MIPS: Workaround clang inline compat branch issue

Clang is unable to handle the situation that a chunk of inline
assembly ends with a compat branch instruction and then compiler
generates another control transfer instruction immediately after
this compat branch. The later instruction will end up in forbidden
slot and cause exception.

Workaround by add a option to control the use of compact branch.
Currently it's selected by CC_IS_CLANG and hopefully we can change
it to a version check in future if clang manages to fix it.

Fix boot on boston board.

Link: https://github.com/llvm/llvm-project/issues/61045
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Acked-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Fix build error due to PTR used in more places

Use PTR_WD instead of PTR to avoid clashes with other parts.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: retire "asm/llsc.h"

all that "asm/llsc.h" does is just to help inline asm, which can be
stringifyed from "asm/asm.h"

+. Since "asm/asm.h" has all we need, retire "asm/llsc.h"

+. remove unused header file

Inspired-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Huang Pei <huangpei@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: rework local_t operation on MIPS64

+. remove "asm/war.h" since R10000_LLSC_WAR became a config option

+. clean up

Suggested-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Huang Pei <huangpei@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS/asm/printk: Fix build failure caused by printk

The commit 337015573718b161 ("printk: Userspace format indexing support")
caused the following build failure:

arch/mips/kernel/genex.o: In function `handle_mcheck_int':
(.text+0x190c): undefined reference to `printk'
arch/mips/kernel/genex.o: In function `handle_reserved_int':
(.text+0x1c8c): undefined reference to `printk'

Fixes: 337015573718b161 ("printk: Userspace format indexing support")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Suggested-by: Chris Down <chris@chrisdown.name>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/YPbBfdz9srIpI+bb@chrisdown.name

MIPS: properly stop .eh_frame generation

Commit 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly") added
-fno-asynchronous-unwind-tables to KBUILD_CFLAGS to prevent compiler
from emitting .eh_frame symbols.
However, as MIPS heavily uses CFI, that's not enough. Use the
approach taken for x86 (as it also uses CFI) and explicitly put CFI
symbols into the .debug_frame section (except for VDSO).
This allows us to drop .eh_frame from DISCARDS as it's no longer
being generated.

Fixes: 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly")
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: asm: Rename some macros to avoid build errors

Use ASM_ prefix to rename some macros (PANIC and PRINT), in order to
avoid build errors (all users are updated as well):

1, PANIC conflicts with drivers/scsi/smartpqi/smartpqi_init.c
2, PRINT conflicts with net/netfilter/nf_conntrack_h323_asn1.c and net/
mac80211/debugfs_sta.c

Fixes: d339cd02b888eb8 ("MIPS: Move unaligned load/store helpers to inst.h")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Move unaligned load/store helpers to inst.h

Move unaligned load/store helpers from unaligned.c to inst.h, then
other parts of the kernel can use these helpers.

Use __ASSEMBLY__ to guard the definition of "LONG" in asm.h to avoid
build error on IPxx platforms.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Pei Huang <huangpei@loongson.cn>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Remove unused PREF, PREFE & PREFX macros

asm/asm.h provides PREF(), PREFE() & PREFX() macros which are now
entirely unused. Delete the dead code.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20908/
Cc: linux-mips@linux-mips.org

MIPS: Remove unused CAT macro

asm/asm.h provides a CAT macro which is unused throughout the tree, and
if anyone wanted it the generic CONCATENATE macro in linux/kernel.h
provides the same functionality. Delete the dead code.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20905/
Cc: linux-mips@linux-mips.org

MIPS: Remove unused TTABLE macro

asm/asm.h contains a TTABLE macro to generate "text tables" which would
appear to be arrays of pointers to strings. It is unused throughout the
kernel tree, so delete the dead code.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20904/
Cc: linux-mips@linux-mips.org

MIPS: Remove unused PIC macros

asm/asm.h contains CPRESTORE, CPADD & CPLOAD macros that are intended
for use with position independent code, but are not used anywhere in the
kernel - along with a comment to that effect. Remove the dead code.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20903/
Cc: linux-mips@linux-mips.org

MIPS: Remove unused MOVN & MOVZ macros

We have macros in asm/asm.h to allow for use of the MOVN & MOVZ
instructions with compare-and-branch sequences providing compatibility
for ISA versions which don't include those instructions. However the
macros are unused, and appear to have always been unused. Delete the
dead code.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20909/
Cc: linux-mips@linux-mips.org

MIPS: Add DWARF unwinding to assembly

This will allow kdump dumps to work correclty with MIPS and
future DWARF unwinding of the stack to give accurate tracebacks.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16990/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: End asm function prologue macros with .insn

When building a kernel targeting a microMIPS ISA, recent GNU linkers
will fail the link if they cannot determine that the target of a branch
or jump is microMIPS code, with errors such as the following:

mips-img-linux-gnu-ld: arch/mips/built-in.o: .text+0x542c:
Unsupported jump between ISA modes; consider recompiling with
interlinking enabled.
mips-img-linux-gnu-ld: final link failed: Bad value

or:

./arch/mips/include/asm/uaccess.h:1017: warning: JALX to a
non-word-aligned address

Placing anything other than an instruction at the start of a function
written in assembly appears to trigger such errors. In order to prepare
for allowing us to follow function prologue macros with an EXPORT_SYMBOL
invocation, end the prologue macros (LEAD, NESTED & FEXPORT) with a
.insn directive. This ensures that the start of the function is marked
as code, which always makes sense for functions & safely prevents us
from hitting the link errors described above.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14508/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Fix gigaton of warning building with microMIPS.

With binutils 2.24 the attempt to switch with microMIPS mode to MIPS III
mode through .set mips3 results in *lots* of warnings like

{standard input}: Assembler messages:
{standard input}:397: Warning: the 64-bit MIPS architecture does not support the `smartmips' extension

during a kernel build. Fixed by using .set arch=r4000 instead.

This breaks support for building the kernel with binutils 2.13 which
was supported for 32 bit kernels only anyway and 2.14 which was a bad
vintage for MIPS anyway.

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

MIPS: asm: Add wrappers for EVA/non-EVA instructions

EVA uses specific instructions for accessing user memory.
Instead of polluting the kernel with numerous #ifdef CONFIG_EVA
we add wrappers for all the instructions that need special
handling when EVA is enabled.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: asm: Add prefetch instruction for EVA

EVA can use the PREFE instruction to perform the virtual address
translation using the user mapping of the address rather than the
kernel mapping.

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: microMIPS: Optimise 'memset' core library function.

Optimise 'memset' to use microMIPS instructions and/or optimisations
for binary size reduction. When the microMIPS ISA is not being used,
the library function compiles to the original binary code.

Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>

MIPS: Whitespace cleanup.

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>

MIPS: Move headfiles to new location below arch/mips/include

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