1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_FSGSBASE_H 3 #define _ASM_FSGSBASE_H 1 4 5 #ifndef __ASSEMBLY__ 6 7 #ifdef CONFIG_X86_64 8 9 #include <asm/msr-index.h> 10 11 unsigned long x86_fsgsbase_read_task(struct task_struct *task, 12 unsigned short selector); 13 14 /* 15 * Read/write a task's fsbase or gsbase. This returns the value that 16 * the FS/GS base would have (if the task were to be resumed). These 17 * work on current or on a different non-running task. 18 */ 19 unsigned long x86_fsbase_read_task(struct task_struct *task); 20 unsigned long x86_gsbase_read_task(struct task_struct *task); 21 int x86_fsbase_write_task(struct task_struct *task, unsigned long fsbase); 22 int x86_gsbase_write_task(struct task_struct *task, unsigned long gsbase); 23 24 /* Helper functions for reading/writing FS/GS base */ 25 26 static inline unsigned long x86_fsbase_read_cpu(void) 27 { 28 unsigned long fsbase; 29 30 rdmsrl(MSR_FS_BASE, fsbase); 31 return fsbase; 32 } 33 34 void x86_fsbase_write_cpu(unsigned long fsbase); 35 36 static inline unsigned long x86_gsbase_read_cpu_inactive(void) 37 { 38 unsigned long gsbase; 39 40 rdmsrl(MSR_KERNEL_GS_BASE, gsbase); 41 return gsbase; 42 } 43 44 void x86_gsbase_write_cpu_inactive(unsigned long gsbase); 45 46 #endif /* CONFIG_X86_64 */ 47 48 #endif /* __ASSEMBLY__ */ 49 50 #endif /* _ASM_FSGSBASE_H */ 51