PPC_INVALIDATE_ERAT is slbia IH=7 which is a new variant introduced
with POWER9, and the result is undefined on earlier CPUs.

Commits 7b9f71f9 ("powerpc/64s: POWER9 machine check handler") and
d4748276 ("powerpc/64s: Improve local TLB flush for boot and MCE on
POWER9") caused POWER7/8 code to use this instruction. Remove it. An
ERAT flush can be made by invalidatig the SLB, but before POWER9 that
requires a flush and rebolt.

Fixes: 7b9f71f9 ("powerpc/64s: POWER9 machine check handler")
Fixes: d4748276 ("powerpc/64s: Improve local TLB flush for boot and MCE on POWER9")
Cc: stable@vger.kernel.org # v4.11+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

If CONFIG_PPC_WATCHDOG is enabled we always cap the decrementer to
0x7fffffff:

       if (IS_ENABLED(CONFIG_PPC_WATCHDOG))
                set_dec(0x7fffffff);
        else
                set_dec(decrementer_max);

If there are no future events, we don't reprogram the decrementer
after this and we end up with 0x7fffffff even on a large decrementer
capable system.

As suggested by Nick, add a set_state_oneshot_stopped callback
so we program the decrementer with decrementer_max if there are
no future events.
Signed-off-by: Anton Blanchard <anton@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

We currently cap the decrementer clockevent at 4 seconds, even on systems
with large decrementer support. Fix this by converting the code to use
clockevents_register_device() which calculates the upper bound based on
the max_delta passed in.
Signed-off-by: Anton Blanchard <anton@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This threshold is no longer used now that all invalidates issue a single
ATSD to each active NPU.
Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Prior to this change only two types of ATSDs were issued to the NPU:
invalidates targeting a single page and invalidates targeting the whole
address space. The crossover point happened at the configurable
atsd_threshold which defaulted to 2M. Invalidates that size or smaller
would issue per-page invalidates for the whole range.

The NPU supports more invalidation sizes however: 64K, 2M, 1G, and all.
These invalidates target addresses aligned to their size. 2M is a common
invalidation size for GPU-enabled applications because that is a GPU
page size, so reducing the number of invalidates by 32x in that case is a
clear improvement.

ATSD latency is high in general so now we always issue a single invalidate
rather than multiple. This will over-invalidate in some cases, but for any
invalidation size over 2M it matches or improves the prior behavior.
There's also an improvement for single-page invalidates since the prior
version issued two invalidates for that case instead of one.

With this change all issued ATSDs now perform a flush, so the flush
parameter has been removed from all the helpers.

To show the benefit here are some performance numbers from a
microbenchmark which creates a 1G allocation then uses mprotect with
PROT_NONE to trigger invalidates in strides across the allocation.

One NPU (1 GPU):

         mprotect rate (GB/s)
Stride   Before      After      Speedup
64K         5.3        5.6           5%
1M         39.3       57.4          46%
2M         49.7       82.6          66%
4M        286.6      285.7           0%

Two NPUs (6 GPUs):

         mprotect rate (GB/s)
Stride   Before      After      Speedup
64K         6.5        7.4          13%
1M         33.4       67.9         103%
2M         38.7       93.1         141%
4M        356.7      354.6          -1%

Anything over 2M is roughly the same as before since both cases issue a
single ATSD.
Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com>
Reviewed-By: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

There are two types of ATSDs issued to the NPU: invalidates targeting a
specific virtual address and invalidates targeting the whole address
space. In both cases prior to this change, the sequence was:

    for each NPU
        - Write the target address to the XTS_ATSD_AVA register
        - EIEIO
        - Write the launch value to issue the ATSD

First, a target address is not required when invalidating the whole
address space, so that write and the EIEIO have been removed. The AP
(size) field in the launch is not needed either.

Second, for per-address invalidates the above sequence is inefficient in
the common case of multiple NPUs because an EIEIO is issued per NPU. This
unnecessarily forces the launches of later ATSDs to be ordered with the
launches of earlier ones. The new sequence only issues a single EIEIO:

    for each NPU
        - Write the target address to the XTS_ATSD_AVA register
    EIEIO
    for each NPU
        - Write the launch value to issue the ATSD

Performance results were gathered using a microbenchmark which creates a
1G allocation then uses mprotect with PROT_NONE to trigger invalidates in
strides across the allocation.

With only a single NPU active (one GPU) the difference is in the noise for
both types of invalidates (+/-1%).

