2005-04-16 18:20:36 -04:00
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/*
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* linux/arch/i386/kernel/process.c
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*
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* Copyright (C) 1995 Linus Torvalds
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*
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* Pentium III FXSR, SSE support
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* Gareth Hughes <gareth@valinux.com>, May 2000
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*/
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/*
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* This file handles the architecture-dependent parts of process handling..
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*/
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#include <stdarg.h>
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2005-06-25 17:54:50 -04:00
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#include <linux/cpu.h>
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2005-04-16 18:20:36 -04:00
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/fs.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/elfcore.h>
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#include <linux/smp.h>
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#include <linux/smp_lock.h>
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#include <linux/stddef.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/user.h>
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#include <linux/a.out.h>
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#include <linux/interrupt.h>
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#include <linux/config.h>
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#include <linux/utsname.h>
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#include <linux/delay.h>
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#include <linux/reboot.h>
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#include <linux/init.h>
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#include <linux/mc146818rtc.h>
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#include <linux/module.h>
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#include <linux/kallsyms.h>
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#include <linux/ptrace.h>
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#include <linux/random.h>
|
[PATCH] kprobes: function-return probes
This patch adds function-return probes to kprobes for the i386
architecture. This enables you to establish a handler to be run when a
function returns.
1. API
Two new functions are added to kprobes:
int register_kretprobe(struct kretprobe *rp);
void unregister_kretprobe(struct kretprobe *rp);
2. Registration and unregistration
2.1 Register
To register a function-return probe, the user populates the following
fields in a kretprobe object and calls register_kretprobe() with the
kretprobe address as an argument:
kp.addr - the function's address
handler - this function is run after the ret instruction executes, but
before control returns to the return address in the caller.
maxactive - The maximum number of instances of the probed function that
can be active concurrently. For example, if the function is non-
recursive and is called with a spinlock or mutex held, maxactive = 1
should be enough. If the function is non-recursive and can never
relinquish the CPU (e.g., via a semaphore or preemption), NR_CPUS should
be enough. maxactive is used to determine how many kretprobe_instance
objects to allocate for this particular probed function. If maxactive <=
0, it is set to a default value (if CONFIG_PREEMPT maxactive=max(10, 2 *
NR_CPUS) else maxactive=NR_CPUS)
For example:
struct kretprobe rp;
rp.kp.addr = /* entrypoint address */
rp.handler = /*return probe handler */
rp.maxactive = /* e.g., 1 or NR_CPUS or 0, see the above explanation */
register_kretprobe(&rp);
The following field may also be of interest:
nmissed - Initialized to zero when the function-return probe is
registered, and incremented every time the probed function is entered but
there is no kretprobe_instance object available for establishing the
function-return probe (i.e., because maxactive was set too low).
2.2 Unregister
To unregiter a function-return probe, the user calls
unregister_kretprobe() with the same kretprobe object as registered
previously. If a probed function is running when the return probe is
unregistered, the function will return as expected, but the handler won't
be run.
3. Limitations
3.1 This patch supports only the i386 architecture, but patches for
x86_64 and ppc64 are anticipated soon.
3.2 Return probes operates by replacing the return address in the stack
(or in a known register, such as the lr register for ppc). This may
cause __builtin_return_address(0), when invoked from the return-probed
function, to return the address of the return-probes trampoline.
3.3 This implementation uses the "Multiprobes at an address" feature in
2.6.12-rc3-mm3.
3.4 Due to a limitation in multi-probes, you cannot currently establish
a return probe and a jprobe on the same function. A patch to remove
this limitation is being tested.
This feature is required by SystemTap (http://sourceware.org/systemtap),
and reflects ideas contributed by several SystemTap developers, including
Will Cohen and Ananth Mavinakayanahalli.
Signed-off-by: Hien Nguyen <hien@us.ibm.com>
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Frederik Deweerdt <frederik.deweerdt@laposte.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23 03:09:19 -04:00
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#include <linux/kprobes.h>
|
2005-04-16 18:20:36 -04:00
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#include <asm/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/system.h>
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#include <asm/io.h>
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#include <asm/ldt.h>
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#include <asm/processor.h>
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#include <asm/i387.h>
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#include <asm/desc.h>
|
2006-01-08 04:05:26 -05:00
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#include <asm/vm86.h>
|
2005-04-16 18:20:36 -04:00
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#ifdef CONFIG_MATH_EMULATION
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#include <asm/math_emu.h>
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#endif
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#include <linux/err.h>
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|
2005-06-25 17:54:50 -04:00
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#include <asm/tlbflush.h>
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#include <asm/cpu.h>
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|
2005-04-16 18:20:36 -04:00
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|
|
asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
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|
|
static int hlt_counter;
|
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|
|
unsigned long boot_option_idle_override = 0;
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|
EXPORT_SYMBOL(boot_option_idle_override);
|
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|
/*
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|
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* Return saved PC of a blocked thread.
|
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|
*/
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|
unsigned long thread_saved_pc(struct task_struct *tsk)
|
|
|
|
|
{
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|
|
|
|
return ((unsigned long *)tsk->thread.esp)[3];
|
|
|
|
|
}
|
|
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|
|
|
|
|
|
/*
|
|
|
|
|
* Powermanagement idle function, if any..
|
|
|
|
|
*/
|
|
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|
|
void (*pm_idle)(void);
|
2005-06-23 03:08:33 -04:00
|
|
|
EXPORT_SYMBOL(pm_idle);
|
2005-04-16 18:20:36 -04:00
|
|
|
static DEFINE_PER_CPU(unsigned int, cpu_idle_state);
|
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|
|
void disable_hlt(void)
|
|
|
|
|
{
|
|
|
|
|
hlt_counter++;
|
|
|
|
|
}
|
|
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|
|
EXPORT_SYMBOL(disable_hlt);
|
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|
|
void enable_hlt(void)
|
|
|
|
|
{
|
|
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|
|
hlt_counter--;
|
|
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|
|
}
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|
|
EXPORT_SYMBOL(enable_hlt);
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* We use this if we don't have any better
|
|
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|
|
* idle routine..
