diff options
Diffstat (limited to 'arch/tile/kernel/process.c')
| -rw-r--r-- | arch/tile/kernel/process.c | 171 |
1 files changed, 45 insertions, 126 deletions
diff --git a/arch/tile/kernel/process.c b/arch/tile/kernel/process.c index 307d010..0e5661e 100644 --- a/arch/tile/kernel/process.c +++ b/arch/tile/kernel/process.c @@ -157,24 +157,43 @@ void arch_release_thread_info(struct thread_info *info) static void save_arch_state(struct thread_struct *t); int copy_thread(unsigned long clone_flags, unsigned long sp, - unsigned long stack_size, - struct task_struct *p, struct pt_regs *regs) + unsigned long arg, struct task_struct *p) { - struct pt_regs *childregs; + struct pt_regs *childregs = task_pt_regs(p), *regs = current_pt_regs(); unsigned long ksp; + unsigned long *callee_regs; /* - * When creating a new kernel thread we pass sp as zero. - * Assign it to a reasonable value now that we have the stack. + * Set up the stack and stack pointer appropriately for the + * new child to find itself woken up in __switch_to(). + * The callee-saved registers must be on the stack to be read; + * the new task will then jump to assembly support to handle + * calling schedule_tail(), etc., and (for userspace tasks) + * returning to the context set up in the pt_regs. */ - if (sp == 0 && regs->ex1 == PL_ICS_EX1(KERNEL_PL, 0)) - sp = KSTK_TOP(p); + ksp = (unsigned long) childregs; + ksp -= C_ABI_SAVE_AREA_SIZE; /* interrupt-entry save area */ + ((long *)ksp)[0] = ((long *)ksp)[1] = 0; + ksp -= CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long); + callee_regs = (unsigned long *)ksp; + ksp -= C_ABI_SAVE_AREA_SIZE; /* __switch_to() save area */ + ((long *)ksp)[0] = ((long *)ksp)[1] = 0; + p->thread.ksp = ksp; - /* - * Do not clone step state from the parent; each thread - * must make its own lazily. - */ - task_thread_info(p)->step_state = NULL; + /* Record the pid of the task that created this one. */ + p->thread.creator_pid = current->pid; + + if (unlikely(p->flags & PF_KTHREAD)) { + /* kernel thread */ + memset(childregs, 0, sizeof(struct pt_regs)); + memset(&callee_regs[2], 0, + (CALLEE_SAVED_REGS_COUNT - 2) * sizeof(unsigned long)); + callee_regs[0] = sp; /* r30 = function */ + callee_regs[1] = arg; /* r31 = arg */ + childregs->ex1 = PL_ICS_EX1(KERNEL_PL, 0); + p->thread.pc = (unsigned long) ret_from_kernel_thread; + return 0; + } /* * Start new thread in ret_from_fork so it schedules properly @@ -182,46 +201,33 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, */ p->thread.pc = (unsigned long) ret_from_fork; - /* Save user stack top pointer so we can ID the stack vm area later. */ - p->thread.usp0 = sp; - - /* Record the pid of the process that created this one. */ - p->thread.creator_pid = current->pid; + /* + * Do not clone step state from the parent; each thread + * must make its own lazily. + */ + task_thread_info(p)->step_state = NULL; /* * Copy the registers onto the kernel stack so the * return-from-interrupt code will reload it into registers. */ - childregs = task_pt_regs(p); - *childregs = *regs; + *childregs = *current_pt_regs(); childregs->regs[0] = 0; /* return value is zero */ - childregs->sp = sp; /* override with new user stack pointer */ + 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]; - /* - * Copy the callee-saved registers from the passed pt_regs struct - * into the context-switch callee-saved registers area. - * This way when we start the interrupt-return sequence, the - * callee-save registers will be correctly in registers, which - * is how we assume the compiler leaves them as we start doing - * the normal return-from-interrupt path after calling C code. - * Zero out the C ABI save area to mark the top of the stack. - */ - ksp = (unsigned long) childregs; - ksp -= C_ABI_SAVE_AREA_SIZE; /* interrupt-entry save area */ - ((long *)ksp)[0] = ((long *)ksp)[1] = 0; - ksp -= CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long); - memcpy((void *)ksp, ®s->regs[CALLEE_SAVED_FIRST_REG], - CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long)); - ksp -= C_ABI_SAVE_AREA_SIZE; /* __switch_to() save area */ - ((long *)ksp)[0] = ((long *)ksp)[1] = 0; - p->thread.ksp = ksp; #if CHIP_HAS_TILE_DMA() /* @@ -577,62 +583,6 @@ int do_work_pending(struct pt_regs *regs, u32 thread_info_flags) panic("work_pending: bad flags %#x\n", thread_info_flags); } -/* Note there is an implicit fifth argument if (clone_flags & CLONE_SETTLS). */ -SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, - void __user *, parent_tidptr, void __user *, child_tidptr, - struct pt_regs *, regs) -{ - if (!newsp) - newsp = regs->sp; - return do_fork(clone_flags, newsp, regs, 0, - parent_tidptr, child_tidptr); -} - -/* - * sys_execve() executes a new program. - */ -SYSCALL_DEFINE4(execve, const char __user *, path, - const char __user *const __user *, argv, - const char __user *const __user *, envp, - struct pt_regs *, regs) -{ - long error; - struct filename *filename; - - filename = getname(path); - error = PTR_ERR(filename); - if (IS_ERR(filename)) - goto out; - error = do_execve(filename->name, argv, envp, regs); - putname(filename); - if (error == 0) - single_step_execve(); -out: - return error; -} - -#ifdef CONFIG_COMPAT -long compat_sys_execve(const char __user *path, - compat_uptr_t __user *argv, - compat_uptr_t __user *envp, - struct pt_regs *regs) -{ - long error; - struct filename *filename; - - filename = getname(path); - error = PTR_ERR(filename); - if (IS_ERR(filename)) - goto out; - error = compat_do_execve(filename->name, argv, envp, regs); - putname(filename); - if (error == 0) - single_step_execve(); -out: - return error; -} -#endif - unsigned long get_wchan(struct task_struct *p) { struct KBacktraceIterator kbt; @@ -650,37 +600,6 @@ unsigned long get_wchan(struct task_struct *p) return 0; } -/* - * We pass in lr as zero (cleared in kernel_thread) and the caller - * part of the backtrace ABI on the stack also zeroed (in copy_thread) - * so that backtraces will stop with this function. - * Note that we don't use r0, since copy_thread() clears it. - */ -static void start_kernel_thread(int dummy, int (*fn)(int), int arg) -{ - do_exit(fn(arg)); -} - -/* - * Create a kernel thread - */ -int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) -{ - struct pt_regs regs; - - memset(®s, 0, sizeof(regs)); - regs.ex1 = PL_ICS_EX1(KERNEL_PL, 0); /* run at kernel PL, no ICS */ - regs.pc = (long) start_kernel_thread; - regs.flags = PT_FLAGS_CALLER_SAVES; /* need to restore r1 and r2 */ - regs.regs[1] = (long) fn; /* function pointer */ - regs.regs[2] = (long) arg; /* parameter register */ - - /* Ok, create the new process.. */ - return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, - 0, NULL, NULL); -} -EXPORT_SYMBOL(kernel_thread); - /* Flush thread state. */ void flush_thread(void) { |