x86/pti: Put the LDT in its own PGD if PTI is on

[mirror_ubuntu-artful-kernel.git] / arch / x86 / include / asm / processor.h

#ifndef _ASM_X86_PROCESSOR_H
#define _ASM_X86_PROCESSOR_H

#include <asm/processor-flags.h>

/* Forward declaration, a strange C thing */
struct task_struct;
struct mm_struct;
struct vm86;

#include <asm/math_emu.h>
#include <asm/segment.h>
#include <asm/types.h>
#include <uapi/asm/sigcontext.h>
#include <asm/current.h>
#include <asm/cpufeatures.h>
#include <asm/page.h>
#include <asm/pgtable_types.h>
#include <asm/percpu.h>
#include <asm/msr.h>
#include <asm/desc_defs.h>
#include <asm/nops.h>
#include <asm/special_insns.h>
#include <asm/fpu/types.h>

#include <linux/personality.h>
#include <linux/cache.h>
#include <linux/threads.h>
#include <linux/math64.h>
#include <linux/err.h>
#include <linux/irqflags.h>

/*
 * We handle most unaligned accesses in hardware.  On the other hand
 * unaligned DMA can be quite expensive on some Nehalem processors.
 *
 * Based on this we disable the IP header alignment in network drivers.
 */
#define NET_IP_ALIGN    0

#define HBP_NUM 4
/*
 * Default implementation of macro that returns current
 * instruction pointer ("program counter").
 */
static inline void *current_text_addr(void)
{
        void *pc;

        asm volatile("mov $1f, %0; 1:":"=r" (pc));

        return pc;
}

/*
 * These alignment constraints are for performance in the vSMP case,
 * but in the task_struct case we must also meet hardware imposed
 * alignment requirements of the FPU state:
 */
#ifdef CONFIG_X86_VSMP
# define ARCH_MIN_TASKALIGN             (1 << INTERNODE_CACHE_SHIFT)
# define ARCH_MIN_MMSTRUCT_ALIGN        (1 << INTERNODE_CACHE_SHIFT)
#else
# define ARCH_MIN_TASKALIGN             __alignof__(union fpregs_state)
# define ARCH_MIN_MMSTRUCT_ALIGN        0
#endif

enum tlb_infos {
        ENTRIES,
        NR_INFO
};

extern u16 __read_mostly tlb_lli_4k[NR_INFO];
extern u16 __read_mostly tlb_lli_2m[NR_INFO];
extern u16 __read_mostly tlb_lli_4m[NR_INFO];
extern u16 __read_mostly tlb_lld_4k[NR_INFO];
extern u16 __read_mostly tlb_lld_2m[NR_INFO];
extern u16 __read_mostly tlb_lld_4m[NR_INFO];
extern u16 __read_mostly tlb_lld_1g[NR_INFO];

/*
 *  CPU type and hardware bug flags. Kept separately for each CPU.
 *  Members of this structure are referenced in head_32.S, so think twice
 *  before touching them. [mj]
 */

struct cpuinfo_x86 {
        __u8                    x86;            /* CPU family */
        __u8                    x86_vendor;     /* CPU vendor */
        __u8                    x86_model;
        __u8                    x86_mask;
#ifdef CONFIG_X86_64
        /* Number of 4K pages in DTLB/ITLB combined(in pages): */
        int                     x86_tlbsize;
#endif
        __u8                    x86_virt_bits;
        __u8                    x86_phys_bits;
        /* CPUID returned core id bits: */
        __u8                    x86_coreid_bits;
        __u8                    cu_id;
        /* Max extended CPUID function supported: */
        __u32                   extended_cpuid_level;
        /* Maximum supported CPUID level, -1=no CPUID: */
        int                     cpuid_level;
        __u32                   x86_capability[NCAPINTS + NBUGINTS];
        char                    x86_vendor_id[16];
        char                    x86_model_id[64];
        /* in KB - valid for CPUS which support this call: */
        int                     x86_cache_size;
        int                     x86_cache_alignment;    /* In bytes */
        /* Cache QoS architectural values: */
        int                     x86_cache_max_rmid;     /* max index */
        int                     x86_cache_occ_scale;    /* scale to bytes */
        int                     x86_power;
        unsigned long           loops_per_jiffy;
        /* cpuid returned max cores value: */
        u16                      x86_max_cores;
        u16                     apicid;
        u16                     initial_apicid;
        u16                     x86_clflush_size;
        /* number of cores as seen by the OS: */
        u16                     booted_cores;
        /* Physical processor id: */
        u16                     phys_proc_id;
        /* Logical processor id: */
        u16                     logical_proc_id;
        /* Core id: */
        u16                     cpu_core_id;
        /* Index into per_cpu list: */
        u16                     cpu_index;
        u32                     microcode;
} __randomize_layout;

