Commit 389d1fb1 authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Ingo Molnar
Browse files

x86: unify chunks of kernel/process*.c 



With x86-32 and -64 using the same mechanism for managing the
tss io permissions bitmap, large chunks of process*.c are
trivially unifyable, including:

 - exit_thread
 - flush_thread
 - __switch_to_xtra (along with tsc enable/disable)

and as bonus pickups:

 - sys_fork
 - sys_vfork

(Note: asmlinkage expands to empty on x86-64)

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent db949bba

arch/x86/include/asm/system.h

+2 −0
Original line number Diff line number Diff line
@@ -20,6 +20,8 @@ 
struct task_struct; /* one of the stranger aspects of C forward declarations */

struct task_struct *__switch_to(struct task_struct *prev,

				struct task_struct *next);

void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,

		      struct tss_struct *tss);



#ifdef CONFIG_X86_32

arch/x86/kernel/process.c

+190 −1
Original line number Diff line number Diff line 
#include <linux/errno.h>

#include <linux/kernel.h>

#include <linux/mm.h>

#include <asm/idle.h>

#include <linux/smp.h>

#include <linux/prctl.h>

#include <linux/slab.h>

#include <linux/sched.h>

#include <linux/module.h>
@@ -11,6 +11,9 @@ 
#include <linux/ftrace.h>

#include <asm/system.h>

#include <asm/apic.h>

#include <asm/idle.h>

#include <asm/uaccess.h>

#include <asm/i387.h>



unsigned long idle_halt;

EXPORT_SYMBOL(idle_halt);
@@ -55,6 +58,192 @@ void arch_task_cache_init(void) 
				  SLAB_PANIC, NULL);

}



/*

 * Free current thread data structures etc..

 */

void exit_thread(void)

{

	struct task_struct *me = current;

	struct thread_struct *t = &me->thread;



	if (me->thread.io_bitmap_ptr) {

		struct tss_struct *tss = &per_cpu(init_tss, get_cpu());



		kfree(t->io_bitmap_ptr);

		t->io_bitmap_ptr = NULL;

		clear_thread_flag(TIF_IO_BITMAP);

		/*

		 * Careful, clear this in the TSS too:

		 */

		memset(tss->io_bitmap, 0xff, t->io_bitmap_max);

		t->io_bitmap_max = 0;

		put_cpu();

	}



	ds_exit_thread(current);

}



void flush_thread(void)

{

	struct task_struct *tsk = current;



#ifdef CONFIG_X86_64

	if (test_tsk_thread_flag(tsk, TIF_ABI_PENDING)) {

		clear_tsk_thread_flag(tsk, TIF_ABI_PENDING);

		if (test_tsk_thread_flag(tsk, TIF_IA32)) {

			clear_tsk_thread_flag(tsk, TIF_IA32);

		} else {

			set_tsk_thread_flag(tsk, TIF_IA32);

			current_thread_info()->status |= TS_COMPAT;

		}

	}

#endif



	clear_tsk_thread_flag(tsk, TIF_DEBUG);



	tsk->thread.debugreg0 = 0;

	tsk->thread.debugreg1 = 0;

	tsk->thread.debugreg2 = 0;

	tsk->thread.debugreg3 = 0;

	tsk->thread.debugreg6 = 0;

	tsk->thread.debugreg7 = 0;

	memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));

	/*

	 * Forget coprocessor state..

	 */

	tsk->fpu_counter = 0;

	clear_fpu(tsk);

	clear_used_math();

}



static void hard_disable_TSC(void)

{

	write_cr4(read_cr4() | X86_CR4_TSD);

}



void disable_TSC(void)

{

	preempt_disable();

	if (!test_and_set_thread_flag(TIF_NOTSC))

		/*

		 * Must flip the CPU state synchronously with

		 * TIF_NOTSC in the current running context.

		 */

		hard_disable_TSC();

	preempt_enable();

}



static void hard_enable_TSC(void)

{

	write_cr4(read_cr4() & ~X86_CR4_TSD);

}



static void enable_TSC(void)

{

	preempt_disable();

	if (test_and_clear_thread_flag(TIF_NOTSC))

		/*

		 * Must flip the CPU state synchronously with

		 * TIF_NOTSC in the current running context.

