diff options
Diffstat (limited to 'arch/hexagon/kernel/process.c')
| -rw-r--r-- | arch/hexagon/kernel/process.c | 163 |
1 files changed, 74 insertions, 89 deletions
diff --git a/arch/hexagon/kernel/process.c b/arch/hexagon/kernel/process.c index 9f6d7411b57..0a0dd5c05b4 100644 --- a/arch/hexagon/kernel/process.c +++ b/arch/hexagon/kernel/process.c @@ -24,33 +24,7 @@ #include <linux/tick.h> #include <linux/uaccess.h> #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); +#include <linux/tracehook.h> /* * Program thread launch. Often defined as a macro in processor.h, @@ -78,28 +52,11 @@ void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) * If hardware or VM offer wait termination even though interrupts * are disabled. */ -static void default_idle(void) +void arch_cpu_idle(void) { __vmwait(); -} - -void (*idle_sleep)(void) = default_idle; - -void cpu_idle(void) -{ - while (1) { - tick_nohz_idle_enter(); - local_irq_disable(); - while (!need_resched()) { - idle_sleep(); - /* interrupts wake us up, but aren't serviced */ - local_irq_enable(); /* service interrupt */ - local_irq_disable(); - } - local_irq_enable(); - tick_nohz_idle_exit(); - schedule(); - } + /* interrupts wake us up, but irqs are still disabled */ + local_irq_enable(); } /* @@ -114,8 +71,7 @@ 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, - struct pt_regs *regs) + unsigned long arg, struct task_struct *p) { struct thread_info *ti = task_thread_info(p); struct hexagon_switch_stack *ss; @@ -125,61 +81,52 @@ 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 (unlikely(p->flags & PF_KTHREAD)) { + memset(childregs, 0, sizeof(struct pt_regs)); + /* r24 <- fn, r25 <- arg */ + ss->r24 = usp; + ss->r25 = arg; + pt_set_kmode(childregs); + return 0; + } + memcpy(childregs, current_pt_regs(), sizeof(*childregs)); + ss->r2524 = 0; - /* If User mode thread, set pt_reg stack pointer as per parameter */ - if (user_mode(childregs)) { + if (usp) 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; - } + /* Child sees zero return value */ + childregs->r00 = 0; /* - * thread_info pointer is pulled out of task_struct "stack" - * field on switch_to. + * 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 */ - p->stack = (void *)ti; return 0; } @@ -240,3 +187,41 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) { return 0; } + + +/* + * Called on the exit path of event entry; see vm_entry.S + * + * Interrupts will already be disabled. + * + * Returns 0 if there's no need to re-check for more work. + */ + +int do_work_pending(struct pt_regs *regs, u32 thread_info_flags) +{ + if (!(thread_info_flags & _TIF_WORK_MASK)) { + return 0; + } /* shortcut -- no work to be done */ + + local_irq_enable(); + + if (thread_info_flags & _TIF_NEED_RESCHED) { + schedule(); + return 1; + } + + if (thread_info_flags & _TIF_SIGPENDING) { + do_signal(regs); + return 1; + } + + if (thread_info_flags & _TIF_NOTIFY_RESUME) { + clear_thread_flag(TIF_NOTIFY_RESUME); + tracehook_notify_resume(regs); + return 1; + } + + /* Should not even reach here */ + panic("%s: bad thread_info flags 0x%08x\n", __func__, + thread_info_flags); +} |