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root/include/asm-x86/segment.h

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INCLUDED FROM


#ifndef ASM_X86__SEGMENT_H
#define ASM_X86__SEGMENT_H

/* Constructor for a conventional segment GDT (or LDT) entry */
/* This is a macro so it can be used in initializers */
#define GDT_ENTRY(flags, base, limit)                   \
        ((((base)  & 0xff000000ULL) << (56-24)) |       \
         (((flags) & 0x0000f0ffULL) << 40) |            \
         (((limit) & 0x000f0000ULL) << (48-16)) |       \
         (((base)  & 0x00ffffffULL) << 16) |            \
         (((limit) & 0x0000ffffULL)))

/* Simple and small GDT entries for booting only */

#define GDT_ENTRY_BOOT_CS       2
#define __BOOT_CS               (GDT_ENTRY_BOOT_CS * 8)

#define GDT_ENTRY_BOOT_DS       (GDT_ENTRY_BOOT_CS + 1)
#define __BOOT_DS               (GDT_ENTRY_BOOT_DS * 8)

#define GDT_ENTRY_BOOT_TSS      (GDT_ENTRY_BOOT_CS + 2)
#define __BOOT_TSS              (GDT_ENTRY_BOOT_TSS * 8)

#ifdef CONFIG_X86_32
/*
 * The layout of the per-CPU GDT under Linux:
 *
 *   0 - null
 *   1 - reserved
 *   2 - reserved
 *   3 - reserved
 *
 *   4 - unused                 <==== new cacheline
 *   5 - unused
 *
 *  ------- start of TLS (Thread-Local Storage) segments:
 *
 *   6 - TLS segment #1                 [ glibc's TLS segment ]
 *   7 - TLS segment #2                 [ Wine's %fs Win32 segment ]
 *   8 - TLS segment #3
 *   9 - reserved
 *  10 - reserved
 *  11 - reserved
 *
 *  ------- start of kernel segments:
 *
 *  12 - kernel code segment            <==== new cacheline
 *  13 - kernel data segment
 *  14 - default user CS
 *  15 - default user DS
 *  16 - TSS
 *  17 - LDT
 *  18 - PNPBIOS support (16->32 gate)
 *  19 - PNPBIOS support
 *  20 - PNPBIOS support
 *  21 - PNPBIOS support
 *  22 - PNPBIOS support
 *  23 - APM BIOS support
 *  24 - APM BIOS support
 *  25 - APM BIOS support
 *
 *  26 - ESPFIX small SS
 *  27 - per-cpu                        [ offset to per-cpu data area ]
 *  28 - unused
 *  29 - unused
 *  30 - unused
 *  31 - TSS for double fault handler
 */
#define GDT_ENTRY_TLS_MIN       6
#define GDT_ENTRY_TLS_MAX       (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)

#define GDT_ENTRY_DEFAULT_USER_CS       14

#define GDT_ENTRY_DEFAULT_USER_DS       15

#define GDT_ENTRY_KERNEL_BASE   12

#define GDT_ENTRY_KERNEL_CS             (GDT_ENTRY_KERNEL_BASE + 0)

#define GDT_ENTRY_KERNEL_DS             (GDT_ENTRY_KERNEL_BASE + 1)

#define GDT_ENTRY_TSS                   (GDT_ENTRY_KERNEL_BASE + 4)
#define GDT_ENTRY_LDT                   (GDT_ENTRY_KERNEL_BASE + 5)

#define GDT_ENTRY_PNPBIOS_BASE          (GDT_ENTRY_KERNEL_BASE + 6)
#define GDT_ENTRY_APMBIOS_BASE          (GDT_ENTRY_KERNEL_BASE + 11)

#define GDT_ENTRY_ESPFIX_SS             (GDT_ENTRY_KERNEL_BASE + 14)
#define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS * 8)

#define GDT_ENTRY_PERCPU                        (GDT_ENTRY_KERNEL_BASE + 15)
#ifdef CONFIG_SMP
#define __KERNEL_PERCPU (GDT_ENTRY_PERCPU * 8)
#else
#define __KERNEL_PERCPU 0
#endif

#define GDT_ENTRY_DOUBLEFAULT_TSS       31

/*
 * The GDT has 32 entries
 */
#define GDT_ENTRIES 32

/* The PnP BIOS entries in the GDT */
#define GDT_ENTRY_PNPBIOS_CS32          (GDT_ENTRY_PNPBIOS_BASE + 0)
#define GDT_ENTRY_PNPBIOS_CS16          (GDT_ENTRY_PNPBIOS_BASE + 1)
#define GDT_ENTRY_PNPBIOS_DS            (GDT_ENTRY_PNPBIOS_BASE + 2)
#define GDT_ENTRY_PNPBIOS_TS1           (GDT_ENTRY_PNPBIOS_BASE + 3)
#define GDT_ENTRY_PNPBIOS_TS2           (GDT_ENTRY_PNPBIOS_BASE + 4)