With two NPUs active (on a 6-GPU system) the effect is more noticeable:

         mprotect rate (GB/s)
Stride   Before      After      Speedup
64K         5.9        6.5          10%
1M         31.2       33.4           7%
2M         36.3       38.7           7%
4M        322.6      356.7          11%
Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Clean up the leftover of commit f2910f0e ("powerpc: remove old
GCC version checks").
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

When enumerating page size definitions to check hardware support,
we construct a constant which is (1U << (def->shift - 10)).

However, the array of page size definitions is only initalised for
various MMU_PAGE_* constants, so it contains a number of 0-initialised
elements with def->shift == 0. This means we end up shifting by a
very large number, which gives the following UBSan splat:

================================================================================
UBSAN: Undefined behaviour in /home/dja/dev/linux/linux/arch/powerpc/mm/tlb_nohash.c:506:21
shift exponent 4294967286 is too large for 32-bit type 'unsigned int'
CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.0-rc3-00045-ga604f927b012-dirty #6
Call Trace:
[c00000000101bc20] [c000000000a13d54] .dump_stack+0xa8/0xec (unreliable)
[c00000000101bcb0] [c0000000004f20a8] .ubsan_epilogue+0x18/0x64
[c00000000101bd30] [c0000000004f2b10] .__ubsan_handle_shift_out_of_bounds+0x110/0x1a4
[c00000000101be20] [c000000000d21760] .early_init_mmu+0x1b4/0x5a0
[c00000000101bf10] [c000000000d1ba28] .early_setup+0x100/0x130
[c00000000101bf90] [c000000000000528] start_here_multiplatform+0x68/0x80
================================================================================

Fix this by first checking if the element exists (shift != 0) before
constructing the constant.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Add call to early_memtest() so that kernel compiled with
CONFIG_MEMTEST really perform memtest at startup when requested
via 'memtest' boot parameter.
Tested-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

When a process allocates a hugepage, the following leak is
reported by kmemleak. This is a false positive which is
due to the pointer to the table being stored in the PGD
as physical memory address and not virtual memory pointer.

unreferenced object 0xc30f8200 (size 512):
  comm "mmap", pid 374, jiffies 4872494 (age 627.630s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<e32b68da>] huge_pte_alloc+0xdc/0x1f8
    [<9e0df1e1>] hugetlb_fault+0x560/0x8f8
    [<7938ec6c>] follow_hugetlb_page+0x14c/0x44c
    [<afbdb405>] __get_user_pages+0x1c4/0x3dc
    [<b8fd7cd9>] __mm_populate+0xac/0x140
    [<3215421e>] vm_mmap_pgoff+0xb4/0xb8
    [<c148db69>] ksys_mmap_pgoff+0xcc/0x1fc
    [<4fcd760f>] ret_from_syscall+0x0/0x38

See commit a984506c ("powerpc/mm: Don't report PUDs as
memory leaks when using kmemleak") for detailed explanation.

To fix that, this patch tells kmemleak to ignore the allocated
hugepage table.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The comments in this file don't conform to the coding style so take
them to "Comment Formatting Re-Education Camp".
Suggested-by: Michael "Camp Drill Sergeant" Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Neuling <mikey@neuling.org>
[mpe: Reflow some comments and add full stops, fix spelling of Sergeant.]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

for 64bit configs which use for CONFIG_LOG_BUF_SHIFT the same
or higher value than the default (currently 17).
Signed-off-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Remove duplicated include.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The code in machine_check_exception excludes 64s hvmode when
incrementing the MCE counter only to call opal_machine_check to
increment it specifically for this case.

Remove the exclusion and special case.

Fixes: a43c1590 ("powerpc/pseries: Flush SLB contents on SLB MCE
		errors.")
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

On a kernel TM Bad thing program exception, the Machine State Register
(MSR) is not being properly displayed. The exception code dumps a 32-bits
value but MSR is a 64 bits register for all platforms that have HTM
enabled.

This patch dumps the MSR value as a 64-bits value instead of 32 bits. In
order to do so, the 'reason' variable could not be used, since it trimmed
MSR to 32-bits (int).
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Currently msr_tm_active() is a wrapper around MSR_TM_ACTIVE() if
CONFIG_PPC_TRANSACTIONAL_MEM is set, or it is just a function that
returns false if CONFIG_PPC_TRANSACTIONAL_MEM is not set.

This function is not necessary, since MSR_TM_ACTIVE() just do the same and
could be used, removing the dualism and simplifying the code.

