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android_kernel_xiaomi_sm8350/arch/sh64/kernel/process.c
Nick Piggin 64c7c8f885 [PATCH] sched: resched and cpu_idle rework 
Make some changes to the NEED_RESCHED and POLLING_NRFLAG to reduce
confusion, and make their semantics rigid.  Improves efficiency of
resched_task and some cpu_idle routines.

* In resched_task:
- TIF_NEED_RESCHED is only cleared with the task's runqueue lock held,
  and as we hold it during resched_task, then there is no need for an
  atomic test and set there. The only other time this should be set is
  when the task's quantum expires, in the timer interrupt - this is
  protected against because the rq lock is irq-safe.

- If TIF_NEED_RESCHED is set, then we don't need to do anything. It
  won't get unset until the task get's schedule()d off.

- If we are running on the same CPU as the task we resched, then set
  TIF_NEED_RESCHED and no further action is required.

- If we are running on another CPU, and TIF_POLLING_NRFLAG is *not* set
  after TIF_NEED_RESCHED has been set, then we need to send an IPI.

Using these rules, we are able to remove the test and set operation in
resched_task, and make clear the previously vague semantics of
POLLING_NRFLAG.

* In idle routines:
- Enter cpu_idle with preempt disabled. When the need_resched() condition
  becomes true, explicitly call schedule(). This makes things a bit clearer
  (IMO), but haven't updated all architectures yet.

- Many do a test and clear of TIF_NEED_RESCHED for some reason. According
  to the resched_task rules, this isn't needed (and actually breaks the
  assumption that TIF_NEED_RESCHED is only cleared with the runqueue lock
  held). So remove that. Generally one less locked memory op when switching
  to the idle thread.

- Many idle routines clear TIF_POLLING_NRFLAG, and only set it in the inner
  most polling idle loops. The above resched_task semantics allow it to be
  set until before the last time need_resched() is checked before going into
  a halt requiring interrupt wakeup.

  Many idle routines simply never enter such a halt, and so POLLING_NRFLAG
  can be always left set, completely eliminating resched IPIs when rescheduling
  the idle task.

  POLLING_NRFLAG width can be increased, to reduce the chance of resched IPIs.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Con Kolivas <kernel@kolivas.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-09 07:56:33 -08:00

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/*
* 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.
*
* arch/sh64/kernel/process.c
*
* Copyright (C) 2000, 2001 Paolo Alberelli
* Copyright (C) 2003 Paul Mundt
* Copyright (C) 2003, 2004 Richard Curnow
*
* Started from SH3/4 version:
* Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
*
* In turn started from i386 version:
* Copyright (C) 1995 Linus Torvalds
*
*/
/*
* This file handles the architecture-dependent parts of process handling..
*/
/* Temporary flags/tests. All to be removed/undefined. BEGIN */
#define IDLE_TRACE
#define VM_SHOW_TABLES
#define VM_TEST_FAULT
#define VM_TEST_RTLBMISS
#define VM_TEST_WTLBMISS
#undef VM_SHOW_TABLES
#undef IDLE_TRACE
/* Temporary flags/tests. All to be removed/undefined. END */
#define __KERNEL_SYSCALLS__
#include <stdarg.h>
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/rwsem.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/interrupt.h>
#include <linux/unistd.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/processor.h> /* includes also <asm/registers.h> */
#include <asm/mmu_context.h>
#include <asm/elf.h>
#include <asm/page.h>
#include <linux/irq.h>
struct task_struct *last_task_used_math = NULL;
#ifdef IDLE_TRACE
#ifdef VM_SHOW_TABLES
/* For testing */
static void print_PTE(long base)
{
int i, skip=0;
long long x, y, *p = (long long *) base;
for (i=0; i< 512; i++, p++){
if (*p == 0) {
if (!skip) {
skip++;
printk("(0s) ");
}
} else {
skip=0;
x = (*p) >> 32;
y = (*p) & 0xffffffff;
printk("%08Lx%08Lx ", x, y);
if (!((i+1)&0x3)) printk("\n");
}
}
}
/* For testing */
static void print_DIR(long base)
{
int i, skip=0;
long *p = (long *) base;
for (i=0; i< 512; i++, p++){
if (*p == 0) {
if (!skip) {
skip++;
printk("(0s) ");
}
} else {
skip=0;
printk("%08lx ", *p);
if (!((i+1)&0x7)) printk("\n");
}
}
}
/* For testing */
static void print_vmalloc_first_tables(void)
{
#define PRESENT 0x800 /* Bit 11 */
/*
* Do it really dirty by looking at raw addresses,
* raw offsets, no types. If we used pgtable/pgalloc
* macros/definitions we could hide potential bugs.
