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-rw-r--r--arch/arm/include/asm/tls.h62
1 files changed, 62 insertions, 0 deletions
diff --git a/arch/arm/include/asm/tls.h b/arch/arm/include/asm/tls.h
index 83259b873333..36172adda9d0 100644
--- a/arch/arm/include/asm/tls.h
+++ b/arch/arm/include/asm/tls.h
@@ -1,6 +1,9 @@
#ifndef __ASMARM_TLS_H
#define __ASMARM_TLS_H
+#include <linux/compiler.h>
+#include <asm/thread_info.h>
+
#ifdef __ASSEMBLY__
#include <asm/asm-offsets.h>
.macro switch_tls_none, base, tp, tpuser, tmp1, tmp2
@@ -50,6 +53,47 @@
#endif
#ifndef __ASSEMBLY__
+
+static inline void set_tls(unsigned long val)
+{
+ struct thread_info *thread;
+
+ thread = current_thread_info();
+
+ thread->tp_value[0] = val;
+
+ /*
+ * This code runs with preemption enabled and therefore must
+ * be reentrant with respect to switch_tls.
+ *
+ * We need to ensure ordering between the shadow state and the
+ * hardware state, so that we don't corrupt the hardware state
+ * with a stale shadow state during context switch.
+ *
+ * If we're preempted here, switch_tls will load TPIDRURO from
+ * thread_info upon resuming execution and the following mcr
+ * is merely redundant.
+ */
+ barrier();
+
+ if (!tls_emu) {
+ if (has_tls_reg) {
+ asm("mcr p15, 0, %0, c13, c0, 3"
+ : : "r" (val));
+ } else {
+ /*
+ * User space must never try to access this
+ * directly. Expect your app to break
+ * eventually if you do so. The user helper
+ * at 0xffff0fe0 must be used instead. (see
+ * entry-armv.S for details)
+ */
+ *((unsigned int *)0xffff0ff0) = val;
+ }
+
+ }
+}
+
static inline unsigned long get_tpuser(void)
{
unsigned long reg = 0;
@@ -59,5 +103,23 @@ static inline unsigned long get_tpuser(void)
return reg;
}
+
+static inline void set_tpuser(unsigned long val)
+{
+ /* Since TPIDRURW is fully context-switched (unlike TPIDRURO),
+ * we need not update thread_info.
+ */
+ if (has_tls_reg && !tls_emu) {
+ asm("mcr p15, 0, %0, c13, c0, 2"
+ : : "r" (val));
+ }
+}
+
+static inline void flush_tls(void)
+{
+ set_tls(0);
+ set_tpuser(0);
+}
+
#endif
#endif /* __ASMARM_TLS_H */