[mirror_ubuntu-bionic-kernel.git] / arch / unicore32 / kernel / process.c

/*
 * linux/arch/unicore32/kernel/process.c
 *
 * Code specific to PKUnity SoC and UniCore ISA
 *
 * Copyright (C) 2001-2010 GUAN Xue-tao
 *
 * 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.
 */
#include <stdarg.h>

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/task.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.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/gpio.h>
#include <linux/stacktrace.h>

#include <asm/cacheflush.h>
#include <asm/processor.h>
#include <asm/stacktrace.h>

#include "setup.h"

static const char * const processor_modes[] = {
	"UK00", "UK01", "UK02", "UK03", "UK04", "UK05", "UK06", "UK07",
	"UK08", "UK09", "UK0A", "UK0B", "UK0C", "UK0D", "UK0E", "UK0F",
	"USER", "REAL", "INTR", "PRIV", "UK14", "UK15", "UK16", "ABRT",
	"UK18", "UK19", "UK1A", "EXTN", "UK1C", "UK1D", "UK1E", "SUSR"
};

void arch_cpu_idle(void)
{
	cpu_do_idle();
	local_irq_enable();
}

void machine_halt(void)
{
	gpio_set_value(GPO_SOFT_OFF, 0);
}

/*
 * Function pointers to optional machine specific functions
 */
void (*pm_power_off)(void) = NULL;
EXPORT_SYMBOL(pm_power_off);

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

void machine_restart(char *cmd)
{
	/* Disable interrupts first */
	local_irq_disable();

	/*
	 * 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 off caching */
	cpu_proc_fin();

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

	/*
	 * Now handle reboot code.
	 */
	if (reboot_mode == REBOOT_SOFT) {
		/* Jump into ROM at address 0xffff0000 */
		cpu_reset(VECTORS_BASE);
	} else {
		writel(0x00002001, PM_PLLSYSCFG); /* cpu clk = 250M */
		writel(0x00100800, PM_PLLDDRCFG); /* ddr clk =  44M */
		writel(0x00002001, PM_PLLVGACFG); /* vga clk = 250M */

		/* Use on-chip reset capability */
		/* following instructions must be in one icache line */
		__asm__ __volatile__(
			"	.align 5\n\t"
			"	stw	%1, [%0]\n\t"
			"201:	ldw	r0, [%0]\n\t"
			"	cmpsub.a	r0, #0\n\t"
			"	bne	201b\n\t"
			"	stw	%3, [%2]\n\t"
			"	nop; nop; nop\n\t"
			/* prefetch 3 instructions at most */
			:
			: "r" (PM_PMCR),
			  "r" (PM_PMCR_CFBSYS | PM_PMCR_CFBDDR
				| PM_PMCR_CFBVGA),
			  "r" (RESETC_SWRR),
			  "r" (RESETC_SWRR_SRB)
			: "r0", "memory");
	}

	/*
	 * Whoops - the architecture was unable to reboot.
	 * Tell the user!
	 */
	mdelay(1000);
	printk(KERN_EMERG "Reboot failed -- System halted\n");
	do { } while (1);
}

void __show_regs(struct pt_regs *regs)
{
	unsigned long flags;
	char buf[64];

	show_regs_print_info(KERN_DEFAULT);
	print_symbol("PC is at %s\n", instruction_pointer(regs));
	print_symbol("LR is at %s\n", regs->UCreg_lr);
	printk(KERN_DEFAULT "pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
	       "sp : %08lx  ip : %08lx  fp : %08lx\n",
		regs->UCreg_pc, regs->UCreg_lr, regs->UCreg_asr,
		regs->UCreg_sp, regs->UCreg_ip, regs->UCreg_fp);
	printk(KERN_DEFAULT "r26: %08lx  r25: %08lx  r24: %08lx\n",
		regs->UCreg_26, regs->UCreg_25,
		regs->UCreg_24);
	printk(KERN_DEFAULT "r23: %08lx  r22: %08lx  r21: %08lx  r20: %08lx\n",
		regs->UCreg_23, regs->UCreg_22,
		regs->UCreg_21, regs->UCreg_20);
	printk(KERN_DEFAULT "r19: %08lx  r18: %08lx  r17: %08lx  r16: %08lx\n",
		regs->UCreg_19, regs->UCreg_18,
		regs->UCreg_17, regs->UCreg_16);
	printk(KERN_DEFAULT "r15: %08lx  r14: %08lx  r13: %08lx  r12: %08lx\n",
		regs->UCreg_15, regs->UCreg_14,
		regs->UCreg_13, regs->UCreg_12);
	printk(KERN_DEFAULT "r11: %08lx  r10: %08lx  r9 : %08lx  r8 : %08lx\n",
		regs->UCreg_11, regs->UCreg_10,
		regs->UCreg_09, regs->UCreg_08);
	printk(KERN_DEFAULT "r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
		regs->UCreg_07, regs->UCreg_06,
		regs->UCreg_05, regs->UCreg_04);
	printk(KERN_DEFAULT "r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
		regs->UCreg_03, regs->UCreg_02,
		regs->UCreg_01, regs->UCreg_00);

