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| author |   Paul Mundt <lethal@linux-sh.org> | 2007-09-28 16:04:49 +0900 |
|---|---|---|
| committer | Paul Mundt <lethal@linux-sh.org> | 2007-09-28 16:04:49 +0900 |
| commit | 836624619b98535079053920a29a7e474ac17cbc (patch) | |
| tree | beb3b4fc1b893b6a422be3645c3611b1c7adb456 /arch/sh/Kconfig | |
| parent | sh: Follow gUSA preempt changes in __switch_to(). (diff) | |
| download | linux-dev-836624619b98535079053920a29a7e474ac17cbc.tar.xz linux-dev-836624619b98535079053920a29a7e474ac17cbc.zip | |
sh: Conditionalize gUSA support.
This conditionalizes gUSA support. gUSA is not supported on
SMP configurations, and it's not necessary there anyways due
to having other atomicity options (ie, movli.l/movco.l).
Anything implementing the LL/SC semantics (all SH-4A CPUs)
can switch to userspace atomicity implementations without
requiring gUSA. This is left default-enabled on all UP so
that glibc doesn't break.
Those that know what they are doing can disable this explicitly.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/Kconfig')
| -rw-r--r-- | arch/sh/Kconfig | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig index a8693edd4f43..44982c1dfa23 100644 --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -570,6 +570,20 @@ config NR_CPUS source "kernel/Kconfig.preempt" +config GUSA + def_bool y + depends on !SMP + help + This enables support for gUSA (general UserSpace Atomicity). + This is the default implementation for both UP and non-ll/sc + CPUs, and is used by the libc, amongst others. + + For additional information, design information can be found + in <http://lc.linux.or.jp/lc2002/papers/niibe0919p.pdf>. + + This should only be disabled for special cases where alternate + atomicity implementations exist. + endmenu menu "Boot options" |