arch/arm64/kernel/process.c - maze/linux - Git at Google

 /*
  * Based on arch/arm/kernel/process.c
  *
  * Original Copyright (C) 1995  Linus Torvalds
  * Copyright (C) 1996-2000 Russell King - Converted to ARM.
  * Copyright (C) 2012 ARM Ltd.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */

 #include <stdarg.h>

 #include <linux/export.h>
 #include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/stddef.h>
 #include <linux/unistd.h>
 #include <linux/user.h>
 #include <linux/delay.h>
 #include <linux/reboot.h>
 #include <linux/interrupt.h>
 #include <linux/kallsyms.h>
 #include <linux/init.h>
 #include <linux/cpu.h>
 #include <linux/elfcore.h>
 #include <linux/pm.h>
 #include <linux/tick.h>
 #include <linux/utsname.h>
 #include <linux/uaccess.h>
 #include <linux/random.h>
 #include <linux/hw_breakpoint.h>
 #include <linux/personality.h>
 #include <linux/notifier.h>

 #include <asm/compat.h>
 #include <asm/cacheflush.h>
 #include <asm/fpsimd.h>
 #include <asm/mmu_context.h>
 #include <asm/processor.h>
 #include <asm/stacktrace.h>

 static void setup_restart(void)
 {
 	/*
 	 * Tell the mm system that we are going to reboot -
 	 * we may need it to insert some 1:1 mappings so that
 	 * soft boot works.
 	 */
 	setup_mm_for_reboot();

 	/* Clean and invalidate caches */
 	flush_cache_all();

 	/* Turn D-cache off */
 	cpu_cache_off();

 	/* Push out any further dirty data, and ensure cache is empty */
 	flush_cache_all();
 }

 void soft_restart(unsigned long addr)
 {
 	setup_restart();
 	cpu_reset(addr);
 }

 /*
  * Function pointers to optional machine specific functions
  */
 void (*pm_power_off)(void);
 EXPORT_SYMBOL_GPL(pm_power_off);

 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
 EXPORT_SYMBOL_GPL(arm_pm_restart);

 void arch_cpu_idle_prepare(void)
 {
 	local_fiq_enable();
 }

 /*
  * This is our default idle handler.
  */
 void arch_cpu_idle(void)
 {
 	/*
 	 * This should do all the clock switching and wait for interrupt
 	 * tricks
 	 */
 	cpu_do_idle();
 	local_irq_enable();
 }

 void machine_shutdown(void)
 {
 #ifdef CONFIG_SMP
 	smp_send_stop();
 #endif
 }

 void machine_halt(void)
 {
 	machine_shutdown();
 	while (1);
 }

 void machine_power_off(void)
 {
 	machine_shutdown();
 	if (pm_power_off)
 		pm_power_off();
 }

 void machine_restart(char *cmd)
 {
 	machine_shutdown();

 	/* Disable interrupts first */
 	local_irq_disable();
 	local_fiq_disable();

 	/* Now call the architecture specific reboot code. */
 	if (arm_pm_restart)
 		arm_pm_restart(reboot_mode, cmd);

 	/*
 	 * Whoops - the architecture was unable to reboot.
 	 */
 	printk("Reboot failed -- System halted\n");
 	while (1);
 }

 void __show_regs(struct pt_regs *regs)
 {
 	int i;

 	show_regs_print_info(KERN_DEFAULT);
 	print_symbol("PC is at %s\n", instruction_pointer(regs));
 	print_symbol("LR is at %s\n", regs->regs[30]);
 	printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
 	       regs->pc, regs->regs[30], regs->pstate);
 	printk("sp : %016llx\n", regs->sp);
 	for (i = 29; i >= 0; i--) {
 		printk("x%-2d: %016llx ", i, regs->regs[i]);
 		if (i % 2 == 0)
 			printk("\n");
 	}
 	printk("\n");
 }

 void show_regs(struct pt_regs * regs)
 {
 	printk("\n");
 	__show_regs(regs);
 }

 /*
  * Free current thread data structures etc..
  */
 void exit_thread(void)
 {
 }

 void flush_thread(void)
 {
 	fpsimd_flush_thread();
 	flush_ptrace_hw_breakpoint(current);
 }

