While implementing TLB miss HW assistance on the 8xx, the following
warning was encountered:

[  423.732965] WARNING: CPU: 0 PID: 345 at mm/slub.c:2412 ___slab_alloc.constprop.30+0x26c/0x46c
[  423.733033] CPU: 0 PID: 345 Comm: mmap Not tainted 4.18.0-rc8-00664-g2dfff9121c55 #671
[  423.733075] NIP:  c0108f90 LR: c0109ad0 CTR: 00000004
[  423.733121] REGS: c455bba0 TRAP: 0700   Not tainted  (4.18.0-rc8-00664-g2dfff9121c55)
[  423.733147] MSR:  00021032 <ME,IR,DR,RI>  CR: 24224848  XER: 20000000
[  423.733319]
[  423.733319] GPR00: c0109ad0 c455bc50 c4521910 c60053c0 007080c0 c0011b34 c7fa41e0 c455be30
[  423.733319] GPR08: 00000001 c00103a0 c7fa41e0 c49afcc4 24282842 10018840 c079b37c 00000040
[  423.733319] GPR16: 73f00000 00210d00 00000000 00000001 c455a000 00000100 00000200 c455a000
[  423.733319] GPR24: c60053c0 c0011b34 007080c0 c455a000 c455a000 c7fa41e0 00000000 00009032
[  423.734190] NIP [c0108f90] ___slab_alloc.constprop.30+0x26c/0x46c
[  423.734257] LR [c0109ad0] kmem_cache_alloc+0x210/0x23c
[  423.734283] Call Trace:
[  423.734326] [c455bc50] [00000100] 0x100 (unreliable)
[  423.734430] [c455bcc0] [c0109ad0] kmem_cache_alloc+0x210/0x23c
[  423.734543] [c455bcf0] [c0011b34] huge_pte_alloc+0xc0/0x1dc
[  423.734633] [c455bd20] [c01044dc] hugetlb_fault+0x408/0x48c
[  423.734720] [c455bdb0] [c0104b20] follow_hugetlb_page+0x14c/0x44c
[  423.734826] [c455be10] [c00e8e54] __get_user_pages+0x1c4/0x3dc
[  423.734919] [c455be80] [c00e9924] __mm_populate+0xac/0x140
[  423.735020] [c455bec0] [c00db14c] vm_mmap_pgoff+0xb4/0xb8
[  423.735127] [c455bf00] [c00f27c0] ksys_mmap_pgoff+0xcc/0x1fc
[  423.735222] [c455bf40] [c000e0f8] ret_from_syscall+0x0/0x38
[  423.735271] Instruction dump:
[  423.735321] 7cbf482e 38fd0008 7fa6eb78 7fc4f378 4bfff5dd 7fe3fb78 4bfffe24 81370010
[  423.735536] 71280004 41a2ff88 4840c571 4bffff80 <0fe00000> 4bfffeb8 81340010 712a0004
[  423.735757] ---[ end trace e9b222919a470790 ]---

This warning occurs when calling kmem_cache_zalloc() on a
cache having a constructor.

In this case it happens because PGD cache and 512k hugepte cache are
the same size (4k). While a cache with constructor is created for
the PGD, hugepages create cache without constructor and uses
kmem_cache_zalloc(). As both expect a cache with the same size,
the hugepages reuse the cache created for PGD, hence the conflict.

In order to avoid this conflict, this patch:
- modifies pgtable_cache_add() so that a zeroising constructor is
added for any cache size.
- replaces calls to kmem_cache_zalloc() by kmem_cache_alloc()
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Instead of opencoding cache handling for the special case
of hugepage tables having a single pte_t element, this
patch makes use of the common pgtable_cache helpers
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

hugepages uses a cache of order 0. Lets allow page tables
of order 0 in the common part in order to avoid open coding
in hugetlb
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

In order to allow the 8xx to handle pte_fragments, this patch
extends the use of pte_fragments to PPC32 platforms.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

In order to handle pte_fragment functions with single fragment
without adding pte_frag in all mm_context_t, this patch creates
two helpers which do nothing on platforms using a single fragment.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This patch move pgtable_t into platform headers.

It gets rid of the CONFIG_PPC_64K_PAGES case for PPC64
as nohash/64 doesn't support CONFIG_PPC_64K_PAGES.
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

The purpose of this patch is to move platform specific
mmu-xxx.h files in platform directories like pte-xxx.h files.

In the meantime this patch creates common nohash and
nohash/32 + nohash/64 mmu.h files for future common parts.
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

There is no point in taking the page table lock as pte_frag or
pmd_frag are always NULL when we have only one fragment.
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

In preparation of next patch which generalises the use of
pte_fragment_alloc() for all, this patch moves the related functions
in a place that is common to all subarches.

The 8xx will need that for supporting 16k pages, as in that mode
page tables still have a size of 4k.