struct cpuid_regs {
        u32 eax, ebx, ecx, edx;
};

enum cpuid_regs_idx {
        CPUID_EAX = 0,
        CPUID_EBX,
        CPUID_ECX,
        CPUID_EDX,
};

#define X86_VENDOR_INTEL        0
#define X86_VENDOR_CYRIX        1
#define X86_VENDOR_AMD          2
#define X86_VENDOR_UMC          3
#define X86_VENDOR_CENTAUR      5
#define X86_VENDOR_TRANSMETA    7
#define X86_VENDOR_NSC          8
#define X86_VENDOR_NUM          9

#define X86_VENDOR_UNKNOWN      0xff

/*
 * capabilities of CPUs
 */
extern struct cpuinfo_x86       boot_cpu_data;
extern struct cpuinfo_x86       new_cpu_data;

#include <linux/thread_info.h>

extern struct x86_hw_tss        doublefault_tss;
extern __u32                    cpu_caps_cleared[NCAPINTS + NBUGINTS];
extern __u32                    cpu_caps_set[NCAPINTS + NBUGINTS];

#ifdef CONFIG_SMP
DECLARE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info);
#define cpu_data(cpu)           per_cpu(cpu_info, cpu)
#else
#define cpu_info                boot_cpu_data
#define cpu_data(cpu)           boot_cpu_data
#endif

extern const struct seq_operations cpuinfo_op;

#define cache_line_size()       (boot_cpu_data.x86_cache_alignment)

extern void cpu_detect(struct cpuinfo_x86 *c);

extern void early_cpu_init(void);
extern void identify_boot_cpu(void);
extern void identify_secondary_cpu(struct cpuinfo_x86 *);
extern void print_cpu_info(struct cpuinfo_x86 *);
void print_cpu_msr(struct cpuinfo_x86 *);
extern void init_scattered_cpuid_features(struct cpuinfo_x86 *c);
extern u32 get_scattered_cpuid_leaf(unsigned int level,
                                    unsigned int sub_leaf,
                                    enum cpuid_regs_idx reg);
extern unsigned int init_intel_cacheinfo(struct cpuinfo_x86 *c);
extern void init_amd_cacheinfo(struct cpuinfo_x86 *c);

extern void detect_extended_topology(struct cpuinfo_x86 *c);
extern void detect_ht(struct cpuinfo_x86 *c);

#ifdef CONFIG_X86_32
extern int have_cpuid_p(void);
#else
static inline int have_cpuid_p(void)
{
        return 1;
}
#endif
static inline void native_cpuid(unsigned int *eax, unsigned int *ebx,
                                unsigned int *ecx, unsigned int *edx)
{
        /* ecx is often an input as well as an output. */
        asm volatile("cpuid"
            : "=a" (*eax),
              "=b" (*ebx),
              "=c" (*ecx),
              "=d" (*edx)
            : "0" (*eax), "2" (*ecx)
            : "memory");
}

#define native_cpuid_reg(reg)                                   \
static inline unsigned int native_cpuid_##reg(unsigned int op)  \
{                                                               \
        unsigned int eax = op, ebx, ecx = 0, edx;               \
                                                                \
        native_cpuid(&eax, &ebx, &ecx, &edx);                   \
                                                                \
        return reg;                                             \
}

