// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/arch/arm/kernel/process.c
*
* Copyright (C) 1996-2000 Russell King - Converted to ARM.
* Original Copyright (C) 1995 Linus Torvalds
*/
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/user.h>
#include <linux/interrupt.h>
#include <linux/init.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/leds.h>
#include <asm/processor.h>
#include <asm/thread_notify.h>
#include <asm/stacktrace.h>
#include <asm/system_misc.h>
#include <asm/mach/time.h>
#include <asm/tls.h>
#include <asm/vdso.h>
#include "signal.h"
#if defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) || defined(CONFIG_SMP)
DEFINE_PER_CPU(struct task_struct *, __entry_task);
#endif
#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
#include <linux/stackprotector.h>
unsigned long __stack_chk_guard __read_mostly;
EXPORT_SYMBOL(__stack_chk_guard);
#endif
#ifndef CONFIG_CURRENT_POINTER_IN_TPIDRURO
asmlinkage struct task_struct *__current;
EXPORT_SYMBOL(__current);
#endif
static const char *processor_modes[] __maybe_unused = {
"USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
"UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
"USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,
"UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
};
static const char *isa_modes[] __maybe_unused = {
"ARM" , "Thumb" , "Jazelle", "ThumbEE"
};
/*
* This is our default idle handler.
*/
void (*arm_pm_idle)(void);
/*
* Called from the core idle loop.
*/
void arch_cpu_idle(void)
{
if (arm_pm_idle)
arm_pm_idle();
else
cpu_do_idle();
}
void arch_cpu_idle_prepare(void)
{
local_fiq_enable();
}
void arch_cpu_idle_enter(void)
{
ledtrig_cpu(CPU_LED_IDLE_START);
#ifdef CONFIG_PL310_ERRATA_769419
wmb();
#endif
}
void arch_cpu_idle_exit(void)
{
ledtrig_cpu(CPU_LED_IDLE_END);
}
void __show_regs_alloc_free(struct pt_regs *regs)
{
int i;
/* check for r0 - r12 only */
for (i = 0; i < 13; i++) {
pr_alert("Register r%d information:", i);
mem_dump_obj((void *)regs->uregs[i]);
}
}
void __show_regs(struct pt_regs *regs)
{
unsigned long flags;
char buf[64];
#ifndef CONFIG_CPU_V7M
unsigned int domain;
#ifdef CONFIG_CPU_SW_DOMAIN_PAN
/*
* Get the domain register for the parent context. In user
* mode, we don't save the DACR, so lets use what it should
* be. For other modes, we place it after the pt_regs struct.
*/
if (user_mode(regs)) {
domain = DACR_UACCESS_ENABLE;
} else {
domain = to_svc_pt_regs(regs)->dacr;
}
#else
domain = get_domain();
#endif
#endif
show_regs_print_info(KERN_DEFAULT);
printk("PC is at %pS\n", (void *)instruction_pointer(regs));
printk("LR is at %pS\n", (void *)regs->ARM_lr);
printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n",
regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);
printk("sp : %08lx ip : %08lx fp : %08lx\n",
regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
regs->ARM_r10, regs->ARM_r9,
regs->ARM_r8);
printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
regs->ARM_r7, regs->ARM_r6,
regs->ARM_r5, regs->ARM_r4);
printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
regs->ARM_r3, regs->ARM_r2,
regs->ARM_r1, regs->ARM_r0);
flags = regs->ARM_cpsr;
buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
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';
#ifndef CONFIG_CPU_V7M
{
const char *segment;
if ((domain & domain_mask(DOMAIN_USER)) ==
domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
segment = "none";
else
segment = "user";
printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n",
buf, interrupts_enabled(regs) ? "n" : "ff",
fast_interrupts_enabled(regs) ? "n" : "ff",
processor_modes[processor_mode(regs)],
isa_modes[isa_mode(regs)], segment);
}
#else
printk("xPSR: %08lx\n", regs->ARM_cpsr);
#endif
#ifdef CONFIG_CPU_CP15
{
unsigned int ctrl;
buf[0] = '\0';
#ifdef CONFIG_CPU_CP15_MMU
{
unsigned int transbase;
asm("mrc p15, 0, %0, c2, c0\n\t"
: "=r" (transbase));
snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x",
transbase, domain);
}
#endif
asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
printk("Control: %08x%s\n", ctrl, buf);
}
#endif
}
void show_regs(struct pt_regs * regs)
{
__show_regs(regs);
dump_backtrace(regs, NULL, KERN_DEFAULT);
}
ATOMIC_NOTIFIER_HEAD(thread_notify_head);
EXPORT_SYMBOL_GPL(thread_notify_head);
/*
* Free current thread data structures etc..