 void release_thread(struct task_struct *dead_task)
 {
 }

 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 {
 	fpsimd_save_state(&current->thread.fpsimd_state);
 	*dst = *src;
 	return 0;
 }

 asmlinkage void ret_from_fork(void) asm("ret_from_fork");

 int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 		unsigned long stk_sz, struct task_struct *p)
 {
 	struct pt_regs *childregs = task_pt_regs(p);
 	unsigned long tls = p->thread.tp_value;

 	memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));

 	if (likely(!(p->flags & PF_KTHREAD))) {
 		*childregs = *current_pt_regs();
 		childregs->regs[0] = 0;
 		if (is_compat_thread(task_thread_info(p))) {
 			if (stack_start)
 				childregs->compat_sp = stack_start;
 		} else {
 			/*
 			 * Read the current TLS pointer from tpidr_el0 as it may be
 			 * out-of-sync with the saved value.
 			 */
 			asm("mrs %0, tpidr_el0" : "=r" (tls));
 			if (stack_start) {
 				/* 16-byte aligned stack mandatory on AArch64 */
 				if (stack_start & 15)
 					return -EINVAL;
 				childregs->sp = stack_start;
 			}
 		}
 		/*
 		 * If a TLS pointer was passed to clone (4th argument), use it
 		 * for the new thread.
 		 */
 		if (clone_flags & CLONE_SETTLS)
 			tls = childregs->regs[3];
 	} else {
 		memset(childregs, 0, sizeof(struct pt_regs));
 		childregs->pstate = PSR_MODE_EL1h;
 		p->thread.cpu_context.x19 = stack_start;
 		p->thread.cpu_context.x20 = stk_sz;
 	}
 	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 	p->thread.cpu_context.sp = (unsigned long)childregs;
 	p->thread.tp_value = tls;

 	ptrace_hw_copy_thread(p);

 	return 0;
 }

 static void tls_thread_switch(struct task_struct *next)
 {
 	unsigned long tpidr, tpidrro;

 	if (!is_compat_task()) {
 		asm("mrs %0, tpidr_el0" : "=r" (tpidr));
 		current->thread.tp_value = tpidr;
 	}

 	if (is_compat_thread(task_thread_info(next))) {
 		tpidr = 0;
 		tpidrro = next->thread.tp_value;
 	} else {
 		tpidr = next->thread.tp_value;
 		tpidrro = 0;
 	}

 	asm(
 	"	msr	tpidr_el0, %0\n"
 	"	msr	tpidrro_el0, %1"
 	: : "r" (tpidr), "r" (tpidrro));
 }

 /*
  * Thread switching.
  */
 struct task_struct *__switch_to(struct task_struct *prev,
 				struct task_struct *next)
 {
 	struct task_struct *last;

 	fpsimd_thread_switch(next);
 	tls_thread_switch(next);
 	hw_breakpoint_thread_switch(next);
 	contextidr_thread_switch(next);

 	/*
 	 * Complete any pending TLB or cache maintenance on this CPU in case
 	 * the thread migrates to a different CPU.
 	 */
 	dsb();

 	/* the actual thread switch */
 	last = cpu_switch_to(prev, next);

 	return last;
 }

 unsigned long get_wchan(struct task_struct *p)
 {
 	struct stackframe frame;
 	int count = 0;
 	if (!p || p == current || p->state == TASK_RUNNING)
 		return 0;

 	frame.fp = thread_saved_fp(p);
 	frame.sp = thread_saved_sp(p);
 	frame.pc = thread_saved_pc(p);
 	do {
 		int ret = unwind_frame(&frame);
 		if (ret < 0)
 			return 0;
 		if (!in_sched_functions(frame.pc))
 			return frame.pc;
 	} while (count ++ < 16);
 	return 0;
 }

 unsigned long arch_align_stack(unsigned long sp)
 {
 	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 		sp -= get_random_int() & ~PAGE_MASK;
 	return sp & ~0xf;
 }

 static unsigned long randomize_base(unsigned long base)
 {
 	unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1;
 	return randomize_range(base, range_end, 0) ? : base;
 }

 unsigned long arch_randomize_brk(struct mm_struct *mm)
 {
 	return randomize_base(mm->brk);
 }

 unsigned long randomize_et_dyn(unsigned long base)
 {
 	return randomize_base(base);
 }
	/*
	* Based on arch/arm/kernel/process.c
	*
	* Original Copyright (C) 1995 Linus Torvalds
	* Copyright (C) 1996-2000 Russell King - Converted to ARM.
	* Copyright (C) 2012 ARM Ltd.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	*/