|
|
|
|
|
*/
|
|
|
|
|
void default_idle(void)
|
|
|
|
|
{
|
[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 00:39:04 -05:00
|
|
|
local_irq_enable();
|
|
|
|
|
|
2005-04-16 18:20:36 -04:00
|
|
|
if (!hlt_counter && boot_cpu_data.hlt_works_ok) {
|
[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 00:39:04 -05:00
|
|
|
clear_thread_flag(TIF_POLLING_NRFLAG);
|
|
|
|
|
smp_mb__after_clear_bit();
|
|
|
|
|
while (!need_resched()) {
|
|
|
|
|
local_irq_disable();
|
|
|
|
|
if (!need_resched())
|
|
|
|
|
safe_halt();
|
|
|
|
|
else
|
|
|
|
|
local_irq_enable();
|
|
|
|
|
}
|
|
|
|
|
set_thread_flag(TIF_POLLING_NRFLAG);
|
2005-04-16 18:20:36 -04:00
|
|
|
} else {
|
[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 00:39:04 -05:00
|
|
|
while (!need_resched())
|
|
|
|
|
cpu_relax();
|
2005-04-16 18:20:36 -04:00
|
|
|
}
|
|
|
|
|
}
|
2005-06-23 03:08:33 -04:00
|
|
|
#ifdef CONFIG_APM_MODULE
|
|
|
|
|
EXPORT_SYMBOL(default_idle);
|
|
|
|
|
#endif
|
2005-04-16 18:20:36 -04:00
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* On SMP it's slightly faster (but much more power-consuming!)
|
|
|
|
|
* to poll the ->work.need_resched flag instead of waiting for the
|
|
|
|
|
* cross-CPU IPI to arrive. Use this option with caution.
|
|
|
|
|
*/
|
|
|
|
|
static void poll_idle (void)
|
|
|
|
|
{
|
|
|
|
|
local_irq_enable();
|
|
|
|
|
|
[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 00:39:04 -05:00
|
|
|
asm volatile(
|
|
|
|
|
"2:"
|
|
|
|
|
"testl %0, %1;"
|
|
|
|
|
"rep; nop;"
|
|
|
|
|
"je 2b;"
|
|
|
|
|
: : "i"(_TIF_NEED_RESCHED), "m" (current_thread_info()->flags));
|
2005-04-16 18:20:36 -04:00
|
|
|
}
|
|
|
|
|
|
2005-06-25 17:54:50 -04:00
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
|
|
|
#include <asm/nmi.h>
|
|
|
|
|
/* We don't actually take CPU down, just spin without interrupts. */
|
|
|
|
|
static inline void play_dead(void)
|
|
|
|
|
{
|
2005-06-25 17:54:56 -04:00
|
|
|
/* This must be done before dead CPU ack */
|
|
|
|
|
cpu_exit_clear();
|
|
|
|
|
wbinvd();
|
|
|
|
|
mb();
|
2005-06-25 17:54:50 -04:00
|
|
|
/* Ack it */
|
|
|
|
|
__get_cpu_var(cpu_state) = CPU_DEAD;
|
|
|
|
|
|
2005-06-25 17:54:56 -04:00
|
|
|
/*
|
|
|
|
|
* With physical CPU hotplug, we should halt the cpu
|
|
|
|
|
*/
|
2005-06-25 17:54:50 -04:00
|
|
|
local_irq_disable();
|
2005-06-25 17:54:56 -04:00
|
|
|
while (1)
|
2005-09-03 18:56:42 -04:00
|
|
|
halt();
|
2005-06-25 17:54:50 -04:00
|
|
|
}
|
|
|
|
|
#else
|
|
|
|
|
static inline void play_dead(void)
|
|
|
|
|
{
|
|
|
|
|
BUG();
|
|
|
|
|
}
|
|
|
|
|
#endif /* CONFIG_HOTPLUG_CPU */
|
|
|
|
|
|
2005-04-16 18:20:36 -04:00
|
|
|
/*
|
|
|
|
|
* 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)
|
|
|
|
|
*/
|
2005-06-25 17:54:50 -04:00
|
|
|
void cpu_idle(void)
|
2005-04-16 18:20:36 -04:00
|
|
|
{
|
2005-11-09 00:39:01 -05:00
|
|
|
int cpu = smp_processor_id();
|
2005-06-25 17:54:50 -04:00
|
|
|
|
[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 00:39:04 -05:00
|
|
|
set_thread_flag(TIF_POLLING_NRFLAG);
|
|
|
|
|
|
2005-04-16 18:20:36 -04:00
|
|
|
/* endless idle loop with no priority at all */
|
|
|
|
|
while (1) {
|
|
|
|
|
while (!need_resched()) {
|
|
|
|
|
void (*idle)(void);
|
|
|
|
|
|
|
|
|
|
if (__get_cpu_var(cpu_idle_state))
|
|
|
|
|
__get_cpu_var(cpu_idle_state) = 0;
|
|
|
|
|
|
|
|
|
|
rmb();
|
|
|
|
|
idle = pm_idle;
|
|
|
|
|
|
|
|
|
|
if (!idle)
|
|
|
|
|
idle = default_idle;
|
|
|
|
|
|
2005-06-25 17:54:50 -04:00
|
|
|
if (cpu_is_offline(cpu))
|
|
|
|
|
play_dead();
|
|
|
|
|
|
2005-04-16 18:20:36 -04:00
|
|
|
__get_cpu_var(irq_stat).idle_timestamp = jiffies;
|
|
|
|
|
idle();
|
|
|
|
|
}
|
2005-11-09 00:39:01 -05:00
|
|
|
preempt_enable_no_resched();
|
2005-04-16 18:20:36 -04:00
|
|
|
schedule();
|
2005-11-09 00:39:01 -05:00
|
|
|
preempt_disable();
|
2005-04-16 18:20:36 -04:00
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
void cpu_idle_wait(void)
|
|
|
|
|
{
|
|
|
|
|
unsigned int cpu, this_cpu = get_cpu();
|
|
|
|
|
cpumask_t map;
|
|
|
|
|
|
|
|
|
|
set_cpus_allowed(current, cpumask_of_cpu(this_cpu));
|
|
|
|
|
put_cpu();
|
|
|
|
|
|
|
|
|
|
cpus_clear(map);
|
|
|
|
|
for_each_online_cpu(cpu) {
|
|
|
|
|
per_cpu(cpu_idle_state, cpu) = 1;
|
|
|
|
|
cpu_set(cpu, map);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
__get_cpu_var(cpu_idle_state) = 0;
|
|
|
|
|
|
|
|
|
|
wmb();
|
|
|
|
|
do {
|
|
|
|
|
ssleep(1);
|
|
|
|
|
for_each_online_cpu(cpu) {
|
|
|
|
|
if (cpu_isset(cpu, map) && !per_cpu(cpu_idle_state, cpu))
|
|
|
|
|
cpu_clear(cpu, map);
|
|
|
|
|
}
|
|
|
|
|
cpus_and(map, map, cpu_online_map);
|
|
|
|
|
} while (!cpus_empty(map));
|
|
|
|
|
}
|
|
|
|
|
EXPORT_SYMBOL_GPL(cpu_idle_wait);
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* This uses new MONITOR/MWAIT instructions on P4 processors with PNI,
|
|
|
|
|
* which can obviate IPI to trigger checking of need_resched.