This patchset remove every instance of msr_tm_active() and replaced it
by MSR_TM_ACTIVE().
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

There is a mismatch between function pnv_platform_error_reboot() definition
and declaration regarding function modifiers. In the declaration part, it
contains the function attribute __noreturn, while function definition
itself lacks it.

This was reported by sparse tool as an error:

  arch/powerpc/platforms/powernv/opal.c:538:6: error: symbol 'pnv_platform_error_reboot' redeclared with different type (originally declared at arch/powerpc/platforms/powernv/powernv.h:11) - different modifiers

I checked and the function is already being considered as being 'noreturn'
by the compiler, thus, I understand this patch does not change any code
being generated.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch adds a new test for the new PTRACE_SYSEMU ptrace request.

This test also relies on PTRACE_GETREGS and PTRACE_SETREGS requests to
run properly, since the trace instruction (gettid() syscall) is being
modified at run-time (by PTRACE_SETREGS) and re-executed three times.
PTRACE_GETREGS is being used to check that the registers are still
sane.

This test basically creates a child process that executes syscalls
and the parent process check if it is being traced appropriately.  The
parent process guarantees that the SYSCALLs are being traced, with
PTRACE_SYSEMU, and ptrace stops the child application before a syscall is
executed. The way the tests validates it, is by guaranteeing that the
system calls arguments, as argv[0] (r3) which is the same register that
will have the syscall return value on powerpc, are not being corrupted on
PTRACE_SYSEMU with a return value, i.e, it continues to have the current
arguments instead, meaning that the registers where not clobbered.

This test is basically the same test for x86 located at
tools/testing/selftests/x86/ptrace_syscall.c, limited to test PTRACE_SYSEMU
request, and ported to PowerPC.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This is a patch that adds support for PTRACE_SYSEMU ptrace request in
PowerPC architecture.

When ptrace(PTRACE_SYSEMU, ...) request is called, it will be handled by
the arch independent function ptrace_resume(), which will tag the task with
the TIF_SYSCALL_EMU flag. This flag needs to be handled from a platform
dependent point of view, which is what this patch does.

This patch adds this task's flag as part of the _TIF_SYSCALL_DOTRACE, which
is the MACRO that is used to trace syscalls at entrance/exit.

Since TIF_SYSCALL_EMU is now part of _TIF_SYSCALL_DOTRACE, if the task has
_TIF_SYSCALL_DOTRACE set, it will hit do_syscall_trace_enter() at syscall
entrance and do_syscall_trace_leave() at syscall leave.
do_syscall_trace_enter() needs to handle the TIF_SYSCALL_EMU flag properly,
which will interrupt the syscall executing if TIF_SYSCALL_EMU is set. The
output values should not be changed, i.e. the return value (r3) should
contain the original syscall argument on exit.

With this flag set, the syscall is not executed fundamentally, because
do_syscall_trace_enter() is returning -1 which is bigger than NR_syscall,
thus, skipping the syscall execution and exiting userspace.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Moving TIF_32BIT to use bit 20 instead of 4 in the task flag field.

This change is making room for an upcoming new task macro
(_TIF_SYSCALL_EMU) which is preferred to set a bit in the lower 16-bits
part of the word.

This upcoming flag macro will take part in a composed macro
(_TIF_SYSCALL_DOTRACE) which will contain other flags as well, and it is
preferred that the whole _TIF_SYSCALL_DOTRACE macro only sets the lower 16
bits of a word, so, it could be handled using immediate operations (as load
immediate, add immediate, ...) where the immediate operand (SI) is limited
to 16-bits.

Another possible solution would be using the LOAD_REG_IMMEDIATE() macro
to load a full 64-bits word immediate, but it takes 5 operations instead of
one.

Having TIF_32BITS being redefined to use an upper bit is not a problem
since there is only one place in the assembly code where TIF_32BIT is being
used, and it could be replaced with an operation with right shift (addis),
since it is used alone, i.e. not being part of a composed macro, which has
different bits set, and would require LOAD_REG_IMMEDIATE().

Tested on a 64 bits Big Endian machine running a 32 bits task.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

On PPC64, as register r13 points to the paca_struct at all time,
this patch adds a copy of the canary there, which is copied at
task_switch.
That new canary is then used by using the following GCC options:
-mstack-protector-guard=tls
-mstack-protector-guard-reg=r13
-mstack-protector-guard-offset=offsetof(struct paca_struct, canary))
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This functionality was tentatively added in the past
(commit 6533b7c1 ("powerpc: Initial stack protector
(-fstack-protector) support")) but had to be reverted
(commit f2574030 ("powerpc: Revert the initial stack
protector support") because of GCC implementing it differently
whether it had been built with libc support or not.

