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commit 884b4269 upstream.

If copy_from_user is called with a large buffer (>= 128 bytes) and the
userspace buffer refers partially to unreadable memory, then it is
possible for Octeon's copy_from_user to report the wrong number of bytes
have been copied. In the case where the buffer size is an exact multiple
of 128 and the fault occurs in the last 64 bytes, copy_from_user will
report that all the bytes were copied successfully but leave some
garbage in the destination buffer.

The bug is in the main __copy_user_common loop in octeon-memcpy.S where
in the middle of the loop, src and dst are incremented by 128 bytes. The
l_exc_copy fault handler is used after this but that assumes that
"src < THREAD_BUADDR($28)". This is not the case if src has already been
incremented.

Fix by adding an extra fault handler which rewinds the src and dst
pointers 128 bytes before falling though to l_exc_copy.

Thanks to the pwritev test from the strace test suite for originally
highlighting this bug!

Fixes: 5b3b1688

 ("MIPS: Add Cavium OCTEON processor support ...")
Signed-off-by: James Cowgill <James.Cowgill@imgtec.com>
Acked-by: David Daney <david.daney@cavium.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14978/

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

Having received another series of whitespace patches I decided to do this
once and for all rather than dealing with this kind of patches trickling
in forever.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

No 32-bit kernels supported on Octeon.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

The generic version seems to prefetch past the end of memory.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3929/

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

These are the rest of the new files needed to add OCTEON processor
support to the Linux kernel.  Other than Makefile and Kconfig which
should be obvious, we have:

csrc-octeon.c   -- Clock source driver for OCTEON.
dma-octeon.c    -- Helper functions for mapping DMA memory.
flash_setup.c   -- Register on-board flash with the MTD subsystem.
octeon-irq.c    -- OCTEON interrupt controller managment.
octeon-memcpy.S -- Optimized memcpy() implementation.
serial.c        -- Register 8250 platform driver and early console.
setup.c         -- Early architecture initialization.
smp.c           -- OCTEON SMP support.
octeon_switch.S -- Scheduler context switch for OCTEON.
c-octeon.c      -- OCTEON cache controller support.
cex-oct.S       -- OCTEON cache exception handler.

asm/mach-cavium-octeon/*.h -- Architecture include files.
Signed-off-by: Tomaso Paoletti <tpaoletti@caviumnetworks.com>
Signed-off-by: David Daney <ddaney@caviumnetwork...

These symbols appear in oprofile output, stacktraces and similar but only
make the output harder to read.  Many identical symbol names such as
"both_aligned" were also being used in multiple source files making it
impossible to see which file actually was meant.  So let's get rid of them.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

IP28 needs special treatment to avoid speculative accesses. gcc
takes care for .c code, but for assembly code we need to do it
manually.

This is taken from Peter Fuersts IP28 patches.
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

 This complements the generic R4000/R4400 errata workaround code and adds 
bits for the daddiu problem.  In most places it just modifies handwritten 
assembly code so that the assembler is allowed to use a temporary register 
as daddiu may now be treated as a macro that expands to a sequence of li 
and daddu.  It is the AT register or, where AT is unavailable or used 
explicitly for another purpose, an explicitly-named register is selected, 
using the .set at=<reg> feature added recently to gas.  This feature is 
only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the 
workaround remains disabled, the required version of binutils stays 
unchanged.

 Similarly, daddiu instructions put in branch delay slots in noreorder 
fragments are now taken out of them and the assembler is allowed to 
reorder them itself as possible (which it does making the whole idea of 
scheduling them into delay slots manually questionable).

 Also in the very few places where s...

Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

    
Prefetching may be fatal on some systems if we're prefetching beyond the
end of memory on some systems.  It's also a seriously bad idea on non
dma-coherent systems.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Removed obsolete stuff from arch makefile.
mips had a special rule for generating asm-offsets.h so preserved it
using an architecture specific hook in top-level Kbuild file.
Renamed .h file to asm-offsets.h
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Start cleaning 32-bit vs. 64-bit configuration.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!