riscv: Remove smp boot code

The SMP code is incomplete and is confusing to have broken code around.

src/arch/riscv/kernel/boot.c

@@ -36,12 +36,6 @@ extern char ki_boot_end[1];
 /* pointer to end of kernel image */
 extern char ki_end[1];
 
-#if CONFIG_MAX_NUM_NODES > 1
-/* sync variable to prevent other nodes from booting
- * until kernel data structures initialized */
-BOOT_DATA static volatile int node_boot_lock = 0;
-#endif /* CONFIG_MAX_NUM_NODES > 1 */
-
 // RVTODO: this is an exact copy of the ARM code
 BOOT_CODE static bool_t
 create_untypeds(cap_t root_cnode_cap, region_t boot_mem_reuse_reg)
@@ -199,11 +193,6 @@ init_irqs(cap_t root_cnode_cap)
     }
     setIRQState(IRQTimer, KERNEL_TIMER_IRQ);
 
-#if CONFIG_MAX_NUM_NODES > 1
-    setIRQState(IRQIPI, irq_remote_call_ipi);
-    setIRQState(IRQIPI, irq_reschedule_ipi);
-#endif /* CONFIG_MAX_NUM_NODES > 1 */
-
     /* provide the IRQ control cap */
     write_slot(SLOT_PTR(pptr_of_cap(root_cnode_cap), seL4_CapIRQControl), cap_irq_control_cap_new());
 }
@@ -230,43 +219,6 @@ init_plat(void)
     initTimer();
 }
 
-#if CONFIG_MAX_NUM_NODES > 1
-BOOT_CODE static bool_t
-try_init_kernel_secondary_core(void)
-{
-    /* need to first wait until some kernel init has been done */
-    while (!node_boot_lock);
-
-    init_core_state(SchedulerAction_ResumeCurrentThread);
-
-    /* Perform cpu init */
-    init_cpu();
-
-    /* Enable per-CPU timer interrupts */
-    maskInterrupt(false, KERNEL_TIMER_IRQ);
-
-    NODE_LOCK_SYS;
-
-    ksNumCPUs++;
-
-    init_core_state(SchedulerAction_ResumeCurrentThread);
-
-    return true;
-}
-
-BOOT_CODE static void
-release_secondary_cpus(void)
-{
-    /* release the cpus at the same time */
-    node_boot_lock = 1;
-
-    // RVTODO: there is no memory barrer in below loop and ksNumCPUs is not
-    // volatile. how does this work?
-    /* Wait until all the secondary cores are done initialising */
-    while (ksNumCPUs != CONFIG_MAX_NUM_NODES);
-}
-#endif /* CONFIG_MAX_NUM_NODES > 1 */
-
 /* Main kernel initialisation function. */
 
 static BOOT_CODE bool_t
@@ -421,14 +373,6 @@ try_init_kernel(
 
     ksNumCPUs = 1;
 
-    printf("Releasing CPUs\n");
-    /* initialize BKL before booting up other cores */
-    SMP_COND_STATEMENT(clh_lock_init());
-    SMP_COND_STATEMENT(release_secondary_cpus());
-
-    /* grab BKL before leaving the kernel */
-    NODE_LOCK_SYS;
-
     printf("Booting all finished, dropped to user space\n");
     return true;
 }
@@ -449,32 +393,14 @@ init_kernel(
     // dtb_output. Until this is fixed we must therefore just throw this away and not use it
     (void)dtb_output;
     // RVTODO: is it safe to initialize the platform before the cpu?
-    bool_t result;
-
     init_plat();
 
-#if CONFIG_MAX_NUM_NODES > 1
-    if (hartid == 0) {
-        printf( "********* seL4 microkernel on RISC-V %d-bit platform *********\n", CONFIG_WORD_SIZE);
-        // RVTODO: why are we initializing the platform again?
-        init_plat();
-        result = try_init_kernel(ui_p_reg_start,
-                                 ui_p_reg_end,
-                                 pv_offset,
-                                 v_entry,
-                                 0
-                                );
+    bool_t result = try_init_kernel(ui_p_reg_start,
+                                    ui_p_reg_end,
+                                    pv_offset,
+                                    v_entry
+                                   );
 
-    } else {
-        result = try_init_kernel_secondary_core();
-    }
-#else
-    result = try_init_kernel(ui_p_reg_start,
-                             ui_p_reg_end,
-                             pv_offset,
-                             v_entry
-                            );
-#endif
     if (!result) {
         fail ("Kernel init failed for some reason :(");
     }