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linux/arch/blackfin/kernel/process.c
Bernd Schmidt 7adfb58fbd Blackfin arch: defines and provides entry points for certain user space functions at fixed addresses 
This patch defines (and provides) entry points for certain user space functions
at fixed addresses.  The Blackfin has no usable atomic instructions, but we can
ensure that these code sequences appear atomic from a user space point of view
by detecting when we're in the process of executing them during the interrupt
handler return path.  This allows much more efficient pthread lock
implementations than the bfin_spinlock syscall we're currently using.

Also provided is a small sys_rt_sigreturn stub which can be used by the signal
handler setup code.  The signal.c part will be committed separately.

Signed-off-by: Bernd Schmidt <bernd.schmidt@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
2007-06-21 11:34:16 +08:00

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/*
* File: arch/blackfin/kernel/process.c
* Based on:
* Author:
*
* Created:
* Description: Blackfin architecture-dependent process handling.
*
* Modified:
* Copyright 2004-2006 Analog Devices Inc.
*
* Bugs: Enter bugs at http://blackfin.uclinux.org/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see the file COPYING, or write
* to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <linux/module.h>
#include <linux/smp_lock.h>
#include <linux/unistd.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <asm/blackfin.h>
#include <asm/uaccess.h>
#include <asm/fixed_code.h>
#define LED_ON 0
#define LED_OFF 1
asmlinkage void ret_from_fork(void);
/* Points to the SDRAM backup memory for the stack that is currently in
* L1 scratchpad memory.
*/
void *current_l1_stack_save;
/* The number of tasks currently using a L1 stack area. The SRAM is
* allocated/deallocated whenever this changes from/to zero.
*/
int nr_l1stack_tasks;
/* Start and length of the area in L1 scratchpad memory which we've allocated
* for process stacks.
*/
void *l1_stack_base;
unsigned long l1_stack_len;
/*
* Powermanagement idle function, if any..
*/
void (*pm_idle)(void) = NULL;
EXPORT_SYMBOL(pm_idle);
void (*pm_power_off)(void) = NULL;
EXPORT_SYMBOL(pm_power_off);
/*
* We are using a different LED from the one used to indicate timer interrupt.
*/
#if defined(CONFIG_BFIN_IDLE_LED)
static inline void leds_switch(int flag)
{
unsigned short tmp = 0;
tmp = bfin_read_CONFIG_BFIN_IDLE_LED_PORT();
SSYNC();
if (flag == LED_ON)
tmp &= ~CONFIG_BFIN_IDLE_LED_PIN; /* light on */
else
tmp |= CONFIG_BFIN_IDLE_LED_PIN; /* light off */
bfin_write_CONFIG_BFIN_IDLE_LED_PORT(tmp);
SSYNC();
}
#else
static inline void leds_switch(int flag)
{
}
#endif
/*
* The idle loop on BFIN
*/
#ifdef CONFIG_IDLE_L1
void default_idle(void)__attribute__((l1_text));
void cpu_idle(void)__attribute__((l1_text));
#endif
void default_idle(void)
{
while (!need_resched()) {
leds_switch(LED_OFF);
local_irq_disable();
if (likely(!need_resched()))
idle_with_irq_disabled();
local_irq_enable();
leds_switch(LED_ON);
}
}
void (*idle)(void) = default_idle;
/*
* The idle thread. There's no useful work to be
* done, so just try to conserve power and have a
* low exit latency (ie sit in a loop waiting for
* somebody to say that they'd like to reschedule)
*/
void cpu_idle(void)
{
/* endless idle loop with no priority at all */
while (1) {
idle();
preempt_enable_no_resched();
schedule();
preempt_disable();
}
}
void machine_restart(char *__unused)
{
#if defined(CONFIG_BLKFIN_CACHE)
bfin_write_IMEM_CONTROL(0x01);
SSYNC();
#endif
bfin_reset();
/* Dont do anything till the reset occurs */
while (1) {
SSYNC();
}
}
void machine_halt(void)
{
for (;;)
asm volatile ("idle");
}
void machine_power_off(void)
{
for (;;)
asm volatile ("idle");
}
void show_regs(struct pt_regs *regs)
{
printk(KERN_NOTICE "\n");
printk(KERN_NOTICE
"PC: %08lu Status: %04lu SysStatus: %04lu RETS: %08lu\n",
regs->pc, regs->astat, regs->seqstat, regs->rets);
printk(KERN_NOTICE
"A0.x: %08lx A0.w: %08lx A1.x: %08lx A1.w: %08lx\n",
regs->a0x, regs->a0w, regs->a1x, regs->a1w);
printk(KERN_NOTICE "P0: %08lx P1: %08lx P2: %08lx P3: %08lx\n",
regs->p0, regs->p1, regs->p2, regs->p3);
printk(KERN_NOTICE "P4: %08lx P5: %08lx\n", regs->p4, regs->p5);
printk(KERN_NOTICE "R0: %08lx R1: %08lx R2: %08lx R3: %08lx\n",
regs->r0, regs->r1, regs->r2, regs->r3);
printk(KERN_NOTICE "R4: %08lx R5: %08lx R6: %08lx R7: %08lx\n",
regs->r4, regs->r5, regs->r6, regs->r7);
if (!(regs->ipend))
printk("USP: %08lx\n", rdusp());
}
/* Fill in the fpu structure for a core dump. */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
{
return 1;
}
/*
* This gets run with P1 containing the
* function to call, and R1 containing
* the "args". Note P0 is clobbered on the way here.
