linux/arch
Yasha Cherikovsky 932afdeec1
MIPS: Add Kconfig variable for CPUs with unaligned load/store instructions
MIPSR6 CPUs do not support unaligned load/store instructions
(LWL, LWR, SWL, SWR and LDL, LDR, SDL, SDR for 64bit).

Currently the MIPS tree has some special cases to avoid these
instructions, and the code is testing for !CONFIG_CPU_MIPSR6.

This patch declares a new Kconfig variable:
CONFIG_CPU_HAS_LOAD_STORE_LR.
This variable indicates that the CPU supports these instructions.

Then, the patch does the following:
- Carefully selects this option on all CPUs except MIPSR6.
- Switches all the special cases to test for the new variable,
  and inverts the logic:
    '#ifndef CONFIG_CPU_MIPSR6' turns into
    '#ifdef CONFIG_CPU_HAS_LOAD_STORE_LR'
    and vice-versa.

Also, when this variable is NOT selected (e.g. MIPSR6),
CONFIG_GENERIC_CSUM will default to 'y', to compile generic
C checksum code (instead of special assembly code that uses the
unsupported instructions).

This commit should not affect any existing CPU, and is required
for future Lexra CPU support, that misses these instructions too.

Signed-off-by: Yasha Cherikovsky <yasha.che3@gmail.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20808/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
2018-09-26 13:38:18 -07:00
..
alpha Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-08-24 09:25:39 -07:00
arc kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
arm ARM: SoC: late updates 2018-08-25 14:12:36 -07:00
arm64 ARM: SoC: late updates 2018-08-25 14:12:36 -07:00
c6x kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
h8300 Kbuild updates for v4.19 (2nd) 2018-08-25 13:40:38 -07:00
hexagon kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
ia64 ia64: Fix allnoconfig section mismatch for ioc_init/ioc_iommu_info 2018-08-22 14:12:47 -07:00
m68k kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
microblaze kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
mips MIPS: Add Kconfig variable for CPUs with unaligned load/store instructions 2018-09-26 13:38:18 -07:00
nds32 kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
nios2 mm: convert return type of handle_mm_fault() caller to vm_fault_t 2018-08-17 16:20:28 -07:00
openrisc OpenRISC updates for 4.19 2018-08-23 14:09:37 -07:00
parisc Merge branch 'parisc-4.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux 2018-08-22 14:06:37 -07:00
powerpc Merge branch 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax 2018-08-26 11:48:42 -07:00
riscv Kbuild updates for v4.19 (2nd) 2018-08-25 13:40:38 -07:00
s390 Kbuild updates for v4.19 (2nd) 2018-08-25 13:40:38 -07:00
sh kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
sparc Kbuild updates for v4.19 (2nd) 2018-08-25 13:40:38 -07:00
um kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
unicore32 mm: convert return type of handle_mm_fault() caller to vm_fault_t 2018-08-17 16:20:28 -07:00
x86 Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-08-26 11:25:21 -07:00
xtensa Kbuild updates for v4.19 (2nd) 2018-08-25 13:40:38 -07:00
.gitignore
Kconfig Merge branch 'tlb-fixes' 2018-08-23 14:55:01 -07:00