commit 839769c35477d4acc2369e45000ca7b0b6af39a7 upstream.

Fast coprocessor exception handler saves a3..a6, but coprocessor context
load/store code uses a4..a7 as temporaries, potentially clobbering a7.
'Potentially' because coprocessor state load/store macros may not use
all four temporary registers (and neither FPU nor HiFi macros do).
Use a3..a6 as intended.

Cc: stable@vger.kernel.org
Fixes: c658eac628aa ("[XTENSA] Add support for configurable registers and coprocessors")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit ab5eb336411f18fd449a1fb37d36a55ec422603f upstream.

coprocessor_flush is not a part of fast exception handlers, but it uses
parts of fast coprocessor handling code that's why it's in the same
source file. It uses call0 opcode to invoke those parts so there are no
limitations on their relative location, but the rest of the code calls
coprocessor_flush with call8 and that doesn't work when vectors are
placed in a different gigabyte-aligned area than the rest of the kernel.

Move coprocessor_flush from the .exception.text section to the .text so
that it's reachable from the rest of the kernel with call8.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Assembly entry/return abstraction change didn't add asmmacro.h include
statement to coprocessor.S, resulting in references to undefined macros
abi_entry and abi_ret on cores that define XTENSA_HAVE_COPROCESSORS.
Fix that by including asm/asmmacro.h from the coprocessor.S.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Provide abi_entry, abi_entry_default, abi_ret and abi_ret_default macros
that allocate aligned stack frame in windowed and call0 ABIs.
Provide XTENSA_SPILL_STACK_RESERVE macro that specifies required stack
frame size when register spilling is involved.
Replace all uses of 'entry' and 'retw' with the above macros.
This makes most of the xtensa assembly code ready for XEA3 and call0 ABI.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Use addresses instead of offsets and drop unneeded offset -> address
calculations. Don't generate any code for undefined coprocessors.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

coprocessor_save, coprocessor_load and coprocessor_restore are neither
used nor exported for use by modules. Drop them.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Now that xtensa assembly sources are compiled with -mlongcalls let the
assembler and linker relax call instructions into l32r + callx where
needed. This change makes the code cleaner and potentially a bit faster.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

fast_io_protect is not used anywhere, drop its definition.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Based on the SMP patch by Joe Taylor and subsequent fixes.
Preserve exception table pointer (normally stored in excsave1 SR) as it
cannot be easily restored in SMP environment.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>