#ifndef _ASM_X86_SEGMENT_H #define _ASM_X86_SEGMENT_H #include /* * 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) & _AC(0xff000000,ULL)) << (56-24)) | \ (((flags) & _AC(0x0000f0ff,ULL)) << 40) | \ (((limit) & _AC(0x000f0000,ULL)) << (48-16)) | \ (((base) & _AC(0x00ffffff,ULL)) << 16) | \ (((limit) & _AC(0x0000ffff,ULL)))) /* Simple and small GDT entries for booting only: */ #define GDT_ENTRY_BOOT_CS 2 #define GDT_ENTRY_BOOT_DS 3 #define GDT_ENTRY_BOOT_TSS 4 #define __BOOT_CS (GDT_ENTRY_BOOT_CS*8) #define __BOOT_DS (GDT_ENTRY_BOOT_DS*8) #define __BOOT_TSS (GDT_ENTRY_BOOT_TSS*8) /* * Bottom two bits of selector give the ring * privilege level */ #define SEGMENT_RPL_MASK 0x3 /* User mode is privilege level 3: */ #define USER_RPL 0x3 /* Bit 2 is Table Indicator (TI): selects between LDT or GDT */ #define SEGMENT_TI_MASK 0x4 /* LDT segment has TI set ... */ #define SEGMENT_LDT 0x4 /* ... GDT has it cleared */ #define SEGMENT_GDT 0x0 #ifdef CONFIG_X86_32 /* * The layout of the per-CPU GDT under Linux: * * 0 - null <=== cacheline #1 * 1 - reserved * 2 - reserved * 3 - reserved * * 4 - unused <=== cacheline #2 * 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 <=== cacheline #3 * 9 - reserved * 10 - reserved * 11 - reserved * * ------- start of kernel segments: * * 12 - kernel code segment <=== cacheline #4 * 13 - kernel data segment * 14 - default user CS * 15 - default user DS * 16 - TSS <=== cacheline #5 * 17 - LDT * 18 - PNPBIOS support (16->32 gate) * 19 - PNPBIOS support * 20 - PNPBIOS support <=== cacheline #6 * 21 - PNPBIOS support * 22 - PNPBIOS support * 23 - APM BIOS support * 24 - APM BIOS support <=== cacheline #7 * 25 - APM BIOS support * * 26 - ESPFIX small SS * 27 - per-cpu [ offset to per-cpu data area ] * 28 - stack_canary-20 [ for stack protector ] <=== cacheline #8 * 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_KERNEL_CS 12 #define GDT_ENTRY_KERNEL_DS 13 #define GDT_ENTRY_DEFAULT_USER_CS 14 #define GDT_ENTRY_DEFAULT_USER_DS 15 #define GDT_ENTRY_TSS 16 #define GDT_ENTRY_LDT 17 #define GDT_ENTRY_PNPBIOS_CS32 18 #define GDT_ENTRY_PNPBIOS_CS16 19 #define GDT_ENTRY_PNPBIOS_DS 20 #define GDT_ENTRY_PNPBIOS_TS1 21 #define GDT_ENTRY_PNPBIOS_TS2 22 #define GDT_ENTRY_APMBIOS_BASE 23 #define GDT_ENTRY_ESPFIX_SS 26 #define GDT_ENTRY_PERCPU 27 #define GDT_ENTRY_STACK_CANARY 28 #define GDT_ENTRY_DOUBLEFAULT_TSS 31 /* * Number of entries in the GDT table: */ #define GDT_ENTRIES 32 /* * Segment selector values corresponding to the above entries: */ #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) #define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS*8) /* segment for calling fn: */ #define PNP_CS32 (GDT_ENTRY_PNPBIOS_CS32*8) /* code segment for BIOS: */ #define PNP_CS16 (GDT_ENTRY_PNPBIOS_CS16*8) /* "Is this PNP code selector (PNP_CS32 or PNP_CS16)?" */ #define SEGMENT_IS_PNP_CODE(x) (((x) & 0xf4) == PNP_CS32) /* data segment for BIOS: */ #define PNP_DS (GDT_ENTRY_PNPBIOS_DS*8) /* transfer data segment: */ #define PNP_TS1 (GDT_ENTRY_PNPBIOS_TS1*8) /* another data segment: */ #define PNP_TS2 (GDT_ENTRY_PNPBIOS_TS2*8) #ifdef CONFIG_SMP # define __KERNEL_PERCPU (GDT_ENTRY_PERCPU*8) #else # define __KERNEL_PERCPU 0 #endif #ifdef CONFIG_CC_STACKPROTECTOR # define __KERNEL_STACK_CANARY (GDT_ENTRY_STACK_CANARY*8) #else # define __KERNEL_STACK_CANARY 