#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) #define SEGMENT_RPL_MASK 0x3 /* * Bottom two bits of selector give the ring * privilege level */ #define SEGMENT_TI_MASK 0x4 /* Bit 2 is table indicator (LDT/GDT) */ #define USER_RPL 0x3 /* User mode is privilege level 3 */ #define SEGMENT_LDT 0x4 /* LDT segment has TI set... */ #define SEGMENT_GDT 0x0 /* ... GDT has it cleared */ #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 - stack_canary-20 [ for stack protector ] * 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 #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) #define PNP_CS32 (GDT_ENTRY_PNPBIOS_CS32 * 8) /* segment for calling fn */ #define PNP_CS16 (GDT_ENTRY_PNPBIOS_CS16 * 8) /* code segment for BIOS */ /* "Is this PNP code selector (PNP_CS32 or PNP_CS16)?" */ #define SEGMENT_IS_PNP_CODE(x) (((x) & 0xf4) == PNP_CS32) #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 */ #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 #define GDT_ENTRIES 32 #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 * -- not even in the long flat mode, because of different DPL /kkeil * GDT layout to get 64bit syscall/sysret 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 #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 */ /* Selectors need to also have a correct RPL (+3 thingy) */ #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 __KERNEL32_CS (GDT_ENTRY_KERNEL32_CS*8) #define __USER32_CS (GDT_ENTRY_DEFAULT_USER32_CS*8+3) #define __USER32_DS __USER_DS #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 #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 */ static inline unsigned long get_limit(unsigned long segment) { unsigned long __limit; asm("lsll %1,%0" : "=r" (__limit) : "r" (segment)); return __limit + 1; } #endif /* !__ASSEMBLY__ */ #endif /* __KERNEL__ */ #endif /* _ASM_X86_SEGMENT_H */