cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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process.c (10676B)


      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 *  linux/arch/arm/kernel/process.c
      4 *
      5 *  Copyright (C) 1996-2000 Russell King - Converted to ARM.
      6 *  Original Copyright (C) 1995  Linus Torvalds
      7 */
      8#include <linux/export.h>
      9#include <linux/sched.h>
     10#include <linux/sched/debug.h>
     11#include <linux/sched/task.h>
     12#include <linux/sched/task_stack.h>
     13#include <linux/kernel.h>
     14#include <linux/mm.h>
     15#include <linux/stddef.h>
     16#include <linux/unistd.h>
     17#include <linux/user.h>
     18#include <linux/interrupt.h>
     19#include <linux/init.h>
     20#include <linux/elfcore.h>
     21#include <linux/pm.h>
     22#include <linux/tick.h>
     23#include <linux/utsname.h>
     24#include <linux/uaccess.h>
     25#include <linux/random.h>
     26#include <linux/hw_breakpoint.h>
     27#include <linux/leds.h>
     28
     29#include <asm/processor.h>
     30#include <asm/thread_notify.h>
     31#include <asm/stacktrace.h>
     32#include <asm/system_misc.h>
     33#include <asm/mach/time.h>
     34#include <asm/tls.h>
     35#include <asm/vdso.h>
     36
     37#include "signal.h"
     38
     39#if defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) || defined(CONFIG_SMP)
     40DEFINE_PER_CPU(struct task_struct *, __entry_task);
     41#endif
     42
     43#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
     44#include <linux/stackprotector.h>
     45unsigned long __stack_chk_guard __read_mostly;
     46EXPORT_SYMBOL(__stack_chk_guard);
     47#endif
     48
     49#ifndef CONFIG_CURRENT_POINTER_IN_TPIDRURO
     50asmlinkage struct task_struct *__current;
     51EXPORT_SYMBOL(__current);
     52#endif
     53
     54static const char *processor_modes[] __maybe_unused = {
     55  "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
     56  "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
     57  "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "MON_32" , "ABT_32" ,
     58  "UK8_32" , "UK9_32" , "HYP_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
     59};
     60
     61static const char *isa_modes[] __maybe_unused = {
     62  "ARM" , "Thumb" , "Jazelle", "ThumbEE"
     63};
     64
     65/*
     66 * This is our default idle handler.
     67 */
     68
     69void (*arm_pm_idle)(void);
     70
     71/*
     72 * Called from the core idle loop.
     73 */
     74
     75void arch_cpu_idle(void)
     76{
     77	if (arm_pm_idle)
     78		arm_pm_idle();
     79	else
     80		cpu_do_idle();
     81	raw_local_irq_enable();
     82}
     83
     84void arch_cpu_idle_prepare(void)
     85{
     86	local_fiq_enable();
     87}
     88
     89void arch_cpu_idle_enter(void)
     90{
     91	ledtrig_cpu(CPU_LED_IDLE_START);
     92#ifdef CONFIG_PL310_ERRATA_769419
     93	wmb();
     94#endif
     95}
     96
     97void arch_cpu_idle_exit(void)
     98{
     99	ledtrig_cpu(CPU_LED_IDLE_END);
    100}
    101
    102void __show_regs_alloc_free(struct pt_regs *regs)
    103{
    104	int i;
    105
    106	/* check for r0 - r12 only */
    107	for (i = 0; i < 13; i++) {
    108		pr_alert("Register r%d information:", i);
    109		mem_dump_obj((void *)regs->uregs[i]);
    110	}
    111}
    112
    113void __show_regs(struct pt_regs *regs)
    114{
    115	unsigned long flags;
    116	char buf[64];
    117#ifndef CONFIG_CPU_V7M
    118	unsigned int domain;
    119#ifdef CONFIG_CPU_SW_DOMAIN_PAN
    120	/*
    121	 * Get the domain register for the parent context. In user
    122	 * mode, we don't save the DACR, so lets use what it should
    123	 * be. For other modes, we place it after the pt_regs struct.