/*
 * Native CPUID functions returning a single datum.
 */
native_cpuid_reg(eax)
native_cpuid_reg(ebx)
native_cpuid_reg(ecx)
native_cpuid_reg(edx)

/*
 * Friendlier CR3 helpers.
 */
static inline unsigned long read_cr3_pa(void)
{
        return __read_cr3() & CR3_ADDR_MASK;
}

static inline void load_cr3(pgd_t *pgdir)
{
        write_cr3(__pa(pgdir));
}

/*
 * Note that while the legacy 'TSS' name comes from 'Task State Segment',
 * on modern x86 CPUs the TSS also holds information important to 64-bit mode,
 * unrelated to the task-switch mechanism:
 */
#ifdef CONFIG_X86_32
/* This is the TSS defined by the hardware. */
struct x86_hw_tss {
        unsigned short          back_link, __blh;
        unsigned long           sp0;
        unsigned short          ss0, __ss0h;
        unsigned long           sp1;

        /*
         * We don't use ring 1, so ss1 is a convenient scratch space in
         * the same cacheline as sp0.  We use ss1 to cache the value in
         * MSR_IA32_SYSENTER_CS.  When we context switch
         * MSR_IA32_SYSENTER_CS, we first check if the new value being
         * written matches ss1, and, if it's not, then we wrmsr the new
         * value and update ss1.
         *
         * The only reason we context switch MSR_IA32_SYSENTER_CS is
         * that we set it to zero in vm86 tasks to avoid corrupting the
         * stack if we were to go through the sysenter path from vm86
         * mode.
         */
        unsigned short          ss1;    /* MSR_IA32_SYSENTER_CS */

        unsigned short          __ss1h;
        unsigned long           sp2;
        unsigned short          ss2, __ss2h;
        unsigned long           __cr3;
        unsigned long           ip;
        unsigned long           flags;
        unsigned long           ax;
        unsigned long           cx;
        unsigned long           dx;
        unsigned long           bx;
        unsigned long           sp;
        unsigned long           bp;
        unsigned long           si;
        unsigned long           di;
        unsigned short          es, __esh;
        unsigned short          cs, __csh;
        unsigned short          ss, __ssh;
        unsigned short          ds, __dsh;
        unsigned short          fs, __fsh;
        unsigned short          gs, __gsh;
        unsigned short          ldt, __ldth;
        unsigned short          trace;
        unsigned short          io_bitmap_base;

} __attribute__((packed));
#else
struct x86_hw_tss {
        u32                     reserved1;
        u64                     sp0;

        /*
         * We store cpu_current_top_of_stack in sp1 so it's always accessible.
         * Linux does not use ring 1, so sp1 is not otherwise needed.
         */
        u64                     sp1;

        u64                     sp2;
        u64                     reserved2;
        u64                     ist[7];
        u32                     reserved3;
        u32                     reserved4;
        u16                     reserved5;
        u16                     io_bitmap_base;

} __attribute__((packed));
#endif

/*
 * IO-bitmap sizes:
 */
#define IO_BITMAP_BITS                  65536
#define IO_BITMAP_BYTES                 (IO_BITMAP_BITS/8)
#define IO_BITMAP_LONGS                 (IO_BITMAP_BYTES/sizeof(long))
#define IO_BITMAP_OFFSET                (offsetof(struct tss_struct, io_bitmap) - offsetof(struct tss_struct, x86_tss))
#define INVALID_IO_BITMAP_OFFSET        0x8000

struct entry_stack {
        unsigned long           words[64];
};

struct entry_stack_page {
        struct entry_stack stack;
} __aligned(PAGE_SIZE);

struct tss_struct {
        /*
         * The fixed hardware portion.  This must not cross a page boundary
         * at risk of violating the SDM's advice and potentially triggering
         * errata.
         */
        struct x86_hw_tss       x86_tss;

