include/asm/segment.h

1 /* SPDX-License-Identifier: GPL-2.0 */
13 	((((base)  & _AC(0xff000000,ULL)) << (56-24)) |	\
15 	 (((limit) & _AC(0x000f0000,ULL)) << (48-16)) |	\
24 #define __BOOT_CS		(GDT_ENTRY_BOOT_CS*8)
25 #define __BOOT_DS		(GDT_ENTRY_BOOT_DS*8)
26 #define __BOOT_TSS		(GDT_ENTRY_BOOT_TSS*8)
35  * When running on Xen PV, the actual privilege level of the kernel is 1,
60  * The layout of the per-CPU GDT under Linux:
62  *   0 - null								<=== cacheline #1
63  *   1 - reserved
64  *   2 - reserved
65  *   3 - reserved
67  *   4 - unused								<=== cacheline #2
68  *   5 - unused
70  *  ------- start of TLS (Thread-Local Storage) segments:
72  *   6 - TLS segment #1			[ glibc's TLS segment ]
73  *   7 - TLS segment #2			[ Wine's %fs Win32 segment ]
74  *   8 - TLS segment #3							<=== cacheline #3
75  *   9 - reserved
76  *  10 - reserved
77  *  11 - reserved
79  *  ------- start of kernel segments:
81  *  12 - kernel code segment						<=== cacheline #4
82  *  13 - kernel data segment
83  *  14 - default user CS
84  *  15 - default user DS
85  *  16 - TSS								<=== cacheline #5
86  *  17 - LDT
87  *  18 - PNPBIOS support (16->32 gate)
88  *  19 - PNPBIOS support
89  *  20 - PNPBIOS support						<=== cacheline #6
90  *  21 - PNPBIOS support
91  *  22 - PNPBIOS support
92  *  23 - APM BIOS support
93  *  24 - APM BIOS support						<=== cacheline #7
94  *  25 - APM BIOS support
96  *  26 - ESPFIX small SS
97  *  27 - per-cpu			[ offset to per-cpu data area ]
98  *  28 - stack_canary-20		[ for stack protector ]		<=== cacheline #8
99  *  29 - unused
100  *  30 - unused
101  *  31 - TSS for double fault handler
104 #define GDT_ENTRY_TLS_MAX 		(GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
134 #define __KERNEL_CS			(GDT_ENTRY_KERNEL_CS*8)
135 #define __KERNEL_DS			(GDT_ENTRY_KERNEL_DS*8)
136 #define __USER_DS			(GDT_ENTRY_DEFAULT_USER_DS*8 + 3)
137 #define __USER_CS			(GDT_ENTRY_DEFAULT_USER_CS*8 + 3)
138 #define __ESPFIX_SS			(GDT_ENTRY_ESPFIX_SS*8)
141 #define PNP_CS32			(GDT_ENTRY_PNPBIOS_CS32*8)
143 #define PNP_CS16			(GDT_ENTRY_PNPBIOS_CS16*8)
149 #define PNP_DS				(GDT_ENTRY_PNPBIOS_DS*8)
151 #define PNP_TS1				(GDT_ENTRY_PNPBIOS_TS1*8)
153 #define PNP_TS2				(GDT_ENTRY_PNPBIOS_TS2*8)
156 # define __KERNEL_PERCPU		(GDT_ENTRY_PERCPU*8)
162 # define __KERNEL_STACK_CANARY		(GDT_ENTRY_STACK_CANARY*8)
167 #else /* 64-bit: */
171 #define GDT_ENTRY_KERNEL32_CS		1
179  * GDT layout to get 64-bit SYSCALL/SYSRET support right. SYSRET hardcodes
182  *   if returning to 32-bit userspace: cs = STAR.SYSRET_CS,
183  *   if returning to 64-bit userspace: cs = STAR.SYSRET_CS+16,
185  * ss = STAR.SYSRET_CS+8 (in either case)
187  * thus USER_DS should be between 32-bit and 64-bit code selectors:
194 #define GDT_ENTRY_TSS			8
212  * expressed with the +3 value for user-space selectors:
214 #define __KERNEL32_CS			(GDT_ENTRY_KERNEL32_CS*8)
215 #define __KERNEL_CS			(GDT_ENTRY_KERNEL_CS*8)
216 #define __KERNEL_DS			(GDT_ENTRY_KERNEL_DS*8)
217 #define __USER32_CS			(GDT_ENTRY_DEFAULT_USER32_CS*8 + 3)
218 #define __USER_DS			(GDT_ENTRY_DEFAULT_USER_DS*8 + 3)
220 #define __USER_CS			(GDT_ENTRY_DEFAULT_USER_CS*8 + 3)
221 #define __CPUNODE_SEG			(GDT_ENTRY_CPUNODE*8 + 3)
231 #define GDT_SIZE			(GDT_ENTRIES*8)
233 #define TLS_SIZE			(GDT_ENTRY_TLS_ENTRIES* 8)
282  * vector has no error code (two bytes), a 'push $vector_number' (two
291  * max 8 bytes.
293 #define XEN_EARLY_IDT_HANDLER_SIZE 8
307  * This is always the case on Intel CPUs and, even on 64-bit AMD CPUs, any
316 		     "1:	movl %k0,%%" #seg "		\n"	\
320 		     "		jmp 1b				\n"	\
323 		     _ASM_EXTABLE(1b, 2b)				\
335  * On 32-bit systems, the hidden parts of FS and GS are unobservable if
336  * the selector is NULL, so there's no funny business here.
346 		     "1:	movw %0, %%fs			\n"  in __loadsegment_fs()
349 		     _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_clear_fs)  in __loadsegment_fs()
367  * x86-32 user GS accessors:
371 #  define get_user_gs(regs)		(u16)({ unsigned long v; savesegment(gs, v); v; })
372 #  define set_user_gs(regs, v)		loadsegment(gs, (unsigned long)(v))  argument
373 #  define task_user_gs(tsk)		((tsk)->thread.gs)
374 #  define lazy_save_gs(v)		savesegment(gs, (v))  argument
375 #  define lazy_load_gs(v)		loadsegment(gs, (v))  argument
377 #  define get_user_gs(regs)		(u16)((regs)->gs)
378 #  define set_user_gs(regs, v)		do { (regs)->gs = (v); } while (0)  argument
379 #  define task_user_gs(tsk)		(task_pt_regs(tsk)->gs)
380 #  define lazy_save_gs(v)		do { } while (0)  argument
381 #  define lazy_load_gs(v)		do { } while (0)  argument