		 */

		hard_enable_TSC();

	preempt_enable();

}



int get_tsc_mode(unsigned long adr)

{

	unsigned int val;



	if (test_thread_flag(TIF_NOTSC))

		val = PR_TSC_SIGSEGV;

	else

		val = PR_TSC_ENABLE;



	return put_user(val, (unsigned int __user *)adr);

}



int set_tsc_mode(unsigned int val)

{

	if (val == PR_TSC_SIGSEGV)

		disable_TSC();

	else if (val == PR_TSC_ENABLE)

		enable_TSC();

	else

		return -EINVAL;



	return 0;

}



void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,

		      struct tss_struct *tss)

{

	struct thread_struct *prev, *next;



	prev = &prev_p->thread;

	next = &next_p->thread;



	if (test_tsk_thread_flag(next_p, TIF_DS_AREA_MSR) ||

	    test_tsk_thread_flag(prev_p, TIF_DS_AREA_MSR))

		ds_switch_to(prev_p, next_p);

	else if (next->debugctlmsr != prev->debugctlmsr)

		update_debugctlmsr(next->debugctlmsr);



	if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {

		set_debugreg(next->debugreg0, 0);

		set_debugreg(next->debugreg1, 1);

		set_debugreg(next->debugreg2, 2);

		set_debugreg(next->debugreg3, 3);

		/* no 4 and 5 */

		set_debugreg(next->debugreg6, 6);

		set_debugreg(next->debugreg7, 7);

	}



	if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^

	    test_tsk_thread_flag(next_p, TIF_NOTSC)) {

		/* prev and next are different */

		if (test_tsk_thread_flag(next_p, TIF_NOTSC))

			hard_disable_TSC();

		else

			hard_enable_TSC();

	}



	if (test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {

		/*

		 * Copy the relevant range of the IO bitmap.

		 * Normally this is 128 bytes or less:

		 */

		memcpy(tss->io_bitmap, next->io_bitmap_ptr,

		       max(prev->io_bitmap_max, next->io_bitmap_max));

	} else if (test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) {

		/*

		 * Clear any possible leftover bits:

		 */

		memset(tss->io_bitmap, 0xff, prev->io_bitmap_max);

	}

}



int sys_fork(struct pt_regs *regs)

{

	return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);

}



/*

 * 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.

 */

int sys_vfork(struct pt_regs *regs)

{

	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs, 0,

		       NULL, NULL);

}





/*

 * Idle related variables and functions

 */

arch/x86/kernel/process_32.c

+0 −172
Original line number Diff line number Diff line
@@ -230,52 +230,6 @@ int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) 
}

EXPORT_SYMBOL(kernel_thread);



/*

 * Free current thread data structures etc..

 */

void exit_thread(void)

{

	/* The process may have allocated an io port bitmap... nuke it. */

	if (unlikely(test_thread_flag(TIF_IO_BITMAP))) {

		struct task_struct *tsk = current;

		struct thread_struct *t = &tsk->thread;

		int cpu = get_cpu();

		struct tss_struct *tss = &per_cpu(init_tss, cpu);



		kfree(t->io_bitmap_ptr);

		t->io_bitmap_ptr = NULL;

		clear_thread_flag(TIF_IO_BITMAP);

		/*

		 * Careful, clear this in the TSS too:

		 */

		memset(tss->io_bitmap, 0xff, t->io_bitmap_max);

		t->io_bitmap_max = 0;

		put_cpu();

	}



	ds_exit_thread(current);

}



void flush_thread(void)

{

	struct task_struct *tsk = current;



	tsk->thread.debugreg0 = 0;

	tsk->thread.debugreg1 = 0;

	tsk->thread.debugreg2 = 0;

	tsk->thread.debugreg3 = 0;

	tsk->thread.debugreg6 = 0;

	tsk->thread.debugreg7 = 0;

	memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));

	clear_tsk_thread_flag(tsk, TIF_DEBUG);

	/*

	 * Forget coprocessor state..

	 */

	tsk->fpu_counter = 0;

	clear_fpu(tsk);

	clear_used_math();

}



void release_thread(struct task_struct *dead_task)

{

	BUG_ON(dead_task->mm);
@@ -363,112 +317,6 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp) 
}

EXPORT_SYMBOL_GPL(start_thread);



static void hard_disable_TSC(void)

{

	write_cr4(read_cr4() | X86_CR4_TSD);

}



void disable_TSC(void)

{

	preempt_disable();

	if (!test_and_set_thread_flag(TIF_NOTSC))

		/*

		 * Must flip the CPU state synchronously with

		 * TIF_NOTSC in the current running context.

		 */

		hard_disable_TSC();

	preempt_enable();

}



static void hard_enable_TSC(void)

{

	write_cr4(read_cr4() & ~X86_CR4_TSD);

}



static void enable_TSC(void)

{

	preempt_disable();

	if (test_and_clear_thread_flag(TIF_NOTSC))

		/*

		 * Must flip the CPU state synchronously with

		 * TIF_NOTSC in the current running context.

