[MIPS] Add basic SMARTMIPS ASE support
This patch adds trivial support for SMARTMIPS extension. This extension
is currently implemented by 4KS[CD] CPUs.
Basically it saves/restores ACX register, which is part of the SMARTMIPS
ASE, when needed. This patch does *not* add any support for Smartmips MMU
features.
Futhermore this patch does not add explicit support for 4KS[CD] CPUs since
they are respectively mips32 and mips32r2 compliant. So with the current
processor configuration, a platform that has such CPUs needs to select
both configs:
CPU_HAS_SMARTMIPS
SYS_HAS_CPU_MIPS32_R[12]
This is due to the processor configuration which is mixing up all the
architecture variants and the processor types.
The drawback of this, is that we currently pass '-march=mips32' option to
gcc when building a kernel instead of '-march=4ksc' for 4KSC case. This
can lead to a kernel image a little bit bigger than required.
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index c6f74f1..58e9788 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -274,6 +274,7 @@
select SYS_SUPPORTS_BIG_ENDIAN
select SYS_SUPPORTS_LITTLE_ENDIAN
select SYS_SUPPORTS_MULTITHREADING if EXPERIMENTAL
+ select SYS_SUPPORTS_SMARTMIPS
select GENERIC_HARDIRQS_NO__DO_IRQ
help
This enables support for the MIPS Technologies Atlas evaluation
@@ -305,6 +306,7 @@
select SYS_SUPPORTS_BIG_ENDIAN
select SYS_SUPPORTS_LITTLE_ENDIAN
select SYS_SUPPORTS_MULTITHREADING
+ select SYS_SUPPORTS_SMARTMIPS
help
This enables support for the MIPS Technologies Malta evaluation
board.
@@ -322,6 +324,7 @@
select SYS_SUPPORTS_64BIT_KERNEL if EXPERIMENTAL
select SYS_SUPPORTS_BIG_ENDIAN
select SYS_SUPPORTS_LITTLE_ENDIAN
+ select SYS_SUPPORTS_SMARTMIPS
help
This enables support for the MIPS Technologies SEAD evaluation
board.
@@ -1641,6 +1644,18 @@
config CPU_HAS_LLSC
bool
+config CPU_HAS_SMARTMIPS
+ depends on SYS_SUPPORTS_SMARTMIPS
+ bool "Support for the SmartMIPS ASE"
+ help
+ SmartMIPS is a extension of the MIPS32 architecture aimed at
+ increased security at both hardware and software level for
+ smartcards. Enabling this option will allow proper use of the
+ SmartMIPS instructions by Linux applications. However a kernel with
+ this option will not work on a MIPS core without SmartMIPS core. If
+ you don't know you probably don't have SmartMIPS and should say N
+ here.
+
config CPU_HAS_WB
bool
@@ -1704,6 +1719,9 @@
config SYS_SUPPORTS_HIGHMEM
bool
+config SYS_SUPPORTS_SMARTMIPS
+ bool
+
config ARCH_FLATMEM_ENABLE
def_bool y
depends on !NUMA