Now, GCC offers the possibility to manually set the
stack-protector mode (global or tls) regardless of libc support.

This time, the patch selects HAVE_STACKPROTECTOR only if
-mstack-protector-guard=tls is supported by GCC.

On PPC32, as register r2 points to current task_struct at
all time, the stack_canary located inside task_struct can be
used directly by using the following GCC options:
-mstack-protector-guard=tls
-mstack-protector-guard-reg=r2
-mstack-protector-guard-offset=offsetof(struct task_struct, stack_canary))

The protector is disabled for prom_init and bootx_init as
it is too early to handle it properly.

 $ echo CORRUPT_STACK > /sys/kernel/debug/provoke-crash/DIRECT
[  134.943666] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: lkdtm_CORRUPT_STACK+0x64/0x64
[  134.943666]
[  134.955414] CPU: 0 PID: 283 Comm: sh Not tainted 4.18.0-s3k-dev-12143-ga3272be41209 #835
[  134.963380] Call Trace:
[  134.965860] [c6615d60] [c001f76c] panic+0x118/0x260 (unreliable)
[  134.971775] [c6615dc0] [c001f654] panic+0x0/0x260
[  134.976435] [c6615dd0] [c032c368] lkdtm_CORRUPT_STACK_STRONG+0x0/0x64
[  134.982769] [c6615e00] [ffffffff] 0xffffffff
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Move the dereference of xc below the NULL test.
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

When CONFIG_VIRT_CPU_ACCOUNTING_NATIVE is not set, we look up dtl_idx in
the lppaca to determine the number of entries in the buffer. Since
lppaca is in big endian, we need to do an endian conversion before using
this in our calculation to determine the number of entries in the
buffer. Without this, we do not iterate over the existing entries in the
DTL buffer properly.

Fixes: 7c105b63 ("powerpc: Add CONFIG_CPU_LITTLE_ENDIAN kernel config option.")
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

When CONFIG_VIRT_CPU_ACCOUNTING_NATIVE is not set, we register the DTL
buffer for a cpu when the associated file under powerpc/dtl in debugfs
is opened. When doing so, we need to set the size of the buffer being
registered in the second u32 word of the buffer. This needs to be in big
endian, but we are not doing the conversion resulting in the below error
showing up in dmesg:

	dtl_start: DTL registration for cpu 0 (hw 0) failed with -4

Fix this in the obvious manner.

Fixes: 7c105b63 ("powerpc: Add CONFIG_CPU_LITTLE_ENDIAN kernel config option.")
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

PPC32 uses nonrecoverable_exception() while PPC64 uses
unrecoverable_exception().

Both functions are doing almost the same thing.

This patch removes nonrecoverable_exception()
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael 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.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Michael 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.
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Instead of calling both of_irq_parse_one() and
irq_create_of_mapping(), call of_irq_get() instead which does
essentially the same thing. of_irq_get() also calls irq_find_host()
for deferred probe support, but this should be fine as
irq_create_of_mapping() also calls that internally. This gets us
closer to making the former 2 functions static.

In the process of simplifying request_event_sources_irqs(), combine
the the pr_err() and WARN_ON() calls to just a WARN().
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Instead of calling both of_irq_parse_one() and
irq_create_of_mapping(), call of_irq_parse_and_map() instead which
does the same thing. This gets us closer to making the former 2
functions static.
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

We need to make sure pmd_trans_huge returns false for a pmd migration entry.
We mark the migration entry by clearing the _PAGE_PRESENT bit. We keep the
_PAGE_PTE bit set to indicate a leaf page table entry. Hence we need to make
sure we check for pmd_present() so that pmd_trans_huge won't return true on
pmd migration entry.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Make sure we are operating on THP and hugetlb entries in the respective hash
fault handling routines.