|
|
|
|
|
* We execute MONITOR against need_resched and enter optimized wait state
|
|
|
|
|
* through MWAIT. Whenever someone changes need_resched, we would be woken
|
|
|
|
|
* up from MWAIT (without an IPI).
|
|
|
|
|
*/
|
|
|
|
|
static void mwait_idle(void)
|
|
|
|
|
{
|
|
|
|
|
local_irq_enable();
|
|
|
|
|
|
[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 00:39:04 -05:00
|
|
|
while (!need_resched()) {
|
|
|
|
|
__monitor((void *)¤t_thread_info()->flags, 0, 0);
|
|
|
|
|
smp_mb();
|
|
|
|
|
if (need_resched())
|
|
|
|
|
break;
|
|
|
|
|
__mwait(0, 0);
|
2005-04-16 18:20:36 -04:00
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2005-06-25 17:54:55 -04:00
|
|
|
void __devinit select_idle_routine(const struct cpuinfo_x86 *c)
|
2005-04-16 18:20:36 -04:00
|
|
|
{
|
|
|
|
|
if (cpu_has(c, X86_FEATURE_MWAIT)) {
|
|
|
|
|
printk("monitor/mwait feature present.\n");
|
|
|
|
|
/*
|
|
|
|
|
* Skip, if setup has overridden idle.
|
|
|
|
|
* One CPU supports mwait => All CPUs supports mwait
|
|
|
|
|
*/
|
|
|
|
|
if (!pm_idle) {
|
|
|
|
|
printk("using mwait in idle threads.\n");
|
|
|
|
|
pm_idle = mwait_idle;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int __init idle_setup (char *str)
|
|
|
|
|
{
|
|
|
|
|
if (!strncmp(str, "poll", 4)) {
|
|
|
|
|
printk("using polling idle threads.\n");
|
|
|
|
|
pm_idle = poll_idle;
|
|
|
|
|
#ifdef CONFIG_X86_SMP
|
|
|
|
|
if (smp_num_siblings > 1)
|
|
|
|
|
printk("WARNING: polling idle and HT enabled, performance may degrade.\n");
|
|
|
|
|
#endif
|
|
|
|
|
} else if (!strncmp(str, "halt", 4)) {
|
|
|
|
|
printk("using halt in idle threads.\n");
|
|
|
|
|
pm_idle = default_idle;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
boot_option_idle_override = 1;
|
|
|
|
|
return 1;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
__setup("idle=", idle_setup);
|
|
|
|
|
|
|
|
|
|
void show_regs(struct pt_regs * regs)
|
|
|
|
|
{
|
|
|
|
|
unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
|
|
|
|
|
|
|
|
|
|
printk("\n");
|
|
|
|
|
printk("Pid: %d, comm: %20s\n", current->pid, current->comm);
|
|
|
|
|
printk("EIP: %04x:[<%08lx>] CPU: %d\n",0xffff & regs->xcs,regs->eip, smp_processor_id());
|
|
|
|
|
print_symbol("EIP is at %s\n", regs->eip);
|
|
|
|
|
|
2006-03-23 05:59:46 -05:00
|
|
|
if (user_mode_vm(regs))
|
2005-04-16 18:20:36 -04:00
|
|
|
printk(" ESP: %04x:%08lx",0xffff & regs->xss,regs->esp);
|
2006-02-05 02:28:04 -05:00
|
|
|
printk(" EFLAGS: %08lx %s (%s %.*s)\n",
|
|
|
|
|
regs->eflags, print_tainted(), system_utsname.release,
|
|
|
|
|
(int)strcspn(system_utsname.version, " "),
|
|
|
|
|
system_utsname.version);
|
2005-04-16 18:20:36 -04:00
|
|
|
printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
|
|
|
|
|
regs->eax,regs->ebx,regs->ecx,regs->edx);
|
|
|
|
|
printk("ESI: %08lx EDI: %08lx EBP: %08lx",
|
|
|
|
|
regs->esi, regs->edi, regs->ebp);
|
|
|
|
|
printk(" DS: %04x ES: %04x\n",
|
|
|
|
|
0xffff & regs->xds,0xffff & regs->xes);
|
|
|
|
|
|
2005-09-03 18:56:36 -04:00
|
|
|
cr0 = read_cr0();
|
|
|
|
|
cr2 = read_cr2();
|
|
|
|
|
cr3 = read_cr3();
|
2006-01-06 03:11:50 -05:00
|
|
|
cr4 = read_cr4_safe();
|
2005-04-16 18:20:36 -04:00
|
|
|
printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0, cr2, cr3, cr4);
|
|
|
|
|
show_trace(NULL, ®s->esp);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* This gets run with %ebx containing the
|
|
|
|
|
* function to call, and %edx containing
|
|
|
|
|
* the "args".