	flags = regs->UCreg_asr;
	buf[0] = flags & PSR_S_BIT ? 'S' : 's';
	buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
	buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
	buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
	buf[4] = '\0';

	printk(KERN_DEFAULT "Flags: %s  INTR o%s  REAL o%s  Mode %s  Segment %s\n",
		buf, interrupts_enabled(regs) ? "n" : "ff",
		fast_interrupts_enabled(regs) ? "n" : "ff",
		processor_modes[processor_mode(regs)],
		segment_eq(get_fs(), get_ds()) ? "kernel" : "user");
	{
		unsigned int ctrl;

		buf[0] = '\0';
		{
			unsigned int transbase;
			asm("movc %0, p0.c2, #0\n"
			    : "=r" (transbase));
			snprintf(buf, sizeof(buf), "  Table: %08x", transbase);
		}
		asm("movc %0, p0.c1, #0\n" : "=r" (ctrl));

		printk(KERN_DEFAULT "Control: %08x%s\n", ctrl, buf);
	}
}

void show_regs(struct pt_regs *regs)
{
	printk(KERN_DEFAULT "\n");
	printk(KERN_DEFAULT "Pid: %d, comm: %20s\n",
			task_pid_nr(current), current->comm);
	__show_regs(regs);
	__backtrace();
}

void flush_thread(void)
{
	struct thread_info *thread = current_thread_info();
	struct task_struct *tsk = current;

	memset(thread->used_cp, 0, sizeof(thread->used_cp));
	memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
#ifdef CONFIG_UNICORE_FPU_F64
	memset(&thread->fpstate, 0, sizeof(struct fp_state));
#endif
}

void release_thread(struct task_struct *dead_task)
{
}

asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread");

int
copy_thread(unsigned long clone_flags, unsigned long stack_start,
	    unsigned long stk_sz, struct task_struct *p)
{
	struct thread_info *thread = task_thread_info(p);
	struct pt_regs *childregs = task_pt_regs(p);

	memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
	thread->cpu_context.sp = (unsigned long)childregs;
	if (unlikely(p->flags & PF_KTHREAD)) {
		thread->cpu_context.pc = (unsigned long)ret_from_kernel_thread;
		thread->cpu_context.r4 = stack_start;
		thread->cpu_context.r5 = stk_sz;
		memset(childregs, 0, sizeof(struct pt_regs));
	} else {
		thread->cpu_context.pc = (unsigned long)ret_from_fork;
		*childregs = *current_pt_regs();
		childregs->UCreg_00 = 0;
		if (stack_start)
			childregs->UCreg_sp = stack_start;

		if (clone_flags & CLONE_SETTLS)
			childregs->UCreg_16 = childregs->UCreg_03;
	}
	return 0;
}

/*
 * Fill in the task's elfregs structure for a core dump.
 */
int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
{
	elf_core_copy_regs(elfregs, task_pt_regs(t));
	return 1;
}

/*
 * fill in the fpe structure for a core dump...
 */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fp)
{
	struct thread_info *thread = current_thread_info();
	int used_math = thread->used_cp[1] | thread->used_cp[2];

#ifdef CONFIG_UNICORE_FPU_F64
	if (used_math)
		memcpy(fp, &thread->fpstate, sizeof(*fp));
#endif
	return used_math != 0;
}
EXPORT_SYMBOL(dump_fpu);

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.lr = 0;			/* recovered from the stack */
	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_randomize_brk(struct mm_struct *mm)
{
	return randomize_page(mm->brk, 0x02000000);
}

