Messages in this thread | | | Date | Sat, 14 Mar 2015 19:54:17 +0200 | From | Alex Dowad <> | Subject | Re: [PATCH 13/32] ia64: copy_thread(): rename 'user_stack_size' argument to 'kthread_arg' |
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Sorry, this patch was in error. (I learned about the IA64-only clone2 syscall too late.)
Please disregard. Thanks! Alex Dowad
On 13/03/15 20:14, Alex Dowad wrote: > '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@gmail.com> > --- > 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;
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