diff options
Diffstat (limited to 'arch/hexagon/kernel/process.c')
| -rw-r--r-- | arch/hexagon/kernel/process.c | 102 |
1 files changed, 32 insertions, 70 deletions
diff --git a/arch/hexagon/kernel/process.c b/arch/hexagon/kernel/process.c index af51de63b835..8a016f7e3949 100644 --- a/arch/hexagon/kernel/process.c +++ b/arch/hexagon/kernel/process.c @@ -26,33 +26,6 @@ #include <linux/slab.h> /* - * Kernel thread creation. The desired kernel function is "wrapped" - * in the kernel_thread_helper function, which does cleanup - * afterwards. - */ -static void __noreturn kernel_thread_helper(void *arg, int (*fn)(void *)) -{ - do_exit(fn(arg)); -} - -int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) -{ - struct pt_regs regs; - - memset(®s, 0, sizeof(regs)); - /* - * Yes, we're exploting illicit knowledge of the ABI here. - */ - regs.r00 = (unsigned long) arg; - regs.r01 = (unsigned long) fn; - pt_set_elr(®s, (unsigned long)kernel_thread_helper); - pt_set_kmode(®s); - - return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); -} -EXPORT_SYMBOL(kernel_thread); - -/* * Program thread launch. Often defined as a macro in processor.h, * but we're shooting for a small footprint and it's not an inner-loop * performance-critical operation. @@ -114,7 +87,7 @@ unsigned long thread_saved_pc(struct task_struct *tsk) * Copy architecture-specific thread state */ int copy_thread(unsigned long clone_flags, unsigned long usp, - unsigned long unused, struct task_struct *p, + unsigned long arg, struct task_struct *p, struct pt_regs *regs) { struct thread_info *ti = task_thread_info(p); @@ -125,61 +98,50 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, childregs = (struct pt_regs *) (((unsigned long) ti + THREAD_SIZE) - sizeof(*childregs)); - memcpy(childregs, regs, sizeof(*childregs)); ti->regs = childregs; /* * Establish kernel stack pointer and initial PC for new thread + * Note that unlike the usual situation, we do not copy the + * parent's callee-saved here; those are in pt_regs and whatever + * we leave here will be overridden on return to userland. */ ss = (struct hexagon_switch_stack *) ((unsigned long) childregs - sizeof(*ss)); ss->lr = (unsigned long)ret_from_fork; p->thread.switch_sp = ss; - - /* If User mode thread, set pt_reg stack pointer as per parameter */ - if (user_mode(childregs)) { - pt_set_rte_sp(childregs, usp); - - /* Child sees zero return value */ - childregs->r00 = 0; - - /* - * The clone syscall has the C signature: - * int [r0] clone(int flags [r0], - * void *child_frame [r1], - * void *parent_tid [r2], - * void *child_tid [r3], - * void *thread_control_block [r4]); - * ugp is used to provide TLS support. - */ - if (clone_flags & CLONE_SETTLS) - childregs->ugp = childregs->r04; - - /* - * Parent sees new pid -- not necessary, not even possible at - * this point in the fork process - * Might also want to set things like ti->addr_limit - */ - } else { - /* - * If kernel thread, resume stack is kernel stack base. - * Note that this is pointer arithmetic on pt_regs * - */ - pt_set_rte_sp(childregs, (unsigned long)(childregs + 1)); - /* - * We need the current thread_info fast path pointer - * set up in pt_regs. The register to be used is - * parametric for assembler code, but the mechanism - * doesn't drop neatly into C. Needs to be fixed. - */ - childregs->THREADINFO_REG = (unsigned long) ti; + if (unlikely(p->flags & PF_KTHREAD)) { + memset(childregs, 0, sizeof(struct pt_regs)); + /* r24 <- fn, r25 <- arg */ + ss->r2524 = usp | ((u64)arg << 32); + pt_set_kmode(childregs); + return 0; } + memcpy(childregs, regs, sizeof(*childregs)); + ss->r2524 = 0; + + pt_set_rte_sp(childregs, usp); + + /* Child sees zero return value */ + childregs->r00 = 0; + + /* + * The clone syscall has the C signature: + * int [r0] clone(int flags [r0], + * void *child_frame [r1], + * void *parent_tid [r2], + * void *child_tid [r3], + * void *thread_control_block [r4]); + * ugp is used to provide TLS support. + */ + if (clone_flags & CLONE_SETTLS) + childregs->ugp = childregs->r04; /* - * thread_info pointer is pulled out of task_struct "stack" - * field on switch_to. + * Parent sees new pid -- not necessary, not even possible at + * this point in the fork process + * Might also want to set things like ti->addr_limit */ - p->stack = (void *)ti; return 0; } |