/*
 * The vectors page is always readable from user space for the
 * atomic helpers and the signal restart code.  Let's declare a mapping
 * for it so it is visible through ptrace and /proc/<pid>/mem.
 */

int vectors_user_mapping(void)
{
	struct mm_struct *mm = current->mm;
	return install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
				       VM_READ | VM_EXEC |
				       VM_MAYREAD | VM_MAYEXEC |
				       VM_DONTEXPAND | VM_DONTDUMP,
				       NULL);
}

const char *arch_vma_name(struct vm_area_struct *vma)
{
	return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL;
}
Commit	Line	Data
f73670e8 G	1	/*
	2	* linux/arch/unicore32/kernel/process.c
	3	*
	4	* Code specific to PKUnity SoC and UniCore ISA
	5	*
	6	* Copyright (C) 2001-2010 GUAN Xue-tao
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
	12	#include <stdarg.h>
	13
	14	#include <linux/module.h>
	15	#include <linux/sched.h>
b17b0153	16	#include <linux/sched/debug.h>
29930025	17	#include <linux/sched/task.h>
f73670e8 G	18	#include <linux/kernel.h>
	19	#include <linux/mm.h>
	20	#include <linux/stddef.h>
	21	#include <linux/unistd.h>
	22	#include <linux/delay.h>
	23	#include <linux/reboot.h>
	24	#include <linux/interrupt.h>
	25	#include <linux/kallsyms.h>
	26	#include <linux/init.h>
	27	#include <linux/cpu.h>
	28	#include <linux/elfcore.h>
	29	#include <linux/pm.h>
	30	#include <linux/tick.h>
	31	#include <linux/utsname.h>
	32	#include <linux/uaccess.h>
	33	#include <linux/random.h>
	34	#include <linux/gpio.h>
	35	#include <linux/stacktrace.h>
	36
	37	#include <asm/cacheflush.h>
	38	#include <asm/processor.h>
f73670e8 G	39	#include <asm/stacktrace.h>
	40
	41	#include "setup.h"
	42
	43	static const char * const processor_modes[] = {
	44	"UK00", "UK01", "UK02", "UK03", "UK04", "UK05", "UK06", "UK07",
	45	"UK08", "UK09", "UK0A", "UK0B", "UK0C", "UK0D", "UK0E", "UK0F",
	46	"USER", "REAL", "INTR", "PRIV", "UK14", "UK15", "UK16", "ABRT",
	47	"UK18", "UK19", "UK1A", "EXTN", "UK1C", "UK1D", "UK1E", "SUSR"
	48	};
	49
aba92c9e	50	void arch_cpu_idle(void)
f73670e8	51	{
aba92c9e TG	52	cpu_do_idle();
aba92c9e TG	53	local_irq_enable();
f73670e8 G	54	}
f73670e8 G	55
f73670e8 G	56	void machine_halt(void)
	57	{
	58	gpio_set_value(GPO_SOFT_OFF, 0);
	59	}
	60
	61	/*
	62	* Function pointers to optional machine specific functions
	63	*/
	64	void (*pm_power_off)(void) = NULL;
3420d49d	65	EXPORT_SYMBOL(pm_power_off);
f73670e8 G	66
	67	void machine_power_off(void)
	68	{
	69	if (pm_power_off)
	70	pm_power_off();
	71	machine_halt();
	72	}
	73
	74	void machine_restart(char *cmd)
	75	{
	76	/* Disable interrupts first */
	77	local_irq_disable();
	78
	79	/*
	80	* Tell the mm system that we are going to reboot -
	81	* we may need it to insert some 1:1 mappings so that
	82	* soft boot works.
	83	*/
c97a7008	84	setup_mm_for_reboot();
f73670e8 G	85
	86	/* Clean and invalidate caches */
	87	flush_cache_all();
	88
	89	/* Turn off caching */
	90	cpu_proc_fin();
	91
	92	/* Push out any further dirty data, and ensure cache is empty */
	93	flush_cache_all();
	94
	95	/*
	96	* Now handle reboot code.
	97	*/
c97a7008	98	if (reboot_mode == REBOOT_SOFT) {
f73670e8 G	99	/* Jump into ROM at address 0xffff0000 */
	100	cpu_reset(VECTORS_BASE);
	101	} else {
e5abf78b G	102	writel(0x00002001, PM_PLLSYSCFG); /* cpu clk = 250M */
	103	writel(0x00100800, PM_PLLDDRCFG); /* ddr clk = 44M */
	104	writel(0x00002001, PM_PLLVGACFG); /* vga clk = 250M */
f73670e8 G	105
	106	/* Use on-chip reset capability */
	107	/* following instructions must be in one icache line */