        /*
         * The extra 1 is there because the CPU will access an
         * additional byte beyond the end of the IO permission
         * bitmap. The extra byte must be all 1 bits, and must
         * be within the limit.
         */
        unsigned long           io_bitmap[IO_BITMAP_LONGS + 1];
} __aligned(PAGE_SIZE);

DECLARE_PER_CPU_PAGE_ALIGNED(struct tss_struct, cpu_tss_rw);

/*
 * sizeof(unsigned long) coming from an extra "long" at the end
 * of the iobitmap.
 *
 * -1? seg base+limit should be pointing to the address of the
 * last valid byte
 */
#define __KERNEL_TSS_LIMIT      \
        (IO_BITMAP_OFFSET + IO_BITMAP_BYTES + sizeof(unsigned long) - 1)

#ifdef CONFIG_X86_32
DECLARE_PER_CPU(unsigned long, cpu_current_top_of_stack);
#else
/* The RO copy can't be accessed with this_cpu_xyz(), so use the RW copy. */
#define cpu_current_top_of_stack cpu_tss_rw.x86_tss.sp1
#endif

/*
 * Save the original ist values for checking stack pointers during debugging
 */
struct orig_ist {
        unsigned long           ist[7];
};

#ifdef CONFIG_X86_64
DECLARE_PER_CPU(struct orig_ist, orig_ist);

union irq_stack_union {
        char irq_stack[IRQ_STACK_SIZE];
        /*
         * GCC hardcodes the stack canary as %gs:40.  Since the
         * irq_stack is the object at %gs:0, we reserve the bottom
         * 48 bytes of the irq stack for the canary.
         */
        struct {
                char gs_base[40];
                unsigned long stack_canary;
        };
};

DECLARE_PER_CPU_FIRST(union irq_stack_union, irq_stack_union) __visible;
DECLARE_INIT_PER_CPU(irq_stack_union);

DECLARE_PER_CPU(char *, irq_stack_ptr);
DECLARE_PER_CPU(unsigned int, irq_count);
extern asmlinkage void ignore_sysret(void);
#else   /* X86_64 */
#ifdef CONFIG_CC_STACKPROTECTOR
/*
 * Make sure stack canary segment base is cached-aligned:
 *   "For Intel Atom processors, avoid non zero segment base address
 *    that is not aligned to cache line boundary at all cost."
 * (Optim Ref Manual Assembly/Compiler Coding Rule 15.)
 */
struct stack_canary {
        char __pad[20];         /* canary at %gs:20 */
        unsigned long canary;
};
DECLARE_PER_CPU_ALIGNED(struct stack_canary, stack_canary);
#endif
/*
 * per-CPU IRQ handling stacks
 */
struct irq_stack {
        u32                     stack[THREAD_SIZE/sizeof(u32)];
} __aligned(THREAD_SIZE);

DECLARE_PER_CPU(struct irq_stack *, hardirq_stack);
DECLARE_PER_CPU(struct irq_stack *, softirq_stack);
#endif  /* X86_64 */

extern unsigned int fpu_kernel_xstate_size;
extern unsigned int fpu_user_xstate_size;

struct perf_event;

typedef struct {
        unsigned long           seg;
} mm_segment_t;

struct thread_struct {
        /* Cached TLS descriptors: */
        struct desc_struct      tls_array[GDT_ENTRY_TLS_ENTRIES];
#ifdef CONFIG_X86_32
        unsigned long           sp0;
#endif
        unsigned long           sp;
#ifdef CONFIG_X86_32
        unsigned long           sysenter_cs;
#else
        unsigned short          es;
        unsigned short          ds;
        unsigned short          fsindex;
        unsigned short          gsindex;
#endif

        u32                     status;         /* thread synchronous flags */

#ifdef CONFIG_X86_64
        unsigned long           fsbase;
        unsigned long           gsbase;
#else
        /*
         * XXX: this could presumably be unsigned short.  Alternatively,
         * 32-bit kernels could be taught to use fsindex instead.
         */
        unsigned long fs;
        unsigned long gs;
#endif

