Replace process local WCET with global WCET

kth-step · Oct 11, 2023 · 55a0d93 · 55a0d93
1 parent 7878104
commit 55a0d93
Show file tree

Hide file tree

Showing 9 changed files with 37 additions and 17 deletions.
diff --git a/common/inc/s3k/syscall.h b/common/inc/s3k/syscall.h
@@ -40,6 +40,7 @@ typedef enum {
 uint64_t s3k_get_pid(void);
 uint64_t s3k_get_time(void);
 uint64_t s3k_get_timeout(void);
+uint64_t s3k_get_wcet(bool reset);
 uint64_t s3k_reg_read(s3k_reg_t reg);
 uint64_t s3k_reg_write(s3k_reg_t reg, uint64_t val);
 void s3k_sync();

diff --git a/common/inc/s3k/types.h b/common/inc/s3k/types.h
@@ -185,7 +185,6 @@ typedef enum {
 	S3K_REG_ECAUSE,
 	S3K_REG_EVAL,
 	S3K_REG_SERVTIME,
-	S3K_REG_WCET,
 	/* Special value for number of registers */
 	S3K_REG_CNT,
 } s3k_reg_t;

diff --git a/common/src/s3k/s3k.c b/common/src/s3k/s3k.c
@@ -376,6 +376,12 @@ uint64_t s3k_get_timeout(void)
 	return do_ecall(S3K_SYS_GET_INFO, args).val;
 }
 
+uint64_t s3k_get_wcet(bool reset)
+{
+	sys_args_t args = {.get_info = {reset ? 4 : 3}};
+	return do_ecall(S3K_SYS_GET_INFO, args).val;
+}
+
 uint64_t s3k_reg_read(s3k_reg_t reg)
 {
 	sys_args_t args = {.reg = {reg}};

diff --git a/kernel/inc/kernel.h b/kernel/inc/kernel.h
@@ -6,6 +6,8 @@
 #include <stdint.h>
 
 void kernel_init(void);
+uint64_t kernel_wcet(void);
+void kernel_wcet_reset(void);
 
 bool kernel_lock(proc_t *p);
 void kernel_unlock(proc_t *p);

diff --git a/kernel/inc/offsets.h b/kernel/inc/offsets.h
@@ -42,13 +42,12 @@
 #define PROC_ECAUSE _OFFSET(36)
 #define PROC_EVAL _OFFSET(37)
 #define PROC_SERVTIME _OFFSET(38)
-#define PROC_WCET _OFFSET(39)
-#define PROC_PMPCFG0 _OFFSET(40)
-#define PROC_PMPADDR0 _OFFSET(41)
-#define PROC_PMPADDR1 _OFFSET(42)
-#define PROC_PMPADDR2 _OFFSET(43)
-#define PROC_PMPADDR3 _OFFSET(44)
-#define PROC_PMPADDR4 _OFFSET(45)
-#define PROC_PMPADDR5 _OFFSET(46)
-#define PROC_PMPADDR6 _OFFSET(47)
-#define PROC_PMPADDR7 _OFFSET(48)
+#define PROC_PMPCFG0 _OFFSET(39)
+#define PROC_PMPADDR0 _OFFSET(40)
+#define PROC_PMPADDR1 _OFFSET(41)
+#define PROC_PMPADDR2 _OFFSET(42)
+#define PROC_PMPADDR3 _OFFSET(43)
+#define PROC_PMPADDR4 _OFFSET(44)
+#define PROC_PMPADDR5 _OFFSET(45)
+#define PROC_PMPADDR6 _OFFSET(46)
+#define PROC_PMPADDR7 _OFFSET(47)
diff --git a/kernel/inc/proc.h b/kernel/inc/proc.h
@@ -70,7 +70,6 @@ typedef enum {
 	REG_ECAUSE,
 	REG_EVAL,
 	REG_SERVTIME,
-	REG_WCET,
 	/* Special value for number of registers */
 	REG_CNT,
 } reg_t;

diff --git a/kernel/src/kernel.c b/kernel/src/kernel.c
@@ -9,6 +9,7 @@
 #include "sched.h"
 
 static mcslock_t lock;
+static uint64_t wcet;
 
 void kernel_init(void)
 {
@@ -20,6 +21,16 @@ void kernel_init(void)
 	uart_puts("kernel initialized");
 }
 
+uint64_t kernel_wcet(void)
+{
+	return wcet;
+}
+
+void kernel_wcet_reset(void)
+{
+	wcet = 0;
+}
+
 bool kernel_lock(proc_t *p)
 {
 	kernel_hook_sys_exit(p);
@@ -44,7 +55,6 @@ void kernel_hook_sys_exit(proc_t *p)
 {
 #ifdef INSTRUMENT
 	uint64_t cycles = csrr_mcycle();
-	if (p->regs[REG_WCET] < cycles)
-		p->regs[REG_WCET] = cycles;
+	__asm__ volatile("amomax.d x0,%0,(%1)" ::"r"(cycles), "r"(&wcet));
 #endif
 }
diff --git a/kernel/src/syscall.c b/kernel/src/syscall.c
@@ -290,6 +290,13 @@ err_t sys_get_info(proc_t *p, const sys_args_t *args, uint64_t *ret)
 	case 2:
 		*ret = timer_get(csrr_mhartid());
 		break;
+	case 3:
+		*ret = kernel_wcet();
+		break;
+	case 4:
+		*ret = kernel_wcet();
+		kernel_wcet_reset();
+		break;
 	default:
 		*ret = 0;
 	}

diff --git a/kernel/src/trap.S b/kernel/src/trap.S
@@ -117,9 +117,6 @@ trap_resume:
 	ld	t0,PROC_PC(a0)
 	csrw	mepc,t0
 
-	ld	t0,PROC_WCET(a0)
-	csrw	mhpmcounter3,t0
-
 	ld	ra,PROC_RA(a0)
 	ld	sp,PROC_SP(a0)
 	ld	gp,PROC_GP(a0)