*/
void kernel_thread_helper(void);
__asm__(".section .text\n"
".align 4\n"
"_kernel_thread_helper:\n\t"
"\tsp += -12;\n\t"
"\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
/*
* Create a kernel thread.
*/
pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
{
struct pt_regs regs;
memset(&regs, 0, sizeof(regs));
regs.r1 = (unsigned long)arg;
regs.p1 = (unsigned long)fn;
regs.pc = (unsigned long)kernel_thread_helper;
regs.orig_p0 = -1;
/* Set bit 2 to tell ret_from_fork we should be returning to kernel
mode. */
regs.ipend = 0x8002;
__asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
NULL);
}
void flush_thread(void)
{
}
asmlinkage int bfin_vfork(struct pt_regs *regs)
{
return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
NULL);
}
asmlinkage int bfin_clone(struct pt_regs *regs)
{
unsigned long clone_flags;
unsigned long newsp;
/* syscall2 puts clone_flags in r0 and usp in r1 */
clone_flags = regs->r0;
newsp = regs->r1;
if (!newsp)
newsp = rdusp();
else
newsp -= 12;
return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
}
int
copy_thread(int nr, unsigned long clone_flags,
unsigned long usp, unsigned long topstk,
struct task_struct *p, struct pt_regs *regs)
{
struct pt_regs *childregs;
childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
*childregs = *regs;
childregs->r0 = 0;
p->thread.usp = usp;
p->thread.ksp = (unsigned long)childregs;
p->thread.pc = (unsigned long)ret_from_fork;
return 0;
}
/*
* fill in the user structure for a core dump..
*/
void dump_thread(struct pt_regs *regs, struct user *dump)
{
dump->magic = CMAGIC;
dump->start_code = 0;
dump->start_stack = rdusp() & ~(PAGE_SIZE - 1);
dump->u_tsize = ((unsigned long)current->mm->end_code) >> PAGE_SHIFT;
dump->u_dsize = ((unsigned long)(current->mm->brk +
(PAGE_SIZE - 1))) >> PAGE_SHIFT;
dump->u_dsize -= dump->u_tsize;
dump->u_ssize = 0;
if (dump->start_stack < TASK_SIZE)
dump->u_ssize =
((unsigned long)(TASK_SIZE -
dump->start_stack)) >> PAGE_SHIFT;
dump->u_ar0 = (struct user_regs_struct *)((int)&dump->regs - (int)dump);
dump->regs.r0 = regs->r0;
dump->regs.r1 = regs->r1;
dump->regs.r2 = regs->r2;
dump->regs.r3 = regs->r3;
dump->regs.r4 = regs->r4;
dump->regs.r5 = regs->r5;
dump->regs.r6 = regs->r6;
dump->regs.r7 = regs->r7;
dump->regs.p0 = regs->p0;
dump->regs.p1 = regs->p1;
dump->regs.p2 = regs->p2;
dump->regs.p3 = regs->p3;
dump->regs.p4 = regs->p4;
dump->regs.p5 = regs->p5;
dump->regs.orig_p0 = regs->orig_p0;
dump->regs.a0w = regs->a0w;
dump->regs.a1w = regs->a1w;
dump->regs.a0x = regs->a0x;
dump->regs.a1x = regs->a1x;
dump->regs.rets = regs->rets;
dump->regs.astat = regs->astat;
dump->regs.pc = regs->pc;
}
/*
* sys_execve() executes a new program.