*
* Note that pointers are 32-bit for CDC.
*/
long pgdt, pmdt, ptet;
pgdt = (long) &swapper_pg_dir;
printk("-->PGD (0x%08lx):\n", pgdt);
print_DIR(pgdt);
printk("\n");
/* VMALLOC pool is mapped at 0xc0000000, second (pointer) entry in PGD */
pgdt += 4;
pmdt = (long) (* (long *) pgdt);
if (!(pmdt & PRESENT)) {
printk("No PMD\n");
return;
} else pmdt &= 0xfffff000;
printk("-->PMD (0x%08lx):\n", pmdt);
print_DIR(pmdt);
printk("\n");
/* Get the pmdt displacement for 0xc0000000 */
pmdt += 2048;
/* just look at first two address ranges ... */
/* ... 0xc0000000 ... */
ptet = (long) (* (long *) pmdt);
if (!(ptet & PRESENT)) {
printk("No PTE0\n");
return;
} else ptet &= 0xfffff000;
printk("-->PTE0 (0x%08lx):\n", ptet);
print_PTE(ptet);
printk("\n");
/* ... 0xc0001000 ... */
ptet += 4;
if (!(ptet & PRESENT)) {
printk("No PTE1\n");
return;
} else ptet &= 0xfffff000;
printk("-->PTE1 (0x%08lx):\n", ptet);
print_PTE(ptet);
printk("\n");
}
#else
#define print_vmalloc_first_tables()
#endif /* VM_SHOW_TABLES */
static void test_VM(void)
{
void *a, *b, *c;
#ifdef VM_SHOW_TABLES
printk("Initial PGD/PMD/PTE\n");
#endif
print_vmalloc_first_tables();
printk("Allocating 2 bytes\n");
a = vmalloc(2);
print_vmalloc_first_tables();
printk("Allocating 4100 bytes\n");
b = vmalloc(4100);
print_vmalloc_first_tables();
printk("Allocating 20234 bytes\n");
c = vmalloc(20234);
print_vmalloc_first_tables();
#ifdef VM_TEST_FAULT
/* Here you may want to fault ! */
#ifdef VM_TEST_RTLBMISS
printk("Ready to fault upon read.\n");
if (* (char *) a) {
printk("RTLBMISSed on area a !\n");
}
printk("RTLBMISSed on area a !\n");
#endif
#ifdef VM_TEST_WTLBMISS
printk("Ready to fault upon write.\n");
*((char *) b) = 'L';
printk("WTLBMISSed on area b !\n");
#endif
#endif /* VM_TEST_FAULT */
printk("Deallocating the 4100 byte chunk\n");
vfree(b);
print_vmalloc_first_tables();
printk("Deallocating the 2 byte chunk\n");
vfree(a);
print_vmalloc_first_tables();
printk("Deallocating the last chunk\n");
vfree(c);
print_vmalloc_first_tables();
}
extern unsigned long volatile jiffies;
int once = 0;
unsigned long old_jiffies;
int pid = -1, pgid = -1;
void idle_trace(void)
{
_syscall0(int, getpid)
_syscall1(int, getpgid, int, pid)
if (!once) {
/* VM allocation/deallocation simple test */
test_VM();
pid = getpid();
printk("Got all through to Idle !!\n");
printk("I'm now going to loop forever ...\n");
printk("Any ! below is a timer tick.\n");
printk("Any . below is a getpgid system call from pid = %d.\n", pid);
old_jiffies = jiffies;
once++;
}
if (old_jiffies != jiffies) {
old_jiffies = jiffies - old_jiffies;
switch (old_jiffies) {
case 1:
printk("!");
break;
case 2:
printk("!!");
break;
case 3:
printk("!!!");
break;
case 4:
printk("!!!!");
break;
default:
printk("(%d!)", (int) old_jiffies);
}
old_jiffies = jiffies;
}
pgid = getpgid(pid);
printk(".");
}
#else
#define idle_trace() do { } while (0)
#endif /* IDLE_TRACE */
static int hlt_counter = 1;
#define HARD_IDLE_TIMEOUT (HZ / 3)
void disable_hlt(void)
{
hlt_counter++;
}
void enable_hlt(void)
{
hlt_counter--;
}
static int __init nohlt_setup(char *__unused)
{
hlt_counter = 1;
return 1;
}
static int __init hlt_setup(char *__unused)
{
hlt_counter = 0;
return 1;
}
__setup("nohlt", nohlt_setup);
__setup("hlt", hlt_setup);
static inline void hlt(void)
{
__asm__ __volatile__ ("sleep" : : : "memory");
}
/*
* The idle loop on a uniprocessor SH..