|
|
|
|
|
*/
|
|
|
|
|
extern void kernel_thread_helper(void);
|
|
|
|
|
__asm__(".section .text\n"
|
|
|
|
|
".align 4\n"
|
|
|
|
|
"kernel_thread_helper:\n\t"
|
|
|
|
|
"movl %edx,%eax\n\t"
|
|
|
|
|
"pushl %edx\n\t"
|
|
|
|
|
"call *%ebx\n\t"
|
|
|
|
|
"pushl %eax\n\t"
|
|
|
|
|
"call do_exit\n"
|
|
|
|
|
".previous");
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Create a kernel thread
|
|
|
|
|
*/
|
|
|
|
|
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
|
|
|
|
|
{
|
|
|
|
|
struct pt_regs regs;
|
|
|
|
|
|
|
|
|
|
memset(®s, 0, sizeof(regs));
|
|
|
|
|
|
|
|
|
|
regs.ebx = (unsigned long) fn;
|
|
|
|
|
regs.edx = (unsigned long) arg;
|
|
|
|
|
|
|
|
|
|
regs.xds = __USER_DS;
|
|
|
|
|
regs.xes = __USER_DS;
|
|
|
|
|
regs.orig_eax = -1;
|
|
|
|
|
regs.eip = (unsigned long) kernel_thread_helper;
|
|
|
|
|
regs.xcs = __KERNEL_CS;
|
|
|
|
|
regs.eflags = X86_EFLAGS_IF | X86_EFLAGS_SF | X86_EFLAGS_PF | 0x2;
|
|
|
|
|
|
|
|
|
|
/* Ok, create the new process.. */
|
|
|
|
|
return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
|
|
|
|
|
}
|
2005-06-23 03:08:33 -04:00
|
|
|
EXPORT_SYMBOL(kernel_thread);
|
2005-04-16 18:20:36 -04:00
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Free current thread data structures etc..
|
|
|
|
|
*/
|
|
|
|
|
void exit_thread(void)
|
|
|
|
|
{
|
|
|
|
|
struct task_struct *tsk = current;
|
|
|
|
|
struct thread_struct *t = &tsk->thread;
|
|
|
|
|
|
[PATCH] kprobes: function-return probes
This patch adds function-return probes to kprobes for the i386
architecture. This enables you to establish a handler to be run when a
function returns.
1. API
Two new functions are added to kprobes:
int register_kretprobe(struct kretprobe *rp);
void unregister_kretprobe(struct kretprobe *rp);
2. Registration and unregistration
2.1 Register
To register a function-return probe, the user populates the following
fields in a kretprobe object and calls register_kretprobe() with the
kretprobe address as an argument:
kp.addr - the function's address
handler - this function is run after the ret instruction executes, but
before control returns to the return address in the caller.
maxactive - The maximum number of instances of the probed function that
can be active concurrently. For example, if the function is non-
recursive and is called with a spinlock or mutex held, maxactive = 1
should be enough. If the function is non-recursive and can never
relinquish the CPU (e.g., via a semaphore or preemption), NR_CPUS should
be enough. maxactive is used to determine how many kretprobe_instance
objects to allocate for this particular probed function. If maxactive <=
0, it is set to a default value (if CONFIG_PREEMPT maxactive=max(10, 2 *
NR_CPUS) else maxactive=NR_CPUS)
For example:
struct kretprobe rp;
rp.kp.addr = /* entrypoint address */
rp.handler = /*return probe handler */
rp.maxactive = /* e.g., 1 or NR_CPUS or 0, see the above explanation */
register_kretprobe(&rp);
The following field may also be of interest:
nmissed - Initialized to zero when the function-return probe is
registered, and incremented every time the probed function is entered but
there is no kretprobe_instance object available for establishing the
function-return probe (i.e., because maxactive was set too low).
2.2 Unregister
To unregiter a function-return probe, the user calls
unregister_kretprobe() with the same kretprobe object as registered
previously. If a probed function is running when the return probe is
unregistered, the function will return as expected, but the handler won't
be run.
3. Limitations
3.1 This patch supports only the i386 architecture, but patches for
x86_64 and ppc64 are anticipated soon.
3.2 Return probes operates by replacing the return address in the stack
(or in a known register, such as the lr register for ppc). This may
cause __builtin_return_address(0), when invoked from the return-probed
function, to return the address of the return-probes trampoline.
3.3 This implementation uses the "Multiprobes at an address" feature in
2.6.12-rc3-mm3.
3.4 Due to a limitation in multi-probes, you cannot currently establish
a return probe and a jprobe on the same function. A patch to remove
this limitation is being tested.
This feature is required by SystemTap (http://sourceware.org/systemtap),
and reflects ideas contributed by several SystemTap developers, including
Will Cohen and Ananth Mavinakayanahalli.
Signed-off-by: Hien Nguyen <hien@us.ibm.com>
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Frederik Deweerdt <frederik.deweerdt@laposte.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23 03:09:19 -04:00
|
|
|
/*
|
|
|
|
|
* Remove function-return probe instances associated with this task
|
|
|
|
|
* and put them back on the free list. Do not insert an exit probe for
|
|
|
|
|
* this function, it will be disabled by kprobe_flush_task if you do.
|
|
|
|
|
*/
|
|
|
|
|
kprobe_flush_task(tsk);
|
|
|
|
|
|
2005-04-16 18:20:36 -04:00
|
|
|
/* The process may have allocated an io port bitmap... nuke it. */
|
|
|
|
|
if (unlikely(NULL != t->io_bitmap_ptr)) {
|
|
|
|
|
int cpu = get_cpu();
|
|
|
|
|
struct tss_struct *tss = &per_cpu(init_tss, cpu);
|
|
|
|
|
|
|
|
|
|
kfree(t->io_bitmap_ptr);
|
|
|
|
|
t->io_bitmap_ptr = NULL;
|
|
|
|
|
/*
|
|
|
|
|
* Careful, clear this in the TSS too:
|
|
|
|
|
*/
|
|
|
|
|
memset(tss->io_bitmap, 0xff, tss->io_bitmap_max);
|
|
|
|
|
t->io_bitmap_max = 0;
|
|
|
|
|
tss->io_bitmap_owner = NULL;
|
|
|
|
|
tss->io_bitmap_max = 0;
|
|
|
|
|
tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
|
|
|
|
|
put_cpu();
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
void flush_thread(void)
|
|
|
|
|
{
|
|
|
|
|
struct task_struct *tsk = current;
|
|
|
|
|
|
|
|
|
|
memset(tsk->thread.debugreg, 0, sizeof(unsigned long)*8);
|
|
|
|
|
memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
|
|
|
|
|
/*
|
|
|
|
|
* Forget coprocessor state..
|
|
|
|
|
*/
|
|
|
|
|
clear_fpu(tsk);
|
|
|
|
|
clear_used_math();
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
void release_thread(struct task_struct *dead_task)
|
|
|
|
|
{
|
2006-01-06 03:11:59 -05:00
|
|
|
BUG_ON(dead_task->mm);
|
2005-04-16 18:20:36 -04:00
|
|
|
release_vm86_irqs(dead_task);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* This gets called before we allocate a new thread and copy
|
|
|
|
|
* the current task into it.