        /* Save middle states of ptrace breakpoints */
        struct perf_event       *ptrace_bps[HBP_NUM];
        /* Debug status used for traps, single steps, etc... */
        unsigned long           debugreg6;
        /* Keep track of the exact dr7 value set by the user */
        unsigned long           ptrace_dr7;
        /* Fault info: */
        unsigned long           cr2;
        unsigned long           trap_nr;
        unsigned long           error_code;
#ifdef CONFIG_VM86
        /* Virtual 86 mode info */
        struct vm86             *vm86;
#endif
        /* IO permissions: */
        unsigned long           *io_bitmap_ptr;
        unsigned long           iopl;
        /* Max allowed port in the bitmap, in bytes: */
        unsigned                io_bitmap_max;

        mm_segment_t            addr_limit;

        unsigned int            sig_on_uaccess_err:1;
        unsigned int            uaccess_err:1;  /* uaccess failed */

        /* Floating point and extended processor state */
        struct fpu              fpu;
        /*
         * WARNING: 'fpu' is dynamically-sized.  It *MUST* be at
         * the end.
         */
};

/*
 * Thread-synchronous status.
 *
 * This is different from the flags in that nobody else
 * ever touches our thread-synchronous status, so we don't
 * have to worry about atomic accesses.
 */
#define TS_COMPAT               0x0002  /* 32bit syscall active (64BIT)*/

/*
 * Set IOPL bits in EFLAGS from given mask
 */
static inline void native_set_iopl_mask(unsigned mask)
{
#ifdef CONFIG_X86_32
        unsigned int reg;

        asm volatile ("pushfl;"
                      "popl %0;"
                      "andl %1, %0;"
                      "orl %2, %0;"
                      "pushl %0;"
                      "popfl"
                      : "=&r" (reg)
                      : "i" (~X86_EFLAGS_IOPL), "r" (mask));
#endif
}

static inline void
native_load_sp0(unsigned long sp0)
{
        this_cpu_write(cpu_tss_rw.x86_tss.sp0, sp0);
}

static inline void native_swapgs(void)
{
#ifdef CONFIG_X86_64
        asm volatile("swapgs" ::: "memory");
#endif
}

static inline unsigned long current_top_of_stack(void)
{
        /*
         *  We can't read directly from tss.sp0: sp0 on x86_32 is special in
         *  and around vm86 mode and sp0 on x86_64 is special because of the
         *  entry trampoline.
         */
        return this_cpu_read_stable(cpu_current_top_of_stack);
}

static inline bool on_thread_stack(void)
{
        return (unsigned long)(current_top_of_stack() -
                               current_stack_pointer()) < THREAD_SIZE;
}

#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#else
#define __cpuid                 native_cpuid

static inline void load_sp0(unsigned long sp0)
{
        native_load_sp0(sp0);
}

#define set_iopl_mask native_set_iopl_mask
#endif /* CONFIG_PARAVIRT */

/* Free all resources held by a thread. */
extern void release_thread(struct task_struct *);

unsigned long get_wchan(struct task_struct *p);

/*
 * Generic CPUID function
 * clear %ecx since some cpus (Cyrix MII) do not set or clear %ecx
 * resulting in stale register contents being returned.
 */
static inline void cpuid(unsigned int op,
                         unsigned int *eax, unsigned int *ebx,
                         unsigned int *ecx, unsigned int *edx)
{
        *eax = op;
        *ecx = 0;
        __cpuid(eax, ebx, ecx, edx);
}

/* Some CPUID calls want 'count' to be placed in ecx */
static inline void cpuid_count(unsigned int op, int count,
                               unsigned int *eax, unsigned int *ebx,
                               unsigned int *ecx, unsigned int *edx)
{
        *eax = op;
        *ecx = count;
        __cpuid(eax, ebx, ecx, edx);
}

