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-rw-r--r--arch/sh/Kconfig14
-rw-r--r--arch/sh/kernel/entry-common.S2
-rw-r--r--arch/sh/kernel/process.c2
-rw-r--r--arch/sh/kernel/signal.c2
4 files changed, 18 insertions, 2 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"
diff --git a/arch/sh/kernel/entry-common.S b/arch/sh/kernel/entry-common.S
index b46728027195..e0317ed080c3 100644
--- a/arch/sh/kernel/entry-common.S
+++ b/arch/sh/kernel/entry-common.S
@@ -176,7 +176,7 @@ work_notifysig:
jmp @r1
lds r0, pr
work_resched:
-#ifndef CONFIG_PREEMPT
+#if defined(CONFIG_GUSA) && !defined(CONFIG_PREEMPT)
! gUSA handling
mov.l @(OFF_SP,r15), r0 ! get user space stack pointer
mov r0, r1
diff --git a/arch/sh/kernel/process.c b/arch/sh/kernel/process.c
index cd8dae16e940..b4469992d6b2 100644
--- a/arch/sh/kernel/process.c
+++ b/arch/sh/kernel/process.c
@@ -350,7 +350,7 @@ struct task_struct *__switch_to(struct task_struct *prev,
unlazy_fpu(prev, task_pt_regs(prev));
#endif
-#ifdef CONFIG_PREEMPT
+#if defined(CONFIG_GUSA) && defined(CONFIG_PREEMPT)
{
struct pt_regs *regs;
diff --git a/arch/sh/kernel/signal.c b/arch/sh/kernel/signal.c
index 0f657d32ceb9..2f42442cf164 100644
--- a/arch/sh/kernel/signal.c
+++ b/arch/sh/kernel/signal.c
@@ -507,6 +507,7 @@ handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
ctrl_inw(regs->pc - 4));
break;
}
+#ifdef CONFIG_GUSA
} else {
/* gUSA handling */
preempt_disable();
@@ -523,6 +524,7 @@ handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
}
preempt_enable_no_resched();
+#endif
}
/* Set up the stack frame */