Simplify reschedule points, mail works now!

ce/ce.c

@@ -9,7 +9,7 @@ void app_main (void) {
     char ch;
 
     mail_receive (&ch, 1);
-    test (ch);
+    /* test (ch); */
-    /* mail_send (e_pgid, &ch, 1); */
+    mail_send (e_pgid, &ch, 1);
   }
 }

init/init.c

@@ -18,8 +18,9 @@ void app_main (void) {
 
     mail_send (ce_pgid, (uint8_t*)&ch, 1);
 
-    /* char rcv; */
+    char rcv;
-    /* mail_receive (&rcv, 1); */
+    mail_receive (&rcv, 1);
-    /* terminal_print (&rcv, 1); */
+    /* test (rcv); */
+    terminal_print (&rcv, 1);
   }
 }

kernel/amd64/bootmain.c

@@ -54,7 +54,7 @@ void bootmain (void) {
   vfs_init ();
 
   struct device* ramdisk_device = device_find (RAMDISK_DEVICE);
-  struct reschedule_ctx rctx = {.entries = NULL, .lock = SPIN_LOCK_INIT};
+  struct reschedule_ctx rctx = {.cpu = thiscpu, .reschedule = false};
   int ret = vfs_create_mountpoint ("ramdisk", VFS_TARFS, ramdisk_device, NULL, &rctx);
 
   if (ret < 0) {

kernel/amd64/debug.c

@@ -26,13 +26,9 @@ static bool amd64_debug_serial_tx_empty (void) {
 
 /* Write a single character to serial */
 static void amd64_debug_serial_write (char x) {
-  spin_lock (&serial_lock);
-
   while (!amd64_debug_serial_tx_empty ())
     ;
   amd64_io_outb (PORT_COM1, (uint8_t)x);
-
-  spin_unlock (&serial_lock);
 }
 
 /*
@@ -54,10 +50,14 @@ void debugprintf (const char* fmt, ...) {
 
   const char* p = buffer;
 
+  spin_lock (&serial_lock);
+
   while (*p) {
     amd64_debug_serial_write (*p);
     p++;
   }
+
+  spin_unlock (&serial_lock);
 }
 
 /* Initialize serial */

kernel/amd64/intr.c

@@ -157,35 +157,13 @@ static void amd64_intr_exception (struct saved_regs* regs) {
                regs->rbx);
 
   if (regs->cs == (GDT_UCODE | 0x03)) {
-    struct reschedule_ctx rctx = {.entries = NULL, .lock = SPIN_LOCK_INIT};
+    struct reschedule_ctx rctx = {.reschedule = false, .cpu = NULL};
-
     proc_kill (thiscpu->proc_current, &rctx);
 
-    bool reschedule_thiscpu = false;
+    if (rctx.reschedule)
-
+      cpu_request_sched (rctx.cpu);
-    spin_lock (&rctx.lock);
-
-    struct list_node_link *node, *tmp;
-    list_foreach (rctx.entries, node, tmp) {
-      struct reschedule_entry* entry = list_entry (node, struct reschedule_entry, link);
-      struct cpu* cpu = entry->cpu;
-
-      if (cpu != thiscpu) {
-        cpu_request_sched (cpu);
-      } else {
-        reschedule_thiscpu = true;
-      }
-
-      list_remove (rctx.entries, &entry->link);
-      free (entry);
-    }
-
-    spin_unlock (&rctx.lock);
-
-    if (reschedule_thiscpu) {
-      proc_sched ();
-    }
   } else {
+    __asm__ volatile ("cli");
     spin ();
   }
 }
@@ -215,33 +193,11 @@ void amd64_intr_handler (void* stack_ptr) {
     if (irq == NULL)
       return;
 
-    struct reschedule_ctx rctx = {.entries = NULL, .lock = SPIN_LOCK_INIT};
+    struct reschedule_ctx rctx = {.reschedule = false, .cpu = NULL};
     irq->func (irq->arg, stack_ptr, &rctx);
 