	108	__asm__ __volatile__(
	109	" .align 5\n\t"
	110	" stw %1, [%0]\n\t"
	111	"201: ldw r0, [%0]\n\t"
	112	" cmpsub.a r0, #0\n\t"
	113	" bne 201b\n\t"
	114	" stw %3, [%2]\n\t"
	115	" nop; nop; nop\n\t"
	116	/* prefetch 3 instructions at most */
	117	:
e5abf78b	118	: "r" (PM_PMCR),
f73670e8 G	119	"r" (PM_PMCR_CFBSYS \| PM_PMCR_CFBDDR
f73670e8 G	120	\| PM_PMCR_CFBVGA),
e5abf78b	121	"r" (RESETC_SWRR),
f73670e8 G	122	"r" (RESETC_SWRR_SRB)
	123	: "r0", "memory");
	124	}
	125
	126	/*
	127	* Whoops - the architecture was unable to reboot.
	128	* Tell the user!
	129	*/
	130	mdelay(1000);
	131	printk(KERN_EMERG "Reboot failed -- System halted\n");
	132	do { } while (1);
	133	}
	134
	135	void __show_regs(struct pt_regs *regs)
	136	{
	137	unsigned long flags;
	138	char buf[64];
	139
a43cb95d	140	show_regs_print_info(KERN_DEFAULT);
f73670e8 G	141	print_symbol("PC is at %s\n", instruction_pointer(regs));
	142	print_symbol("LR is at %s\n", regs->UCreg_lr);
	143	printk(KERN_DEFAULT "pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n"
	144	"sp : %08lx ip : %08lx fp : %08lx\n",
	145	regs->UCreg_pc, regs->UCreg_lr, regs->UCreg_asr,
	146	regs->UCreg_sp, regs->UCreg_ip, regs->UCreg_fp);
	147	printk(KERN_DEFAULT "r26: %08lx r25: %08lx r24: %08lx\n",
	148	regs->UCreg_26, regs->UCreg_25,
	149	regs->UCreg_24);
	150	printk(KERN_DEFAULT "r23: %08lx r22: %08lx r21: %08lx r20: %08lx\n",
	151	regs->UCreg_23, regs->UCreg_22,
	152	regs->UCreg_21, regs->UCreg_20);
	153	printk(KERN_DEFAULT "r19: %08lx r18: %08lx r17: %08lx r16: %08lx\n",
	154	regs->UCreg_19, regs->UCreg_18,
	155	regs->UCreg_17, regs->UCreg_16);
	156	printk(KERN_DEFAULT "r15: %08lx r14: %08lx r13: %08lx r12: %08lx\n",
	157	regs->UCreg_15, regs->UCreg_14,
	158	regs->UCreg_13, regs->UCreg_12);
	159	printk(KERN_DEFAULT "r11: %08lx r10: %08lx r9 : %08lx r8 : %08lx\n",
	160	regs->UCreg_11, regs->UCreg_10,
	161	regs->UCreg_09, regs->UCreg_08);
	162	printk(KERN_DEFAULT "r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
	163	regs->UCreg_07, regs->UCreg_06,
	164	regs->UCreg_05, regs->UCreg_04);
	165	printk(KERN_DEFAULT "r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
	166	regs->UCreg_03, regs->UCreg_02,
	167	regs->UCreg_01, regs->UCreg_00);
	168
	169	flags = regs->UCreg_asr;
	170	buf[0] = flags & PSR_S_BIT ? 'S' : 's';
	171	buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
	172	buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
	173	buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
	174	buf[4] = '\0';
	175
	176	printk(KERN_DEFAULT "Flags: %s INTR o%s REAL o%s Mode %s Segment %s\n",
	177	buf, interrupts_enabled(regs) ? "n" : "ff",
	178	fast_interrupts_enabled(regs) ? "n" : "ff",
	179	processor_modes[processor_mode(regs)],
	180	segment_eq(get_fs(), get_ds()) ? "kernel" : "user");
	181	{
	182	unsigned int ctrl;
	183
	184	buf[0] = '\0';
	185	{
	186	unsigned int transbase;
	187	asm("movc %0, p0.c2, #0\n"
	188	: "=r" (transbase));
	189	snprintf(buf, sizeof(buf), " Table: %08x", transbase);
	190	}
	191	asm("movc %0, p0.c1, #0\n" : "=r" (ctrl));
	192
	193	printk(KERN_DEFAULT "Control: %08x%s\n", ctrl, buf);
	194	}
	195	}
	196
	197	void show_regs(struct pt_regs *regs)
	198	{
	199	printk(KERN_DEFAULT "\n");
	200	printk(KERN_DEFAULT "Pid: %d, comm: %20s\n",
	201	task_pid_nr(current), current->comm);
	202	__show_regs(regs);
	203	__backtrace();
	204	}
205
f73670e8 G	206	void flush_thread(void)
	207	{
	208	struct thread_info *thread = current_thread_info();
	209	struct task_struct *tsk = current;
	210
	211	memset(thread->used_cp, 0, sizeof(thread->used_cp));