*/
void cpu_idle(void)
{
/* endless idle loop with no priority at all */
while (1) {
if (hlt_counter) {
while (!need_resched())
cpu_relax();
} else {
local_irq_disable();
while (!need_resched()) {
local_irq_enable();
idle_trace();
hlt();
local_irq_disable();
}
local_irq_enable();
}
preempt_enable_no_resched();
schedule();
preempt_disable();
}
}
void machine_restart(char * __unused)
{
extern void phys_stext(void);
phys_stext();
}
void machine_halt(void)
{
for (;;);
}
void machine_power_off(void)
{
extern void enter_deep_standby(void);
enter_deep_standby();
}
void show_regs(struct pt_regs * regs)
{
unsigned long long ah, al, bh, bl, ch, cl;
printk("\n");
ah = (regs->pc) >> 32;
al = (regs->pc) & 0xffffffff;
bh = (regs->regs[18]) >> 32;
bl = (regs->regs[18]) & 0xffffffff;
ch = (regs->regs[15]) >> 32;
cl = (regs->regs[15]) & 0xffffffff;
printk("PC : %08Lx%08Lx LINK: %08Lx%08Lx SP : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->sr) >> 32;
al = (regs->sr) & 0xffffffff;
asm volatile ("getcon " __TEA ", %0" : "=r" (bh));
asm volatile ("getcon " __TEA ", %0" : "=r" (bl));
bh = (bh) >> 32;
bl = (bl) & 0xffffffff;
asm volatile ("getcon " __KCR0 ", %0" : "=r" (ch));
asm volatile ("getcon " __KCR0 ", %0" : "=r" (cl));
ch = (ch) >> 32;
cl = (cl) & 0xffffffff;
printk("SR : %08Lx%08Lx TEA : %08Lx%08Lx KCR0: %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[0]) >> 32;
al = (regs->regs[0]) & 0xffffffff;
bh = (regs->regs[1]) >> 32;
bl = (regs->regs[1]) & 0xffffffff;
ch = (regs->regs[2]) >> 32;
cl = (regs->regs[2]) & 0xffffffff;
printk("R0 : %08Lx%08Lx R1 : %08Lx%08Lx R2 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[3]) >> 32;
al = (regs->regs[3]) & 0xffffffff;
bh = (regs->regs[4]) >> 32;
bl = (regs->regs[4]) & 0xffffffff;
ch = (regs->regs[5]) >> 32;
cl = (regs->regs[5]) & 0xffffffff;
printk("R3 : %08Lx%08Lx R4 : %08Lx%08Lx R5 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[6]) >> 32;
al = (regs->regs[6]) & 0xffffffff;
bh = (regs->regs[7]) >> 32;
bl = (regs->regs[7]) & 0xffffffff;
ch = (regs->regs[8]) >> 32;
cl = (regs->regs[8]) & 0xffffffff;
printk("R6 : %08Lx%08Lx R7 : %08Lx%08Lx R8 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[9]) >> 32;
al = (regs->regs[9]) & 0xffffffff;
bh = (regs->regs[10]) >> 32;
bl = (regs->regs[10]) & 0xffffffff;
ch = (regs->regs[11]) >> 32;
cl = (regs->regs[11]) & 0xffffffff;
printk("R9 : %08Lx%08Lx R10 : %08Lx%08Lx R11 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[12]) >> 32;
al = (regs->regs[12]) & 0xffffffff;
bh = (regs->regs[13]) >> 32;
bl = (regs->regs[13]) & 0xffffffff;
ch = (regs->regs[14]) >> 32;
cl = (regs->regs[14]) & 0xffffffff;
printk("R12 : %08Lx%08Lx R13 : %08Lx%08Lx R14 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[16]) >> 32;
al = (regs->regs[16]) & 0xffffffff;
bh = (regs->regs[17]) >> 32;
bl = (regs->regs[17]) & 0xffffffff;
ch = (regs->regs[19]) >> 32;
cl = (regs->regs[19]) & 0xffffffff;
printk("R16 : %08Lx%08Lx R17 : %08Lx%08Lx R19 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[20]) >> 32;
