Hook up threading

Signed-off-by: Will Deacon <will.deacon@arm.com>

5 files changed, 61 insertions, 25 deletions

diff --git a/Makefile b/Makefile
index bc17b90..efee9a1 100644
--- a/Makefile
+++ b/Makefile
@@ -1,9 +1,11 @@
 CC=aarch64-linux-gnu-gcc
-CFLAGS=-Wall -O2 -fno-strict-aliasing
+CFLAGS=-Wall -O2 -fno-strict-aliasing -g -ffreestanding
+LDFLAGS=-static -nostdlib
 TARGET=qrwlock
+HDRS= kernel.h compiler.h rmem.h
 OBJS= main.o qrwlock.o
 
-$(TARGET) : $(OBJS) kernel.h
+$(TARGET) : $(OBJS) $(HDRS)
 all: $(TARGET)
 
 clean:
diff --git a/compiler.h b/compiler.h
new file mode 100644
index 0000000..b188726
--- /dev/null
+++ b/compiler.h
@@ -0,0 +1,18 @@
+#ifndef __COMPILER_H
+#define __COMPILER_H
+
+#define __branch_check__(x, expect, is_constant) ({			\
+			int ______r;					\
+			______r = __builtin_expect(!!(x), expect);	\
+			______r;					\
+		})
+
+#define likely(x)	(__branch_check__(x, 1, __builtin_constant_p(x)))
+#define unlikely(x)	(__branch_check__(x, 0, __builtin_constant_p(x)))
+#define __force
+#define __aligned(x)	__attribute__((aligned(x)))
+#define __always_inline	inline __attribute__((always_inline))
+#define noinline	__attribute__((noinline))
+#define __noreturn	__attribute__((noreturn))
+
+#endif /* __COMPILER_H */
diff --git a/kernel.h b/kernel.h
index b2b3789..afecbaf 100644
--- a/kernel.h
+++ b/kernel.h
@@ -5,20 +5,10 @@
 #ifndef __KERNEL_H
 #define __KERNEL_H
 
-extern void abort(void);
+#include "compiler.h"
+#include "rmem.h"
 
-/* Compiler bits */
-#define __branch_check__(x, expect, is_constant) ({			\
-			int ______r;					\
-			______r = __builtin_expect(!!(x), expect);	\
-			______r;					\
-		})
-
-#define likely(x)	(__branch_check__(x, 1, __builtin_constant_p(x)))
-#define unlikely(x)	(__branch_check__(x, 0, __builtin_constant_p(x)))
-#define __force
-#define __aligned(x)	__attribute__((aligned(x)))
-#define __always_inline	inline __attribute__((always_inline))
+#define _abort	__rmem_stop
 
 /* Type definitions */
 typedef unsigned char		u8;
@@ -70,7 +60,7 @@ typedef struct qrwlock {
 	case 4: *(u32 *)res = *(volatile u32 *)p; break;		\
 	case 8: *(u64 *)res = *(volatile u64 *)p; break;		\
 	default:							\
-		abort(); /* hack for userspace */			\
+		_abort(); /* hack for userspace */			\
 	}								\
 })
 
@@ -140,7 +130,7 @@ static inline unsigned long __cmpxchg##sfx(volatile void *ptr,		\
 	case 8:								\
 		return __cmpxchg_case##sfx##_8(ptr, old, new);		\
 	default:							\
-		abort(); /* hack for userspace */			\
+		_abort(); /* hack for userspace */			\
 	}								\
 }
 
@@ -259,7 +249,7 @@ static inline void __cmpwait##sfx(volatile void *ptr,			\
 	case 8:								\
 		return __cmpwait_case##sfx##_8(ptr, val);		\
 	default:							\
-		abort(); /* hack for userspace */			\
+		_abort(); /* hack for userspace */			\
 	}								\
 }
 
diff --git a/main.c b/main.c
index 7114add..589ce79 100644
--- a/main.c
+++ b/main.c
@@ -1,17 +1,26 @@
 #include "qrwlock.h"
 
-struct qrwlock lock;
+struct qrwlock lock = __ARCH_RW_LOCK_UNLOCKED;
 
-void abort(void)
+/*
+ * Test driver for qrwlock.
+ * Want to ensure that writers are serialised wrt everybody else.
+ */
+static void writer(void)
 {
-	while (1);
+	arch_write_lock(&lock);
+	arch_write_unlock(&lock);
 }
 
-int main(void)
+static void reader(void)
 {
 	arch_read_lock(&lock);
 	arch_read_unlock(&lock);
-	arch_write_lock(&lock);
-	arch_write_unlock(&lock);
-	return 0;
+}
+
+void _start(void)
+{
+	__rmem_thread_start(writer);
+	//__rmem_thread_start(reader);
+	reader();
 }
diff --git a/rmem.h b/rmem.h
new file mode 100644
index 0000000..3ab1294
--- /dev/null
+++ b/rmem.h
@@ -0,0 +1,17 @@
+#ifndef __RMEM_H
+#define __RMEM_H
+
+#include "compiler.h"
+
+static void __noreturn __rmem_stop(void)
+{
+	while (1)
+		asm volatile(".inst	0xd50bb001");
+}
+
+static void noinline __rmem_thread_start(void *fn)
+{
+	asm volatile(".inst	0xd50bb003" :: "r" (fn) : "memory");
+}
+
+#endif /* __RMEM_H */