arch/x86/include/asm/desc.h

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This source file includes following definitions.
fill_ldt
get_cpu_gdt_table
pack_gate
pack_gate
desc_empty
paravirt_alloc_ldt
paravirt_free_ldt
native_write_idt_entry
native_write_ldt_entry
native_write_gdt_entry
pack_descriptor
set_tssldt_descriptor
__set_tss_desc
native_set_ldt
native_load_tr_desc
native_load_gdt
native_load_idt
native_store_gdt
native_store_idt
native_store_tr
native_load_tls
LDT_zero
clear_LDT
load_LDT_nolock
load_LDT
get_desc_base
set_desc_base
get_desc_limit
set_desc_limit
set_nmi_gate
write_trace_idt_entry
_trace_set_gate
write_trace_idt_entry
_set_gate
alloc_system_vector
set_system_intr_gate
set_system_trap_gate
set_trap_gate
set_task_gate
set_intr_gate_ist
set_system_intr_gate_ist
is_debug_idt_enabled
load_debug_idt
is_debug_idt_enabled
load_debug_idt
is_trace_idt_enabled
load_trace_idt
is_trace_idt_enabled
load_trace_idt
load_current_idt
#ifndef _ASM_X86_DESC_H
#define _ASM_X86_DESC_H

#include <asm/desc_defs.h>
#include <asm/ldt.h>
#include <asm/mmu.h>

#include <linux/smp.h>
#include <linux/percpu.h>

static inline void fill_ldt(struct desc_struct *desc, const struct user_desc *info)
{
        desc->limit0            = info->limit & 0x0ffff;

        desc->base0             = (info->base_addr & 0x0000ffff);
        desc->base1             = (info->base_addr & 0x00ff0000) >> 16;

        desc->type              = (info->read_exec_only ^ 1) << 1;
        desc->type             |= info->contents << 2;

        desc->s                 = 1;
        desc->dpl               = 0x3;
        desc->p                 = info->seg_not_present ^ 1;
        desc->limit             = (info->limit & 0xf0000) >> 16;
        desc->avl               = info->useable;
        desc->d                 = info->seg_32bit;
        desc->g                 = info->limit_in_pages;

        desc->base2             = (info->base_addr & 0xff000000) >> 24;
        /*
         * Don't allow setting of the lm bit. It would confuse
         * user_64bit_mode and would get overridden by sysret anyway.
         */
        desc->l                 = 0;
}

extern struct desc_ptr idt_descr;
extern gate_desc idt_table[];
extern struct desc_ptr debug_idt_descr;
extern gate_desc debug_idt_table[];

struct gdt_page {
        struct desc_struct gdt[GDT_ENTRIES];
} __attribute__((aligned(PAGE_SIZE)));

DECLARE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page);

static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu)
{
        return per_cpu(gdt_page, cpu).gdt;
}

#ifdef CONFIG_X86_64

static inline void pack_gate(gate_desc *gate, unsigned type, unsigned long func,
                             unsigned dpl, unsigned ist, unsigned seg)
{
        gate->offset_low        = PTR_LOW(func);
        gate->segment           = __KERNEL_CS;
        gate->ist               = ist;
        gate->p                 = 1;
        gate->dpl               = dpl;
        gate->zero0             = 0;
        gate->zero1             = 0;
        gate->type              = type;
        gate->offset_middle     = PTR_MIDDLE(func);
        gate->offset_high       = PTR_HIGH(func);
}

#else
static inline void pack_gate(gate_desc *gate, unsigned char type,
                             unsigned long base, unsigned dpl, unsigned flags,
                             unsigned short seg)
{
        gate->a = (seg << 16) | (base & 0xffff);
        gate->b = (base & 0xffff0000) | (((0x80 | type | (dpl << 5)) & 0xff) << 8);
}

#endif

static inline int desc_empty(const void *ptr)
{
        const u32 *desc = ptr;

        return !(desc[0] | desc[1]);
}

#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#else
#define load_TR_desc()                          native_load_tr_desc()
#define load_gdt(dtr)                           native_load_gdt(dtr)
#define load_idt(dtr)                           native_load_idt(dtr)
#define load_tr(tr)                             asm volatile("ltr %0"::"m" (tr))
#define load_ldt(ldt)                           asm volatile("lldt %0"::"m" (ldt))

#define store_gdt(dtr)                          native_store_gdt(dtr)
#define store_idt(dtr)                          native_store_idt(dtr)
#define store_tr(tr)                            (tr = native_store_tr())

