cell, powernv, and pseries had the same implementation, so switch
them to use a generic version. A2 apparently had a version, but
removed it at some point, so we remove the declaration, too.
Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Cell and PSeries both implemented their own versions of a
cpu_bootable smp_op which do the same thing (well, the PSeries
one has support for more than 2 threads). Copy the PSeries one
to generic code, and rename it smp_generic_cpu_bootable.
Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

And now the function flush_icache_range() is just a wrapper which
only invoke the function __flush_icache_range() directly. So we
don't have reason to keep it anymore.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

In function flush_icache_range(), we use cpu_has_feature() to test
the feature bit of CPU_FTR_COHERENT_ICACHE. But this seems not optimal
for two reasons:
 a) For ppc32, the function __flush_icache_range() already do this
    check with the macro END_FTR_SECTION_IFSET.
 b) Compare with the cpu_has_feature(), the method of using macro
    END_FTR_SECTION_IFSET will not introduce any runtime overhead.

[And while at it, add the missing required isync] -- BenH
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Although the shared_proc field in the lppaca works today, it is
not architected. A shared processor partition will always have a non
zero yield_count so use that instead. Create a wrapper so users
don't have to know about the details.

In order for older kernels to continue to work on KVM we need
to set the shared_proc bit. While here, remove the ugly bitfield.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Fix a sparse warning about force_32bit_msi being a one bit bitfield.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Address some of the trivial sparse warnings in arch/powerpc.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

plpar_get_term_char is only used once and just adds a layer
of complexity to H_GET_TERM_CHAR. plpar_put_term_char isn't
used at all so we can remove it.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>