	212	memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
	213	#ifdef CONFIG_UNICORE_FPU_F64
	214	memset(&thread->fpstate, 0, sizeof(struct fp_state));
	215	#endif
	216	}
	217
	218	void release_thread(struct task_struct *dead_task)
	219	{
	220	}
	221
	222	asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
38e99353	223	asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread");
f73670e8 G	224
	225	int
	226	copy_thread(unsigned long clone_flags, unsigned long stack_start,
afa86fc4	227	unsigned long stk_sz, struct task_struct *p)
f73670e8 G	228	{
	229	struct thread_info *thread = task_thread_info(p);
	230	struct pt_regs *childregs = task_pt_regs(p);
	231
f73670e8 G	232	memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
f73670e8 G	233	thread->cpu_context.sp = (unsigned long)childregs;
cb562173	234	if (unlikely(p->flags & PF_KTHREAD)) {
38e99353 AV	235	thread->cpu_context.pc = (unsigned long)ret_from_kernel_thread;
	236	thread->cpu_context.r4 = stack_start;
	237	thread->cpu_context.r5 = stk_sz;
	238	memset(childregs, 0, sizeof(struct pt_regs));
	239	} else {
	240	thread->cpu_context.pc = (unsigned long)ret_from_fork;
cb562173	241	childregs = current_pt_regs();
38e99353	242	childregs->UCreg_00 = 0;
cb562173 AV	243	if (stack_start)
cb562173 AV	244	childregs->UCreg_sp = stack_start;
f73670e8	245
38e99353	246	if (clone_flags & CLONE_SETTLS)
cb562173	247	childregs->UCreg_16 = childregs->UCreg_03;
38e99353	248	}
f73670e8 G	249	return 0;
	250	}
	251
	252	/*
	253	* Fill in the task's elfregs structure for a core dump.
	254	*/
	255	int dump_task_regs(struct task_struct t, elf_gregset_t elfregs)
	256	{
	257	elf_core_copy_regs(elfregs, task_pt_regs(t));
	258	return 1;
	259	}
	260
	261	/*
	262	* fill in the fpe structure for a core dump...
	263	*/
	264	int dump_fpu(struct pt_regs regs, elf_fpregset_t fp)
	265	{
	266	struct thread_info *thread = current_thread_info();
	267	int used_math = thread->used_cp[1] \| thread->used_cp[2];
	268
	269	#ifdef CONFIG_UNICORE_FPU_F64
	270	if (used_math)
	271	memcpy(fp, &thread->fpstate, sizeof(*fp));
	272	#endif
	273	return used_math != 0;
	274	}
	275	EXPORT_SYMBOL(dump_fpu);
	276
f73670e8 G	277	unsigned long get_wchan(struct task_struct *p)
	278	{
	279	struct stackframe frame;
	280	int count = 0;
	281	if (!p \|\| p == current \|\| p->state == TASK_RUNNING)
	282	return 0;
	283
	284	frame.fp = thread_saved_fp(p);
	285	frame.sp = thread_saved_sp(p);
	286	frame.lr = 0; /* recovered from the stack */
	287	frame.pc = thread_saved_pc(p);
	288	do {
	289	int ret = unwind_frame(&frame);
	290	if (ret < 0)
	291	return 0;
	292	if (!in_sched_functions(frame.pc))
	293	return frame.pc;
	294	} while ((count++) < 16);
	295	return 0;
	296	}
	297
	298	unsigned long arch_randomize_brk(struct mm_struct *mm)
	299	{
05c2679e	300	return randomize_page(mm->brk, 0x02000000);
f73670e8 G	301	}
	302
	303	/*
	304	* The vectors page is always readable from user space for the
	305	* atomic helpers and the signal restart code. Let's declare a mapping
	306	* for it so it is visible through ptrace and /proc/<pid>/mem.
	307	*/
	308
	309	int vectors_user_mapping(void)
	310	{
	311	struct mm_struct *mm = current->mm;
	312	return install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
	313	VM_READ \| VM_EXEC \|
	314	VM_MAYREAD \| VM_MAYEXEC \|
314e51b9	315	VM_DONTEXPAND \| VM_DONTDUMP,
f73670e8 G	316	NULL);
	317	}
	318
	319	const char arch_vma_name(struct vm_area_struct vma)
	320	{
	321	return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL;
	322	}