Since pte_fragment with only once fragment is not different
from what is done in the general case, we can easily migrate all
subarchs to pte fragments.
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

commit 1bc54c03 ("powerpc: rework 4xx PTE access and TLB miss")
introduced non atomic PTE updates and started the work of removing
PTE updates in TLB miss handlers, but kept PTE_ATOMIC_UPDATES for the
8xx with the following comment:
/* Until my rework is finished, 8xx still needs atomic PTE updates */

commit fe11dc3f ("powerpc/8xx: Update TLB asm so it behaves as
linux mm expects") removed all PTE updates done in TLB miss handlers

Therefore, atomic PTE updates are not needed anymore for the 8xx
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

BOOK3S/32 cannot be BOOKE, so remove useless code
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

There is a plan to build the kernel with -Wimplicit-fallthrough and these
places in the code produced warnings, but because we build arch/powerpc
with -Werror, they became errors.  Fix them up.

This patch produces no change in behaviour, but should be reviewed in
case these are actually bugs not intentional fallthoughs.
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Commit f384796c ("powerpc/mm: Add support for handling > 512TB address
in SLB miss") removed function slb_miss_bad_addr(struct pt_regs *regs), but
kept its declaration in the prototype file. This patch simply removes the
function definition.
Signed-off-by: NBreno Leitao <leitao@debian.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

When booting a pseries kernel with PREEMPT enabled, it dumps the
following warning:

   BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
   caller is pseries_processor_idle_init+0x5c/0x22c
   CPU: 13 PID: 1 Comm: swapper/0 Not tainted 4.20.0-rc3-00090-g12201a0128bc-dirty #828
   Call Trace:
   [c000000429437ab0] [c0000000009c8878] dump_stack+0xec/0x164 (unreliable)
   [c000000429437b00] [c0000000005f2f24] check_preemption_disabled+0x154/0x160
   [c000000429437b90] [c000000000cab8e8] pseries_processor_idle_init+0x5c/0x22c
   [c000000429437c10] [c000000000010ed4] do_one_initcall+0x64/0x300
   [c000000429437ce0] [c000000000c54500] kernel_init_freeable+0x3f0/0x500
   [c000000429437db0] [c0000000000112dc] kernel_init+0x2c/0x160
   [c000000429437e20] [c00000000000c1d0] ret_from_kernel_thread+0x5c/0x6c

This happens because the code calls get_lppaca() which calls
get_paca() and it checks if preemption is disabled through
check_preemption_disabled().

Preemption should be disabled because the per CPU variable may make no
sense if there is a preemption (and a CPU switch) after it reads the
per CPU data and when it is used.

In this device driver specifically, it is not a problem, because this
code just needs to have access to one lppaca struct, and it does not
matter if it is the current per CPU lppaca struct or not (i.e. when
there is a preemption and a CPU migration).

That said, the most appropriate fix seems to be related to avoiding
the debug_smp_processor_id() call at get_paca(), instead of calling
preempt_disable() before get_paca().
Signed-off-by: NBreno Leitao <leitao@debian.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Currently xmon needs to get devtree_lock (through rtas_token()) during its
invocation (at crash time). If there is a crash while devtree_lock is being
held, then xmon tries to get the lock but spins forever and never get into
the interactive debugger, as in the following case:

	int *ptr = NULL;
	raw_spin_lock_irqsave(&devtree_lock, flags);
	*ptr = 0xdeadbeef;

This patch avoids calling rtas_token(), thus trying to get the same lock,
at crash time. This new mechanism proposes getting the token at
initialization time (xmon_init()) and just consuming it at crash time.

This would allow xmon to be possible invoked independent of devtree_lock
being held or not.
Signed-off-by: NBreno Leitao <leitao@debian.org>
Reviewed-by: NThiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

PPC_STD_MMU_32 and PPC_STD_MMU are not used anymore. Remove them.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Today we have:

config PPC_BOOK3S
        def_bool y
        depends on PPC_BOOK3S_32 || PPC_BOOK3S_64

config PPC_STD_MMU
        def_bool y
        depends on PPC_BOOK3S

PPC_STD_MMU is therefore redundant with PPC_BOOK3S. Lets remove it.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Today we have:

config PPC_BOOK3S_32
        bool "512x/52xx/6xx/7xx/74xx/82xx/83xx/86xx"
        [depends on PPC32 within a choice]

config PPC_BOOK3S
        def_bool y
        depends on PPC_BOOK3S_32 || PPC_BOOK3S_64

config PPC_STD_MMU
	def_bool y
	depends on PPC_BOOK3S

config PPC_STD_MMU_32
	def_bool y
	depends on PPC_STD_MMU && PPC32

PPC_STD_MMU_32 is therefore redundant with PPC_BOOK3S_32.

In order to make the code clearer, lets use preferably PPC_BOOK3S_32.
This will allow to remove CONFIG_PPC_STD_MMU_32 in a later patch.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

asm/book3s/32/pgtable.h is only included when CONFIG_PPC_BOOK3S_32 is set.
Whenever CONFIG_PPC_BOOK3S_32 is set, CONFIG_PPC_STD_MMU_32 is set as well.

