include/asm/segment.h

1 /* SPDX-License-Identifier: GPL-2.0 */
14 	((((base)  & _AC(0xff000000,ULL)) << (56-24)) |	\
16 	 (((limit) & _AC(0x000f0000,ULL)) << (48-16)) |	\
61  * The layout of the per-CPU GDT under Linux:
63  *   0 - null								<=== cacheline #1
64  *   1 - reserved
65  *   2 - reserved
66  *   3 - reserved
68  *   4 - unused								<=== cacheline #2
69  *   5 - unused
71  *  ------- start of TLS (Thread-Local Storage) segments:
73  *   6 - TLS segment #1			[ glibc's TLS segment ]
74  *   7 - TLS segment #2			[ Wine's %fs Win32 segment ]
75  *   8 - TLS segment #3							<=== cacheline #3
76  *   9 - reserved
77  *  10 - reserved
78  *  11 - reserved
80  *  ------- start of kernel segments:
82  *  12 - kernel code segment						<=== cacheline #4
83  *  13 - kernel data segment
84  *  14 - default user CS
85  *  15 - default user DS
86  *  16 - TSS								<=== cacheline #5
87  *  17 - LDT
88  *  18 - PNPBIOS support (16->32 gate)
89  *  19 - PNPBIOS support
90  *  20 - PNPBIOS support						<=== cacheline #6
91  *  21 - PNPBIOS support
92  *  22 - PNPBIOS support
93  *  23 - APM BIOS support
94  *  24 - APM BIOS support						<=== cacheline #7
95  *  25 - APM BIOS support
97  *  26 - ESPFIX small SS
98  *  27 - per-cpu			[ offset to per-cpu data area ]
99  *  28 - VDSO getcpu
100  *  29 - unused
101  *  30 - unused
102  *  31 - TSS for double fault handler
105 #define GDT_ENTRY_TLS_MAX 		(GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
165 #else /* 64-bit: */
177  * GDT layout to get 64-bit SYSCALL/SYSRET support right. SYSRET hardcodes
180  *   if returning to 32-bit userspace: cs = STAR.SYSRET_CS,
181  *   if returning to 64-bit userspace: cs = STAR.SYSRET_CS+16,
185  * thus USER_DS should be between 32-bit and 64-bit code selectors:
210  * expressed with the +3 value for user-space selectors:
225 /* Bitmask of exception vectors which push an error code on the stack: */
232 /* Bit size and mask of CPU number stored in the per CPU data (and TSC_AUX) */
238 /* Helper functions to store/load CPU and node numbers */
240 static inline unsigned long vdso_encode_cpunode(int cpu, unsigned long node)  in vdso_encode_cpunode()  argument
242 	return (node << VDSO_CPUNODE_BITS) | cpu;  in vdso_encode_cpunode()
245 static inline void vdso_read_cpunode(unsigned *cpu, unsigned *node)  in vdso_read_cpunode()  argument
250 	 * Load CPU and node number from the GDT.  LSL is faster than RDTSCP  in vdso_read_cpunode()
262 	if (cpu)  in vdso_read_cpunode()
263 		*cpu = (p & VDSO_CPUNODE_MASK);  in vdso_read_cpunode()
301  * This is always the case on Intel CPUs and, even on 64-bit AMD CPUs, any
322  * On 32-bit systems, the hidden parts of FS and GS are unobservable if