No functional change in this patch. If we walked the table wrongly before, we
will retry the access.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Update few code paths to check for pmd_large.

set_pmd_at:
We want to use this to store swap pte at pmd level. For swap ptes we don't want
to set H_PAGE_THP_HUGE. Hence check for pmd_large in set_pmd_at. This remove
the false WARN_ON when using this with swap pmd entry.

pmd_page:
We don't really use them on pmd migration entries. But they can also work with
migration entries and we don't differentiate at the pte level. Hence update
pmd_page to work with pmd migration entries too

__find_linux_pte:
lockless page table walk need to handle pmd migration entries. pmd_trans_huge
check will return false on them. We don't set thp = 1 for such entries, but
update hpage_shift correctly. Without this we will walk pmd migration entries
as a pte page pointer which is wrong.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This make hugetlb directory pointer similar to other page able entries. A hugepd
entry is identified by lack of _PAGE_PTE bit set and directory size stored in
HUGEPD_SHIFT_MASK. We update that to also look at _PAGE_PRESENT
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

With this patch we use 0x8000000000000000UL (_PAGE_PRESENT) to indicate a valid
pgd/pud/pmd entry. We also switch the p**_present() to look at this bit.

With pmd_present, we have a special case. We need to make sure we consider a
pmd marked invalid during THP split as present. Right now we clear the
_PAGE_PRESENT bit during a pmdp_invalidate. Inorder to consider this special
case we add a new pte bit _PAGE_INVALID (mapped to _RPAGE_SW0). This bit is
only used with _PAGE_PRESENT cleared. Hence we are not really losing a pte bit
for this special case. pmd_present is also updated to look at _PAGE_INVALID.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Ever since fast reboot is enabled by default in opal,
opal_cec_reboot() will use fast-reset instead of full IPL to perform
system reboot. This leaves the user with no direct way to force a full
IPL reboot except changing an nvram setting that persistently disables
fast-reset for all subsequent reboots.

This patch provides a more direct way for the user to force a one-shot
full IPL reboot by passing the command line argument 'full' to the
reboot command. So the user will be able to tweak the reboot behavior
via:

  $ sudo reboot full	# Force a full ipl reboot skipping fast-reset

  or
  $ sudo reboot  	# default reboot path (usually fast-reset)

The reboot command passes the un-parsed command argument to the kernel
via the 'Reboot' syscall which is then passed on to the arch function
pnv_restart(). The patch updates pnv_restart() to handle this cmd-arg
and issues opal_cec_reboot2 with OPAL_REBOOT_FULL_IPL to force a full
IPL reset.
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Acked-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

In power7_marked_instr_event() there is a switch case that is missing
a break or an explicit fallthrough, it's not immediately clear which
it should be.

The function determines based on the PMU event code, whether the event
is a "marked" event (which then requires us to configure the PMU in a
certain way). On Power7 there is no specific bit(s) in the event to
tell us that, we just have to know.

Rather than having a full list of every event and whether they are
marked, we pull apart the event code and for events with certain
values of certain fields we can say that those are all marked events.

We take the psel (bits 0-7) of the event, and look at bits 4-7. For a
value of 6 we say that if the entire psel == 0x64 then if the pmc == 3
the event is marked, else not, and otherwise we continue.

It is then that we fallthrough to the 8 case, where we return true if
the unit == 0xd.

The question is should the 6 case also fallthrough and check for
unit == 0xd, or should it return.

Looking at the full list of events we see that there are zero events
where (psel >> 4) == 0x6 and unit == 0xd.

So the answer is it doesn't really matter, there are no valid event
codes that will return a different result whether we fallthrough or
break.

But equally, testing the 6 case events against unit == 0xd is slightly
bogus, as there are no such events. So to make the code clearer, and
avoid any future confusion, have the 6 case break rather than falling
through.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>

This reverts commits:
  5e46e29e ("powerpc/64s/hash: convert SLB miss handlers to C")
  8fed04d0 ("powerpc/64s/hash: remove user SLB data from the paca")
  655deecf ("powerpc/64s/hash: SLB allocation status bitmaps")
  2e162674 ("powerpc/64s/hash: provide arch_setup_exec hooks for hash slice setup")
  89ca4e12 ("powerpc/64s/hash: Add a SLB preload cache")

This series had a few bugs, and the fixes are not all trivial. So
revert most of it for now.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Firmware-Assisted Dump (FADump) needs to be registered again after any
memory hot add/remove operation to update the crash memory ranges. But
currently, the kernel returns '-EEXIST' if we try to register without
uregistering it first. This could expose the system to racing issues
while unregistering and registering FADump from userspace during udev
events. Spare the userspace of this and let it be taken care of in the
kernel space for a simpler interface.

Since this change, running 'echo 1 > /sys/kernel/fadump_registered'
would result in re-regisering (unregistering and registering) FADump,
if it was already registered.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Acked-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>