al = (regs->regs[20]) & 0xffffffff;
bh = (regs->regs[21]) >> 32;
bl = (regs->regs[21]) & 0xffffffff;
ch = (regs->regs[22]) >> 32;
cl = (regs->regs[22]) & 0xffffffff;
printk("R20 : %08Lx%08Lx R21 : %08Lx%08Lx R22 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[23]) >> 32;
al = (regs->regs[23]) & 0xffffffff;
bh = (regs->regs[24]) >> 32;
bl = (regs->regs[24]) & 0xffffffff;
ch = (regs->regs[25]) >> 32;
cl = (regs->regs[25]) & 0xffffffff;
printk("R23 : %08Lx%08Lx R24 : %08Lx%08Lx R25 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[26]) >> 32;
al = (regs->regs[26]) & 0xffffffff;
bh = (regs->regs[27]) >> 32;
bl = (regs->regs[27]) & 0xffffffff;
ch = (regs->regs[28]) >> 32;
cl = (regs->regs[28]) & 0xffffffff;
printk("R26 : %08Lx%08Lx R27 : %08Lx%08Lx R28 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[29]) >> 32;
al = (regs->regs[29]) & 0xffffffff;
bh = (regs->regs[30]) >> 32;
bl = (regs->regs[30]) & 0xffffffff;
ch = (regs->regs[31]) >> 32;
cl = (regs->regs[31]) & 0xffffffff;
printk("R29 : %08Lx%08Lx R30 : %08Lx%08Lx R31 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[32]) >> 32;
al = (regs->regs[32]) & 0xffffffff;
bh = (regs->regs[33]) >> 32;
bl = (regs->regs[33]) & 0xffffffff;
ch = (regs->regs[34]) >> 32;
cl = (regs->regs[34]) & 0xffffffff;
printk("R32 : %08Lx%08Lx R33 : %08Lx%08Lx R34 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[35]) >> 32;
al = (regs->regs[35]) & 0xffffffff;
bh = (regs->regs[36]) >> 32;
bl = (regs->regs[36]) & 0xffffffff;
ch = (regs->regs[37]) >> 32;
cl = (regs->regs[37]) & 0xffffffff;
printk("R35 : %08Lx%08Lx R36 : %08Lx%08Lx R37 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[38]) >> 32;
al = (regs->regs[38]) & 0xffffffff;
bh = (regs->regs[39]) >> 32;
bl = (regs->regs[39]) & 0xffffffff;
ch = (regs->regs[40]) >> 32;
cl = (regs->regs[40]) & 0xffffffff;
printk("R38 : %08Lx%08Lx R39 : %08Lx%08Lx R40 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[41]) >> 32;
al = (regs->regs[41]) & 0xffffffff;
bh = (regs->regs[42]) >> 32;
bl = (regs->regs[42]) & 0xffffffff;
ch = (regs->regs[43]) >> 32;
cl = (regs->regs[43]) & 0xffffffff;
printk("R41 : %08Lx%08Lx R42 : %08Lx%08Lx R43 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[44]) >> 32;
al = (regs->regs[44]) & 0xffffffff;
bh = (regs->regs[45]) >> 32;
bl = (regs->regs[45]) & 0xffffffff;
ch = (regs->regs[46]) >> 32;
cl = (regs->regs[46]) & 0xffffffff;
printk("R44 : %08Lx%08Lx R45 : %08Lx%08Lx R46 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[47]) >> 32;
al = (regs->regs[47]) & 0xffffffff;
bh = (regs->regs[48]) >> 32;
bl = (regs->regs[48]) & 0xffffffff;
ch = (regs->regs[49]) >> 32;
cl = (regs->regs[49]) & 0xffffffff;
printk("R47 : %08Lx%08Lx R48 : %08Lx%08Lx R49 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[50]) >> 32;
al = (regs->regs[50]) & 0xffffffff;
bh = (regs->regs[51]) >> 32;
bl = (regs->regs[51]) & 0xffffffff;
ch = (regs->regs[52]) >> 32;
cl = (regs->regs[52]) & 0xffffffff;
printk("R50 : %08Lx%08Lx R51 : %08Lx%08Lx R52 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[53]) >> 32;
