fix arm timer baremetal!

baremetal/arch/aarch64/svc.c

@@ -71,7 +71,7 @@ int main(void) {
     printf("&after_svc %p\n", &&after_svc);
     assert(myvar == 0);
     /* Max 16-bits. */
-    LKMC_SVC(0xABCD);
+    lkmc_svc(0xABCD);
 after_svc:
     assert(myvar == 1);
     return 0;

baremetal/arch/aarch64/timer.c

@@ -4,15 +4,25 @@
 #include <lkmc.h>
 #include <lkmc/gicv3.h>
 
-#define IRQ_FOUND          (0)
+#define CLOCK_FREQUENCY 10
-#define IRQ_NOT_FOUND      (1)
+#define INTERRUPT_FREQUENCY 1
 
 void enable_irq(void) {
-	__asm__ __volatile__("msr DAIFClr, %0\n\t" : : "i" (LKMC_SYSREG_BITS_DAIF_IRQ)  : "memory");
+	__asm__ __volatile__(
+	    "msr DAIFClr, %0\n\t"
+	    :
+	    : "i" (LKMC_SYSREG_BITS_DAIF_IRQ)
+	    : "memory"
+	);
 }
 
 void disable_irq(void) {
-	__asm__ __volatile__("msr DAIFSet, %0\n\t" : : "i" (LKMC_SYSREG_BITS_DAIF_IRQ)  : "memory");
+	__asm__ __volatile__(
+	    "msr DAIFSet, %0\n\t"
+	    :
+	    : "i" (LKMC_SYSREG_BITS_DAIF_IRQ)
+	    : "memory"
+	);
 }
 
 /* Processor status word. */
@@ -23,6 +33,20 @@ void psw_disable_and_save_interrupt(uint64_t *pswp) {
 	*pswp = psw;
 }
 
+void disable_cntv(void) {
+    lkmc_sysreg_write_cntv_ctl_el0(
+        lkmc_sysreg_read_cntv_ctl_el0() &
+        LKMC_SYSREG_CNTV_CTL_ENABLE
+    );
+}
+
+void enable_cntv(void) {
+    lkmc_sysreg_write_cntv_ctl_el0(
+        lkmc_sysreg_read_cntv_ctl_el0() |
+        LKMC_SYSREG_CNTV_CTL_ENABLE
+    );
+}
+
 /* Processor status word. */
 void psw_restore_interrupt(uint64_t *pswp) {
 	uint64_t psw;
@@ -39,7 +63,7 @@ void lkmc_vector_trap_handler(
     if ((exception->exc_type & 0xff) == LKMC_VECTOR_IRQ_SPX) {
         psw_disable_and_save_interrupt(&psw);
         rc = gic_v3_find_pending_irq(exception, &irq);
-        if (rc != IRQ_FOUND)  {
+        if (rc) {
             puts("IRQ not found!");
             goto restore_irq_out;
         } else {
@@ -47,17 +71,23 @@ void lkmc_vector_trap_handler(
         }
         gicd_disable_int(irq);
         gic_v3_eoi(irq);
-        printf("CNTVCT_EL0 0x%" PRIX64 "\n", lkmc_sysreg_read_cntvct_el0());
+        // Timer specific stuff.
+        {
+            disable_cntv();
+            gicd_clear_pending(TIMER_IRQ);
+            lkmc_sysreg_print_cntvct_el0();
+            raw_write_cntv_cval_el0(
+                lkmc_sysreg_read_cntvct_el0() +
+                CLOCK_FREQUENCY / INTERRUPT_FREQUENCY
+            );
+            enable_cntv();
+        }
         gicd_enable_int(irq);
 restore_irq_out:
         psw_restore_interrupt(&psw);
     }
 }
 
-void enable_cntv(void) {
-    lkmc_sysreg_write_cntv_ctl_el0(lkmc_sysreg_read_cntv_ctl_el0() | LKMC_CNTV_CTL_ENABLE);
-}
-
 int main(void) {
     /* Initial state. */
     lkmc_sysreg_print_cntv_ctl_el0();
@@ -73,7 +103,7 @@ int main(void) {
     {
         /*uint64_t ticks, current_cnt;*/
         /*uint32_t cntfrq;*/
-        lkmc_sysreg_write_cntfrq_el0(1);
+        lkmc_sysreg_write_cntfrq_el0(CLOCK_FREQUENCY);
         /*ticks = cntfrq;*/
         /*current_cnt = lkmc_sysreg_read_cntvct_el0();*/
         /*lkmc_sysreg_write_cntv_cval_el0(current_cnt + ticks);*/
@@ -81,7 +111,7 @@ int main(void) {
         enable_irq();
     }
     while (1) {
-        LKMC_WFI;
+        lkmc_wfi();
     }
     return 0;
 }

common.py

@@ -719,6 +719,8 @@ Incompatible archs are skipped.
                         # http://lists.nongnu.org/archive/html/qemu-discuss/2018-08/msg00034.html
                         env['machine2'] = 'highmem=off'
                     elif env['arch'] == 'aarch64':
+                        # TODO allow the Gic version to be controlled from the CLI.
+                        # env['machine2'] = 'gic_version=3'
                         env['machine2'] = None
         else:
             env['machine2'] = None

lkmc/aarch64.h

@@ -293,9 +293,9 @@ typedef struct {
 
 void lkmc_vector_trap_handler(LkmcVectorExceptionFrame *exception);
 
-/* Mistc assembly instructions. */
+/* Misc assembly instructions. */
-#define LKMC_SVC(immediate) __asm__ __volatile__("svc " #immediate : : : )
+#define lkmc_svc(immediate) __asm__ __volatile__("svc " #immediate : : : )
-#define LKMC_WFI() __asm__ __volatile__ ("wfi" : : : "memory")
+#define lkmc_wfi() __asm__ __volatile__ ("wfi" : : : "memory")
 
 /* Sysreg read and write functions, e.g.:
  *

lkmc/gicv3.h

@@ -286,8 +286,8 @@ void gic_v3_initialize(void) {
     init_gicd();
     init_gicc();
     gicd_config(TIMER_IRQ, GIC_GICD_ICFGR_EDGE);
-    gicd_set_priority(TIMER_IRQ, 0 << GIC_PRI_SHIFT );  /* Set priority */
+    gicd_set_priority(TIMER_IRQ, 0 << GIC_PRI_SHIFT);
-    gicd_set_target(TIMER_IRQ, 0x1);  /* processor 0 */
+    gicd_set_target(TIMER_IRQ, 0x1); /* processor 0 */
     gicd_clear_pending(TIMER_IRQ);
     gicd_enable_int(TIMER_IRQ);
 }
@@ -296,6 +296,7 @@ void gic_v3_initialize(void) {
 /* Find pending IRQ
  * @param[in]     exc  An exception frame
  * @param[in,out] irqp An IRQ number to be processed
+ * @return        0 if found, 1 if not found
  */
 int gic_v3_find_pending_irq(
     LkmcVectorExceptionFrame *exc __attribute__((unused)),
@@ -305,12 +306,12 @@ int gic_v3_find_pending_irq(
     irq_no i;
     for (i = 0; GIC_INT_MAX > i; ++i) {
         if (gicd_probe_pending(i)) {
-            rc = 1;
+            rc = 0;
             *irqp = i;
             goto found;
         }
     }
-    rc = 0;
+    rc = 1;
 found:
     return rc;
 }