commit 8865bbe6ba1120e67f72201b7003a16202cd42be upstream.

PA-RISC defines a get_cycles() function, but it does not do the usual
`#define get_cycles get_cycles` dance, making it impossible for generic
code to see if an arch-specific function was defined. While the
get_cycles() ifdef is not currently used, the following timekeeping
patch in this series will depend on the macro existing (or not existing)
when defining random_get_entropy().

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This change fixes the following:

1) The flags variable is not initialized. Always use raw_spin_lock_irqsave
and raw_spin_unlock_irqrestore to serialize patching.

2) flush_kernel_vmap_range is primarily intended for DMA flushes.
The whole cache flush in flush_kernel_vmap_range is only possible
when interrupts are enabled on SMP machines. Since __patch_text_multiple
calls flush_kernel_vmap_range with interrupts disabled, it is better
to directly call flush_kernel_dcache_range_asm and
flush_kernel_icache_range_asm.

3) The final call to flush_icache_range is unnecessary.

Tested with `[PATCH, V3] parisc: Rewrite cache flush code for
PA8800/PA8900' change on rp3440, c8000 and c3750 (32 and 64-bit).

Note by Helge:
This patch had been temporarily reverted shortly before v5.18-rc6 in order
to fix boot issues. Now it can be re-applied.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

Originally, I was convinced that we needed to use tmpalias flushes
everwhere, for both user and kernel flushes. However, when I modified
flush_kernel_dcache_page_addr, to use a tmpalias flush, my c8000
would crash quite early when booting.

The PDC returns alias values of 0 for the icache and dcache. This
indicates that either the alias boundary is greater than 16MB or
equivalent aliasing doesn't work. I modified the tmpalias code to
make it easy to try alternate boundaries. I tried boundaries up to
128MB but still kernel tmpalias flushes didn't work on c8000.

This led me to conclude that tmpalias flushes don't work on PA8800
and PA8900 machines, and that we needed to flush directly using the
virtual address of user and kernel pages. This is likely the major
cause of instability on the c8000 and rp34xx machines.

Flushing user pages requires doing a temporary context switch as we
have to flush pages that don't belong to the current context. Further,
we have to deal with pages that aren't present. If a page isn't
present, the flush instructions fault on every line.

Other code has been rearranged and simplified based on testing. For
example, I introduced a flush_cache_dup_mm routine. flush_cache_mm
and flush_cache_dup_mm differ in that flush_cache_mm calls
purge_cache_pages and flush_cache_dup_mm calls flush_cache_pages.
In some implementations, pdc is more efficient than fdc. Based on
my testing, I don't believe there's any performance benefit on the
c8000.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

Change the "BUG" to "WARNING" and disable the message because it triggers
occasionally in spite of the check in flush_cache_page_if_present.

The pte value extracted for the "from" page in copy_user_highpage is racy and
occasionally the pte is cleared before the flush is complete.  I assume that
the page is simultaneously flushed by flush_cache_mm before the pte is cleared
as nullifying the fdc doesn't seem to cause problems.

I investigated various locking scenarios but I wasn't able to find a way to
sequence the flushes.  This code is called for every COW break and locks impact
performance.

This patch is related to the bigger cache flush patch because we need the pte
on PA8800/PA8900 to flush using the vma context.
I have also seen this from copy_to_user_page and copy_from_user_page.

The messages appear infrequently when enabled.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

This reverts commit a58e9d0984e8dad53f17ec73ae3c1cc7f8d88151.

Triggers segfaults with 32-bit kernels on PA8500 machines.

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

The cr16 interval timers are not synchronized across CPUs, even with just
one dual-core CPU. This becomes visible if the machines have a longer
uptime.

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

Various spelling mistakes in comments.
Detected with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Helge Deller <deller@gmx.de>

Dave noticed that for the 32-bit kernel MAX_ADDRESS should be a ULL,
otherwise this define would become 0:
	MAX_ADDRESS   (1UL << MAX_ADDRBITS)
It has no real effect on the kernel.

Signed-off-by: Helge Deller <deller@gmx.de>
Noticed-by: John David Anglin <dave.anglin@bell.net>

The Linux tool "lscpu" shows the double amount of CPUs if we have
"model" and "model name" in two different lines in /proc/cpuinfo.
This change combines the model and the model name into one line.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org

In commit 62773112acc5 ("parisc: Switch from GENERIC_CPU_DEVICES to
GENERIC_ARCH_TOPOLOGY") GENERIC_CPU_DEVICES was unconditionally turned
off, but this triggers a warning in topology_add_dev(). Turning it back
on for the !SMP case avoids this warning.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Fixes: 62773112acc5 ("parisc: Switch from GENERIC_CPU_DEVICES to GENERIC_ARCH_TOPOLOGY")
Signed-off-by: Helge Deller <deller@gmx.de>