	#include <stdarg.h>

	#include <linux/export.h>
	#include <linux/sched.h>
	#include <linux/kernel.h>
	#include <linux/mm.h>
	#include <linux/stddef.h>
	#include <linux/unistd.h>
	#include <linux/user.h>
	#include <linux/delay.h>
	#include <linux/reboot.h>
	#include <linux/interrupt.h>
	#include <linux/kallsyms.h>
	#include <linux/init.h>
	#include <linux/cpu.h>
	#include <linux/elfcore.h>
	#include <linux/pm.h>
	#include <linux/tick.h>
	#include <linux/utsname.h>
	#include <linux/uaccess.h>
	#include <linux/random.h>
	#include <linux/hw_breakpoint.h>
	#include <linux/personality.h>
	#include <linux/notifier.h>

	#include <asm/compat.h>
	#include <asm/cacheflush.h>
	#include <asm/fpsimd.h>
	#include <asm/mmu_context.h>
	#include <asm/processor.h>
	#include <asm/stacktrace.h>

	static void setup_restart(void)
	{
	/*
	* Tell the mm system that we are going to reboot -
	* we may need it to insert some 1:1 mappings so that
	* soft boot works.
	*/
	setup_mm_for_reboot();

	/* Clean and invalidate caches */
	flush_cache_all();

	/* Turn D-cache off */
	cpu_cache_off();

	/* Push out any further dirty data, and ensure cache is empty */
	flush_cache_all();
	}

	void soft_restart(unsigned long addr)
	{
	setup_restart();
	cpu_reset(addr);
	}

	/*
	* Function pointers to optional machine specific functions
	*/
	void (*pm_power_off)(void);
	EXPORT_SYMBOL_GPL(pm_power_off);

	void (arm_pm_restart)(enum reboot_mode reboot_mode, const char cmd);
	EXPORT_SYMBOL_GPL(arm_pm_restart);

	void arch_cpu_idle_prepare(void)
	{
	local_fiq_enable();
	}

	/*
	* This is our default idle handler.
	*/
	void arch_cpu_idle(void)
	{
	/*
	* This should do all the clock switching and wait for interrupt
	* tricks
	*/
	cpu_do_idle();
	local_irq_enable();
	}

	void machine_shutdown(void)
	{
	#ifdef CONFIG_SMP
	smp_send_stop();
	#endif
	}

	void machine_halt(void)
	{
	machine_shutdown();
	while (1);
	}

	void machine_power_off(void)
	{
	machine_shutdown();
	if (pm_power_off)
	pm_power_off();
	}

	void machine_restart(char *cmd)
	{
	machine_shutdown();

	/* Disable interrupts first */
	local_irq_disable();
	local_fiq_disable();

	/* Now call the architecture specific reboot code. */
	if (arm_pm_restart)
	arm_pm_restart(reboot_mode, cmd);

	/*
	* Whoops - the architecture was unable to reboot.
	*/
	printk("Reboot failed -- System halted\n");
	while (1);
	}

	void __show_regs(struct pt_regs *regs)
	{
	int i;

	show_regs_print_info(KERN_DEFAULT);
	print_symbol("PC is at %s\n", instruction_pointer(regs));
	print_symbol("LR is at %s\n", regs->regs[30]);
	printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
	regs->pc, regs->regs[30], regs->pstate);
	printk("sp : %016llx\n", regs->sp);
	for (i = 29; i >= 0; i--) {
	printk("x%-2d: %016llx ", i, regs->regs[i]);
	if (i % 2 == 0)
	printk("\n");
	}
	printk("\n");
	}

	void show_regs(struct pt_regs * regs)
	{
	printk("\n");
	__show_regs(regs);
	}

	/*
	* Free current thread data structures etc..
	*/
	void exit_thread(void)
	{
	}

	void flush_thread(void)
	{
	fpsimd_flush_thread();
	flush_ptrace_hw_breakpoint(current);
	}