|
|
|
|
|
*/
|
|
|
|
|
void prepare_to_copy(struct task_struct *tsk)
|
|
|
|
|
{
|
|
|
|
|
unlazy_fpu(tsk);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
int copy_thread(int nr, unsigned long clone_flags, unsigned long esp,
|
|
|
|
|
unsigned long unused,
|
|
|
|
|
struct task_struct * p, struct pt_regs * regs)
|
|
|
|
|
{
|
|
|
|
|
struct pt_regs * childregs;
|
|
|
|
|
struct task_struct *tsk;
|
|
|
|
|
int err;
|
|
|
|
|
|
2006-01-12 04:05:41 -05:00
|
|
|
childregs = task_pt_regs(p);
|
2005-05-05 19:15:03 -04:00
|
|
|
*childregs = *regs;
|
|
|
|
|
childregs->eax = 0;
|
|
|
|
|
childregs->esp = esp;
|
|
|
|
|
|
|
|
|
|
p->thread.esp = (unsigned long) childregs;
|
|
|
|
|
p->thread.esp0 = (unsigned long) (childregs+1);
|
2005-04-16 18:20:36 -04:00
|
|
|
|
|
|
|
|
p->thread.eip = (unsigned long) ret_from_fork;
|
|
|
|
|
|
|
|
|
|
savesegment(fs,p->thread.fs);
|
|
|
|
|
savesegment(gs,p->thread.gs);
|
|
|
|
|
|
|
|
|
|
tsk = current;
|
|
|
|
|
if (unlikely(NULL != tsk->thread.io_bitmap_ptr)) {
|
|
|
|
|
p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
|
|
|
|
|
if (!p->thread.io_bitmap_ptr) {
|
|
|
|
|
p->thread.io_bitmap_max = 0;
|
|
|
|
|
return -ENOMEM;
|
|
|
|
|
}
|
|
|
|
|
memcpy(p->thread.io_bitmap_ptr, tsk->thread.io_bitmap_ptr,
|
|
|
|
|
IO_BITMAP_BYTES);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Set a new TLS for the child thread?
|
|
|
|
|
*/
|
|
|
|
|
if (clone_flags & CLONE_SETTLS) {
|
|
|
|
|
struct desc_struct *desc;
|
|
|
|
|
struct user_desc info;
|
|
|
|
|
int idx;
|
|
|
|
|
|
|
|
|
|
err = -EFAULT;
|
|
|
|
|
if (copy_from_user(&info, (void __user *)childregs->esi, sizeof(info)))
|
|
|
|
|
goto out;
|
|
|
|
|
err = -EINVAL;
|
|
|
|
|
if (LDT_empty(&info))
|
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
|
|
idx = info.entry_number;
|
|
|
|
|
if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
|
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
|
|
desc = p->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
|
|
|
|
|
desc->a = LDT_entry_a(&info);
|
|
|
|
|
desc->b = LDT_entry_b(&info);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
err = 0;
|
|
|
|
|
out:
|
|
|
|
|
if (err && p->thread.io_bitmap_ptr) {
|
|
|
|
|
kfree(p->thread.io_bitmap_ptr);
|
|
|
|
|
p->thread.io_bitmap_max = 0;
|
|
|
|
|
}
|
|
|
|
|
return err;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* fill in the user structure for a core dump..
|
|
|
|
|
*/
|
|
|
|
|
void dump_thread(struct pt_regs * regs, struct user * dump)
|
|
|
|
|
{
|
|
|
|
|
int i;
|
|
|
|
|
|
|
|
|
|
/* changed the size calculations - should hopefully work better. lbt */
|
|
|
|
|
dump->magic = CMAGIC;
|
|
|
|
|
dump->start_code = 0;
|
|
|
|
|
dump->start_stack = regs->esp & ~(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;
|
|
|
|
|
for (i = 0; i < 8; i++)
|
|
|
|
|
dump->u_debugreg[i] = current->thread.debugreg[i];
|
|
|
|
|
|
|
|
|
|
if (dump->start_stack < TASK_SIZE)
|
|
|
|
|
dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT;
|
|
|
|
|
|
|
|
|
|
dump->regs.ebx = regs->ebx;
|
|
|
|
|
dump->regs.ecx = regs->ecx;
|
|
|
|
|
dump->regs.edx = regs->edx;
|
|
|
|
|
dump->regs.esi = regs->esi;
|
|
|
|
|
dump->regs.edi = regs->edi;
|
|
|
|
|
dump->regs.ebp = regs->ebp;
|
|
|
|
|
dump->regs.eax = regs->eax;
|
|
|
|
|
dump->regs.ds = regs->xds;
|
|
|
|
|
dump->regs.es = regs->xes;
|
|
|
|
|
savesegment(fs,dump->regs.fs);
|
|
|
|
|
savesegment(gs,dump->regs.gs);
|
|
|
|
|
dump->regs.orig_eax = regs->orig_eax;
|
|
|
|
|
dump->regs.eip = regs->eip;
|
|
|
|
|
dump->regs.cs = regs->xcs;
|
|
|
|
|
dump->regs.eflags = regs->eflags;
|
|
|
|
|
dump->regs.esp = regs->esp;
|
|
|
|
|
dump->regs.ss = regs->xss;
|
|
|
|
|
|
|
|
|
|
dump->u_fpvalid = dump_fpu (regs, &dump->i387);
|
|
|
|
|
}
|
2005-06-23 03:08:33 -04:00
|
|
|
EXPORT_SYMBOL(dump_thread);
|
2005-04-16 18:20:36 -04:00
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Capture the user space registers if the task is not running (in user space)
|
|
|
|
|
*/
|
|
|
|
|
int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
|
|
|
|
|
{
|
2006-01-12 04:05:41 -05:00
|
|
|
struct pt_regs ptregs = *task_pt_regs(tsk);
|
2005-04-16 18:20:36 -04:00
|
|
|
ptregs.xcs &= 0xffff;
|
|
|
|
|
ptregs.xds &= 0xffff;
|
|
|
|
|
ptregs.xes &= 0xffff;
|
|
|
|
|
ptregs.xss &= 0xffff;
|
|
|
|
|
|
|
|
|
|
elf_core_copy_regs(regs, &ptregs);
|
|
|
|
|
|
|
|
|
|
return 1;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static inline void
|
|
|
|
|
handle_io_bitmap(struct thread_struct *next, struct tss_struct *tss)
|
|
|
|
|
{
|
|
|
|
|
if (!next->io_bitmap_ptr) {
|
|
|
|
|
/*
|
|
|
|
|
* Disable the bitmap via an invalid offset. We still cache
|
|
|
|
|
* the previous bitmap owner and the IO bitmap contents:
|
|
|
|
|
*/
|
|
|
|
|
tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET;
|
|
|
|
|
return;
|
|
|
|
|
}
|
|
|
|
|
if (likely(next == tss->io_bitmap_owner)) {
|
|
|
|
|
/*
|
|
|
|
|
* Previous owner of the bitmap (hence the bitmap content)
|
|
|
|
|
* matches the next task, we dont have to do anything but
|
|
|
|
|
* to set a valid offset in the TSS:
|
|
|
|
|
*/
|
|
|
|
|
tss->io_bitmap_base = IO_BITMAP_OFFSET;
|
|
|
|
|
return;
|
|
|
|
|
}
|
|
|
|
|
/*
|
|
|
|
|
* Lazy TSS's I/O bitmap copy. We set an invalid offset here
|
|
|
|
|
* and we let the task to get a GPF in case an I/O instruction
|
|
|
|
|
* is performed. The handler of the GPF will verify that the
|
|
|
|
|
* faulting task has a valid I/O bitmap and, it true, does the
|
|
|
|
|
* real copy and restart the instruction. This will save us
|
|
|
|
|
* redundant copies when the currently switched task does not
|
|
|
|
|
* perform any I/O during its timeslice.
