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linux/arch/blackfin/kernel/process.c
Mike Frysinger 926494943b Blackfin: optimize fixed code handling for the most common case 
The majority of the time we are returning to user space, it is not in the
fixed atomic code region.  So rather than branch to a function where we
check the PC and return, do the check inline and branch only when needed.

Also, tweak some of the fixed code handling based on assumptions we are
aware of but cannot be expressed in C.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2009-09-16 22:10:28 -04:00

490 lines
13 KiB
C
Raw Blame History

/*
* 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/uaccess.h>
#include <linux/sched.h>
#include <linux/tick.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <asm/blackfin.h>
#include <asm/fixed_code.h>
#include <asm/mem_map.h>
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);
/*
* The idle loop on BFIN
*/
#ifdef CONFIG_IDLE_L1
static void default_idle(void)__attribute__((l1_text));
void cpu_idle(void)__attribute__((l1_text));
#endif
/*
* This is our default idle handler. We need to disable
* interrupts here to ensure we don't miss a wakeup call.
*/
static void default_idle(void)
{
#ifdef CONFIG_IPIPE
ipipe_suspend_domain();
#endif
local_irq_disable_hw();
if (!need_resched())
idle_with_irq_disabled();
local_irq_enable_hw();
}
/*
* The idle thread. We try to conserve power, while trying to keep
* overall latency low. The architecture specific idle is passed
* a value to indicate the level of "idleness" of the system.
*/
void cpu_idle(void)
{
/* endless idle loop with no priority at all */
while (1) {
void (*idle)(void) = pm_idle;
#ifdef CONFIG_HOTPLUG_CPU
if (cpu_is_offline(smp_processor_id()))
cpu_die();
#endif
if (!idle)
idle = default_idle;
tick_nohz_stop_sched_tick(1);
while (!need_resched())
idle();
tick_nohz_restart_sched_tick();
preempt_enable_no_resched();
schedule();
preempt_disable();
}
}
/* 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);
}
EXPORT_SYMBOL(kernel_thread);
/*
* Do necessary setup to start up a newly executed thread.
*
* pass the data segment into user programs if it exists,
* it can't hurt anything as far as I can tell
*/
void start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
{
set_fs(USER_DS);
regs->pc = new_ip;
if (current->mm)
regs->p5 = current->mm->start_data;
#ifdef CONFIG_SMP
task_thread_info(current)->l1_task_info.stack_start =
(void *)current->mm->context.stack_start;
task_thread_info(current)->l1_task_info.lowest_sp = (void *)new_sp;
memcpy(L1_SCRATCH_TASK_INFO, &task_thread_info(current)->l1_task_info,
sizeof(*L1_SCRATCH_TASK_INFO));
#endif
wrusp(new_sp);
}
EXPORT_SYMBOL_GPL(start_thread);
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;
#ifdef __ARCH_SYNC_CORE_DCACHE
if (current->rt.nr_cpus_allowed == num_possible_cpus()) {
current->cpus_allowed = cpumask_of_cpu(smp_processor_id());
current->rt.nr_cpus_allowed = 1;
}
#endif
/* 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(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;
}
/*
* sys_execve() executes a new program.
*/
asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *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)
{
int __user *up0 = (int __user *)regs->p0;
switch (regs->pc) {
case ATOMIC_XCHG32 + 2:
put_user(regs->r1, up0);
regs->pc = ATOMIC_XCHG32 + 4;
break;
case ATOMIC_CAS32 + 2:
case ATOMIC_CAS32 + 4:
if (regs->r0 == regs->r1)
case ATOMIC_CAS32 + 6:
put_user(regs->r2, up0);
regs->pc = ATOMIC_CAS32 + 8;
break;
case ATOMIC_ADD32 + 2:
regs->r0 = regs->r1 + regs->r0;
/* fall through */
case ATOMIC_ADD32 + 4:
put_user(regs->r0, up0);
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, up0);
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, up0);
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, up0);
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, up0);
regs->pc = ATOMIC_XOR32 + 6;
break;
}
}
static inline
int in_mem(unsigned long addr, unsigned long size,
unsigned long start, unsigned long end)
{
return addr >= start && addr + size <= end;
}
static inline
int in_mem_const_off(unsigned long addr, unsigned long size, unsigned long off,
unsigned long const_addr, unsigned long const_size)
{
return const_size &&
in_mem(addr, size, const_addr + off, const_addr + const_size);
}
static inline
