MIPS: make CPU_HAS_LOAD_STORE_LR opt-out

CPU_HAS_LOAD_STORE_LR was introduced in 932afdeec18b ("MIPS: Add Kconfig
variable for CPUs with unaligned load/store instructions") to make code
in kernel/unaligned.c and lib/mem{cpy,set}.S more intuitive and give a
possibility to easily add new CPUs without these instruction sets in
future.

Hovewer, this variant is not optimal for mainly two reasons:
* For now, we have 20+ CPUs with such instructions and only two (MIPS R6)
  without. It will obviously be more effective and straightforward to
  have an option for these two rather than for the rest.
* You can easily miss the fact that you need to select this option when
  adding a new CPU, while all processors lacking these sets are
  well-known, so the probability of missing something is way much lower.

We can address both points by turning CPU_HAS_LOAD_STORE_LR into opt-out
CPU_NO_LOAD_STORE_LR. This also makes MIPS root Kconfig more clear and
understandable.

Signed-off-by: Alexander Lobakin <alobakin@dlink.ru>
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>
Cc: Will Deacon <will@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Allison Randal <allison@lohutok.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

1 files changed, 7 insertions, 27 deletions

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index c5498146bd3b..8ff846ef2345 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1218,8 +1218,7 @@ config NO_IOPORT_MAP
 	def_bool n
 
 config GENERIC_CSUM
-	bool
-	default y if !CPU_HAS_LOAD_STORE_LR
+	def_bool CPU_NO_LOAD_STORE_LR
 
 config GENERIC_ISA_DMA
 	bool
@@ -1441,7 +1440,6 @@ config CPU_LOONGSON64
 	select CPU_SUPPORTS_HIGHMEM
 	select CPU_SUPPORTS_HUGEPAGES
 	select CPU_SUPPORTS_MSA
-	select CPU_HAS_LOAD_STORE_LR
 	select WEAK_ORDERING
 	select WEAK_REORDERING_BEYOND_LLSC
 	select MIPS_ASID_BITS_VARIABLE
@@ -1537,7 +1535,6 @@ config CPU_MIPS32_R1
 	bool "MIPS32 Release 1"
 	depends on SYS_HAS_CPU_MIPS32_R1
 	select CPU_HAS_PREFETCH
-	select CPU_HAS_LOAD_STORE_LR
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_HIGHMEM
 	help
@@ -1555,7 +1552,6 @@ config CPU_MIPS32_R2
 	bool "MIPS32 Release 2"
 	depends on SYS_HAS_CPU_MIPS32_R2
 	select CPU_HAS_PREFETCH
-	select CPU_HAS_LOAD_STORE_LR
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_HIGHMEM
 	select CPU_SUPPORTS_MSA
@@ -1571,6 +1567,7 @@ config CPU_MIPS32_R6
 	bool "MIPS32 Release 6"
 	depends on SYS_HAS_CPU_MIPS32_R6
 	select CPU_HAS_PREFETCH
+	select CPU_NO_LOAD_STORE_LR
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_HIGHMEM
 	select CPU_SUPPORTS_MSA
@@ -1586,7 +1583,6 @@ config CPU_MIPS64_R1
 	bool "MIPS64 Release 1"
 	depends on SYS_HAS_CPU_MIPS64_R1
 	select CPU_HAS_PREFETCH
-	select CPU_HAS_LOAD_STORE_LR
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_64BIT_KERNEL
 	select CPU_SUPPORTS_HIGHMEM
@@ -1606,7 +1602,6 @@ config CPU_MIPS64_R2
 	bool "MIPS64 Release 2"
 	depends on SYS_HAS_CPU_MIPS64_R2
 	select CPU_HAS_PREFETCH
-	select CPU_HAS_LOAD_STORE_LR
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_64BIT_KERNEL
 	select CPU_SUPPORTS_HIGHMEM
@@ -1624,6 +1619,7 @@ config CPU_MIPS64_R6
 	bool "MIPS64 Release 6"
 	depends on SYS_HAS_CPU_MIPS64_R6
 	select CPU_HAS_PREFETCH
+	select CPU_NO_LOAD_STORE_LR
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_64BIT_KERNEL
 	select CPU_SUPPORTS_HIGHMEM
@@ -1641,7 +1637,6 @@ config CPU_R3000
 	bool "R3000"
 	depends on SYS_HAS_CPU_R3000
 	select CPU_HAS_WB
-	select CPU_HAS_LOAD_STORE_LR
 	select CPU_R3K_TLB
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_HIGHMEM
@@ -1657,7 +1652,6 @@ config CPU_TX39XX
 	bool "R39XX"
 	depends on SYS_HAS_CPU_TX39XX
 	select CPU_SUPPORTS_32BIT_KERNEL
-	select CPU_HAS_LOAD_STORE_LR
 	select CPU_R3K_TLB
 
 config CPU_VR41XX
@@ -1665,7 +1659,6 @@ config CPU_VR41XX
 	depends on SYS_HAS_CPU_VR41XX
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_64BIT_KERNEL
-	select CPU_HAS_LOAD_STORE_LR
 	help
 	  The options selects support for the NEC VR4100 series of processors.
 	  Only choose this option if you have one of these processors as a
@@ -1678,7 +1671,6 @@ config CPU_R4X00
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_64BIT_KERNEL
 	select CPU_SUPPORTS_HUGEPAGES
-	select CPU_HAS_LOAD_STORE_LR
 	help
 	  MIPS Technologies R4000-series processors other than 4300, including
 	  the R4000, R4400, R4600, and 4700.
@@ -1687,7 +1679,6 @@ config CPU_TX49XX
 	bool "R49XX"
 	depends on SYS_HAS_CPU_TX49XX
 	select CPU_HAS_PREFETCH
-	select CPU_HAS_LOAD_STORE_LR
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_64BIT_KERNEL
 	select CPU_SUPPORTS_HUGEPAGES
@@ -1698,7 +1689,6 @@ config CPU_R5000
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_64BIT_KERNEL
 	select CPU_SUPPORTS_HUGEPAGES
-	select CPU_HAS_LOAD_STORE_LR
 	help
 	  MIPS Technologies R5000-series processors other than the Nevada.
 
