Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

This patch modifies the initial page mapping functions in the following way:

During bootup the init, text and data pages will be mapped RWX and if
supported, with huge pages.

At final stage of the bootup, the kernel calls free_initmem() and then all
pages will be remapped either R-X (for text and read-only data) or RW- (for
data). The __init pages will be dropped.

This reflects the behaviour of the x86 platform.
Signed-off-by: Helge Deller <deller@gmx.de>

When running an SMP kernel on a single-CPU machine, we can speed up the
CAS code by replacing the LDCW sync barrier with NOP.
Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

The LEVEL define clashed with the DRBD code.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v4.14+

LEVEL is a very common word, and now after many years it suddenly
clashed with another LEVEL define in the DRBD code.
Rename it to PA_ASM_LEVEL instead.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org>

This patch updates the parisc huge TLB page support to use per-pagetable spinlocks.

This patch requires Mikulas' per-pagetable spinlock patch and the revised TLB
serialization patch from Helge and myself.  With Mikulas' patch, we need to use
the per-pagetable spinlock for page table updates.  The TLB lock is only used
to serialize TLB flushes on machines with the Merced bus.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

PA-RISC uses a global spinlock to protect pagetable updates in the TLB
fault handlers. When multiple cores are taking TLB faults simultaneously,
the cache line containing the spinlock becomes a bottleneck.

This patch embeds the spinlock in the top level page directory, so that
every process has its own lock. It improves performance by 30% when
doing parallel compilations.

At least on the N class systems, only one PxTLB inter processor
broadcast can be active at any one time on the Merced bus. If a Merced
bus is found, this patch serializes the TLB flushes with the
pa_tlb_flush_lock spinlock.

v1: Initial patch by Mikulas
v2: Added Merced detection by Helge
v3: Revised TLB serialization by Dave & Helge
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

When making the text sections writeable with set_kernel_text_rw(1),
include all text sections including those in the __init section.
Otherwise functions marked with __meminit will stay read-only.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org>	# 4.20+

Add compiler memory barriers to ensure the compiler doesn't reorder memory
operations around these instructions.

Cc: stable@vger.kernel.org # v4.20+
Fixes: 3847dab7 ("parisc: Add alternative coding infrastructure")
Signed-off-by: Helge Deller <deller@gmx.de>

The pdtlb and pitlb instructions are strongly ordered. The asms invoking
these instructions should be compiler memory barriers to ensure the
compiler doesn't reorder memory operations around these instructions.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
CC: stable@vger.kernel.org # v4.20+
Fixes: 3847dab7 ("parisc: Add alternative coding infrastructure")
Signed-off-by: Helge Deller <deller@gmx.de>

There are only a couple of instructions that can function as a memory
barrier on parisc.  Currently, we use the sync instruction as a memory
barrier when releasing a spinlock.  However, the ldcw instruction is a
better barrier when we have a handy memory location since it operates in
the cache on coherent machines.

This patch updates the spinlock release code to use ldcw.  I also
changed the "stw,ma" instructions to "stw" instructions as it is not an
adequate barrier.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

TLB operations only need to be serialized on machines with the Merced
(Stretch) bus. The only machines in this category are L and N class, and
they require a 64-bit PA 2.0 kernel. On these machines, we use local TLB
purges in the tmpalias routines.
We don't need to serialize TLB purges on all other machines. Thus, the
lock/unlock code can be removed when CONFIG_PA20 is not defined.
Further, when CONFIG_PA20 is not defined, alternative patching converts
the TLB purges to local purges when PA 2.0 hardware has been detected.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Tested-By: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

The commit 1c30844d ("mm: reclaim small amounts of memory when an
external fragmentation event occurs") breaks memory management on a
parisc c8000 workstation with this memory layout:

	0) Start 0x0000000000000000 End 0x000000003fffffff Size   1024 MB
	1) Start 0x0000000100000000 End 0x00000001bfdfffff Size   3070 MB
	2) Start 0x0000004040000000 End 0x00000040ffffffff Size   3072 MB

With the patch 1c30844d, the kernel will incorrectly reclaim the
first zone when it fills up, ignoring the fact that there are two
completely free zones. Basiscally, it limits cache size to 1GiB.

The parisc kernel is currently using the DISCONTIGMEM implementation,
but isn't NUMA. Avoid this issue or strange work-arounds by switching to
the more commonly used SPARSEMEM implementation.
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 1c30844d ("mm: reclaim small amounts of memory when an external fragmentation event occurs")
Signed-off-by: Helge Deller <deller@gmx.de>

The idle task might have been allocated above 4GB. With the current code
we cannot access that memory because the CPU is still running in narrow
mode.
This was found on a J5000 machine and the patch is required to enable
SPARSEMEM on that machine.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Update lists to reflect that we have now KGDB and kretprobes
support.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

It's not used by patch_map()/patch_unmap(), so lets remove
it.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Now that kprobes and kretprobes are implemented, update the list in
Documentation to reflect that.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Implement kretprobes on parisc, parts stolen from powerpc.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

We're providing our own version now.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Implement kprobes support for PA-RISC.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

implement regs_get_register(), regs_get_kernel_stack_nth() and
regs_within_kernel_stack()
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Even a 32-bit kernel requires at least 27 MB to decompress itself, so
halt the system with a message if the system has less memory than 32 MB.
Signed-off-by: Helge Deller <deller@gmx.de>

No need to spend CPU cycles when we run on QEMU.
Signed-off-by: Helge Deller <deller@gmx.de>
CC: stable@vger.kernel.org # v4.9+

Do not loose cycles when we run on QEMU, and fix one trivial typo.
Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>
CC: stable@vger.kernel.org # v4.9+

This patch add KGDB support to PA-RISC. It also implements
single-stepping utilizing the recovery counter.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Instead of re-mapping the whole kernel text with RWX rights
add a patch_text() which can be used to replace instructions
in the kernel .text section. Based on the ARM implementation.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

These functions will be used for adding code patching
functions later.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Do not offset mmap base address because of stack randomization if
current task does not want randomization.
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Signed-off-by: Helge Deller <deller@gmx.de>