More pread/syscall stuff

7c537db5 · Silas Boyd-Wickizer · 0f906e2c · 7c537db5 · 7c537db5 · 7c537db5
--- a/ipc.h
+++ b/ipc.h
+struct ipcctl {
+  volatile char done;
+  volatile long result;
+};
--- a/kernlet.c
+++ b/kernlet.c
 #include "types.h"
 #include "kernel.h"
+#include "spinlock.h"
+#include "condvar.h"
+#include "cpu.h"
+#include "proc.h"
+#include "vm.h"
+#include "fs.h"
+#include "file.h"
+#include "wq.h"
+#include "ipc.h"
+static void
+pread_work(struct work *w, void *a0, void *a1, void *a2, void *a3)
+{
+  struct inode *ip = a0;
+  void *kshared = a1;
+  struct ipcctl *ipc = kshared;
+  size_t count = (uptr)a2;
+  off_t off = (uptr)a3;
+  int r;
+  if (count > KSHAREDSIZE-PGSIZE)
+    panic("pread_work");
+  //cprintf("1: %p %p %lu %lu\n", ip, buf, count, off);
+  ilock(ip, 0);
+  r = readi(ip, kshared+PGSIZE, off, count);
+  iunlock(ip);
+  ipc->result = r;
+  barrier();
+  ipc->done = 1;
+}
+static struct work *
+pread_allocwork(struct inode *ip, void *buf, size_t count, off_t off)
+{
+  struct work *w = allocwork();
+  if (w == NULL)
+    return NULL;
+  //cprintf("0: %p %p %lu %lu\n", ip, buf, count, off);
+  w->rip = pread_work;
+  w->arg0 = ip;
+  w->arg1 = buf;
+  w->arg2 = (void*)count;
+  w->arg3 = (void*)off;
+  return w;
+}
 long
 sys_kernlet(int fd, size_t count, off_t off)
 {
+  struct file *f;
-  return -1;
+  struct work *w;
+  if(fd < 0 || fd >= NOFILE || (f=myproc()->ofile[fd]) == 0)
+    return -1;
+  if(f->type != FD_INODE)
+    return -1;
+  w = pread_allocwork(f->ip, myproc()->vmap->kshared, count, off);
+  if (w == NULL)
+    return -1;
+  if (wq_push(w) < 0) {
+    freework(w);
+    return -1;
+  }
+  return 0;
 }
--- a/preadtest.c
+++ b/preadtest.c
@@ -3,6 +3,7 @@
 #include "fcntl.h"
 #include "user.h"
 #include "amd64.h"
+#include "ipc.h"
 // XXX(sbw) add a memlayout.h?
 #define KSHARED 0xFFFFF00000000000ull
@@ -13,11 +14,6 @@
 static char buf[BSIZE];
-struct ipcctl {
-  volatile char done;
-  volatile long result;
-};
 struct ipcctl *ipcctl = (struct ipcctl*)KSHARED;
 static void
@@ -46,6 +42,12 @@ main(int ac, char **av)
  t0 = rdtsc();
  for (k = 0; k < FSIZE; k+=PSIZE) {
    kernlet_pread(fd, PSIZE, k);
+    while (ipcctl->done == 0)
+        nop_pause();
+    die("preadtest: %d\n", (int)ipcctl->result);
    for (i = k; i < k+PSIZE; i+=BSIZE)
      if (pread(fd, buf, BSIZE, i) != BSIZE)
        die("pread failed");