-    bool reschedule_thiscpu = false;
+    if (rctx.reschedule)
-
+      cpu_request_sched (rctx.cpu);
-    spin_lock (&rctx.lock);
-
-    struct list_node_link *node, *tmp;
-    list_foreach (rctx.entries, node, tmp) {
-      struct reschedule_entry* entry = list_entry (node, struct reschedule_entry, link);
-      struct cpu* cpu = entry->cpu;
-
-      if (cpu != thiscpu) {
-        cpu_request_sched (cpu);
-      } else {
-        reschedule_thiscpu = true;
-      }
-
-      list_remove (rctx.entries, &entry->link);
-      free (entry);
-    }
-
-    spin_unlock (&rctx.lock);
-
-    if (reschedule_thiscpu) {
-      proc_sched ();
-    }
   }
 }
 

kernel/amd64/syscall.c

@@ -37,7 +37,7 @@ uintptr_t amd64_syscall_dispatch (void* stack_ptr) {
     return -ST_SYSCALL_NOT_FOUND;
   }
 
-  struct reschedule_ctx rctx = {.entries = NULL, .lock = SPIN_LOCK_INIT};
+  struct reschedule_ctx rctx = {.reschedule = false, .cpu = NULL};
 
   uintptr_t r =
       func (caller, regs, &rctx, regs->rdi, regs->rsi, regs->rdx, regs->r10, regs->r8, regs->r9);
@@ -50,30 +50,8 @@ uintptr_t amd64_syscall_dispatch (void* stack_ptr) {
     spin_unlock (&caller->lock);
   }
 
-  bool reschedule_thiscpu = false;
+  if (rctx.reschedule)
-
+    cpu_request_sched (rctx.cpu);
-  spin_lock (&rctx.lock);
-
-  struct list_node_link *node, *tmp;
-  list_foreach (rctx.entries, node, tmp) {
-    struct reschedule_entry* entry = list_entry (node, struct reschedule_entry, link);
-    struct cpu* cpu = entry->cpu;
-
-    if (cpu != thiscpu) {
-      cpu_request_sched (cpu);
-    } else {
-      reschedule_thiscpu = true;
-    }
-
-    list_remove (rctx.entries, &entry->link);
-    free (entry);
-  }
-
-  spin_unlock (&rctx.lock);
-
-  if (reschedule_thiscpu) {
-    proc_sched ();
-  }
 
   return r;
 }

kernel/proc/mail.c

@@ -37,7 +37,6 @@ void proc_cleanup_resource_mail (struct proc_resource* resource, struct reschedu
   }
 
   spin_unlock (&mail->send_sq.lock);
-
   spin_unlock (&mail->resource->lock);
 }
 
@@ -82,9 +81,12 @@ void proc_mail_send (struct proc* proc, struct proc_mail* mail, struct reschedul
   spin_unlock (&mail->recv_sq.lock);
 
   /* mail is empty and nobody is waiting */
-  mail->pending_mesg = malloc (data_size);
+  void* mesg = malloc (data_size);
+  if (mesg != NULL) {
+    mail->pending_mesg = mesg;
     memcpy (mail->pending_mesg, data, data_size);
     mail->pending_mesg_size = data_size;
+  }
 
   spin_unlock (&mail->resource->lock);
 }
@@ -100,7 +102,7 @@ void proc_mail_receive (struct proc* proc, struct proc_mail* mail, struct resche
 
   /* consume mesg if available */
   if (mail->pending_mesg != NULL) {
-    memcpy (recv_buffer, mail->pending_mesg, recv_size);
+    memcpy (recv_buffer, mail->pending_mesg, min (recv_size, mail->pending_mesg_size));
     free (mail->pending_mesg);
     mail->pending_mesg = NULL;
     mail->pending_mesg_size = 0;

kernel/proc/proc.c

@@ -181,8 +181,10 @@ void proc_register (struct proc* proc, struct cpu* register_cpu, struct reschedu
   spin_unlock (&cpu->lock);
   spin_unlock (&proc_tree_lock);
 
-  if (rctx != NULL)
+  if (rctx != NULL) {
-    reschedule_list_append (rctx, cpu);
+    rctx->reschedule = true;
+    rctx->cpu = cpu;
+  }
 }
 
