'user_stack_size' is very misleading, since the argument is never used for the
size of the user stack. Rather, it is an argument which is passed to the main
function executed by a newly forked kernel thread. Hence, rename it to
'kthread_arg'.
When forking a new user thread, the kernel thread arg was (uselessly) added
to the new user stack pointer. This "worked", since the kernel thread arg is
always zero when forking a user thread, but it was obviously not intended.
Signed-off-by: Alex Dowad <alexinbeijing@xxxxxxxxx>
---
arch/ia64/kernel/process.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index b515149..d4a78da 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -300,7 +300,7 @@ ia64_load_extra (struct task_struct *task)
}
/*
- * Copy the state of an ia-64 thread.
+ * Copy the architecture-specific state of an ia-64 thread.
*
* We get here through the following call chain:
*
@@ -332,7 +332,7 @@ ia64_load_extra (struct task_struct *task)
*/
int
copy_thread(unsigned long clone_flags,
- unsigned long user_stack_base, unsigned long user_stack_size,
+ unsigned long user_stack_base, unsigned long kthread_arg,
struct task_struct *p)
{
extern char ia64_ret_from_clone;
@@ -376,13 +376,14 @@ copy_thread(unsigned long clone_flags,
ia64_drop_fpu(p); /* don't pick up stale state from a CPU's fph */
if (unlikely(p->flags & PF_KTHREAD)) {
+ /* kernel thread */
if (unlikely(!user_stack_base)) {
/* fork_idle() called us */
return 0;
}
memset(child_stack, 0, sizeof(*child_ptregs) + sizeof(*child_stack));
child_stack->r4 = user_stack_base; /* payload */
- child_stack->r5 = user_stack_size; /* argument */
+ child_stack->r5 = kthread_arg;
/*
* Preserve PSR bits, except for bits 32-34 and 37-45,
* which we can't read.
@@ -406,6 +407,8 @@ copy_thread(unsigned long clone_flags,
return 0;
}
+
+ /* user thread */
stack = ((struct switch_stack *) regs) - 1;
/* copy parent's switch_stack & pt_regs to child: */
memcpy(child_stack, stack, sizeof(*child_ptregs) + sizeof(*child_stack));
@@ -416,7 +419,7 @@ copy_thread(unsigned long clone_flags,
if (clone_flags & CLONE_SETTLS)
child_ptregs->r13 = regs->r16; /* see sys_clone2() in entry.S */
if (user_stack_base) {
- child_ptregs->r12 = user_stack_base + user_stack_size - 16;
+ child_ptregs->r12 = user_stack_base - 16;
child_ptregs->ar_bspstore = user_stack_base;
child_ptregs->ar_rnat = 0;
child_ptregs->loadrs = 0;
--
2.0.0.GIT
--
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