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Diffstat (limited to 'arch/powerpc/kernel/rtas.c')
-rw-r--r--arch/powerpc/kernel/rtas.c69
1 files changed, 60 insertions, 9 deletions
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index ee4c7609b649..c434823b8c83 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -38,9 +38,10 @@
#include <asm/syscalls.h>
#include <asm/smp.h>
#include <asm/atomic.h>
+#include <asm/time.h>
struct rtas_t rtas = {
- .lock = SPIN_LOCK_UNLOCKED
+ .lock = __RAW_SPIN_LOCK_UNLOCKED
};
EXPORT_SYMBOL(rtas);
@@ -67,6 +68,28 @@ unsigned long rtas_rmo_buf;
void (*rtas_flash_term_hook)(int);
EXPORT_SYMBOL(rtas_flash_term_hook);
+/* RTAS use home made raw locking instead of spin_lock_irqsave
+ * because those can be called from within really nasty contexts
+ * such as having the timebase stopped which would lockup with
+ * normal locks and spinlock debugging enabled
+ */
+static unsigned long lock_rtas(void)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ preempt_disable();
+ __raw_spin_lock_flags(&rtas.lock, flags);
+ return flags;
+}
+
+static void unlock_rtas(unsigned long flags)
+{
+ __raw_spin_unlock(&rtas.lock);
+ local_irq_restore(flags);
+ preempt_enable();
+}
+
/*
* call_rtas_display_status and call_rtas_display_status_delay
* are designed only for very early low-level debugging, which
@@ -79,7 +102,7 @@ static void call_rtas_display_status(char c)
if (!rtas.base)
return;
- spin_lock_irqsave(&rtas.lock, s);
+ s = lock_rtas();
args->token = 10;
args->nargs = 1;
@@ -89,7 +112,7 @@ static void call_rtas_display_status(char c)
enter_rtas(__pa(args));
- spin_unlock_irqrestore(&rtas.lock, s);
+ unlock_rtas(s);
}
static void call_rtas_display_status_delay(char c)
@@ -411,8 +434,7 @@ int rtas_call(int token, int nargs, int nret, int *outputs, ...)
if (!rtas.entry || token == RTAS_UNKNOWN_SERVICE)
return -1;
- /* Gotta do something different here, use global lock for now... */
- spin_lock_irqsave(&rtas.lock, s);
+ s = lock_rtas();
rtas_args = &rtas.args;
rtas_args->token = token;
@@ -439,8 +461,7 @@ int rtas_call(int token, int nargs, int nret, int *outputs, ...)
outputs[i] = rtas_args->rets[i+1];
ret = (nret > 0)? rtas_args->rets[0]: 0;
- /* Gotta do something different here, use global lock for now... */
- spin_unlock_irqrestore(&rtas.lock, s);
+ unlock_rtas(s);
if (buff_copy) {
log_error(buff_copy, ERR_TYPE_RTAS_LOG, 0);
@@ -837,7 +858,7 @@ asmlinkage int ppc_rtas(struct rtas_args __user *uargs)
buff_copy = get_errorlog_buffer();
- spin_lock_irqsave(&rtas.lock, flags);
+ flags = lock_rtas();
rtas.args = args;
enter_rtas(__pa(&rtas.args));
@@ -848,7 +869,7 @@ asmlinkage int ppc_rtas(struct rtas_args __user *uargs)
if (args.rets[0] == -1)
errbuf = __fetch_rtas_last_error(buff_copy);
- spin_unlock_irqrestore(&rtas.lock, flags);
+ unlock_rtas(flags);
if (buff_copy) {
if (errbuf)
@@ -951,3 +972,33 @@ int __init early_init_dt_scan_rtas(unsigned long node,
/* break now */
return 1;
}
+
+static raw_spinlock_t timebase_lock;
+static u64 timebase = 0;
+
+void __cpuinit rtas_give_timebase(void)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ hard_irq_disable();
+ __raw_spin_lock(&timebase_lock);
+ rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
+ timebase = get_tb();
+ __raw_spin_unlock(&timebase_lock);
+
+ while (timebase)
+ barrier();
+ rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
+ local_irq_restore(flags);
+}
+
+void __cpuinit rtas_take_timebase(void)
+{
+ while (!timebase)
+ barrier();
+ __raw_spin_lock(&timebase_lock);
+ set_tb(timebase >> 32, timebase & 0xffffffff);
+ timebase = 0;
+ __raw_spin_unlock(&timebase_lock);
+}