/*
* 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(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;
}