	void release_thread(struct task_struct *dead_task)
	{
	}

	int arch_dup_task_struct(struct task_struct dst, struct task_struct src)
	{
	fpsimd_save_state(&current->thread.fpsimd_state);
	dst = src;
	return 0;
	}

	asmlinkage void ret_from_fork(void) asm("ret_from_fork");

	int copy_thread(unsigned long clone_flags, unsigned long stack_start,
	unsigned long stk_sz, struct task_struct *p)
	{
	struct pt_regs *childregs = task_pt_regs(p);
	unsigned long tls = p->thread.tp_value;

	memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));

	if (likely(!(p->flags & PF_KTHREAD))) {
	childregs = current_pt_regs();
	childregs->regs[0] = 0;
	if (is_compat_thread(task_thread_info(p))) {
	if (stack_start)
	childregs->compat_sp = stack_start;
	} else {
	/*
	* Read the current TLS pointer from tpidr_el0 as it may be
	* out-of-sync with the saved value.
	*/
	asm("mrs %0, tpidr_el0" : "=r" (tls));
	if (stack_start) {
	/* 16-byte aligned stack mandatory on AArch64 */
	if (stack_start & 15)
	return -EINVAL;
	childregs->sp = stack_start;
	}
	}
	/*
	* If a TLS pointer was passed to clone (4th argument), use it
	* for the new thread.
	*/
	if (clone_flags & CLONE_SETTLS)
	tls = childregs->regs[3];
	} else {
	memset(childregs, 0, sizeof(struct pt_regs));
	childregs->pstate = PSR_MODE_EL1h;
	p->thread.cpu_context.x19 = stack_start;
	p->thread.cpu_context.x20 = stk_sz;
	}
	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
	p->thread.cpu_context.sp = (unsigned long)childregs;
	p->thread.tp_value = tls;

	ptrace_hw_copy_thread(p);

	return 0;
	}

	static void tls_thread_switch(struct task_struct *next)
	{
	unsigned long tpidr, tpidrro;

	if (!is_compat_task()) {
	asm("mrs %0, tpidr_el0" : "=r" (tpidr));
	current->thread.tp_value = tpidr;
	}

	if (is_compat_thread(task_thread_info(next))) {
	tpidr = 0;
	tpidrro = next->thread.tp_value;
	} else {
	tpidr = next->thread.tp_value;
	tpidrro = 0;
	}

	asm(
	" msr tpidr_el0, %0\n"
	" msr tpidrro_el0, %1"
	: : "r" (tpidr), "r" (tpidrro));
	}

	/*
	* Thread switching.
	*/
	struct task_struct __switch_to(struct task_struct prev,
	struct task_struct *next)
	{
	struct task_struct *last;

	fpsimd_thread_switch(next);
	tls_thread_switch(next);
	hw_breakpoint_thread_switch(next);
	contextidr_thread_switch(next);

	/*
	* Complete any pending TLB or cache maintenance on this CPU in case
	* the thread migrates to a different CPU.
	*/
	dsb();

	/* the actual thread switch */
	last = cpu_switch_to(prev, next);

	return last;
	}

	unsigned long get_wchan(struct task_struct *p)
	{
	struct stackframe frame;
	int count = 0;
	if (!p \|\| p == current \|\| p->state == TASK_RUNNING)
	return 0;

	frame.fp = thread_saved_fp(p);
	frame.sp = thread_saved_sp(p);
	frame.pc = thread_saved_pc(p);
	do {
	int ret = unwind_frame(&frame);
	if (ret < 0)
	return 0;
	if (!in_sched_functions(frame.pc))
	return frame.pc;
	} while (count ++ < 16);
	return 0;
	}

	unsigned long arch_align_stack(unsigned long sp)
	{
	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
	sp -= get_random_int() & ~PAGE_MASK;
	return sp & ~0xf;
	}

	static unsigned long randomize_base(unsigned long base)
	{
	unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1;
	return randomize_range(base, range_end, 0) ? : base;
	}

	unsigned long arch_randomize_brk(struct mm_struct *mm)
	{
	return randomize_base(mm->brk);
	}

	unsigned long randomize_et_dyn(unsigned long base)
	{
	return randomize_base(base);
	}