#define load_TLS(t, cpu)                        native_load_tls(t, cpu)
#define set_ldt                                 native_set_ldt

#define write_ldt_entry(dt, entry, desc)        native_write_ldt_entry(dt, entry, desc)
#define write_gdt_entry(dt, entry, desc, type)  native_write_gdt_entry(dt, entry, desc, type)
#define write_idt_entry(dt, entry, g)           native_write_idt_entry(dt, entry, g)

static inline void paravirt_alloc_ldt(struct desc_struct *ldt, unsigned entries)
{
}

static inline void paravirt_free_ldt(struct desc_struct *ldt, unsigned entries)
{
}
#endif  /* CONFIG_PARAVIRT */

#define store_ldt(ldt) asm("sldt %0" : "=m"(ldt))

static inline void native_write_idt_entry(gate_desc *idt, int entry, const gate_desc *gate)
{
        memcpy(&idt[entry], gate, sizeof(*gate));
}

static inline void native_write_ldt_entry(struct desc_struct *ldt, int entry, const void *desc)
{
        memcpy(&ldt[entry], desc, 8);
}

static inline void
native_write_gdt_entry(struct desc_struct *gdt, int entry, const void *desc, int type)
{
        unsigned int size;

        switch (type) {
        case DESC_TSS:  size = sizeof(tss_desc);        break;
        case DESC_LDT:  size = sizeof(ldt_desc);        break;
        default:        size = sizeof(*gdt);            break;
        }

        memcpy(&gdt[entry], desc, size);
}

static inline void pack_descriptor(struct desc_struct *desc, unsigned long base,
                                   unsigned long limit, unsigned char type,
                                   unsigned char flags)
{
        desc->a = ((base & 0xffff) << 16) | (limit & 0xffff);
        desc->b = (base & 0xff000000) | ((base & 0xff0000) >> 16) |
                (limit & 0x000f0000) | ((type & 0xff) << 8) |
                ((flags & 0xf) << 20);
        desc->p = 1;
}


static inline void set_tssldt_descriptor(void *d, unsigned long addr, unsigned type, unsigned size)
{
#ifdef CONFIG_X86_64
        struct ldttss_desc64 *desc = d;

        memset(desc, 0, sizeof(*desc));

        desc->limit0            = size & 0xFFFF;
        desc->base0             = PTR_LOW(addr);
        desc->base1             = PTR_MIDDLE(addr) & 0xFF;
        desc->type              = type;
        desc->p                 = 1;
        desc->limit1            = (size >> 16) & 0xF;
        desc->base2             = (PTR_MIDDLE(addr) >> 8) & 0xFF;
        desc->base3             = PTR_HIGH(addr);
#else
        pack_descriptor((struct desc_struct *)d, addr, size, 0x80 | type, 0);
#endif
}

static inline void __set_tss_desc(unsigned cpu, unsigned int entry, void *addr)
{
        struct desc_struct *d = get_cpu_gdt_table(cpu);
        tss_desc tss;

        /*
         * sizeof(unsigned long) coming from an extra "long" at the end
         * of the iobitmap. See tss_struct definition in processor.h
         *
         * -1? seg base+limit should be pointing to the address of the
         * last valid byte
         */
        set_tssldt_descriptor(&tss, (unsigned long)addr, DESC_TSS,
                              IO_BITMAP_OFFSET + IO_BITMAP_BYTES +
                              sizeof(unsigned long) - 1);
        write_gdt_entry(d, entry, &tss, DESC_TSS);
}

#define set_tss_desc(cpu, addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)

static inline void native_set_ldt(const void *addr, unsigned int entries)
{
        if (likely(entries == 0))
                asm volatile("lldt %w0"::"q" (0));
        else {
                unsigned cpu = smp_processor_id();
                ldt_desc ldt;

                set_tssldt_descriptor(&ldt, (unsigned long)addr, DESC_LDT,
                                      entries * LDT_ENTRY_SIZE - 1);
                write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT,
                                &ldt, DESC_LDT);
                asm volatile("lldt %w0"::"q" (GDT_ENTRY_LDT*8));
        }
}

static inline void native_load_tr_desc(void)
{
        asm volatile("ltr %w0"::"q" (GDT_ENTRY_TSS*8));
}

static inline void native_load_gdt(const struct desc_ptr *dtr)
{
        asm volatile("lgdt %0"::"m" (*dtr));
}