/*
 * CPUID functions returning a single datum
 */
static inline unsigned int cpuid_eax(unsigned int op)
{
        unsigned int eax, ebx, ecx, edx;

        cpuid(op, &eax, &ebx, &ecx, &edx);

        return eax;
}

static inline unsigned int cpuid_ebx(unsigned int op)
{
        unsigned int eax, ebx, ecx, edx;

        cpuid(op, &eax, &ebx, &ecx, &edx);

        return ebx;
}

static inline unsigned int cpuid_ecx(unsigned int op)
{
        unsigned int eax, ebx, ecx, edx;

        cpuid(op, &eax, &ebx, &ecx, &edx);

        return ecx;
}

static inline unsigned int cpuid_edx(unsigned int op)
{
        unsigned int eax, ebx, ecx, edx;

        cpuid(op, &eax, &ebx, &ecx, &edx);

        return edx;
}

/* REP NOP (PAUSE) is a good thing to insert into busy-wait loops. */
static __always_inline void rep_nop(void)
{
        asm volatile("rep; nop" ::: "memory");
}

static __always_inline void cpu_relax(void)
{
        rep_nop();
}

/*
 * This function forces the icache and prefetched instruction stream to
 * catch up with reality in two very specific cases:
 *
 *  a) Text was modified using one virtual address and is about to be executed
 *     from the same physical page at a different virtual address.
 *
 *  b) Text was modified on a different CPU, may subsequently be
 *     executed on this CPU, and you want to make sure the new version
 *     gets executed.  This generally means you're calling this in a IPI.
 *
 * If you're calling this for a different reason, you're probably doing
 * it wrong.
 */
static inline void sync_core(void)
{
        /*
         * There are quite a few ways to do this.  IRET-to-self is nice
         * because it works on every CPU, at any CPL (so it's compatible
         * with paravirtualization), and it never exits to a hypervisor.
         * The only down sides are that it's a bit slow (it seems to be
         * a bit more than 2x slower than the fastest options) and that
         * it unmasks NMIs.  The "push %cs" is needed because, in
         * paravirtual environments, __KERNEL_CS may not be a valid CS
         * value when we do IRET directly.
         *
         * In case NMI unmasking or performance ever becomes a problem,
         * the next best option appears to be MOV-to-CR2 and an
         * unconditional jump.  That sequence also works on all CPUs,
         * but it will fault at CPL3 (i.e. Xen PV and lguest).
         *
         * CPUID is the conventional way, but it's nasty: it doesn't
         * exist on some 486-like CPUs, and it usually exits to a
         * hypervisor.
         *
         * Like all of Linux's memory ordering operations, this is a
         * compiler barrier as well.
         */
        register void *__sp asm(_ASM_SP);

#ifdef CONFIG_X86_32
        asm volatile (
                "pushfl\n\t"
                "pushl %%cs\n\t"
                "pushl $1f\n\t"
                "iret\n\t"
                "1:"
                : "+r" (__sp) : : "memory");
#else
        unsigned int tmp;

        asm volatile (
                "mov %%ss, %0\n\t"
                "pushq %q0\n\t"
                "pushq %%rsp\n\t"
                "addq $8, (%%rsp)\n\t"
                "pushfq\n\t"
                "mov %%cs, %0\n\t"
                "pushq %q0\n\t"
                "pushq $1f\n\t"
                "iretq\n\t"
                "1:"
                : "=&r" (tmp), "+r" (__sp) : : "cc", "memory");
#endif
}

extern void select_idle_routine(const struct cpuinfo_x86 *c);
extern void amd_e400_c1e_apic_setup(void);

extern unsigned long            boot_option_idle_override;

enum idle_boot_override {IDLE_NO_OVERRIDE=0, IDLE_HALT, IDLE_NOMWAIT,
                         IDLE_POLL};

extern void enable_sep_cpu(void);
extern int sysenter_setup(void);

extern void early_trap_init(void);
void early_trap_pf_init(void);

