Messages in this thread Patch in this message | | | Date | Tue, 13 Aug 2002 20:32:06 +0200 (CEST) | From | Ingo Molnar <> | Subject | [patch] CLONE_SETTLS, CLONE_SETTID, 2.5.31-BK |
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okay, the attached patch gets rid of clone_startup() and adds two new clone() flags instead:
CLONE_SETTLS => if present then the third clone() syscall parameter is the new TLS.
CLONE_SETTID => if present then the child TID is written to the address specified by the fourth clone() parameter.
the new parameters are handled in a safe way, clone() returns -EFAULT or -EINVAL if there's some problem with them.
No current code is affected by these new flags. Patch was testbooted on 2.5.31-BK-current.
Ingo
--- linux/arch/i386/kernel/process.c.orig Tue Aug 13 20:10:25 2002 +++ linux/arch/i386/kernel/process.c Tue Aug 13 20:30:11 2002 @@ -559,6 +559,7 @@ unsigned long unused, struct task_struct * p, struct pt_regs * regs) { + struct thread_struct *t = &p->thread; struct pt_regs * childregs; struct task_struct *tsk; @@ -567,17 +568,45 @@ childregs->eax = 0; childregs->esp = esp; - p->thread.esp = (unsigned long) childregs; - p->thread.esp0 = (unsigned long) (childregs+1); + t->esp = (unsigned long) childregs; + t->esp0 = (unsigned long) (childregs+1); + t->eip = (unsigned long) ret_from_fork; - p->thread.eip = (unsigned long) ret_from_fork; - - savesegment(fs,p->thread.fs); - savesegment(gs,p->thread.gs); + savesegment(fs, t->fs); + savesegment(gs, t->gs); tsk = current; unlazy_fpu(tsk); - struct_cpy(&p->thread.i387, &tsk->thread.i387); + struct_cpy(&t->i387, &tsk->thread.i387); + + /* + * Set a new TLS for the child thread? + */ + if (clone_flags & CLONE_SETTLS) { + struct desc_struct *desc; + struct user_desc info; + int idx; + + if (copy_from_user(&info, (void *)childregs->esi, sizeof(info))) + return -EFAULT; + if (LDT_empty(&info)) + return -EINVAL; + + idx = info.entry_number; + if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX) + return -EINVAL; + + desc = t->tls_array + idx - GDT_ENTRY_TLS_MIN; + desc->a = LDT_entry_a(&info); + desc->b = LDT_entry_b(&info); + } + + /* + * Notify the child of the TID? + */ + if (clone_flags & CLONE_SETTLS) + if (put_user(p->pid, (pid_t *)childregs->edx)) + return -EFAULT; if (unlikely(NULL != tsk->thread.ts_io_bitmap)) { p->thread.ts_io_bitmap = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL); @@ -747,8 +776,7 @@ asmlinkage int sys_clone(struct pt_regs regs) { struct task_struct *p; - unsigned long clone_flags; - unsigned long newsp; + unsigned long clone_flags, newsp; clone_flags = regs.ebx; newsp = regs.ecx; --- linux/include/linux/sched.h.orig Tue Aug 13 19:55:06 2002 +++ linux/include/linux/sched.h Tue Aug 13 20:27:23 2002 @@ -45,6 +45,8 @@ #define CLONE_THREAD 0x00010000 /* Same thread group? */ #define CLONE_NEWNS 0x00020000 /* New namespace group? */ #define CLONE_SYSVSEM 0x00040000 /* share system V SEM_UNDO semantics */ +#define CLONE_SETTLS 0x00080000 /* create a new TLS for the child */ +#define CLONE_SETTID 0x00100000 /* write the TID back to userspace */ #define CLONE_SIGNAL (CLONE_SIGHAND | CLONE_THREAD) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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