int in_mem_const(unsigned long addr, unsigned long size,
unsigned long const_addr, unsigned long const_size)
{
return in_mem_const_off(addr, size, 0, const_addr, const_size);
}
#define IN_ASYNC(bnum, bctlnum) \
({ \
(bfin_read_EBIU_AMGCTL() & 0xe) < ((bnum + 1) << 1) ? -EFAULT : \
bfin_read_EBIU_AMBCTL##bctlnum() & B##bnum##RDYEN ? -EFAULT : \
BFIN_MEM_ACCESS_CORE; \
})
int bfin_mem_access_type(unsigned long addr, unsigned long size)
{
int cpu = raw_smp_processor_id();
/* Check that things do not wrap around */
if (addr > ULONG_MAX - size)
return -EFAULT;
if (in_mem(addr, size, FIXED_CODE_START, physical_mem_end))
return BFIN_MEM_ACCESS_CORE;
if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
return cpu == 0 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
if (in_mem_const(addr, size, L1_SCRATCH_START, L1_SCRATCH_LENGTH))
return cpu == 0 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
if (in_mem_const(addr, size, L1_DATA_A_START, L1_DATA_A_LENGTH))
return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
if (in_mem_const(addr, size, L1_DATA_B_START, L1_DATA_B_LENGTH))
return cpu == 0 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
#ifdef COREB_L1_CODE_START
if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
return cpu == 1 ? BFIN_MEM_ACCESS_ITEST : BFIN_MEM_ACCESS_IDMA;
if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
return cpu == 1 ? BFIN_MEM_ACCESS_CORE_ONLY : -EFAULT;
if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
return cpu == 1 ? BFIN_MEM_ACCESS_CORE : BFIN_MEM_ACCESS_IDMA;
#endif
if (in_mem_const(addr, size, L2_START, L2_LENGTH))
return BFIN_MEM_ACCESS_CORE;
if (addr >= SYSMMR_BASE)
return BFIN_MEM_ACCESS_CORE_ONLY;
/* We can't read EBIU banks that aren't enabled or we end up hanging
* on the access to the async space.
*/
if (in_mem_const(addr, size, ASYNC_BANK0_BASE, ASYNC_BANK0_SIZE))
return IN_ASYNC(0, 0);
if (in_mem_const(addr, size, ASYNC_BANK1_BASE, ASYNC_BANK1_SIZE))
return IN_ASYNC(1, 0);
if (in_mem_const(addr, size, ASYNC_BANK2_BASE, ASYNC_BANK2_SIZE))
return IN_ASYNC(2, 1);
if (in_mem_const(addr, size, ASYNC_BANK3_BASE, ASYNC_BANK3_SIZE))
return IN_ASYNC(3, 1);
if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
return BFIN_MEM_ACCESS_CORE;
if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
return BFIN_MEM_ACCESS_DMA;
return -EFAULT;
}
#if defined(CONFIG_ACCESS_CHECK)
#ifdef CONFIG_ACCESS_OK_L1
__attribute__((l1_text))
#endif
/* Return 1 if access to memory range is OK, 0 otherwise */
int _access_ok(unsigned long addr, unsigned long size)
{
if (size == 0)
return 1;
/* Check that things do not wrap around */
if (addr > ULONG_MAX - size)
return 0;
if (segment_eq(get_fs(), KERNEL_DS))
return 1;
#ifdef CONFIG_MTD_UCLINUX
if (1)
#else
if (0)
#endif
{
if (in_mem(addr, size, memory_start, memory_end))
return 1;
if (in_mem(addr, size, memory_mtd_end, physical_mem_end))
return 1;
# ifndef CONFIG_ROMFS_ON_MTD
if (0)
# endif
/* For XIP, allow user space to use pointers within the ROMFS. */
if (in_mem(addr, size, memory_mtd_start, memory_mtd_end))
return 1;
} else {
if (in_mem(addr, size, memory_start, physical_mem_end))
return 1;
}
if (in_mem(addr, size, (unsigned long)__init_begin, (unsigned long)__init_end))
return 1;
if (in_mem_const(addr, size, L1_CODE_START, L1_CODE_LENGTH))
return 1;
if (in_mem_const_off(addr, size, _etext_l1 - _stext_l1, L1_CODE_START, L1_CODE_LENGTH))
return 1;
if (in_mem_const_off(addr, size, _ebss_l1 - _sdata_l1, L1_DATA_A_START, L1_DATA_A_LENGTH))
return 1;
if (in_mem_const_off(addr, size, _ebss_b_l1 - _sdata_b_l1, L1_DATA_B_START, L1_DATA_B_LENGTH))
return 1;
#ifdef COREB_L1_CODE_START
if (in_mem_const(addr, size, COREB_L1_CODE_START, COREB_L1_CODE_LENGTH))
return 1;
if (in_mem_const(addr, size, COREB_L1_SCRATCH_START, L1_SCRATCH_LENGTH))
return 1;
if (in_mem_const(addr, size, COREB_L1_DATA_A_START, COREB_L1_DATA_A_LENGTH))
return 1;
if (in_mem_const(addr, size, COREB_L1_DATA_B_START, COREB_L1_DATA_B_LENGTH))
return 1;
#endif
if (in_mem_const_off(addr, size, _ebss_l2 - _stext_l2, L2_START, L2_LENGTH))
return 1;
if (in_mem_const(addr, size, BOOT_ROM_START, BOOT_ROM_LENGTH))
return 1;
if (in_mem_const(addr, size, L1_ROM_START, L1_ROM_LENGTH))
return 1;
return 0;
}
EXPORT_SYMBOL(_access_ok);
#endif /* CONFIG_ACCESS_CHECK */
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