/* Defined in head.S */
extern struct desc_ptr          early_gdt_descr;

extern void cpu_set_gdt(int);
extern void switch_to_new_gdt(int);
extern void load_direct_gdt(int);
extern void load_fixmap_gdt(int);
extern void load_percpu_segment(int);
extern void cpu_init(void);

static inline unsigned long get_debugctlmsr(void)
{
        unsigned long debugctlmsr = 0;

#ifndef CONFIG_X86_DEBUGCTLMSR
        if (boot_cpu_data.x86 < 6)
                return 0;
#endif
        rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctlmsr);

        return debugctlmsr;
}

static inline void update_debugctlmsr(unsigned long debugctlmsr)
{
#ifndef CONFIG_X86_DEBUGCTLMSR
        if (boot_cpu_data.x86 < 6)
                return;
#endif
        wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctlmsr);
}

extern void set_task_blockstep(struct task_struct *task, bool on);

/* Boot loader type from the setup header: */
extern int                      bootloader_type;
extern int                      bootloader_version;

extern char                     ignore_fpu_irq;

#define HAVE_ARCH_PICK_MMAP_LAYOUT 1
#define ARCH_HAS_PREFETCHW
#define ARCH_HAS_SPINLOCK_PREFETCH

#ifdef CONFIG_X86_32
# define BASE_PREFETCH          ""
# define ARCH_HAS_PREFETCH
#else
# define BASE_PREFETCH          "prefetcht0 %P1"
#endif

/*
 * Prefetch instructions for Pentium III (+) and AMD Athlon (+)
 *
 * It's not worth to care about 3dnow prefetches for the K6
 * because they are microcoded there and very slow.
 */
static inline void prefetch(const void *x)
{
        alternative_input(BASE_PREFETCH, "prefetchnta %P1",
                          X86_FEATURE_XMM,
                          "m" (*(const char *)x));
}

/*
 * 3dnow prefetch to get an exclusive cache line.
 * Useful for spinlocks to avoid one state transition in the
 * cache coherency protocol:
 */
static inline void prefetchw(const void *x)
{
        alternative_input(BASE_PREFETCH, "prefetchw %P1",
                          X86_FEATURE_3DNOWPREFETCH,
                          "m" (*(const char *)x));
}

static inline void spin_lock_prefetch(const void *x)
{
        prefetchw(x);
}

#define TOP_OF_INIT_STACK ((unsigned long)&init_stack + sizeof(init_stack) - \
                           TOP_OF_KERNEL_STACK_PADDING)

#define task_top_of_stack(task) ((unsigned long)(task_pt_regs(task) + 1))

#define task_pt_regs(task) \
({                                                                      \
        unsigned long __ptr = (unsigned long)task_stack_page(task);     \
        __ptr += THREAD_SIZE - TOP_OF_KERNEL_STACK_PADDING;             \
        ((struct pt_regs *)__ptr) - 1;                                  \
})

#ifdef CONFIG_X86_32
/*
 * User space process size: 3GB (default).
 */
#define IA32_PAGE_OFFSET        PAGE_OFFSET
#define TASK_SIZE               PAGE_OFFSET
#define TASK_SIZE_MAX           TASK_SIZE
#define STACK_TOP               TASK_SIZE
#define STACK_TOP_MAX           STACK_TOP

#define INIT_THREAD  {                                                    \
        .sp0                    = TOP_OF_INIT_STACK,                      \
        .sysenter_cs            = __KERNEL_CS,                            \
        .io_bitmap_ptr          = NULL,                                   \
        .addr_limit             = KERNEL_DS,                              \
}

#define KSTK_ESP(task)          (task_pt_regs(task)->sp)

