On Tue, Oct 23, 2012 at 03:22:36PM -0400, Chris Metcalf wrote:
> On 10/23/2012 2:41 PM, Al Viro wrote:
> > On Tue, Oct 23, 2012 at 01:30:26PM -0400, Chris Metcalf wrote:
> >> As you had suggested in an earlier email, I went ahead and eliminated the
> >> special pt_regs handling for sigaltstack, rt_sigreturn, and clone. (Also a
> >> tilepro-specific syscall that was also using PTREG_SYSCALL.) I'll send it
> >> separately and you can include it in your tree if you like.
> > OK by me... Or just pull this arch-tile into a separate branch in your
> > tree, add commit on top of it and I'll pull that.
>
> Done in
>
> git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile.git
> viro-signal-tile
Argh... That's exactly the reason why I would like to get amending commits -
you've done that commit on top of the identical tree, but without your
Acked-by on the last commit. Result: merge conflict ;-/
Could you test the following on top of your patch? It gets rid of
regs use in sys_clone() *and* of the regs argument in copy_thread().
If that work (including SMP - note that it changes the path taken
by copy_thread() when called by fork_idle()), that should be all
we'll need in arch/tile for killing idle_regs() and killing the pt_regs
passing to do_fork()/copy_process()/copy_thread().
diff --git a/arch/tile/kernel/process.c b/arch/tile/kernel/process.c
index 6e7fb4e..1c20029 100644
--- a/arch/tile/kernel/process.c
+++ b/arch/tile/kernel/process.c
@@ -158,7 +158,7 @@ static void save_arch_state(struct thread_struct *t);
int copy_thread(unsigned long clone_flags, unsigned long sp,
unsigned long arg,
- struct task_struct *p, struct pt_regs *regs)
+ struct task_struct *p, struct pt_regs *unused)
{
struct pt_regs *childregs = task_pt_regs(p);
unsigned long ksp;
@@ -184,7 +184,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
/* Record the pid of the task that created this one. */
p->thread.creator_pid = current->pid;
- if (unlikely(!regs)) {
+ if (unlikely(p->flags & PF_KTHREAD)) {
/* kernel thread */
memset(childregs, 0, sizeof(struct pt_regs));
memset(&callee_regs[2], 0,
@@ -208,25 +208,26 @@ int copy_thread(unsigned long clone_flags, unsigned long
sp,
*/
task_thread_info(p)->step_state = NULL;
- /* Save user stack top pointer so we can ID the stack vm area later. */
- p->thread.usp0 = sp;
-
/*
* Copy the registers onto the kernel stack so the
* return-from-interrupt code will reload it into registers.
*/
- *childregs = *regs;
+ *childregs = *current_pt_regs();
childregs->regs[0] = 0; /* return value is zero */
- childregs->sp = sp; /* override with new user stack pointer */
- memcpy(callee_regs, ®s->regs[CALLEE_SAVED_FIRST_REG],
+ if (sp)
+ childregs->sp = sp; /* override with new user stack pointer */
+ memcpy(callee_regs, &childregs->regs[CALLEE_SAVED_FIRST_REG],
CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long));
+ /* Save user stack top pointer so we can ID the stack vm area later. */
+ p->thread.usp0 = childregs->sp;
+
/*
* If CLONE_SETTLS is set, set "tp" in the new task to "r4",
* which is passed in as arg #5 to sys_clone().
*/
if (clone_flags & CLONE_SETTLS)
- childregs->tp = regs->regs[4];
+ childregs->tp = childregs->regs[4];
#if CHIP_HAS_TILE_DMA()
@@ -587,10 +588,7 @@ int do_work_pending(struct pt_regs *regs, u32
thread_info_flags)
SYSCALL_DEFINE4(clone, unsigned long, clone_flags, unsigned long, newsp,
void __user *, parent_tidptr, void __user *, child_tidptr)
{
- struct pt_regs *regs = current_pt_regs();
- if (!newsp)
- newsp = regs->sp;
- return do_fork(clone_flags, newsp, regs, 0,
+ return do_fork(clone_flags, newsp, current_pt_regs(), 0,
parent_tidptr, child_tidptr);
}
--
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