*/
void exit_thread(struct task_struct *tsk)
{
thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
}
void flush_thread(void)
{
struct thread_info *thread = current_thread_info();
struct task_struct *tsk = current;
flush_ptrace_hw_breakpoint(tsk);
memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
memset(&thread->fpstate, 0, sizeof(union fp_state));
flush_tls();
thread_notify(THREAD_NOTIFY_FLUSH, thread);
}
asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
{
unsigned long clone_flags = args->flags;
unsigned long stack_start = args->stack;
unsigned long tls = args->tls;
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));
#ifdef CONFIG_CPU_USE_DOMAINS
/*
* Copy the initial value of the domain access control register
* from the current thread: thread->addr_limit will have been
* copied from the current thread via setup_thread_stack() in
* kernel/fork.c
*/
thread->cpu_domain = get_domain();
#endif
if (likely(!args->fn)) {
*childregs = *current_pt_regs();
childregs->ARM_r0 = 0;
if (stack_start)
childregs->ARM_sp = stack_start;
} else {
memset(childregs, 0, sizeof(struct pt_regs));
thread->cpu_context.r4 = (unsigned long)args->fn_arg;
thread->cpu_context.r5 = (unsigned long)args->fn;
childregs->ARM_cpsr = SVC_MODE;
}
thread->cpu_context.pc = (unsigned long)ret_from_fork;
thread->cpu_context.sp = (unsigned long)childregs;
clear_ptrace_hw_breakpoint(p);
if (clone_flags & CLONE_SETTLS)
thread->tp_value[0] = tls;
thread->tp_value[1] = get_tpuser();
thread_notify(THREAD_NOTIFY_COPY, thread);
return 0;
}
unsigned long __get_wchan(struct task_struct *p)
{
struct stackframe frame;
unsigned long stack_page;
int count = 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);
stack_page = (unsigned long)task_stack_page(p);
do {
if (frame.sp < stack_page ||
frame.sp >= stack_page + THREAD_SIZE ||
unwind_frame(&frame) < 0)
return 0;
if (!in_sched_functions(frame.pc))
return frame.pc;
} while (count ++ < 16);
return 0;
}
#ifdef CONFIG_MMU
#ifdef CONFIG_KUSER_HELPERS
/*
* The vectors page is always readable from user space for the
* atomic helpers. Insert it into the gate_vma so that it is visible
* through ptrace and /proc/<pid>/mem.
*/
static struct vm_area_struct gate_vma;
static int __init gate_vma_init(void)
{
vma_init(&gate_vma, NULL);
gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
gate_vma.vm_start = 0xffff0000;
gate_vma.vm_end = 0xffff0000 + PAGE_SIZE;
vm_flags_init(&gate_vma, VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC);
return 0;
}
arch_initcall(gate_vma_init);
struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
{
return &gate_vma;
}
int in_gate_area(struct mm_struct *mm, unsigned long addr)
{
return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
}
int in_gate_area_no_mm(unsigned long addr)
{
return in_gate_area(NULL, addr);
}
#define is_gate_vma(vma) ((vma) == &gate_vma)
#else
#define is_gate_vma(vma) 0
#endif
const char *arch_vma_name(struct vm_area_struct *vma)
{
return is_gate_vma(vma) ? "[vectors]" : NULL;
}
/* If possible, provide a placement hint at a random offset from the
* stack for the sigpage and vdso pages.
*/
static unsigned long sigpage_addr(const struct mm_struct *mm,
unsigned int npages)
{
unsigned long offset;
unsigned long first;
unsigned long last;
unsigned long addr;
unsigned int slots;
first = PAGE_ALIGN(mm->start_stack);
last = TASK_SIZE - (npages << PAGE_SHIFT);
/* No room after stack? */
if (first > last)
return 0;
/* Just enough room? */
if (first == last)
return first;
slots = ((last - first) >> PAGE_SHIFT) + 1;
offset = get_random_u32_below(slots);
addr = first + (offset << PAGE_SHIFT);
return addr;
}
static struct page *signal_page;
extern struct page *get_signal_page(void);
static int sigpage_mremap(const struct vm_special_mapping *sm,
struct vm_area_struct *new_vma)
{
current->mm->context.sigpage = new_vma->vm_start;
return 0;
}
static const struct vm_special_mapping sigpage_mapping = {
.name = "[sigpage]",
.pages = &signal_page,
.mremap = sigpage_mremap,
};
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long npages;
unsigned long addr;
unsigned long hint;
int ret = 0;
if (!signal_page)
signal_page = get_signal_page();
if (!signal_page)
return -ENOMEM;
npages = 1; /* for sigpage */
npages += vdso_total_pages;
if (mmap_write_lock_killable(mm))
return -EINTR;
hint = sigpage_addr(mm, npages);
addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
if (IS_ERR_VALUE(addr)) {
ret = addr;
goto up_fail;
}
vma = _install_special_mapping(mm, addr, PAGE_SIZE,
VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
&sigpage_mapping);
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
goto up_fail;
}
mm->context.sigpage = addr;
/* Unlike the sigpage, failure to install the vdso is unlikely
* to be fatal to the process, so no error check needed
* here.
*/
arm_install_vdso(mm, addr + PAGE_SIZE);
up_fail:
mmap_write_unlock(mm);
return ret;
}
#endif
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