static inline void native_load_idt(const struct desc_ptr *dtr)
{
        asm volatile("lidt %0"::"m" (*dtr));
}

static inline void native_store_gdt(struct desc_ptr *dtr)
{
        asm volatile("sgdt %0":"=m" (*dtr));
}

static inline void native_store_idt(struct desc_ptr *dtr)
{
        asm volatile("sidt %0":"=m" (*dtr));
}

static inline unsigned long native_store_tr(void)
{
        unsigned long tr;

        asm volatile("str %0":"=r" (tr));

        return tr;
}

static inline void native_load_tls(struct thread_struct *t, unsigned int cpu)
{
        struct desc_struct *gdt = get_cpu_gdt_table(cpu);
        unsigned int i;

        for (i = 0; i < GDT_ENTRY_TLS_ENTRIES; i++)
                gdt[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i];
}

/* This intentionally ignores lm, since 32-bit apps don't have that field. */
#define LDT_empty(info)                                 \
        ((info)->base_addr              == 0    &&      \
         (info)->limit                  == 0    &&      \
         (info)->contents               == 0    &&      \
         (info)->read_exec_only         == 1    &&      \
         (info)->seg_32bit              == 0    &&      \
         (info)->limit_in_pages         == 0    &&      \
         (info)->seg_not_present        == 1    &&      \
         (info)->useable                == 0)

/* Lots of programs expect an all-zero user_desc to mean "no segment at all". */
static inline bool LDT_zero(const struct user_desc *info)
{
        return (info->base_addr         == 0 &&
                info->limit             == 0 &&
                info->contents          == 0 &&
                info->read_exec_only    == 0 &&
                info->seg_32bit         == 0 &&
                info->limit_in_pages    == 0 &&
                info->seg_not_present   == 0 &&
                info->useable           == 0);
}

static inline void clear_LDT(void)
{
        set_ldt(NULL, 0);
}

/*
 * load one particular LDT into the current CPU
 */
static inline void load_LDT_nolock(mm_context_t *pc)
{
        set_ldt(pc->ldt, pc->size);
}

static inline void load_LDT(mm_context_t *pc)
{
        preempt_disable();
        load_LDT_nolock(pc);
        preempt_enable();
}

static inline unsigned long get_desc_base(const struct desc_struct *desc)
{
        return (unsigned)(desc->base0 | ((desc->base1) << 16) | ((desc->base2) << 24));
}

static inline void set_desc_base(struct desc_struct *desc, unsigned long base)
{
        desc->base0 = base & 0xffff;
        desc->base1 = (base >> 16) & 0xff;
        desc->base2 = (base >> 24) & 0xff;
}

static inline unsigned long get_desc_limit(const struct desc_struct *desc)
{
        return desc->limit0 | (desc->limit << 16);
}

static inline void set_desc_limit(struct desc_struct *desc, unsigned long limit)
{
        desc->limit0 = limit & 0xffff;
        desc->limit = (limit >> 16) & 0xf;
}

#ifdef CONFIG_X86_64
static inline void set_nmi_gate(int gate, void *addr)
{
        gate_desc s;

        pack_gate(&s, GATE_INTERRUPT, (unsigned long)addr, 0, 0, __KERNEL_CS);
        write_idt_entry(debug_idt_table, gate, &s);
}
#endif

#ifdef CONFIG_TRACING
extern struct desc_ptr trace_idt_descr;
extern gate_desc trace_idt_table[];
static inline void write_trace_idt_entry(int entry, const gate_desc *gate)
{
        write_idt_entry(trace_idt_table, entry, gate);
}

static inline void _trace_set_gate(int gate, unsigned type, void *addr,
                                   unsigned dpl, unsigned ist, unsigned seg)
{
        gate_desc s;

        pack_gate(&s, type, (unsigned long)addr, dpl, ist, seg);
        /*
         * does not need to be atomic because it is only done once at
         * setup time
         */
        write_trace_idt_entry(gate, &s);
}
#else
static inline void write_trace_idt_entry(int entry, const gate_desc *gate)
{
}

#define _trace_set_gate(gate, type, addr, dpl, ist, seg)
#endif

static inline void _set_gate(int gate, unsigned type, void *addr,
                             unsigned dpl, unsigned ist, unsigned seg)
{
        gate_desc s;

        pack_gate(&s, type, (unsigned long)addr, dpl, ist, seg);
        /*
         * does not need to be atomic because it is only done once at
         * setup time
         */
        write_idt_entry(idt_table, gate, &s);
        write_trace_idt_entry(gate, &s);
}