		 */

		hard_enable_TSC();

	preempt_enable();

}



int get_tsc_mode(unsigned long adr)

{

	unsigned int val;



	if (test_thread_flag(TIF_NOTSC))

		val = PR_TSC_SIGSEGV;

	else

		val = PR_TSC_ENABLE;



	return put_user(val, (unsigned int __user *)adr);

}



int set_tsc_mode(unsigned int val)

{

	if (val == PR_TSC_SIGSEGV)

		disable_TSC();

	else if (val == PR_TSC_ENABLE)

		enable_TSC();

	else

		return -EINVAL;



	return 0;

}



static noinline void

__switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,

		 struct tss_struct *tss)

{

	struct thread_struct *prev, *next;



	prev = &prev_p->thread;

	next = &next_p->thread;



	if (test_tsk_thread_flag(next_p, TIF_DS_AREA_MSR) ||

	    test_tsk_thread_flag(prev_p, TIF_DS_AREA_MSR))

		ds_switch_to(prev_p, next_p);

	else if (next->debugctlmsr != prev->debugctlmsr)

		update_debugctlmsr(next->debugctlmsr);



	if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {

		set_debugreg(next->debugreg0, 0);

		set_debugreg(next->debugreg1, 1);

		set_debugreg(next->debugreg2, 2);

		set_debugreg(next->debugreg3, 3);

		/* no 4 and 5 */

		set_debugreg(next->debugreg6, 6);

		set_debugreg(next->debugreg7, 7);

	}



	if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^

	    test_tsk_thread_flag(next_p, TIF_NOTSC)) {

		/* prev and next are different */

		if (test_tsk_thread_flag(next_p, TIF_NOTSC))

			hard_disable_TSC();

		else

			hard_enable_TSC();

	}



	if (test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {

		/*

		 * Copy the relevant range of the IO bitmap.

		 * Normally this is 128 bytes or less:

		 */

		memcpy(tss->io_bitmap, next->io_bitmap_ptr,

		       max(prev->io_bitmap_max, next->io_bitmap_max));

	} else if (test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) {

		/*

		 * Clear any possible leftover bits:

		 */

		memset(tss->io_bitmap, 0xff, prev->io_bitmap_max);

	}

}



/*

 *	switch_to(x,yn) should switch tasks from x to y.
@@ -582,11 +430,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) 
	return prev_p;

}



int sys_fork(struct pt_regs *regs)

{

	return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);

}



int sys_clone(struct pt_regs *regs)

{

	unsigned long clone_flags;
@@ -602,21 +445,6 @@ int sys_clone(struct pt_regs *regs) 
	return do_fork(clone_flags, newsp, regs, 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.

 */

int sys_vfork(struct pt_regs *regs)

{

	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs, 0, NULL, NULL);

}



/*

 * sys_execve() executes a new program.

 */

arch/x86/kernel/process_64.c

+0 −188
Original line number Diff line number Diff line
@@ -237,61 +237,6 @@ void show_regs(struct pt_regs *regs) 
	show_trace(NULL, regs, (void *)(regs + 1), regs->bp);

}



/*

 * Free current thread data structures etc..

 */

void exit_thread(void)

{

	struct task_struct *me = current;

	struct thread_struct *t = &me->thread;



	if (me->thread.io_bitmap_ptr) {

		struct tss_struct *tss = &per_cpu(init_tss, get_cpu());



		kfree(t->io_bitmap_ptr);

		t->io_bitmap_ptr = NULL;

		clear_thread_flag(TIF_IO_BITMAP);

		/*

		 * Careful, clear this in the TSS too:

		 */

		memset(tss->io_bitmap, 0xff, t->io_bitmap_max);

		t->io_bitmap_max = 0;

		put_cpu();

	}



	ds_exit_thread(current);

}



void flush_thread(void)

{

	struct task_struct *tsk = current;



	if (test_tsk_thread_flag(tsk, TIF_ABI_PENDING)) {

		clear_tsk_thread_flag(tsk, TIF_ABI_PENDING);

		if (test_tsk_thread_flag(tsk, TIF_IA32)) {

			clear_tsk_thread_flag(tsk, TIF_IA32);

		} else {

			set_tsk_thread_flag(tsk, TIF_IA32);

			current_thread_info()->status |= TS_COMPAT;

		}

	}

	clear_tsk_thread_flag(tsk, TIF_DEBUG);



	tsk->thread.debugreg0 = 0;

	tsk->thread.debugreg1 = 0;

	tsk->thread.debugreg2 = 0;

	tsk->thread.debugreg3 = 0;

	tsk->thread.debugreg6 = 0;

	tsk->thread.debugreg7 = 0;

	memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));

	/*

	 * Forget coprocessor state..