This patch removes useless CONFIG_PPC_STD_MMU_32 #ifdefs
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

CONFIG_6xx is not used anymore. Remove it.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Today we have:

config PPC_BOOK3S_32
	bool "512x/52xx/6xx/7xx/74xx/82xx/83xx/86xx"
	[depends on PPC32 within a choice]

config PPC_BOOK3S
	def_bool y
	depends on PPC_BOOK3S_32 || PPC_BOOK3S_64

config 6xx
	def_bool y
	depends on PPC32 && PPC_BOOK3S

6xx is therefore redundant with PPC_BOOK3S_32.

In order to make the code clearer, lets use preferably PPC_BOOK3S_32.
This will allow to remove CONFIG_6xx in a later patch.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Today, powerpc has three CONFIG labels which means exactly the same:
- CONFIG_6xx
- CONFIG_PPC_BOOK3S_32
- CONFIG_PPC_STD_MMU_32

By consistency with PPC64, CONFIG_PPC_BOOK3S_32 is the preferred one.
Using a label with includes _PPC_ also makes it clearer that it is
linked to powerpc.

In preparation of the removal of CONFIG_6xx, this patch replaces it
by CONFIG_PPC_BOOK3S_32
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Remove directly accessing device_node.type pointer and use the
accessors instead. This will eventually allow removing the type
pointer.
Signed-off-by: NRob Herring <robh@kernel.org>
Acked-by: NAndrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Remove directly accessing device_node.type pointer and use the
accessors instead. This will eventually allow removing the type
pointer.
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

In preparation to remove the node name pointer from struct
device_node, convert printf users to use the %pOFn format specifier.

Convert the open coded iterating thru child nodes to
for_each_child_of_node() while we're here.
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Remove directly accessing device_node.type pointer and use the
accessors instead. This will eventually allow removing the type
pointer.

Replace the open coded iterating over child nodes with
for_each_child_of_node() while we're here.
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Remove directly accessing device_node.type pointer and use the
accessors instead. This will eventually allow removing the type
pointer.

In the process, the of_stdout pointer can be used instead of finding
the stdout node again.
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This patch adds new defconfig options for powerpc KVM guest
and guest.config with additional config symbols enabled,
which is to build kernel to boot without initramfs and can be used
as place holder for guest specific additional config symbols in future.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NSatheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This patch adds missing config symbols for ppc64_defconfig
to enable cgroups, memhotplug, numa balancing and XFS
in core kernel image.
Signed-off-by: NSatheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

CONFIG_NR_CPUS is not set in ppc64_defconfig, So it gets default of 32
which is quite small for modern powerpc systems. Instead set a default
of 2048 like other powerpc defconfigs.
Signed-off-by: NSatheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Update ppc64_defconfig with savedefconfig. No symbols are added or
removed, this is 100% movement.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

In commit 539df7fc ("powerpc/configs: Enable function trace by
default") we added:

  CONFIG_FTRACE=y
  CONFIG_FUNCTION_TRACER=y
  CONFIG_FUNCTION_GRAPH_TRACER=y

To ppc64_defconfig, powernv_defconfig and pseries_defconfig.

But only CONFIG_FUNCTION_TRACER=y is required, CONFIG_FTRACE is
default y if DEBUG_KERNEL is enabled, which we have. And then
CONFIG_FUNCTION_GRAPH_TRACER is default y when CONFIG_FUNCTION_TRACER
is enabled.

The extra symbols were already removed from powernv_defconfig in
commit 9a018fb1 ("powerpc/config: powernv_defconfig updates").
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Replace dma_alloc_coherent() + memset() with dma_zalloc_coherent().
Signed-off-by: NSabyasachi Gupta <sabyasachi.linux@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

There is no need to have the 'void __iomem *cpld_base' variable static
since new value always be assigned before use it.
Signed-off-by: NYue Haibing <yuehaibing@huawei.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

There is no need to have the 'intoffset' variable static since new value
always be assigned before use it.
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Reviewed-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Use DEFINE_SHOW_ATTRIBUTE macro to simplify the code.
Signed-off-by: NYangtao Li <tiny.windzz@gmail.com>
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Use DEFINE_SHOW_ATTRIBUTE macro to simplify the code.
Signed-off-by: NYangtao Li <tiny.windzz@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

When compiled for 64-bit, the PD_HUGE constant is a 64-bit integer.
Mark it as an unsigned long.

This squashes over a thousand sparse warnings on my minimal T4240RDB
(e6500, ppc64be) config, of the following 2 forms:

arch/powerpc/include/asm/hugetlb.h:52:49: warning: constant 0x8000000000000000 is so big it is unsigned long
arch/powerpc/include/asm/nohash/pgtable.h:269:49: warning: constant 0x8000000000000000 is so big it is unsigned long
Signed-off-by: NDaniel Axtens <dja@axtens.net>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Type qualifier on return type is ignored. Remove warning in W=1:

  arch/powerpc/include/asm/book3s/64/pgtable.h:1268:25: error: type qualifiers ignored on function return type [-Werror=ignored-qualifiers]
Signed-off-by: NMathieu Malaterre <malat@debian.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>