[patch] user-vm-unlock-2.5.31-A2

From: Ingo Molnar (mingo@elte.hu)
Date: Tue Aug 13 2002 - 16:23:30 EST


and here's a merged CLONE_VM_RELEASE patch against the previous
clone-detached patch. (the sched.h reorganization broke it.)

I've tested it and userspace VM-release still works (after fixing the test
tool to use the repositioned clone flag bit):

  [mingo@a mingo]$ ./start-detached 1000 1 0
  stack end: 0x12341234
  started up 1000 threads!
  stack end after all threads exited: 0x00000000.

        Ingo

--- linux/arch/i386/kernel/process.c.orig Tue Aug 13 23:14:39 2002
+++ linux/arch/i386/kernel/process.c Tue Aug 13 23:20:48 2002
@@ -566,6 +566,7 @@
         struct_cpy(childregs, regs);
         childregs->eax = 0;
         childregs->esp = esp;
+ p->user_vm_lock = NULL;
 
         p->thread.esp = (unsigned long) childregs;
         p->thread.esp0 = (unsigned long) (childregs+1);
@@ -579,6 +580,19 @@
         unlazy_fpu(tsk);
         struct_cpy(&p->thread.i387, &tsk->thread.i387);
 
+ if (unlikely(NULL != tsk->thread.ts_io_bitmap)) {
+ p->thread.ts_io_bitmap = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
+ if (!p->thread.ts_io_bitmap)
+ return -ENOMEM;
+ memcpy(p->thread.ts_io_bitmap, tsk->thread.ts_io_bitmap,
+ IO_BITMAP_BYTES);
+ }
+
+ /*
+ * The common fastpath:
+ */
+ if (!(clone_flags & (CLONE_SETTLS | CLONE_SETTID | CLONE_RELEASE_VM)))
+ return 0;
         /*
          * Set a new TLS for the child thread?
          */
@@ -608,14 +622,13 @@
                 if (put_user(p->pid, (pid_t *)childregs->edx))
                         return -EFAULT;
 
- if (unlikely(NULL != tsk->thread.ts_io_bitmap)) {
- p->thread.ts_io_bitmap = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
- if (!p->thread.ts_io_bitmap)
- return -ENOMEM;
- memcpy(p->thread.ts_io_bitmap, tsk->thread.ts_io_bitmap,
- IO_BITMAP_BYTES);
+ /*
+ * Does the userspace VM want any unlock on mm_release()?
+ */
+ if (clone_flags & CLONE_RELEASE_VM) {
+ childregs->esp -= sizeof(0UL);
+ p->user_vm_lock = (long *) esp;
         }
-
         return 0;
 }
 
--- linux/include/linux/sched.h.orig Tue Aug 13 23:14:51 2002
+++ linux/include/linux/sched.h Tue Aug 13 23:21:21 2002
@@ -48,6 +48,7 @@
 #define CLONE_SETTLS 0x00080000 /* create a new TLS for the child */
 #define CLONE_SETTID 0x00100000 /* write the TID back to userspace */
 #define CLONE_DETACHED 0x00200000 /* parent wants no child-exit signal */
+#define CLONE_RELEASE_VM 0x00400000 /* release the userspace VM */
 
 #define CLONE_SIGNAL (CLONE_SIGHAND | CLONE_THREAD)
 
@@ -306,6 +307,7 @@
 
         wait_queue_head_t wait_chldexit; /* for wait4() */
         struct completion *vfork_done; /* for vfork() */
+ long *user_vm_lock; /* for CLONE_RELEASE_VM */
 
         unsigned long rt_priority;
         unsigned long it_real_value, it_prof_value, it_virt_value;
--- linux/kernel/fork.c.orig Tue Aug 13 23:14:51 2002
+++ linux/kernel/fork.c Tue Aug 13 23:20:48 2002
@@ -367,6 +367,12 @@
                 tsk->vfork_done = NULL;
                 complete(vfork_done);
         }
+ if (tsk->user_vm_lock)
+ /*
+ * We dont check the error code - if userspace has
+ * not set up a proper pointer then tough luck.
+ */
+ put_user(0UL, tsk->user_vm_lock);
 }
 
 static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)

-
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This archive was generated by hypermail 2b29 : Thu Aug 15 2002 - 22:00:34 EST