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| author | Stuart Menefy <stuart.menefy@st.com> | 2007-11-30 16:12:36 +0900 |
|---|---|---|
| committer | Paul Mundt <lethal@linux-sh.org> | 2008-01-28 13:18:58 +0900 |
| commit | 1efe4ce3ca126da77e450d5a83f7201949d76f62 (patch) | |
| tree | fbae9902aa4103a9e86d06f841d580f24682e7b3 /arch/sh/Kconfig | |
| parent | 53ff09422e5e7a6d6198b767c8f494e43ec8e3ae (diff) | |
| download | lwn-1efe4ce3ca126da77e450d5a83f7201949d76f62.tar.gz lwn-1efe4ce3ca126da77e450d5a83f7201949d76f62.zip | |
sh: GUSA atomic rollback support.
This implements kernel-level atomic rollback built on top of gUSA,
as an alternative non-IRQ based atomicity method. This is generally
a faster method for platforms that are lacking the LL/SC pairs that
SH-4A and later use, and is only supportable on legacy cores.
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/Kconfig')
| -rw-r--r-- | arch/sh/Kconfig | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig index 2dc3b177193c..f645f8416f1c 100644 --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -692,7 +692,7 @@ source "kernel/Kconfig.preempt" config GUSA def_bool y - depends on !SMP + depends on !SMP && SUPERH32 help This enables support for gUSA (general UserSpace Atomicity). This is the default implementation for both UP and non-ll/sc @@ -704,6 +704,16 @@ config GUSA This should only be disabled for special cases where alternate atomicity implementations exist. +config GUSA_RB + bool "Implement atomic operations by roll-back (gRB) (EXPERIMENTAL)" + depends on GUSA && CPU_SH3 || (CPU_SH4 && !CPU_SH4A) + help + Enabling this option will allow the kernel to implement some + atomic operations using a software implemention of load-locked/ + store-conditional (LLSC). On machines which do not have hardware + LLSC, this should be more efficient than the other alternative of + disabling insterrupts around the atomic sequence. + endmenu menu "Boot options" |