parisc: Avoid clobbering the C/B bits in the PSW with tophys and tovirt macros

Use add,l to avoid clobbering the C/B bits in the PSW.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # v5.10+

parisc: Fix random data corruption from exception handler

The current exception handler implementation, which assists when accessing
user space memory, may exhibit random data corruption if the compiler decides
to use a different register than the specified register %r29 (defined in
ASM_EXCEPTIONTABLE_REG) for the error code. If the compiler choose another
register, the fault handler will nevertheless store -EFAULT into %r29 and thus
trash whatever this register is used for.
Looking at the assembly I found that this happens sometimes in emulate_ldd().

To solve the issue, the easiest solution would be if it somehow is
possible to tell the fault handler which register is used to hold the error
code. Using %0 or %1 in the inline assembly is not posssible as it will show
up as e.g. %r29 (with the "%r" prefix), which the GNU assembler can not
convert to an integer.

This patch takes another, better and more flexible approach:
We extend the __ex_table (which is out of the execution path) by one 32-word.
In this word we tell the compiler to insert the assembler instruction
"or %r0,%r0,%reg", where %reg references the register which the compiler
choosed for the error return code.
In case of an access failure, the fault handler finds the __ex_table entry and
can examine the opcode. The used register is encoded in the lowest 5 bits, and
the fault handler can then store -EFAULT into this register.

Since we extend the __ex_table to 3 words we can't use the BUILDTIME_TABLE_SORT
config option any longer.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v6.0+

parisc: Mark ex_table entries 32-bit aligned in assembly.h

Add an align statement to tell the linker that all ex_table entries and as
such the whole ex_table section should be 32-bit aligned in vmlinux and modules.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # v6.0+

parisc: Delete redundant register definitions in <asm/assembly.h>

We define sp and ipsw in <asm/asmregs.h> using ".reg", and when using
current binutils (snapshot 2.40.50.20230611) the definitions in
<asm/assembly.h> using "=" conflict with those:

arch/parisc/include/asm/assembly.h: Assembler messages:
arch/parisc/include/asm/assembly.h:93: Error: symbol `sp' is already defined
arch/parisc/include/asm/assembly.h:95: Error: symbol `ipsw' is already defined

Delete the duplicate definitions in <asm/assembly.h>.

Also delete the definition of gp, which isn't used anywhere.

Signed-off-by: Ben Hutchings <benh@debian.org>
Cc: stable@vger.kernel.org # v6.0+
Signed-off-by: Helge Deller <deller@gmx.de>

parisc: Add dep_safe() macro to deposit a register in 32- and 64-kernels

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

parisc: Fix wrong comment for shr macro

The comment that the source and target register can not be the same is
wrong. Instead on PA2.0 usage of extru can clobber upper 32-bits.
This patch fixes the comment.

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

parisc: Add defines for various space register

Provide defines for space registers (SR_KERNEL, SR_USER, ...) which
should be used instead of hardcoding the values.

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

parisc: Define depi_safe macro

The depi instruction is similar to the extru instruction on 64-bit machines.
It leaves the most-significant 32 bits of the target register in an undefined
state. On 64-bit machines, the macro uses depdi to perform safe deposits in
the least-significant 32 bits.

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

parisc: Provide an extru_safe() macro to extract unsigned bits

The extru instruction leaves the most significant 32 bits of the
target register in an undefined state on PA 2.0 systems.
Provide a macro to safely use extru on 32- and 64-bit machines.

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

parisc: Wrap assembler related defines inside __ASSEMBLY__

Building allmodconfig shows errors in the gpu/drm/msm snapdragon drivers,
because a COND() define is used there which conflicts with the COND() for
PA-RISC assembly. Although the snapdragon driver isn't relevant for parisc, it
is nevertheless compiled when CONFIG_COMPILE_TEST is defined.

Move the COND() define and other PA-RISC mnemonics inside the #ifdef
__ASSEMBLY__ part to avoid this conflict.

Signed-off-by: Helge Deller <deller@gmx.de>
Reported-by: kernel test robot <lkp@intel.com>

parisc: move virt_map macro to assembly.h

This macro will also be used by the TOC code, so move it
into asm/assembly.h to avoid duplication.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

parisc: Define FRAME_ALIGN and PRIV_USER/PRIV_KERNEL in assembly.h

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

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 153

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 or at your option any
later version this program is distributed in the hope that it will
be useful but without any warranty without even the implied warranty
of merchantability or fitness for a particular purpose see the gnu
general public license for more details you should have received a
copy of the gnu general public license along with this program if
not write to the free software foundation inc 675 mass ave cambridge
ma 02139 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 77 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.837555891@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parisc: Rename LEVEL to PA_ASM_LEVEL to avoid name clash with DRBD code

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>

parisc: Use zdep for shlw macro on PA1.1 and PA2.0

The zdep and depw,z mnemonics generate the same code. The assembler will
accept the depw,z mnemonic when generating PA 1.x code. The zdep
mnemonic is okay when generating PA 2.0 code. This patch changes depw,z
to zdep in the current shlw macro, while the binary code will be the
same.

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

parisc: Fix and improve kernel stack unwinding

This patchset fixes and improves stack unwinding a lot:
1. Show backward stack traces with up to 30 callsites
2. Add callinfo to ENTRY_CFI() such that every assembler function will get an
entry in the unwind table
3. Use constants instead of numbers in call_on_stack()
4. Do not depend on CONFIG_KALLSYMS to generate backtraces.
5. Speed up backtrace generation

Make sure you have this patch to GNU as installed:
https://sourceware.org/ml/binutils/2018-07/msg00474.html
Without this patch, unwind info in the kernel is often wrong for various
functions.

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

parisc: Use generic extable search and sort routines

Switch to the generic extable search and sort routines which were introduced
with commit a272858 from Ard Biesheuvel. This saves quite some memory in the
vmlinux binary with the 64bit kernel.

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

parisc: provide macro to create exception table entries

Provide a macro ASM_EXCEPTIONTABLE_ENTRY() to create exception table
entries and convert all open-coded places to use that macro.

This patch is a first step toward creating a exception table which only
holds 32bit pointers even on a 64bit kernel. That way in my own kernel
I was able to reduce the in-kernel exception table from 44kB to 22kB.

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

parisc: make interrupt and interruption stack allocation reentrant

The get_stack_use_cr30 and get_stack_use_r30 macros allocate a stack
frame for external interrupts and interruptions requiring a stack frame.
They are currently not reentrant in that they save register context
before the stack is set or adjusted.

I have observed a number of system crashes where there was clear
evidence of stack corruption during interrupt processing, and as a
result register corruption. Some interruptions can still occur during
interruption processing, however external interrupts are disabled and
data TLB misses don't occur for absolute accesses. So, it's not entirely
clear what triggers this issue. Also, if an interruption occurs when
Q=0, it is generally not possible to recover as the shadowed registers
are not copied.

The attached patch reworks the get_stack_use_cr30 and get_stack_use_r30
macros to allocate stack before doing register saves. The new code is a
couple of instructions shorter than the old implementation. Thus, it's
an improvement even if it doesn't fully resolve the stack corruption
issue. Based on limited testing, it improves SMP system stability.

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

parisc: fix 64bit build

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>

parisc: add braces around arguments in assembler macros

Add braces around the macro arguments, else for example
"shl %r1, 5-3, %r2" would not expand to what you would assume.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>

parisc: move include/asm-parisc to arch/parisc/include/asm