|
|
|
|
|
*/
|
|
|
|
|
tss->io_bitmap_base = INVALID_IO_BITMAP_OFFSET_LAZY;
|
|
|
|
|
}
|
|
|
|
|
|
2005-06-27 17:36:36 -04:00
|
|
|
/*
|
|
|
|
|
* This function selects if the context switch from prev to next
|
|
|
|
|
* has to tweak the TSC disable bit in the cr4.
|
|
|
|
|
*/
|
|
|
|
|
static inline void disable_tsc(struct task_struct *prev_p,
|
|
|
|
|
struct task_struct *next_p)
|
|
|
|
|
{
|
|
|
|
|
struct thread_info *prev, *next;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* gcc should eliminate the ->thread_info dereference if
|
|
|
|
|
* has_secure_computing returns 0 at compile time (SECCOMP=n).
|
|
|
|
|
*/
|
2006-01-12 04:05:40 -05:00
|
|
|
prev = task_thread_info(prev_p);
|
|
|
|
|
next = task_thread_info(next_p);
|
2005-06-27 17:36:36 -04:00
|
|
|
|
|
|
|
|
if (has_secure_computing(prev) || has_secure_computing(next)) {
|
|
|
|
|
/* slow path here */
|
|
|
|
|
if (has_secure_computing(prev) &&
|
|
|
|
|
!has_secure_computing(next)) {
|
|
|
|
|
write_cr4(read_cr4() & ~X86_CR4_TSD);
|
|
|
|
|
} else if (!has_secure_computing(prev) &&
|
|
|
|
|
has_secure_computing(next))
|
|
|
|
|
write_cr4(read_cr4() | X86_CR4_TSD);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2005-04-16 18:20:36 -04:00
|
|
|
/*
|
|
|
|
|
* switch_to(x,yn) should switch tasks from x to y.
|
|
|
|
|
*
|
|
|
|
|
* We fsave/fwait so that an exception goes off at the right time
|
|
|
|
|
* (as a call from the fsave or fwait in effect) rather than to
|
|
|
|
|
* the wrong process. Lazy FP saving no longer makes any sense
|
|
|
|
|
* with modern CPU's, and this simplifies a lot of things (SMP
|
|
|
|
|
* and UP become the same).
|
|
|
|
|
*
|
|
|
|
|
* NOTE! We used to use the x86 hardware context switching. The
|
|
|
|
|
* reason for not using it any more becomes apparent when you
|
|
|
|
|
* try to recover gracefully from saved state that is no longer
|
|
|
|
|
* valid (stale segment register values in particular). With the
|
|
|
|
|
* hardware task-switch, there is no way to fix up bad state in
|
|
|
|
|
* a reasonable manner.
|
|
|
|
|
*
|
|
|
|
|
* The fact that Intel documents the hardware task-switching to
|
|
|
|
|
* be slow is a fairly red herring - this code is not noticeably
|
|
|
|
|
* faster. However, there _is_ some room for improvement here,
|
|
|
|
|
* so the performance issues may eventually be a valid point.
|
|
|
|
|
* More important, however, is the fact that this allows us much
|
|
|
|
|
* more flexibility.
|
|
|
|
|
*
|
|
|
|
|
* The return value (in %eax) will be the "prev" task after
|
|
|
|
|
* the task-switch, and shows up in ret_from_fork in entry.S,
|
|
|
|
|
* for example.
|
|
|
|
|
*/
|
|
|
|
|
struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
|
|
|
|
|
{
|
|
|
|
|
struct thread_struct *prev = &prev_p->thread,
|
|
|
|
|
*next = &next_p->thread;
|
|
|
|
|
int cpu = smp_processor_id();
|
|
|
|
|
struct tss_struct *tss = &per_cpu(init_tss, cpu);
|
|
|
|
|
|
|
|
|
|
/* never put a printk in __switch_to... printk() calls wake_up*() indirectly */
|
|
|
|
|
|
|
|
|
|
__unlazy_fpu(prev_p);
|
|
|
|
|
|
|
|
|
|
/*
|
2005-09-03 18:56:39 -04:00
|
|
|
* Reload esp0.
|
2005-04-16 18:20:36 -04:00
|
|
|
*/
|
|
|
|
|
load_esp0(tss, next);
|
|
|
|
|
|
|
|
|
|
/*
|
2005-09-03 18:56:39 -04:00
|
|
|
* Save away %fs and %gs. No need to save %es and %ds, as
|
|
|
|
|
* those are always kernel segments while inside the kernel.
|
|
|
|
|
* Doing this before setting the new TLS descriptors avoids
|
|
|
|
|
* the situation where we temporarily have non-reloadable
|
|
|
|
|
* segments in %fs and %gs. This could be an issue if the
|
|
|
|
|
* NMI handler ever used %fs or %gs (it does not today), or
|
|
|
|
|
* if the kernel is running inside of a hypervisor layer.
