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D32057.diff
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diff --git a/sys/amd64/amd64/vm_machdep.c b/sys/amd64/amd64/vm_machdep.c
--- a/sys/amd64/amd64/vm_machdep.c
+++ b/sys/amd64/amd64/vm_machdep.c
@@ -193,6 +193,24 @@
td2->td_md.md_spinlock_count = 1;
td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
pmap_thread_init_invl_gen(td2);
+
+ /*
+ * Copy the trap frame for the return to user mode as if from a syscall.
+ * This copies most of the user mode register values. Some of these
+ * registers are rewritten by cpu_set_upcall() and linux_set_upcall().
+ */
+ if ((td1->td_proc->p_flag & P_KPROC) == 0) {
+ bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe));
+
+ /*
+ * If the current thread has the trap bit set (i.e. a debugger
+ * had single stepped the process to the system call), we need
+ * to clear the trap flag from the new frame. Otherwise, the new
+ * thread will receive a (likely unexpected) SIGTRAP when it
+ * executes the first instruction after returning to userland.
+ */
+ td2->td_frame->tf_rflags &= ~PSL_T;
+ }
}
/*
@@ -236,23 +254,9 @@
mdp2 = &p2->p_md;
bcopy(&p1->p_md, mdp2, sizeof(*mdp2));
- /*
- * Copy the trap frame for the return to user mode as if from a
- * syscall. This copies most of the user mode register values.
- */
- td2->td_frame = (struct trapframe *)td2->td_md.md_stack_base - 1;
- bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe));
-
/* Set child return values. */
p2->p_sysent->sv_set_fork_retval(td2);
- /*
- * If the parent process has the trap bit set (i.e. a debugger
- * had single stepped the process to the system call), we need
- * to clear the trap flag from the new frame.
- */
- td2->td_frame->tf_rflags &= ~PSL_T;
-
/* As on i386, do not copy io permission bitmap. */
pcb2->pcb_tssp = NULL;
@@ -602,22 +606,6 @@
{
copy_thread(td0, td);
- /*
- * Copy user general-purpose registers.
- *
- * Some of these registers are rewritten by cpu_set_upcall()
- * and linux_set_upcall().
- */
- bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe));
-
- /* If the current thread has the trap bit set (i.e. a debugger had
- * single stepped the process to the system call), we need to clear
- * the trap flag from the new frame. Otherwise, the new thread will
- * receive a (likely unexpected) SIGTRAP when it executes the first
- * instruction after returning to userland.
- */
- td->td_frame->tf_rflags &= ~PSL_T;
-
set_pcb_flags_raw(td->td_pcb, PCB_FULL_IRET);
}
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