al = (regs->regs[53]) & 0xffffffff;
bh = (regs->regs[54]) >> 32;
bl = (regs->regs[54]) & 0xffffffff;
ch = (regs->regs[55]) >> 32;
cl = (regs->regs[55]) & 0xffffffff;
printk("R53 : %08Lx%08Lx R54 : %08Lx%08Lx R55 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[56]) >> 32;
al = (regs->regs[56]) & 0xffffffff;
bh = (regs->regs[57]) >> 32;
bl = (regs->regs[57]) & 0xffffffff;
ch = (regs->regs[58]) >> 32;
cl = (regs->regs[58]) & 0xffffffff;
printk("R56 : %08Lx%08Lx R57 : %08Lx%08Lx R58 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[59]) >> 32;
al = (regs->regs[59]) & 0xffffffff;
bh = (regs->regs[60]) >> 32;
bl = (regs->regs[60]) & 0xffffffff;
ch = (regs->regs[61]) >> 32;
cl = (regs->regs[61]) & 0xffffffff;
printk("R59 : %08Lx%08Lx R60 : %08Lx%08Lx R61 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->regs[62]) >> 32;
al = (regs->regs[62]) & 0xffffffff;
bh = (regs->tregs[0]) >> 32;
bl = (regs->tregs[0]) & 0xffffffff;
ch = (regs->tregs[1]) >> 32;
cl = (regs->tregs[1]) & 0xffffffff;
printk("R62 : %08Lx%08Lx T0 : %08Lx%08Lx T1 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->tregs[2]) >> 32;
al = (regs->tregs[2]) & 0xffffffff;
bh = (regs->tregs[3]) >> 32;
bl = (regs->tregs[3]) & 0xffffffff;
ch = (regs->tregs[4]) >> 32;
cl = (regs->tregs[4]) & 0xffffffff;
printk("T2 : %08Lx%08Lx T3 : %08Lx%08Lx T4 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
ah = (regs->tregs[5]) >> 32;
al = (regs->tregs[5]) & 0xffffffff;
bh = (regs->tregs[6]) >> 32;
bl = (regs->tregs[6]) & 0xffffffff;
ch = (regs->tregs[7]) >> 32;
cl = (regs->tregs[7]) & 0xffffffff;
printk("T5 : %08Lx%08Lx T6 : %08Lx%08Lx T7 : %08Lx%08Lx\n",
ah, al, bh, bl, ch, cl);
/*
* If we're in kernel mode, dump the stack too..
*/
if (!user_mode(regs)) {
void show_stack(struct task_struct *tsk, unsigned long *sp);
unsigned long sp = regs->regs[15] & 0xffffffff;
struct task_struct *tsk = get_current();
tsk->thread.kregs = regs;
show_stack(tsk, (unsigned long *)sp);
}
}
struct task_struct * alloc_task_struct(void)
{
/* Get task descriptor pages */
return (struct task_struct *)
__get_free_pages(GFP_KERNEL, get_order(THREAD_SIZE));
}
void free_task_struct(struct task_struct *p)
{
free_pages((unsigned long) p, get_order(THREAD_SIZE));
}
/*
* Create a kernel thread
*/
/*
* This is the mechanism for creating a new kernel thread.
*
* NOTE! Only a kernel-only process(ie the swapper or direct descendants
* who haven't done an "execve()") should use this: it will work within
* a system call from a "real" process, but the process memory space will
* not be free'd until both the parent and the child have exited.
*/
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
/* A bit less processor dependent than older sh ... */
unsigned int reply;
static __inline__ _syscall2(int,clone,unsigned long,flags,unsigned long,newsp)
static __inline__ _syscall1(int,exit,int,ret)
reply = clone(flags | CLONE_VM, 0);
if (!reply) {
/* Child */
reply = exit(fn(arg));
}
return reply;
}
/*
* Free current thread data structures etc..
