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85 lines
2.0 KiB
85 lines
2.0 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#ifndef _ASM_FSGSBASE_H |
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#define _ASM_FSGSBASE_H |
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#ifndef __ASSEMBLY__ |
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#ifdef CONFIG_X86_64 |
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#include <asm/msr-index.h> |
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/* |
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* Read/write a task's FSBASE or GSBASE. This returns the value that |
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* the FS/GS base would have (if the task were to be resumed). These |
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* work on the current task or on a non-running (typically stopped |
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* ptrace child) task. |
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*/ |
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extern unsigned long x86_fsbase_read_task(struct task_struct *task); |
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extern unsigned long x86_gsbase_read_task(struct task_struct *task); |
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extern void x86_fsbase_write_task(struct task_struct *task, unsigned long fsbase); |
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extern void x86_gsbase_write_task(struct task_struct *task, unsigned long gsbase); |
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/* Must be protected by X86_FEATURE_FSGSBASE check. */ |
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static __always_inline unsigned long rdfsbase(void) |
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{ |
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unsigned long fsbase; |
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asm volatile("rdfsbase %0" : "=r" (fsbase) :: "memory"); |
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return fsbase; |
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} |
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static __always_inline unsigned long rdgsbase(void) |
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{ |
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unsigned long gsbase; |
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asm volatile("rdgsbase %0" : "=r" (gsbase) :: "memory"); |
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return gsbase; |
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} |
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static __always_inline void wrfsbase(unsigned long fsbase) |
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{ |
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asm volatile("wrfsbase %0" :: "r" (fsbase) : "memory"); |
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} |
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static __always_inline void wrgsbase(unsigned long gsbase) |
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{ |
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asm volatile("wrgsbase %0" :: "r" (gsbase) : "memory"); |
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} |
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#include <asm/cpufeature.h> |
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/* Helper functions for reading/writing FS/GS base */ |
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static inline unsigned long x86_fsbase_read_cpu(void) |
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{ |
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unsigned long fsbase; |
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if (boot_cpu_has(X86_FEATURE_FSGSBASE)) |
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fsbase = rdfsbase(); |
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else |
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rdmsrl(MSR_FS_BASE, fsbase); |
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return fsbase; |
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} |
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static inline void x86_fsbase_write_cpu(unsigned long fsbase) |
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{ |
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if (boot_cpu_has(X86_FEATURE_FSGSBASE)) |
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wrfsbase(fsbase); |
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else |
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wrmsrl(MSR_FS_BASE, fsbase); |
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} |
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extern unsigned long x86_gsbase_read_cpu_inactive(void); |
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extern void x86_gsbase_write_cpu_inactive(unsigned long gsbase); |
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extern unsigned long x86_fsgsbase_read_task(struct task_struct *task, |
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unsigned short selector); |
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#endif /* CONFIG_X86_64 */ |
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#endif /* __ASSEMBLY__ */ |
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#endif /* _ASM_FSGSBASE_H */
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