/*
 * This needs to use 'idt_table' rather than 'idt', and
 * thus use the _nonmapped_ version of the IDT, as the
 * Pentium F0 0F bugfix can have resulted in the mapped
 * IDT being write-protected.
 */
#define set_intr_gate(n, addr)                                          \
        do {                                                            \
                BUG_ON((unsigned)n > 0xFF);                             \
                _set_gate(n, GATE_INTERRUPT, (void *)addr, 0, 0,        \
                          __KERNEL_CS);                                 \
                _trace_set_gate(n, GATE_INTERRUPT, (void *)trace_##addr,\
                                0, 0, __KERNEL_CS);                     \
        } while (0)

extern int first_system_vector;
/* used_vectors is BITMAP for irq is not managed by percpu vector_irq */
extern unsigned long used_vectors[];

static inline void alloc_system_vector(int vector)
{
        if (!test_bit(vector, used_vectors)) {
                set_bit(vector, used_vectors);
                if (first_system_vector > vector)
                        first_system_vector = vector;
        } else {
                BUG();
        }
}

#define alloc_intr_gate(n, addr)                                \
        do {                                                    \
                alloc_system_vector(n);                         \
                set_intr_gate(n, addr);                         \
        } while (0)

/*
 * This routine sets up an interrupt gate at directory privilege level 3.
 */
static inline void set_system_intr_gate(unsigned int n, void *addr)
{
        BUG_ON((unsigned)n > 0xFF);
        _set_gate(n, GATE_INTERRUPT, addr, 0x3, 0, __KERNEL_CS);
}

static inline void set_system_trap_gate(unsigned int n, void *addr)
{
        BUG_ON((unsigned)n > 0xFF);
        _set_gate(n, GATE_TRAP, addr, 0x3, 0, __KERNEL_CS);
}

static inline void set_trap_gate(unsigned int n, void *addr)
{
        BUG_ON((unsigned)n > 0xFF);
        _set_gate(n, GATE_TRAP, addr, 0, 0, __KERNEL_CS);
}

static inline void set_task_gate(unsigned int n, unsigned int gdt_entry)
{
        BUG_ON((unsigned)n > 0xFF);
        _set_gate(n, GATE_TASK, (void *)0, 0, 0, (gdt_entry<<3));
}

static inline void set_intr_gate_ist(int n, void *addr, unsigned ist)
{
        BUG_ON((unsigned)n > 0xFF);
        _set_gate(n, GATE_INTERRUPT, addr, 0, ist, __KERNEL_CS);
}

static inline void set_system_intr_gate_ist(int n, void *addr, unsigned ist)
{
        BUG_ON((unsigned)n > 0xFF);
        _set_gate(n, GATE_INTERRUPT, addr, 0x3, ist, __KERNEL_CS);
}

#ifdef CONFIG_X86_64
DECLARE_PER_CPU(u32, debug_idt_ctr);
static inline bool is_debug_idt_enabled(void)
{
        if (this_cpu_read(debug_idt_ctr))
                return true;

        return false;
}

static inline void load_debug_idt(void)
{
        load_idt((const struct desc_ptr *)&debug_idt_descr);
}
#else
static inline bool is_debug_idt_enabled(void)
{
        return false;
}

static inline void load_debug_idt(void)
{
}
#endif

#ifdef CONFIG_TRACING
extern atomic_t trace_idt_ctr;
static inline bool is_trace_idt_enabled(void)
{
        if (atomic_read(&trace_idt_ctr))
                return true;

        return false;
}

static inline void load_trace_idt(void)
{
        load_idt((const struct desc_ptr *)&trace_idt_descr);
}
#else
static inline bool is_trace_idt_enabled(void)
{
        return false;
}

static inline void load_trace_idt(void)
{
}
#endif

/*
 * The load_current_idt() must be called with interrupts disabled
 * to avoid races. That way the IDT will always be set back to the expected
 * descriptor. It's also called when a CPU is being initialized, and
 * that doesn't need to disable interrupts, as nothing should be
 * bothering the CPU then.
 */
static inline void load_current_idt(void)
{
        if (is_debug_idt_enabled())
                load_debug_idt();
        else if (is_trace_idt_enabled())
                load_trace_idt();
        else
                load_idt((const struct desc_ptr *)&idt_descr);
}
#endif /* _ASM_X86_DESC_H */
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root/arch/x86/include/asm/desc.h

INCLUDED FROM

DEFINITIONS