*/
void exit_thread(void)
{
/* See arch/sparc/kernel/process.c for the precedent for doing this -- RPC.
The SH-5 FPU save/restore approach relies on last_task_used_math
pointing to a live task_struct. When another task tries to use the
FPU for the 1st time, the FPUDIS trap handling (see
arch/sh64/kernel/fpu.c) will save the existing FPU state to the
FP regs field within last_task_used_math before re-loading the new
task's FPU state (or initialising it if the FPU has been used
before). So if last_task_used_math is stale, and its page has already been
re-allocated for another use, the consequences are rather grim. Unless we
null it here, there is no other path through which it would get safely
nulled. */
#ifdef CONFIG_SH_FPU
if (last_task_used_math == current) {
last_task_used_math = NULL;
}
#endif
}
void flush_thread(void)
{
/* Called by fs/exec.c (flush_old_exec) to remove traces of a
* previously running executable. */
#ifdef CONFIG_SH_FPU
if (last_task_used_math == current) {
last_task_used_math = NULL;
}
/* Force FPU state to be reinitialised after exec */
clear_used_math();
#endif
/* if we are a kernel thread, about to change to user thread,
* update kreg
*/
if(current->thread.kregs==&fake_swapper_regs) {
current->thread.kregs =
((struct pt_regs *)(THREAD_SIZE + (unsigned long) current) - 1);
current->thread.uregs = current->thread.kregs;
}
}
void release_thread(struct task_struct *dead_task)
{
/* do nothing */
}
/* Fill in the fpu structure for a core dump.. */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
{
#ifdef CONFIG_SH_FPU
int fpvalid;
struct task_struct *tsk = current;
fpvalid = !!tsk_used_math(tsk);
if (fpvalid) {
if (current == last_task_used_math) {
grab_fpu();
fpsave(&tsk->thread.fpu.hard);
release_fpu();
last_task_used_math = 0;
regs->sr |= SR_FD;
}
memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
}
return fpvalid;
#else
return 0; /* Task didn't use the fpu at all. */
#endif
}
asmlinkage void ret_from_fork(void);
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;
unsigned long long se; /* Sign extension */
#ifdef CONFIG_SH_FPU
if(last_task_used_math == current) {
grab_fpu();
fpsave(&current->thread.fpu.hard);
release_fpu();
last_task_used_math = NULL;
regs->sr |= SR_FD;
}
#endif
/* Copy from sh version */
childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long) p->thread_info )) - 1;
*childregs = *regs;
if (user_mode(regs)) {
childregs->regs[15] = usp;
p->thread.uregs = childregs;
} else {
childregs->regs[15] = (unsigned long)p->thread_info + THREAD_SIZE;
}
childregs->regs[9] = 0; /* Set return value for child */
childregs->sr |= SR_FD; /* Invalidate FPU flag */
p->thread.sp = (unsigned long) childregs;
p->thread.pc = (unsigned long) ret_from_fork;
/*
* Sign extend the edited stack.
* Note that thread.pc and thread.pc will stay
* 32-bit wide and context switch must take care
* of NEFF sign extension.
*/
se = childregs->regs[15];
se = (se & NEFF_SIGN) ? (se | NEFF_MASK) : se;
childregs->regs[15] = se;
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 = current->mm->start_code;
dump->start_data = current->mm->start_data;
dump->start_stack = regs->regs[15] & ~(PAGE_SIZE - 1);
dump->u_tsize = (current->mm->end_code - dump->start_code) >> PAGE_SHIFT;
dump->u_dsize = (current->mm->brk + (PAGE_SIZE-1) - dump->start_data) >> PAGE_SHIFT;
dump->u_ssize = (current->mm->start_stack - dump->start_stack +
PAGE_SIZE - 1) >> PAGE_SHIFT;
/* Debug registers will come here. */
dump->regs = *regs;
dump->u_fpvalid = dump_fpu(regs, &dump->fpu);
}
asmlinkage int sys_fork(unsigned long r2, unsigned long r3,
unsigned long r4, unsigned long r5,
unsigned long r6, unsigned long r7,
struct pt_regs *pregs)
{
return do_fork(SIGCHLD, pregs->regs[15], pregs, 0, 0, 0);
}
asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
unsigned long r4, unsigned long r5,
unsigned long r6, unsigned long r7,
struct pt_regs *pregs)
{
if (!newsp)
newsp = pregs->regs[15];
return do_fork(clone_flags, newsp, pregs, 0, 0, 0);
}
/*
* This is trivial, and on the face of it looks like it
* could equally well be done in user mode.
