8b71340d70
[ luto: Rename the variables from FS and GS to FSBASE and GSBASE and make <asm/fsgsbase.h> safe to include on 32-bit kernels. ] Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Andi Kleen <ak@linux.intel.com> Cc: Ravi Shankar <ravi.v.shankar@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Link: https://lkml.kernel.org/r/1557309753-24073-6-git-send-email-chang.seok.bae@intel.com
87 lines
1.9 KiB
C
87 lines
1.9 KiB
C
/* 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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/* 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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rdmsrl(MSR_FS_BASE, fsbase);
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return fsbase;
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}
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static inline unsigned long x86_gsbase_read_cpu_inactive(void)
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{
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unsigned long gsbase;
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rdmsrl(MSR_KERNEL_GS_BASE, gsbase);
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return gsbase;
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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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wrmsrl(MSR_FS_BASE, fsbase);
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}
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static inline void x86_gsbase_write_cpu_inactive(unsigned long gsbase)
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{
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wrmsrl(MSR_KERNEL_GS_BASE, gsbase);
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}
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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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