|
2005-04-16 18:20:36 -04:00
|
|
|
*/
|
2005-09-03 18:56:39 -04:00
|
|
|
savesegment(fs, prev->fs);
|
|
|
|
|
savesegment(gs, prev->gs);
|
2005-04-16 18:20:36 -04:00
|
|
|
|
|
|
|
|
/*
|
2005-09-03 18:56:39 -04:00
|
|
|
* Load the per-thread Thread-Local Storage descriptor.
|
2005-04-16 18:20:36 -04:00
|
|
|
*/
|
2005-09-03 18:56:39 -04:00
|
|
|
load_TLS(next, cpu);
|
2005-04-16 18:20:36 -04:00
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Restore %fs and %gs if needed.
|
2005-07-22 15:23:47 -04:00
|
|
|
*
|
|
|
|
|
* Glibc normally makes %fs be zero, and %gs is one of
|
|
|
|
|
* the TLS segments.
|
2005-04-16 18:20:36 -04:00
|
|
|
*/
|
2005-07-22 15:23:47 -04:00
|
|
|
if (unlikely(prev->fs | next->fs))
|
2005-04-16 18:20:36 -04:00
|
|
|
loadsegment(fs, next->fs);
|
2005-07-22 15:23:47 -04:00
|
|
|
|
|
|
|
|
if (prev->gs | next->gs)
|
2005-04-16 18:20:36 -04:00
|
|
|
loadsegment(gs, next->gs);
|
|
|
|
|
|
2005-09-03 18:56:44 -04:00
|
|
|
/*
|
|
|
|
|
* Restore IOPL if needed.
|
|
|
|
|
*/
|
|
|
|
|
if (unlikely(prev->iopl != next->iopl))
|
|
|
|
|
set_iopl_mask(next->iopl);
|
|
|
|
|
|
2005-04-16 18:20:36 -04:00
|
|
|
/*
|
|
|
|
|
* Now maybe reload the debug registers
|
|
|
|
|
*/
|
|
|
|
|
if (unlikely(next->debugreg[7])) {
|
2005-07-22 15:23:47 -04:00
|
|
|
set_debugreg(next->debugreg[0], 0);
|
|
|
|
|
set_debugreg(next->debugreg[1], 1);
|
|
|
|
|
set_debugreg(next->debugreg[2], 2);
|
|
|
|
|
set_debugreg(next->debugreg[3], 3);
|
2005-04-16 18:20:36 -04:00
|
|
|
/* no 4 and 5 */
|
2005-07-22 15:23:47 -04:00
|
|
|
set_debugreg(next->debugreg[6], 6);
|
|
|
|
|
set_debugreg(next->debugreg[7], 7);
|
2005-04-16 18:20:36 -04:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if (unlikely(prev->io_bitmap_ptr || next->io_bitmap_ptr))
|
|
|
|
|
handle_io_bitmap(next, tss);
|
|
|
|
|
|
2005-06-27 17:36:36 -04:00
|
|
|
disable_tsc(prev_p, next_p);
|
|
|
|
|
|
2005-04-16 18:20:36 -04:00
|
|
|
return prev_p;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
asmlinkage int sys_fork(struct pt_regs regs)
|
|
|
|
|
{
|
|
|
|
|
return do_fork(SIGCHLD, regs.esp, ®s, 0, NULL, NULL);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
asmlinkage int sys_clone(struct pt_regs regs)
|
|
|
|
|
{
|
|
|
|
|
unsigned long clone_flags;
|
|
|
|
|
unsigned long newsp;
|
|
|
|
|
int __user *parent_tidptr, *child_tidptr;
|
|
|
|
|
|
|
|
|
|
clone_flags = regs.ebx;
|
|
|
|
|
newsp = regs.ecx;
|
|
|
|
|
parent_tidptr = (int __user *)regs.edx;
|
|
|
|
|
child_tidptr = (int __user *)regs.edi;
|
|
|
|
|
if (!newsp)
|
|
|
|
|
newsp = regs.esp;
|
|
|
|
|
return do_fork(clone_flags, newsp, ®s, 0, parent_tidptr, child_tidptr);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* 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(struct pt_regs regs)
|
|
|
|
|
{
|
|
|
|
|
return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.esp, ®s, 0, NULL, NULL);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* sys_execve() executes a new program.
|
|
|
|
|
*/
|
|
|
|
|
asmlinkage int sys_execve(struct pt_regs regs)
|
|
|
|
|
{
|
|
|
|
|
int error;
|
|
|
|
|
char * filename;
|
|
|
|
|
|
|
|
|
|
filename = getname((char __user *) regs.ebx);
|
|
|
|
|
error = PTR_ERR(filename);
|
|
|
|
|
if (IS_ERR(filename))
|
|
|
|
|
goto out;
|
|
|
|
|
error = do_execve(filename,
|
|
|
|
|
(char __user * __user *) regs.ecx,
|
|
|
|
|
(char __user * __user *) regs.edx,
|
|
|
|
|
®s);
|
|
|
|
|
if (error == 0) {
|
|
|
|
|
task_lock(current);
|
|
|
|
|
current->ptrace &= ~PT_DTRACE;
|
|
|
|
|
task_unlock(current);
|
|
|
|
|
/* Make sure we don't return using sysenter.. */
|
|
|
|
|
set_thread_flag(TIF_IRET);
|
|
|
|
|
}
|
|
|
|
|
putname(filename);
|
|
|
|
|
out:
|
|
|
|
|
return error;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
#define top_esp (THREAD_SIZE - sizeof(unsigned long))
|
|
|
|
|
#define top_ebp (THREAD_SIZE - 2*sizeof(unsigned long))
|
|
|
|
|
|
|
|
|
|
unsigned long get_wchan(struct task_struct *p)
|
|
|
|
|
{
|
|
|
|
|
unsigned long ebp, esp, eip;
|
|
|
|
|
unsigned long stack_page;
|
|
|
|
|
int count = 0;
|
|
|
|
|
if (!p || p == current || p->state == TASK_RUNNING)
|
|
|
|
|
return 0;
|
2006-01-12 04:05:41 -05:00
|
|
|
stack_page = (unsigned long)task_stack_page(p);
|
2005-04-16 18:20:36 -04:00
|
|
|
esp = p->thread.esp;
|
|
|
|
|
if (!stack_page || esp < stack_page || esp > top_esp+stack_page)
|
|
|
|
|
return 0;
|
|
|
|
|
/* include/asm-i386/system.h:switch_to() pushes ebp last. */
|
|
|
|
|
ebp = *(unsigned long *) esp;
|
|
|
|
|
do {
|
|
|
|
|
if (ebp < stack_page || ebp > top_ebp+stack_page)
|
|
|
|
|
return 0;
|
|
|
|
|
eip = *(unsigned long *) (ebp+4);
|
|
|
|
|
if (!in_sched_functions(eip))
|
|
|
|
|
return eip;
|
|
|
|
|
ebp = *(unsigned long *) ebp;
|
|
|
|
|
} while (count++ < 16);
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
2005-06-23 03:08:33 -04:00
|
|
|
EXPORT_SYMBOL(get_wchan);
|
2005-04-16 18:20:36 -04:00
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* sys_alloc_thread_area: get a yet unused TLS descriptor index.