*
* Not so, for quite unobvious reasons - register pressure.
* In user mode vfork() cannot have a stack frame, and if
* done by calling the "clone()" system call directly, you
* do not have enough call-clobbered registers to hold all
* the information you need.
*/
asmlinkage int sys_vfork(unsigned long r2, unsigned long r3,
unsigned long r4, unsigned long r5,
unsigned long r6, unsigned long r7,
struct pt_regs *pregs)
{
return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, pregs->regs[15], pregs, 0, 0, 0);
}
/*
* sys_execve() executes a new program.
*/
asmlinkage int sys_execve(char *ufilename, char **uargv,
char **uenvp, unsigned long r5,
unsigned long r6, unsigned long r7,
struct pt_regs *pregs)
{
int error;
char *filename;
lock_kernel();
filename = getname((char __user *)ufilename);
error = PTR_ERR(filename);
if (IS_ERR(filename))
goto out;
error = do_execve(filename,
(char __user * __user *)uargv,
(char __user * __user *)uenvp,
pregs);
if (error == 0) {
task_lock(current);
current->ptrace &= ~PT_DTRACE;
task_unlock(current);
}
putname(filename);
out:
unlock_kernel();
return error;
}
/*
* These bracket the sleeping functions..
*/
extern void interruptible_sleep_on(wait_queue_head_t *q);
#define mid_sched ((unsigned long) interruptible_sleep_on)
static int in_sh64_switch_to(unsigned long pc)
{
extern char __sh64_switch_to_end;
/* For a sleeping task, the PC is somewhere in the middle of the function,
so we don't have to worry about masking the LSB off */
return (pc >= (unsigned long) sh64_switch_to) &&
(pc < (unsigned long) &__sh64_switch_to_end);
}
unsigned long get_wchan(struct task_struct *p)
{
unsigned long schedule_fp;
unsigned long sh64_switch_to_fp;
unsigned long schedule_caller_pc;
unsigned long pc;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
/*
* The same comment as on the Alpha applies here, too ...
*/
pc = thread_saved_pc(p);
#ifdef CONFIG_FRAME_POINTER
if (in_sh64_switch_to(pc)) {
sh64_switch_to_fp = (long) p->thread.sp;
/* r14 is saved at offset 4 in the sh64_switch_to frame */
schedule_fp = *(unsigned long *) (long)(sh64_switch_to_fp + 4);
/* and the caller of 'schedule' is (currently!) saved at offset 24
in the frame of schedule (from disasm) */
schedule_caller_pc = *(unsigned long *) (long)(schedule_fp + 24);
return schedule_caller_pc;
}
#endif
return pc;
}
/* Provide a /proc/asids file that lists out the
ASIDs currently associated with the processes. (If the DM.PC register is
examined through the debug link, this shows ASID + PC. To make use of this,
the PID->ASID relationship needs to be known. This is primarily for
debugging.)
*/
#if defined(CONFIG_SH64_PROC_ASIDS)
#include <linux/init.h>
#include <linux/proc_fs.h>
static int
asids_proc_info(char *buf, char **start, off_t fpos, int length, int *eof, void *data)
{
int len=0;
struct task_struct *p;
read_lock(&tasklist_lock);
for_each_process(p) {
int pid = p->pid;
struct mm_struct *mm;
if (!pid) continue;
mm = p->mm;
if (mm) {
unsigned long asid, context;
context = mm->context;
asid = (context & 0xff);
len += sprintf(buf+len, "%5d : %02lx\n", pid, asid);
} else {
len += sprintf(buf+len, "%5d : (none)\n", pid);
}
}
read_unlock(&tasklist_lock);
*eof = 1;
return len;
}
static int __init register_proc_asids(void)
{
create_proc_read_entry("asids", 0, NULL, asids_proc_info, NULL);
return 0;
}
__initcall(register_proc_asids);
#endif
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