@@ -1708,7 +1698,6 @@ config CPU_R5500
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_64BIT_KERNEL
 	select CPU_SUPPORTS_HUGEPAGES
-	select CPU_HAS_LOAD_STORE_LR
 	help
 	  NEC VR5500 and VR5500A series processors implement 64-bit MIPS IV
 	  instruction set.
@@ -1719,7 +1708,6 @@ config CPU_NEVADA
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_64BIT_KERNEL
 	select CPU_SUPPORTS_HUGEPAGES
-	select CPU_HAS_LOAD_STORE_LR
 	help
 	  QED / PMC-Sierra RM52xx-series ("Nevada") processors.
 
@@ -1727,7 +1715,6 @@ config CPU_R10000
 	bool "R10000"
 	depends on SYS_HAS_CPU_R10000
 	select CPU_HAS_PREFETCH
-	select CPU_HAS_LOAD_STORE_LR
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_64BIT_KERNEL
 	select CPU_SUPPORTS_HIGHMEM
@@ -1739,7 +1726,6 @@ config CPU_RM7000
 	bool "RM7000"
 	depends on SYS_HAS_CPU_RM7000
 	select CPU_HAS_PREFETCH
-	select CPU_HAS_LOAD_STORE_LR
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_64BIT_KERNEL
 	select CPU_SUPPORTS_HIGHMEM
@@ -1748,7 +1734,6 @@ config CPU_RM7000
 config CPU_SB1
 	bool "SB1"
 	depends on SYS_HAS_CPU_SB1
-	select CPU_HAS_LOAD_STORE_LR
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_64BIT_KERNEL
 	select CPU_SUPPORTS_HIGHMEM
@@ -1759,7 +1744,6 @@ config CPU_CAVIUM_OCTEON
 	bool "Cavium Octeon processor"
 	depends on SYS_HAS_CPU_CAVIUM_OCTEON
 	select CPU_HAS_PREFETCH
-	select CPU_HAS_LOAD_STORE_LR
 	select CPU_SUPPORTS_64BIT_KERNEL
 	select WEAK_ORDERING
 	select CPU_SUPPORTS_HIGHMEM
@@ -1789,7 +1773,6 @@ config CPU_BMIPS
 	select WEAK_ORDERING
 	select CPU_SUPPORTS_HIGHMEM
 	select CPU_HAS_PREFETCH
-	select CPU_HAS_LOAD_STORE_LR
 	select CPU_SUPPORTS_CPUFREQ
 	select MIPS_EXTERNAL_TIMER
 	help
@@ -1798,7 +1781,6 @@ config CPU_BMIPS
 config CPU_XLR
 	bool "Netlogic XLR SoC"
 	depends on SYS_HAS_CPU_XLR
-	select CPU_HAS_LOAD_STORE_LR
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_64BIT_KERNEL
 	select CPU_SUPPORTS_HIGHMEM
@@ -1817,7 +1799,6 @@ config CPU_XLP
 	select WEAK_ORDERING
 	select WEAK_REORDERING_BEYOND_LLSC
 	select CPU_HAS_PREFETCH
-	select CPU_HAS_LOAD_STORE_LR
 	select CPU_MIPSR2
 	select CPU_SUPPORTS_HUGEPAGES
 	select MIPS_ASID_BITS_VARIABLE
@@ -1923,14 +1904,12 @@ config CPU_LOONGSON2EF
 	select CPU_SUPPORTS_HIGHMEM
 	select CPU_SUPPORTS_HUGEPAGES
 	select ARCH_HAS_PHYS_TO_DMA
-	select CPU_HAS_LOAD_STORE_LR
 
 config CPU_LOONGSON32
 	bool
 	select CPU_MIPS32
 	select CPU_MIPSR2
 	select CPU_HAS_PREFETCH
-	select CPU_HAS_LOAD_STORE_LR
 	select CPU_SUPPORTS_32BIT_KERNEL
 	select CPU_SUPPORTS_HIGHMEM
 	select CPU_SUPPORTS_CPUFREQ
@@ -2573,12 +2552,13 @@ config XKS01
 config CPU_HAS_RIXI
 	bool
 
-config CPU_HAS_LOAD_STORE_LR
+config CPU_NO_LOAD_STORE_LR
 	bool
 	help
-	  CPU has support for unaligned load and store instructions:
+	  CPU lacks support for unaligned load and store instructions:
 	  LWL, LWR, SWL, SWR (Load/store word left/right).
-	  LDL, LDR, SDL, SDR (Load/store doubleword left/right, for 64bit systems).
+	  LDL, LDR, SDL, SDR (Load/store doubleword left/right, for 64bit
+	  systems).
 
 #
 # Vectored interrupt mode is an R2 feature