Re: [PATCH] tile: support GENERIC_KERNEL_THREAD and GENERIC_KERNEL_EXECVE
From: Al Viro <viro@ZenIV.linux.org.uk>
Date: 2012-10-23 20:36:38
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Subsystem:
the rest · Maintainer:
Linus Torvalds
On Tue, Oct 23, 2012 at 03:22:36PM -0400, Chris Metcalf wrote:
On 10/23/2012 2:41 PM, Al Viro wrote:quoted
On Tue, Oct 23, 2012 at 01:30:26PM -0400, Chris Metcalf wrote:quoted
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); }