    124	 */
    125	if (user_mode(regs)) {
    126		domain = DACR_UACCESS_ENABLE;
    127	} else {
    128		domain = to_svc_pt_regs(regs)->dacr;
    129	}
    130#else
    131	domain = get_domain();
    132#endif
    133#endif
    134
    135	show_regs_print_info(KERN_DEFAULT);
    136
    137	printk("PC is at %pS\n", (void *)instruction_pointer(regs));
    138	printk("LR is at %pS\n", (void *)regs->ARM_lr);
    139	printk("pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n",
    140	       regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);
    141	printk("sp : %08lx  ip : %08lx  fp : %08lx\n",
    142	       regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
    143	printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
    144		regs->ARM_r10, regs->ARM_r9,
    145		regs->ARM_r8);
    146	printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
    147		regs->ARM_r7, regs->ARM_r6,
    148		regs->ARM_r5, regs->ARM_r4);
    149	printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
    150		regs->ARM_r3, regs->ARM_r2,
    151		regs->ARM_r1, regs->ARM_r0);
    152
    153	flags = regs->ARM_cpsr;
    154	buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
    155	buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
    156	buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
    157	buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
    158	buf[4] = '\0';
    159
    160#ifndef CONFIG_CPU_V7M
    161	{
    162		const char *segment;
    163
    164		if ((domain & domain_mask(DOMAIN_USER)) ==
    165		    domain_val(DOMAIN_USER, DOMAIN_NOACCESS))
    166			segment = "none";
    167		else
    168			segment = "user";
    169
    170		printk("Flags: %s  IRQs o%s  FIQs o%s  Mode %s  ISA %s  Segment %s\n",
    171			buf, interrupts_enabled(regs) ? "n" : "ff",
    172			fast_interrupts_enabled(regs) ? "n" : "ff",
    173			processor_modes[processor_mode(regs)],
    174			isa_modes[isa_mode(regs)], segment);
    175	}
    176#else
    177	printk("xPSR: %08lx\n", regs->ARM_cpsr);
    178#endif
    179
    180#ifdef CONFIG_CPU_CP15
    181	{
    182		unsigned int ctrl;
    183
    184		buf[0] = '\0';
    185#ifdef CONFIG_CPU_CP15_MMU
    186		{
    187			unsigned int transbase;
    188			asm("mrc p15, 0, %0, c2, c0\n\t"
    189			    : "=r" (transbase));
    190			snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",
    191				transbase, domain);
    192		}
    193#endif
    194		asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
    195
    196		printk("Control: %08x%s\n", ctrl, buf);
    197	}
    198#endif
    199}
    200
    201void show_regs(struct pt_regs * regs)
    202{
    203	__show_regs(regs);
    204	dump_stack();
    205}
    206
    207ATOMIC_NOTIFIER_HEAD(thread_notify_head);
    208
    209EXPORT_SYMBOL_GPL(thread_notify_head);
    210
    211/*
    212 * Free current thread data structures etc..
    213 */
    214void exit_thread(struct task_struct *tsk)
    215{
    216	thread_notify(THREAD_NOTIFY_EXIT, task_thread_info(tsk));
    217}
    218
    219void flush_thread(void)
    220{
    221	struct thread_info *thread = current_thread_info();
    222	struct task_struct *tsk = current;
    223
    224	flush_ptrace_hw_breakpoint(tsk);
    225
    226	memset(thread->used_cp, 0, sizeof(thread->used_cp));
    227	memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
    228	memset(&thread->fpstate, 0, sizeof(union fp_state));
    229
    230	flush_tls();
    231
    232	thread_notify(THREAD_NOTIFY_FLUSH, thread);
    233}
    234
    235void release_thread(struct task_struct *dead_task)
    236{
    237}
    238
    239asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
    240
    241int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
    242{
    243	unsigned long clone_flags = args->flags;
    244	unsigned long stack_start = args->stack;
    245	unsigned long tls = args->tls;
    246	struct thread_info *thread = task_thread_info(p);
    247	struct pt_regs *childregs = task_pt_regs(p);
    248
    249	memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
    250
    251#ifdef CONFIG_CPU_USE_DOMAINS
    252	/*
    253	 * Copy the initial value of the domain access control register
    254	 * from the current thread: thread->addr_limit will have been
    255	 * copied from the current thread via setup_thread_stack() in
    256	 * kernel/fork.c
    257	 */
    258	thread->cpu_domain = get_domain();
    259#endif
    260
    261	if (likely(!args->fn)) {
    262		*childregs = *current_pt_regs();
    263		childregs->ARM_r0 = 0;
    264		if (stack_start)
    265			childregs->ARM_sp = stack_start;
    266	} else {
    267		memset(childregs, 0, sizeof(struct pt_regs));
    268		thread->cpu_context.r4 = (unsigned long)args->fn_arg;
    269		thread->cpu_context.r5 = (unsigned long)args->fn;
    270		childregs->ARM_cpsr = SVC_MODE;
    271	}
    272	thread->cpu_context.pc = (unsigned long)ret_from_fork;
    273	thread->cpu_context.sp = (unsigned long)childregs;
    274
    275	clear_ptrace_hw_breakpoint(p);
    276
    277	if (clone_flags & CLONE_SETTLS)
    278		thread->tp_value[0] = tls;
    279	thread->tp_value[1] = get_tpuser();
    280
    281	thread_notify(THREAD_NOTIFY_COPY, thread);
    282
    283	return 0;
    284}
    285
    286unsigned long __get_wchan(struct task_struct *p)
    287{
    288	struct stackframe frame;
    289	unsigned long stack_page;
    290	int count = 0;
    291
    292	frame.fp = thread_saved_fp(p);
    293	frame.sp = thread_saved_sp(p);
    294	frame.lr = 0;			/* recovered from the stack */
    295	frame.pc = thread_saved_pc(p);
    296	stack_page = (unsigned long)task_stack_page(p);
    297	do {
    298		if (frame.sp < stack_page ||
    299		    frame.sp >= stack_page + THREAD_SIZE ||
    300		    unwind_frame(&frame) < 0)
    301			return 0;
    302		if (!in_sched_functions(frame.pc))
    303			return frame.pc;
    304	} while (count ++ < 16);
    305	return 0;
    306}
    307
    308#ifdef CONFIG_MMU
    309#ifdef CONFIG_KUSER_HELPERS
    310/*
    311 * The vectors page is always readable from user space for the
    312 * atomic helpers. Insert it into the gate_vma so that it is visible
    313 * through ptrace and /proc/<pid>/mem.