/* The PnP BIOS selectors */
#define PNP_CS32   (GDT_ENTRY_PNPBIOS_CS32 * 8) /* segment for calling fn */
#define PNP_CS16   (GDT_ENTRY_PNPBIOS_CS16 * 8) /* code segment for BIOS */
#define PNP_DS     (GDT_ENTRY_PNPBIOS_DS * 8)   /* data segment for BIOS */
#define PNP_TS1    (GDT_ENTRY_PNPBIOS_TS1 * 8)  /* transfer data segment */
#define PNP_TS2    (GDT_ENTRY_PNPBIOS_TS2 * 8)  /* another data segment */

/* Bottom two bits of selector give the ring privilege level */
#define SEGMENT_RPL_MASK        0x3
/* Bit 2 is table indicator (LDT/GDT) */
#define SEGMENT_TI_MASK         0x4

/* User mode is privilege level 3 */
#define USER_RPL                0x3
/* LDT segment has TI set, GDT has it cleared */
#define SEGMENT_LDT             0x4
#define SEGMENT_GDT             0x0

/*
 * Matching rules for certain types of segments.
 */

/* Matches PNP_CS32 and PNP_CS16 (they must be consecutive) */
#define SEGMENT_IS_PNP_CODE(x)   (((x) & 0xf4) == GDT_ENTRY_PNPBIOS_BASE * 8)


#else
#include <asm/cache.h>

#define GDT_ENTRY_KERNEL32_CS 1
#define GDT_ENTRY_KERNEL_CS 2
#define GDT_ENTRY_KERNEL_DS 3

#define __KERNEL32_CS   (GDT_ENTRY_KERNEL32_CS * 8)

/*
 * we cannot use the same code segment descriptor for user and kernel
 * -- not even in the long flat mode, because of different DPL /kkeil
 * The segment offset needs to contain a RPL. Grr. -AK
 * GDT layout to get 64bit syscall right (sysret hardcodes gdt offsets)
 */
#define GDT_ENTRY_DEFAULT_USER32_CS 4
#define GDT_ENTRY_DEFAULT_USER_DS 5
#define GDT_ENTRY_DEFAULT_USER_CS 6
#define __USER32_CS   (GDT_ENTRY_DEFAULT_USER32_CS * 8 + 3)
#define __USER32_DS     __USER_DS

#define GDT_ENTRY_TSS 8 /* needs two entries */
#define GDT_ENTRY_LDT 10 /* needs two entries */
#define GDT_ENTRY_TLS_MIN 12
#define GDT_ENTRY_TLS_MAX 14

#define GDT_ENTRY_PER_CPU 15    /* Abused to load per CPU data from limit */
#define __PER_CPU_SEG   (GDT_ENTRY_PER_CPU * 8 + 3)

/* TLS indexes for 64bit - hardcoded in arch_prctl */
#define FS_TLS 0
#define GS_TLS 1

#define GS_TLS_SEL ((GDT_ENTRY_TLS_MIN+GS_TLS)*8 + 3)
#define FS_TLS_SEL ((GDT_ENTRY_TLS_MIN+FS_TLS)*8 + 3)

#define GDT_ENTRIES 16

#endif

#define __KERNEL_CS     (GDT_ENTRY_KERNEL_CS * 8)
#define __KERNEL_DS     (GDT_ENTRY_KERNEL_DS * 8)
#define __USER_DS     (GDT_ENTRY_DEFAULT_USER_DS* 8 + 3)
#define __USER_CS     (GDT_ENTRY_DEFAULT_USER_CS* 8 + 3)
#ifndef CONFIG_PARAVIRT
#define get_kernel_rpl()  0
#endif

/* User mode is privilege level 3 */
#define USER_RPL                0x3
/* LDT segment has TI set, GDT has it cleared */
#define SEGMENT_LDT             0x4
#define SEGMENT_GDT             0x0

/* Bottom two bits of selector give the ring privilege level */
#define SEGMENT_RPL_MASK        0x3
/* Bit 2 is table indicator (LDT/GDT) */
#define SEGMENT_TI_MASK         0x4

#define IDT_ENTRIES 256
#define NUM_EXCEPTION_VECTORS 32
#define GDT_SIZE (GDT_ENTRIES * 8)
#define GDT_ENTRY_TLS_ENTRIES 3
#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)

#ifdef __KERNEL__
#ifndef __ASSEMBLY__
extern const char early_idt_handlers[NUM_EXCEPTION_VECTORS][10];
#endif
#endif

#endif /* ASM_X86__SEGMENT_H */

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