Implement generic lock

6 files changed, 38 insertions, 15 deletions

diff --git a/include/cpu.h b/include/cpu.h
index c200016..6dbaa74 100644
--- a/include/cpu.h
+++ b/include/cpu.h
@@ -91,5 +91,7 @@ static inline void* getirqstack(void)
 #define SYS_TIME        1
 #define SYS_SCHED       2
 #define SYS_FREE_STACK  3
+#define SYS_LOCK        4
+#define SYS_UNLOCK      5
 
 #endif
diff --git a/include/util/lock.h b/include/util/lock.h
new file mode 100644
index 0000000..78add88
--- /dev/null
+++ b/include/util/lock.h
@@ -0,0 +1,12 @@
+#ifndef UTIL_LOCK_H
+#define UTIL_LOCK_H
+
+#include <util/mutex.h>
+
+struct Lock {
+	unsigned long pid;
+} __attribute__((packed, aligned(4)));
+
+struct Lock* create_lock(void);
+
+#endif
diff --git a/include/util/mutex.h b/include/util/mutex.h
index 907fe5b..61237b8 100644
--- a/include/util/mutex.h
+++ b/include/util/mutex.h
@@ -8,10 +8,12 @@
 #define CORE3_PID 4
 #define FIRST_AVAIL_PID CORE3_PID+1
 
+// PID field is first so that it can be treated
+//  as a lock
 struct Mutex {
-	void* addr;
 	unsigned long pid;
-} __attribute__((packed, aligned(4)));;
+	void* addr;
+} __attribute__((packed, aligned(4)));
 
 struct Mutex* create_mutex(void* addr);
 
diff --git a/src/exceptions/svc.S b/src/exceptions/svc.S
index dc1a351..cffa09c 100644
--- a/src/exceptions/svc.S
+++ b/src/exceptions/svc.S
@@ -50,12 +50,11 @@ svc_000003: // Clean task stack
 	sub r2, #1
 	str r2, [r3]
 	b svc_exit
-svc_000004: // Lock Mutex (usr_r0 = struct Mutex*)
+svc_000004: // Lock Lock (usr_r0 = struct Lock*)
 	ldr r3, =scheduler
 	ldr r2, [r3, #0] // struct Thread* rthread
 	ldr r1, [r2, #0x10] // unsigned long pid
-	ldr r0, [sp, #0] // struct Mutex* m
-	add r0, #4 // Point to pid
+	ldr r0, [sp, #0] // struct Lock* m
 1:	clrex
 	ldrex r2, [r0, #0]
 	cmp r2, #0
@@ -66,20 +65,17 @@ svc_000004: // Lock Mutex (usr_r0 = struct Mutex*)
 	dmb
 	b svc_exit
 svc_000004_delay_mutex:
-	// r0 = struct Mutex* m
-	sub r0, #4
+	// r0 = struct Lock* m
 	bl sched_mutex_yield
 	ldmfd sp!, {r0-r12,lr}
 	b schedule
-svc_000005: // Release Mutex
-	ldr r0, [sp, #0] // struct Mutex* m
-	add r0, #4
+svc_000005: // Release Lock
+	ldr r0, [sp, #0] // struct Lock* m
 	mov r1, #0
 	dmb
 	str r1, [r0, #0]
 	dsb
 	sev
-	sub r0, #4
 	bl sched_mutex_resurrect
 	ldmfd sp!, {r0-r12,lr}
 	b schedule
diff --git a/src/tests/test.c b/src/tests/test.c
index 8b01706..40e2679 100644
--- a/src/tests/test.c
+++ b/src/tests/test.c
@@ -5,6 +5,7 @@
 #include <sys/core.h>
 #include <sys/schedule.h>
 #include <util/mutex.h>
+#include <util/lock.h>
 
 extern void atest(void);
 void btest(void);
@@ -33,26 +34,27 @@ void test_entry(void)
 }
 
 static struct Mutex testm = {.addr = 0, .pid = 0};
+//static struct Lock testm = {.pid = 0};
 
 void ctest1(void)
 {
 	uart_string("1 Started\n");
-	sys1(4, &testm);
+	sys1(SYS_LOCK, &testm);
 	uart_string("1 Finished\n");
 }
 
 void ctest2(void)
 {
 	uart_string("2 Started\n");
-	sys1(4, &testm);
+	sys1(SYS_LOCK, &testm);
 	uart_string("2 Finished\n");
-	sys1(5, &testm);
+	sys1(SYS_UNLOCK, &testm);
 }
 
 void ctest3(void)
 {
 	uart_string("3 Started\n");
-	sys1(5, &testm);
+	sys1(SYS_UNLOCK, &testm);
 	uart_string("3 Finished\n");
 }
 
diff --git a/src/util/lock.c b/src/util/lock.c
new file mode 100644
index 0000000..2a7d35e
--- /dev/null
+++ b/src/util/lock.c
@@ -0,0 +1,9 @@
+#include <util/lock.h>
+#include <lib/kmem.h>
+
+struct Lock* create_lock(void)
+{
+	struct Lock* l = (struct Lock*)kmalloc(sizeof(struct Lock));
+	l->pid = 0;
+	return l;
+}