    314 */
    315static struct vm_area_struct gate_vma;
    316
    317static int __init gate_vma_init(void)
    318{
    319	vma_init(&gate_vma, NULL);
    320	gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
    321	gate_vma.vm_start = 0xffff0000;
    322	gate_vma.vm_end	= 0xffff0000 + PAGE_SIZE;
    323	gate_vma.vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC;
    324	return 0;
    325}
    326arch_initcall(gate_vma_init);
    327
    328struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
    329{
    330	return &gate_vma;
    331}
    332
    333int in_gate_area(struct mm_struct *mm, unsigned long addr)
    334{
    335	return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
    336}
    337
    338int in_gate_area_no_mm(unsigned long addr)
    339{
    340	return in_gate_area(NULL, addr);
    341}
    342#define is_gate_vma(vma)	((vma) == &gate_vma)
    343#else
    344#define is_gate_vma(vma)	0
    345#endif
    346
    347const char *arch_vma_name(struct vm_area_struct *vma)
    348{
    349	return is_gate_vma(vma) ? "[vectors]" : NULL;
    350}
    351
    352/* If possible, provide a placement hint at a random offset from the
    353 * stack for the sigpage and vdso pages.
    354 */
    355static unsigned long sigpage_addr(const struct mm_struct *mm,
    356				  unsigned int npages)
    357{
    358	unsigned long offset;
    359	unsigned long first;
    360	unsigned long last;
    361	unsigned long addr;
    362	unsigned int slots;
    363
    364	first = PAGE_ALIGN(mm->start_stack);
    365
    366	last = TASK_SIZE - (npages << PAGE_SHIFT);
    367
    368	/* No room after stack? */
    369	if (first > last)
    370		return 0;
    371
    372	/* Just enough room? */
    373	if (first == last)
    374		return first;
    375
    376	slots = ((last - first) >> PAGE_SHIFT) + 1;
    377
    378	offset = get_random_int() % slots;
    379
    380	addr = first + (offset << PAGE_SHIFT);
    381
    382	return addr;
    383}
    384
    385static struct page *signal_page;
    386extern struct page *get_signal_page(void);
    387
    388static int sigpage_mremap(const struct vm_special_mapping *sm,
    389		struct vm_area_struct *new_vma)
    390{
    391	current->mm->context.sigpage = new_vma->vm_start;
    392	return 0;
    393}
    394
    395static const struct vm_special_mapping sigpage_mapping = {
    396	.name = "[sigpage]",
    397	.pages = &signal_page,
    398	.mremap = sigpage_mremap,
    399};
    400
    401int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
    402{
    403	struct mm_struct *mm = current->mm;
    404	struct vm_area_struct *vma;
    405	unsigned long npages;
    406	unsigned long addr;
    407	unsigned long hint;
    408	int ret = 0;
    409
    410	if (!signal_page)
    411		signal_page = get_signal_page();
    412	if (!signal_page)
    413		return -ENOMEM;
    414
    415	npages = 1; /* for sigpage */
    416	npages += vdso_total_pages;
    417
    418	if (mmap_write_lock_killable(mm))
    419		return -EINTR;
    420	hint = sigpage_addr(mm, npages);
    421	addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
    422	if (IS_ERR_VALUE(addr)) {
    423		ret = addr;
    424		goto up_fail;
    425	}
    426
    427	vma = _install_special_mapping(mm, addr, PAGE_SIZE,
    428		VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
    429		&sigpage_mapping);
    430
    431	if (IS_ERR(vma)) {
    432		ret = PTR_ERR(vma);
    433		goto up_fail;
    434	}
    435
    436	mm->context.sigpage = addr;
    437
    438	/* Unlike the sigpage, failure to install the vdso is unlikely
    439	 * to be fatal to the process, so no error check needed
    440	 * here.
    441	 */
    442	arm_install_vdso(mm, addr + PAGE_SIZE);
    443
    444 up_fail:
    445	mmap_write_unlock(mm);
    446	return ret;
    447}
    448#endif