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