	 */

	tsk->fpu_counter = 0;

	clear_fpu(tsk);

	clear_used_math();

}



void release_thread(struct task_struct *dead_task)

{

	if (dead_task->mm) {
@@ -425,118 +370,6 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp) 
}

EXPORT_SYMBOL_GPL(start_thread);



static void hard_disable_TSC(void)

{

	write_cr4(read_cr4() | X86_CR4_TSD);

}



void disable_TSC(void)

{

	preempt_disable();

	if (!test_and_set_thread_flag(TIF_NOTSC))

		/*

		 * Must flip the CPU state synchronously with

		 * TIF_NOTSC in the current running context.

		 */

		hard_disable_TSC();

	preempt_enable();

}



static void hard_enable_TSC(void)

{

	write_cr4(read_cr4() & ~X86_CR4_TSD);

}



static void enable_TSC(void)

{

	preempt_disable();

	if (test_and_clear_thread_flag(TIF_NOTSC))

		/*

		 * Must flip the CPU state synchronously with

		 * TIF_NOTSC in the current running context.

		 */

		hard_enable_TSC();

	preempt_enable();

}



int get_tsc_mode(unsigned long adr)

{

	unsigned int val;



	if (test_thread_flag(TIF_NOTSC))

		val = PR_TSC_SIGSEGV;

	else

		val = PR_TSC_ENABLE;



	return put_user(val, (unsigned int __user *)adr);

}



int set_tsc_mode(unsigned int val)

{

	if (val == PR_TSC_SIGSEGV)

		disable_TSC();

	else if (val == PR_TSC_ENABLE)

		enable_TSC();

	else

		return -EINVAL;



	return 0;

}



/*

 * This special macro can be used to load a debugging register

 */

#define loaddebug(thread, r) set_debugreg(thread->debugreg ## r, r)



static inline void __switch_to_xtra(struct task_struct *prev_p,

				    struct task_struct *next_p,

				    struct tss_struct *tss)

{

	struct thread_struct *prev, *next;



	prev = &prev_p->thread,

	next = &next_p->thread;



	if (test_tsk_thread_flag(next_p, TIF_DS_AREA_MSR) ||

	    test_tsk_thread_flag(prev_p, TIF_DS_AREA_MSR))

		ds_switch_to(prev_p, next_p);

	else if (next->debugctlmsr != prev->debugctlmsr)

		update_debugctlmsr(next->debugctlmsr);



	if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {

		loaddebug(next, 0);

		loaddebug(next, 1);

		loaddebug(next, 2);

		loaddebug(next, 3);

		/* no 4 and 5 */

		loaddebug(next, 6);

		loaddebug(next, 7);

	}



	if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^

	    test_tsk_thread_flag(next_p, TIF_NOTSC)) {

		/* prev and next are different */

		if (test_tsk_thread_flag(next_p, TIF_NOTSC))

			hard_disable_TSC();

		else

			hard_enable_TSC();

	}



	if (test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) {

		/*

		 * Copy the relevant range of the IO bitmap.

		 * Normally this is 128 bytes or less:

		 */

		memcpy(tss->io_bitmap, next->io_bitmap_ptr,

		       max(prev->io_bitmap_max, next->io_bitmap_max));

	} else if (test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) {

		/*

		 * Clear any possible leftover bits:

		 */

		memset(tss->io_bitmap, 0xff, prev->io_bitmap_max);

	}

}



/*

 *	switch_to(x,y) should switch tasks from x to y.

 *
@@ -694,11 +527,6 @@ void set_personality_64bit(void) 
	current->personality &= ~READ_IMPLIES_EXEC;

}



asmlinkage long sys_fork(struct pt_regs *regs)

{

	return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);

}



asmlinkage long

sys_clone(unsigned long clone_flags, unsigned long newsp,

	  void __user *parent_tid, void __user *child_tid, struct pt_regs *regs)
@@ -708,22 +536,6 @@ sys_clone(unsigned long clone_flags, unsigned long newsp, 
	return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid);

}



/*

 * 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 long sys_vfork(struct pt_regs *regs)

{

	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs, 0,

		    NULL, NULL);

}



unsigned long get_wchan(struct task_struct *p)

{

	unsigned long stack;

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