#else
/*
 * User space process size.  This is the first address outside the user range.
 * There are a few constraints that determine this:
 *
 * On Intel CPUs, if a SYSCALL instruction is at the highest canonical
 * address, then that syscall will enter the kernel with a
 * non-canonical return address, and SYSRET will explode dangerously.
 * We avoid this particular problem by preventing anything executable
 * from being mapped at the maximum canonical address.
 *
 * On AMD CPUs in the Ryzen family, there's a nasty bug in which the
 * CPUs malfunction if they execute code from the highest canonical page.
 * They'll speculate right off the end of the canonical space, and
 * bad things happen.  This is worked around in the same way as the
 * Intel problem.
 *
 * With page table isolation enabled, we map the LDT in ... [stay tuned]
 */
#define TASK_SIZE_MAX   ((1UL << 47) - PAGE_SIZE)

/* This decides where the kernel will search for a free chunk of vm
 * space during mmap's.
 */
#define IA32_PAGE_OFFSET        ((current->personality & ADDR_LIMIT_3GB) ? \
                                        0xc0000000 : 0xFFFFe000)

#define TASK_SIZE               (test_thread_flag(TIF_ADDR32) ? \
                                        IA32_PAGE_OFFSET : TASK_SIZE_MAX)
#define TASK_SIZE_OF(child)     ((test_tsk_thread_flag(child, TIF_ADDR32)) ? \
                                        IA32_PAGE_OFFSET : TASK_SIZE_MAX)

#define STACK_TOP               TASK_SIZE
#define STACK_TOP_MAX           TASK_SIZE_MAX

#define INIT_THREAD  {                                          \
        .addr_limit             = KERNEL_DS,                    \
}

extern unsigned long KSTK_ESP(struct task_struct *task);

#endif /* CONFIG_X86_64 */

extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
                                               unsigned long new_sp);

/*
 * This decides where the kernel will search for a free chunk of vm
 * space during mmap's.
 */
#define __TASK_UNMAPPED_BASE(task_size) (PAGE_ALIGN(task_size / 3))
#define TASK_UNMAPPED_BASE              __TASK_UNMAPPED_BASE(TASK_SIZE)

#define KSTK_EIP(task)          (task_pt_regs(task)->ip)

/* Get/set a process' ability to use the timestamp counter instruction */
#define GET_TSC_CTL(adr)        get_tsc_mode((adr))
#define SET_TSC_CTL(val)        set_tsc_mode((val))

extern int get_tsc_mode(unsigned long adr);
extern int set_tsc_mode(unsigned int val);

DECLARE_PER_CPU(u64, msr_misc_features_shadow);

/* Register/unregister a process' MPX related resource */
#define MPX_ENABLE_MANAGEMENT() mpx_enable_management()
#define MPX_DISABLE_MANAGEMENT()        mpx_disable_management()

#ifdef CONFIG_X86_INTEL_MPX
extern int mpx_enable_management(void);
extern int mpx_disable_management(void);
#else
static inline int mpx_enable_management(void)
{
        return -EINVAL;
}
static inline int mpx_disable_management(void)
{
        return -EINVAL;
}
#endif /* CONFIG_X86_INTEL_MPX */

#ifdef CONFIG_CPU_SUP_AMD
extern u16 amd_get_nb_id(int cpu);
extern u32 amd_get_nodes_per_socket(void);
#else
static inline u16 amd_get_nb_id(int cpu)                { return 0; }
static inline u32 amd_get_nodes_per_socket(void)        { return 0; }
#endif

static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves)
{
        uint32_t base, eax, signature[3];

        for (base = 0x40000000; base < 0x40010000; base += 0x100) {
                cpuid(base, &eax, &signature[0], &signature[1], &signature[2]);

                if (!memcmp(sig, signature, 12) &&
                    (leaves == 0 || ((eax - base) >= leaves)))
                        return base;
        }

        return 0;
}

extern unsigned long arch_align_stack(unsigned long sp);
extern void free_init_pages(char *what, unsigned long begin, unsigned long end);

void default_idle(void);
#ifdef  CONFIG_XEN
bool xen_set_default_idle(void);
#else
#define xen_set_default_idle 0
#endif

void stop_this_cpu(void *dummy);
void df_debug(struct pt_regs *regs, long error_code);
#endif /* _ASM_X86_PROCESSOR_H */