*/
asmlinkage int sys_execve(char *name, char **argv, char **envp)
{
int error;
char *filename;
struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
lock_kernel();
filename = getname(name);
error = PTR_ERR(filename);
if (IS_ERR(filename))
goto out;
error = do_execve(filename, argv, envp, regs);
putname(filename);
out:
unlock_kernel();
return error;
}
unsigned long get_wchan(struct task_struct *p)
{
unsigned long fp, pc;
unsigned long stack_page;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_page = (unsigned long)p;
fp = p->thread.usp;
do {
if (fp < stack_page + sizeof(struct thread_info) ||
fp >= 8184 + stack_page)
return 0;
pc = ((unsigned long *)fp)[1];
if (!in_sched_functions(pc))
return pc;
fp = *(unsigned long *)fp;
}
while (count++ < 16);
return 0;
}
void finish_atomic_sections (struct pt_regs *regs)
{
if (regs->pc < ATOMIC_SEQS_START || regs->pc >= ATOMIC_SEQS_END)
return;
switch (regs->pc) {
case ATOMIC_XCHG32 + 2:
put_user(regs->r1, (int *)regs->p0);
regs->pc += 2;
break;
case ATOMIC_CAS32 + 2:
case ATOMIC_CAS32 + 4:
if (regs->r0 == regs->r1)
put_user(regs->r2, (int *)regs->p0);
regs->pc = ATOMIC_CAS32 + 8;
break;
case ATOMIC_CAS32 + 6:
put_user(regs->r2, (int *)regs->p0);
regs->pc += 2;
break;
case ATOMIC_ADD32 + 2:
regs->r0 = regs->r1 + regs->r0;
/* fall through */
case ATOMIC_ADD32 + 4:
put_user(regs->r0, (int *)regs->p0);
regs->pc = ATOMIC_ADD32 + 6;
break;
case ATOMIC_SUB32 + 2:
regs->r0 = regs->r1 - regs->r0;
/* fall through */
case ATOMIC_SUB32 + 4:
put_user(regs->r0, (int *)regs->p0);
regs->pc = ATOMIC_SUB32 + 6;
break;
case ATOMIC_IOR32 + 2:
regs->r0 = regs->r1 | regs->r0;
/* fall through */
case ATOMIC_IOR32 + 4:
put_user(regs->r0, (int *)regs->p0);
regs->pc = ATOMIC_IOR32 + 6;
break;
case ATOMIC_AND32 + 2:
regs->r0 = regs->r1 & regs->r0;
/* fall through */
case ATOMIC_AND32 + 4:
put_user(regs->r0, (int *)regs->p0);
regs->pc = ATOMIC_AND32 + 6;
break;
case ATOMIC_XOR32 + 2:
regs->r0 = regs->r1 ^ regs->r0;
/* fall through */
case ATOMIC_XOR32 + 4:
put_user(regs->r0, (int *)regs->p0);
regs->pc = ATOMIC_XOR32 + 6;
break;
}
}
#if defined(CONFIG_ACCESS_CHECK)
int _access_ok(unsigned long addr, unsigned long size)
{
if (addr > (addr + size))
return 0;
if (segment_eq(get_fs(),KERNEL_DS))
return 1;
#ifdef CONFIG_MTD_UCLINUX
if (addr >= memory_start && (addr + size) <= memory_end)
return 1;
if (addr >= memory_mtd_end && (addr + size) <= physical_mem_end)
return 1;
#else
if (addr >= memory_start && (addr + size) <= physical_mem_end)
return 1;
#endif
if (addr >= (unsigned long)__init_begin &&
addr + size <= (unsigned long)__init_end)
return 1;
if (addr >= L1_SCRATCH_START
&& addr + size <= L1_SCRATCH_START + L1_SCRATCH_LENGTH)
return 1;
#if L1_CODE_LENGTH != 0
if (addr >= L1_CODE_START + (_etext_l1 - _stext_l1)
&& addr + size <= L1_CODE_START + L1_CODE_LENGTH)
return 1;
#endif
#if L1_DATA_A_LENGTH != 0
if (addr >= L1_DATA_A_START + (_ebss_l1 - _sdata_l1)
&& addr + size <= L1_DATA_A_START + L1_DATA_A_LENGTH)
return 1;
#endif
#if L1_DATA_B_LENGTH != 0
if (addr >= L1_DATA_B_START
&& addr + size <= L1_DATA_B_START + L1_DATA_B_LENGTH)
return 1;
#endif
return 0;
}
EXPORT_SYMBOL(_access_ok);
#endif /* CONFIG_ACCESS_CHECK */
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