0 #endif #else /* 64-bit: */ #include #define GDT_ENTRY_KERNEL32_CS 1 #define GDT_ENTRY_KERNEL_CS 2 #define GDT_ENTRY_KERNEL_DS 3 /* * We cannot use the same code segment descriptor for user and kernel mode, * not even in long flat mode, because of different DPL. * * GDT layout to get 64-bit SYSCALL/SYSRET support right. SYSRET hardcodes * selectors: * * if returning to 32-bit userspace: cs = STAR.SYSRET_CS, * if returning to 64-bit userspace: cs = STAR.SYSRET_CS+16, * * ss = STAR.SYSRET_CS+8 (in either case) * * thus USER_DS should be between 32-bit and 64-bit code selectors: */ #define GDT_ENTRY_DEFAULT_USER32_CS 4 #define GDT_ENTRY_DEFAULT_USER_DS 5 #define GDT_ENTRY_DEFAULT_USER_CS 6 /* Needs two entries */ #define GDT_ENTRY_TSS 8 /* Needs two entries */ #define GDT_ENTRY_LDT 10 #define GDT_ENTRY_TLS_MIN 12 #define GDT_ENTRY_TLS_MAX 14 /* Abused to load per CPU data from limit */ #define GDT_ENTRY_PER_CPU 15 /* * Number of entries in the GDT table: */ #define GDT_ENTRIES 16 /* * Segment selector values corresponding to the above entries: * * Note, selectors also need to have a correct RPL, * expressed with the +3 value for user-space selectors: */ #define __KERNEL32_CS (GDT_ENTRY_KERNEL32_CS*8) #define __KERNEL_CS (GDT_ENTRY_KERNEL_CS*8) #define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8) #define __USER32_CS (GDT_ENTRY_DEFAULT_USER32_CS*8 + 3) #define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8 + 3) #define __USER32_DS __USER_DS #define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8 + 3) #define __PER_CPU_SEG (GDT_ENTRY_PER_CPU*8 + 3) /* TLS indexes for 64-bit - 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) #endif #ifndef CONFIG_PARAVIRT # define get_kernel_rpl() 0 #endif #define IDT_ENTRIES 256 #define NUM_EXCEPTION_VECTORS 32 /* Bitmask of exception vectors which push an error code on the stack: */ #define EXCEPTION_ERRCODE_MASK 0x00027d00 #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][2+2+5]; #ifdef CONFIG_TRACING # define trace_early_idt_handlers early_idt_handlers #endif /* * Load a segment. Fall back on loading the zero * segment if something goes wrong.. */ #define loadsegment(seg, value) \ do { \ unsigned short __val = (value); \ \ asm volatile(" \n" \ "1: movl %k0,%%" #seg " \n" \ \ ".section .fixup,\"ax\" \n" \ "2: xorl %k0,%k0 \n" \ " jmp 1b \n" \ ".previous \n" \ \ _ASM_EXTABLE(1b, 2b) \ \ : "+r" (__val) : : "memory"); \ } while (0) /* * Save a segment register away: */ #define savesegment(seg, value) \ asm("mov %%" #seg ",%0":"=r" (value) : : "memory") /* * x86-32 user GS accessors: */ #ifdef CONFIG_X86_32 # ifdef CONFIG_X86_32_LAZY_GS # define get_user_gs(regs) (u16)({ unsigned long v; savesegment(gs, v); v; }) # define set_user_gs(regs, v) loadsegment(gs, (unsigned long)(v)) # define task_user_gs(tsk) ((tsk)->thread.gs) # define lazy_save_gs(v) savesegment(gs, (v)) # define lazy_load_gs(v) loadsegment(gs, (v)) # else /* X86_32_LAZY_GS */ # define get_user_gs(regs) (u16)((regs)->gs) # define set_user_gs(regs, v) do { (regs)->gs = (v); } while (0) # define task_user_gs(tsk) (task_pt_regs(tsk)->gs) # define lazy_save_gs(v) do { } while (0) # define lazy_load_gs(v) do { } while (0) # endif /* X86_32_LAZY_GS */ #endif /* X86_32 */ #endif /* !__ASSEMBLY__ */ #endif /* __KERNEL__ */ #endif /* _ASM_X86_SEGMENT_H */