/* * arch/xtensa/kernel/process.c * * Xtensa Processor version. * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 2001 - 2005 Tensilica Inc. * * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com> * Chris Zankel <chris@zankel.net> * Marc Gauthier <marc@tensilica.com, marc@alumni.uwaterloo.ca> * Kevin Chea */ #include <linux/errno.h> #include <linux/sched.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/smp.h> #include <linux/stddef.h> #include <linux/unistd.h> #include <linux/ptrace.h> #include <linux/slab.h> #include <linux/elf.h> #include <linux/init.h> #include <linux/prctl.h> #include <linux/init_task.h> #include <linux/module.h> #include <linux/mqueue.h> #include <linux/fs.h> #include <asm/pgtable.h> #include <asm/uaccess.h> #include <asm/system.h> #include <asm/io.h> #include <asm/processor.h> #include <asm/platform.h> #include <asm/mmu.h> #include <asm/irq.h> #include <asm/atomic.h> #include <asm/asm-offsets.h> #include <asm/regs.h> extern void ret_from_fork(void); struct task_struct *current_set[NR_CPUS] = {&init_task, }; void (*pm_power_off)(void) = NULL; EXPORT_SYMBOL(pm_power_off); #if XTENSA_HAVE_COPROCESSORS void coprocessor_release_all(struct thread_info *ti) { unsigned long cpenable; int i; /* Make sure we don't switch tasks during this operation. */ preempt_disable(); /* Walk through all cp owners and release it for the requested one. */ cpenable = ti->cpenable; for (i = 0; i < XCHAL_CP_MAX; i++) { if (coprocessor_owner[i] == ti) { coprocessor_owner[i] = 0; cpenable &= ~(1 << i); } } ti->cpenable = cpenable; coprocessor_clear_cpenable(); preempt_enable(); } void coprocessor_flush_all(struct thread_info *ti) { unsigned long cpenable; int i; preempt_disable(); cpenable = ti->cpenable; for (i = 0; i < XCHAL_CP_MAX; i++) { if ((cpenable & 1) != 0 && coprocessor_owner[i] == ti) coprocessor_flush(ti, i); cpenable >>= 1; } preempt_enable(); } #endif /* * Powermanagement idle function, if any is provided by the platform. */ void cpu_idle(void) { local_irq_enable(); /* endless idle loop with no priority at all */ while (1) { while (!need_resched()) platform_idle(); preempt_enable_no_resched(); schedule(); preempt_disable(); } } /* * This is called when the thread calls exit(). */ void exit_thread(void) { #if XTENSA_HAVE_COPROCESSORS coprocessor_release_all(current_thread_info()); #endif } /* * Flush thread state. This is called when a thread does an execve() * Note that we flush coprocessor registers for the case execve fails. */ void flush_thread(void) { #if XTENSA_HAVE_COPROCESSORS struct thread_info *ti = current_thread_info(); coprocessor_flush_all(ti); coprocessor_release_all(ti); #endif } /* * This is called before the thread is copied. */ void prepare_to_copy(struct task_struct *tsk) { #if XTENSA_HAVE_COPROCESSORS coprocessor_flush_all(task_thread_info(tsk)); #endif } /* * Copy thread. * * The stack layout for the new thread looks like this: * * +------------------------+ <- sp in childregs (= tos) * | childregs | * +------------------------+ <- thread.sp = sp in dummy-frame * | dummy-frame | (saved in dummy-frame spill-area) * +------------------------+ * * We create a dummy frame to return to ret_from_fork: * a0 points to ret_from_fork (simulating a call4) * sp points to itself (thread.sp) * a2, a3 are unused. * * Note: This is a pristine frame, so we don't need any spill region on top of * childregs. */ int copy_thread(int nr, unsigned long clone_flags, unsigned long usp, unsigned long unused, struct task_struct * p, struct pt_regs * regs) { struct pt_regs *childregs; struct thread_info *ti; unsigned long tos; int user_mode = user_mode(regs); /* Set up new TSS. */ tos = (unsigned long)task_stack_page(p) + THREAD_SIZE; if (user_mode) childregs = (struct pt_regs*)(tos - PT_USER_SIZE); else childregs = (struct pt_regs*)tos - 1; *childregs = *regs; /* Create a call4 dummy-frame: a0 = 0, a1 = childregs. */ *((int*)childregs - 3) = (unsigned long)childregs; *((int*)childregs - 4) = 0; childregs->areg[1] = tos; childregs->areg[2] = 0; p->set_child_tid = p->clear_child_tid = NULL; p->thread.ra = MAKE_RA_FOR_CALL((unsigned long)ret_from_fork, 0x1); p->thread.sp = (unsigned long)childregs; if (user_mode(regs)) { int len = childregs->wmask & ~0xf; childregs->areg[1] = usp; memcpy(&childregs->areg[XCHAL_NUM_AREGS - len/4], ®s->areg[XCHAL_NUM_AREGS - len/4], len); // FIXME: we need to set THREADPTR in thread_info... if (clone_flags & CLONE_SETTLS) childregs->areg[2] = childregs->areg[6]; } else { /* In kernel space, we start a new thread with a new stack. */ childregs->wmask = 1; } #if (XTENSA_HAVE_COPROCESSORS || XTENSA_HAVE_IO_PORTS) ti = task_thread_info(p); ti->cpenable = 0; #endif return 0; } /* * These bracket the sleeping functions.. */ unsigned long get_wchan(struct task_struct *p) { unsigned long sp, pc; unsigned long stack_page = (unsigned long) task_stack_page(p); int count = 0; if (!p || p == current || p->state == TASK_RUNNING) return 0; sp = p->thread.sp; pc = MAKE_PC_FROM_RA(p->thread.ra, p->thread.sp); do { if (sp < stack_page + sizeof(struct task_struct) || sp >= (stack_page + THREAD_SIZE) || pc == 0) return 0; if (!in_sched_functions(pc)) return pc; /* Stack layout: sp-4: ra, sp-3: sp' */ pc = MAKE_PC_FROM_RA(*(unsigned long*)sp - 4, sp); sp = *(unsigned long *)sp - 3; } while (count++ < 16); return 0; } /* * xtensa_gregset_t and 'struct pt_regs' are vastly different formats * of processor registers. Besides different ordering, * xtensa_gregset_t contains non-live register information that * 'struct pt_regs' does not. Exception handling (primarily) uses * 'struct pt_regs'. Core files and ptrace use xtensa_gregset_t. * */ void xtensa_elf_core_copy_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs) { unsigned long wb, ws, wm; int live, last; wb = regs->windowbase; ws = regs->windowstart; wm = regs->wmask; ws = ((ws >> wb) | (ws << (WSBITS - wb))) & ((1 << WSBITS) - 1); /* Don't leak any random bits. */ memset(elfregs, 0, sizeof (elfregs)); /* Note: PS.EXCM is not set while user task is running; its * being set in regs->ps is for exception handling convenience. */ elfregs->pc = regs->pc; elfregs->ps = (regs->ps & ~(1 << PS_EXCM_BIT)); elfregs->lbeg = regs->lbeg; elfregs->lend = regs->lend; elfregs->lcount = regs->lcount; elfregs->sar = regs->sar; elfregs->windowstart = ws; live = (wm & 2) ? 4 : (wm & 4) ? 8 : (wm & 8) ? 12 : 16; last = XCHAL_NUM_AREGS - (wm >> 4) * 4; memcpy(elfregs->a, regs->areg, live * 4); memcpy(elfregs->a + last, regs->areg + last, (wm >> 4) * 16); } int dump_fpu(void) { return 0; } asmlinkage long xtensa_clone(unsigned long clone_flags, unsigned long newsp, void __user *parent_tid, void *child_tls, void __user *child_tid, long a5, struct pt_regs *regs) { if (!newsp) newsp = regs->areg[1]; return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid); } /* * xtensa_execve() executes a new program. */ asmlinkage long xtensa_execve(char __user *name, char __user * __user *argv, char __user * __user *envp, long a3, long a4, long a5, struct pt_regs *regs) { long error; char * filename; filename = getname(name); error = PTR_ERR(filename); if (IS_ERR(filename)) goto out; error = do_execve(filename, argv, envp, regs); if (error == 0) { task_lock(current); current->ptrace &= ~PT_DTRACE; task_unlock(current); } putname(filename); out: return error; }