|
|
|
|
|
*/
|
|
|
|
|
static int get_free_idx(void)
|
|
|
|
|
{
|
|
|
|
|
struct thread_struct *t = ¤t->thread;
|
|
|
|
|
int idx;
|
|
|
|
|
|
|
|
|
|
for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++)
|
|
|
|
|
if (desc_empty(t->tls_array + idx))
|
|
|
|
|
return idx + GDT_ENTRY_TLS_MIN;
|
|
|
|
|
return -ESRCH;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Set a given TLS descriptor:
|
|
|
|
|
*/
|
|
|
|
|
asmlinkage int sys_set_thread_area(struct user_desc __user *u_info)
|
|
|
|
|
{
|
|
|
|
|
struct thread_struct *t = ¤t->thread;
|
|
|
|
|
struct user_desc info;
|
|
|
|
|
struct desc_struct *desc;
|
|
|
|
|
int cpu, idx;
|
|
|
|
|
|
|
|
|
|
if (copy_from_user(&info, u_info, sizeof(info)))
|
|
|
|
|
return -EFAULT;
|
|
|
|
|
idx = info.entry_number;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* index -1 means the kernel should try to find and
|
|
|
|
|
* allocate an empty descriptor:
|
|
|
|
|
*/
|
|
|
|
|
if (idx == -1) {
|
|
|
|
|
idx = get_free_idx();
|
|
|
|
|
if (idx < 0)
|
|
|
|
|
return idx;
|
|
|
|
|
if (put_user(idx, &u_info->entry_number))
|
|
|
|
|
return -EFAULT;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
|
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
|
|
desc = t->tls_array + idx - GDT_ENTRY_TLS_MIN;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* We must not get preempted while modifying the TLS.
|
|
|
|
|
*/
|
|
|
|
|
cpu = get_cpu();
|
|
|
|
|
|
|
|
|
|
if (LDT_empty(&info)) {
|
|
|
|
|
desc->a = 0;
|
|
|
|
|
desc->b = 0;
|
|
|
|
|
} else {
|
|
|
|
|
desc->a = LDT_entry_a(&info);
|
|
|
|
|
desc->b = LDT_entry_b(&info);
|
|
|
|
|
}
|
|
|
|
|
load_TLS(t, cpu);
|
|
|
|
|
|
|
|
|
|
put_cpu();
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Get the current Thread-Local Storage area:
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
#define GET_BASE(desc) ( \
|
|
|
|
|
(((desc)->a >> 16) & 0x0000ffff) | \
|
|
|
|
|
(((desc)->b << 16) & 0x00ff0000) | \
|
|
|
|
|
( (desc)->b & 0xff000000) )
|
|
|
|
|
|
|
|
|
|
#define GET_LIMIT(desc) ( \
|
|
|
|
|
((desc)->a & 0x0ffff) | \
|
|
|
|
|
((desc)->b & 0xf0000) )
|
|
|
|
|
|
|
|
|
|
#define GET_32BIT(desc) (((desc)->b >> 22) & 1)
|
|
|
|
|
#define GET_CONTENTS(desc) (((desc)->b >> 10) & 3)
|
|
|
|
|
#define GET_WRITABLE(desc) (((desc)->b >> 9) & 1)
|
|
|
|
|
#define GET_LIMIT_PAGES(desc) (((desc)->b >> 23) & 1)
|
|
|
|
|
#define GET_PRESENT(desc) (((desc)->b >> 15) & 1)
|
|
|
|
|
#define GET_USEABLE(desc) (((desc)->b >> 20) & 1)
|
|
|
|
|
|
|
|
|
|
asmlinkage int sys_get_thread_area(struct user_desc __user *u_info)
|
|
|
|
|
{
|
|
|
|
|
struct user_desc info;
|
|
|
|
|
struct desc_struct *desc;
|
|
|
|
|
int idx;
|
|
|
|
|
|
|
|
|
|
if (get_user(idx, &u_info->entry_number))
|
|
|
|
|
return -EFAULT;
|
|
|
|
|
if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
|
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
2005-07-27 14:45:18 -04:00
|
|
|
memset(&info, 0, sizeof(info));
|
|
|
|
|
|
2005-04-16 18:20:36 -04:00
|
|
|
desc = current->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
|
|
|
|
|
|
|
|
|
|
info.entry_number = idx;
|
|
|
|
|
info.base_addr = GET_BASE(desc);
|
|
|
|
|
info.limit = GET_LIMIT(desc);
|
|
|
|
|
info.seg_32bit = GET_32BIT(desc);
|
|
|
|
|
info.contents = GET_CONTENTS(desc);
|
|
|
|
|
info.read_exec_only = !GET_WRITABLE(desc);
|
|
|
|
|
info.limit_in_pages = GET_LIMIT_PAGES(desc);
|
|
|
|
|
info.seg_not_present = !GET_PRESENT(desc);
|
|
|
|
|
info.useable = GET_USEABLE(desc);
|
|
|
|
|
|
|
|
|
|
if (copy_to_user(u_info, &info, sizeof(info)))
|
|
|
|
|
return -EFAULT;
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
unsigned long arch_align_stack(unsigned long sp)
|
|
|
|
|
{
|
|
|
|
|
if (randomize_va_space)
|
|
|
|
|
sp -= get_random_int() % 8192;
|
|
|
|
|
return sp & ~0xf;
|
|
|
|
|
}
|