 /* caller holds cpu->lock */
@@ -252,7 +254,7 @@ static void proc_reap (struct reschedule_ctx* rctx) {
 
 void proc_sched (void) {
   int s_cycles = atomic_fetch_add (&sched_cycles, 1);
-  struct reschedule_ctx rctx = {.entries = NULL, .lock = SPIN_LOCK_INIT};
+  struct reschedule_ctx rctx = {.reschedule = false, .cpu = NULL};
 
   if (s_cycles % SCHED_REAP_FREQ == 0)
     proc_reap (&rctx);
@@ -295,7 +297,8 @@ void proc_kill (struct proc* proc, struct reschedule_ctx* rctx) {
   spin_unlock (&proc->lock);
   spin_unlock (&cpu->lock);
 
-  reschedule_list_append (rctx, cpu);
+  rctx->reschedule = true;
+  rctx->cpu = cpu;
 
   DEBUG ("killed PID %d\n", proc->pid);
 }

kernel/proc/reschedule.c

@@ -1,32 +0,0 @@
-#include <libk/list.h>
-#include <mm/liballoc.h>
-#include <proc/reschedule.h>
-#include <sync/spin_lock.h>
-#include <sys/smp.h>
-
-void reschedule_list_append (struct reschedule_ctx* rctx, struct cpu* cpu) {
-  spin_lock (&rctx->lock);
-
-  struct list_node_link *node, *tmp;
-  list_foreach (rctx->entries, node, tmp) {
-    struct reschedule_entry* entry = list_entry (node, struct reschedule_entry, link);
-
-    if (entry->cpu == cpu) {
-      spin_unlock (&rctx->lock);
-      return;
-    }
-  }
-
-  struct reschedule_entry* entry = malloc (sizeof (*entry));
-
-  if (entry == NULL) {
-    spin_unlock (&rctx->lock);
-    return;
-  }
-
-  entry->cpu = cpu;
-
-  list_append (rctx->entries, &entry->link);
-
-  spin_unlock (&rctx->lock);
-}

kernel/proc/reschedule.h

@@ -5,16 +5,9 @@
 #include <sync/spin_lock.h>
 #include <sys/smp.h>
 
-struct reschedule_entry {
-  struct cpu* cpu;
-  struct list_node_link link;
-};
-
 struct reschedule_ctx {
-  struct list_node_link* entries;
+  bool reschedule;
-  spin_lock_t lock;
+  struct cpu* cpu;
 };
 
-void reschedule_list_append (struct reschedule_ctx* rctx, struct cpu* cpu);
-
 #endif // _KERNEL_PROC_RESCHEDULE_H

kernel/proc/src.mk

@@ -3,13 +3,11 @@ c += proc/proc.c \
 		 proc/mutex.c \
 		 proc/procgroup.c \
 		 proc/suspension_q.c \
-		 proc/mail.c \
+		 proc/mail.c
-		 proc/reschedule.c
 
 o += proc/proc.o \
 		 proc/resource.o \
 		 proc/mutex.o \
 		 proc/procgroup.o \
 		 proc/suspension_q.o \
-		 proc/mail.o \
+		 proc/mail.o
-		 proc/reschedule.o

kernel/proc/suspension_q.c

@@ -48,7 +48,8 @@ void proc_sq_suspend (struct proc* proc, struct proc_suspension_q* sq, spin_lock
   spin_unlock (&proc->lock);
   spin_unlock (&cpu->lock);
 
-  reschedule_list_append (rctx, cpu);
+  rctx->reschedule = true;
+  rctx->cpu = cpu;
 }
 
 void proc_sq_resume (struct proc* proc, struct proc_sq_entry* sq_entry,
@@ -80,7 +81,8 @@ void proc_sq_resume (struct proc* proc, struct proc_sq_entry* sq_entry,
 
   free (sq_entry);
 
-  reschedule_list_append (rctx, cpu);
+  rctx->reschedule = true;
+  rctx->cpu = cpu;
 }
 
 void proc_sqs_cleanup (struct proc* proc) {

kernel/syscall/syscall.c

@@ -108,7 +108,8 @@ DEFINE_SYSCALL (sys_argument_ptr) { return proc->uvaddr_argument; }
 
 /* int sched (void) */
 DEFINE_SYSCALL (sys_sched) {
-  reschedule_list_append (rctx, thiscpu);
+  rctx->reschedule = true;
+  rctx->cpu = thiscpu;
   return SYSRESULT (ST_OK);
 }