mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs.git
synced 2026-11-14 05:52:16 +01:00
Kyle Huey
e9ea1e7f53
Intel supports faulting on the CPUID instruction beginning with Ivy Bridge. When enabled, the processor will fault on attempts to execute the CPUID instruction with CPL>0. Exposing this feature to userspace will allow a ptracer to trap and emulate the CPUID instruction. When supported, this feature is controlled by toggling bit 0 of MSR_MISC_FEATURES_ENABLES. It is documented in detail in Section 2.3.2 of https://bugzilla.kernel.org/attachment.cgi?id=243991 Implement a new pair of arch_prctls, available on both x86-32 and x86-64. ARCH_GET_CPUID: Returns the current CPUID state, either 0 if CPUID faulting is enabled (and thus the CPUID instruction is not available) or 1 if CPUID faulting is not enabled. ARCH_SET_CPUID: Set the CPUID state to the second argument. If cpuid_enabled is 0 CPUID faulting will be activated, otherwise it will be deactivated. Returns ENODEV if CPUID faulting is not supported on this system. The state of the CPUID faulting flag is propagated across forks, but reset upon exec. Signed-off-by: Kyle Huey <[email protected]> Cc: Grzegorz Andrejczuk <[email protected]> Cc: [email protected] Cc: Radim Krčmář <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Andi Kleen <[email protected]> Cc: [email protected] Cc: Nadav Amit <[email protected]> Cc: Robert O'Callahan <[email protected]> Cc: Richard Weinberger <[email protected]> Cc: "Rafael J. Wysocki" <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Len Brown <[email protected]> Cc: Shuah Khan <[email protected]> Cc: [email protected] Cc: Jeff Dike <[email protected]> Cc: Alexander Viro <[email protected]> Cc: [email protected] Cc: David Matlack <[email protected]> Cc: Boris Ostrovsky <[email protected]> Cc: Dmitry Safonov <[email protected]> Cc: [email protected] Cc: Paolo Bonzini <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Thomas Gleixner <[email protected]>
111 lines
3.0 KiB
C
111 lines
3.0 KiB
C
/* thread_info.h: common low-level thread information accessors
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*
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* Copyright (C) 2002 David Howells ([email protected])
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* - Incorporating suggestions made by Linus Torvalds
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*/
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#ifndef _LINUX_THREAD_INFO_H
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#define _LINUX_THREAD_INFO_H
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#include <linux/types.h>
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#include <linux/bug.h>
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#include <linux/restart_block.h>
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#ifdef CONFIG_THREAD_INFO_IN_TASK
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/*
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* For CONFIG_THREAD_INFO_IN_TASK kernels we need <asm/current.h> for the
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* definition of current, but for !CONFIG_THREAD_INFO_IN_TASK kernels,
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* including <asm/current.h> can cause a circular dependency on some platforms.
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*/
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#include <asm/current.h>
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#define current_thread_info() ((struct thread_info *)current)
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#endif
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#include <linux/bitops.h>
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#include <asm/thread_info.h>
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#ifdef __KERNEL__
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#ifdef CONFIG_DEBUG_STACK_USAGE
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# define THREADINFO_GFP (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK | \
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__GFP_ZERO)
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#else
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# define THREADINFO_GFP (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK)
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#endif
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/*
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* flag set/clear/test wrappers
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* - pass TIF_xxxx constants to these functions
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*/
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static inline void set_ti_thread_flag(struct thread_info *ti, int flag)
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{
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set_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline void clear_ti_thread_flag(struct thread_info *ti, int flag)
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{
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clear_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline int test_and_set_ti_thread_flag(struct thread_info *ti, int flag)
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{
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return test_and_set_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline int test_and_clear_ti_thread_flag(struct thread_info *ti, int flag)
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{
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return test_and_clear_bit(flag, (unsigned long *)&ti->flags);
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}
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static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
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{
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return test_bit(flag, (unsigned long *)&ti->flags);
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}
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#define set_thread_flag(flag) \
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set_ti_thread_flag(current_thread_info(), flag)
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#define clear_thread_flag(flag) \
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clear_ti_thread_flag(current_thread_info(), flag)
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#define test_and_set_thread_flag(flag) \
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test_and_set_ti_thread_flag(current_thread_info(), flag)
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#define test_and_clear_thread_flag(flag) \
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test_and_clear_ti_thread_flag(current_thread_info(), flag)
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#define test_thread_flag(flag) \
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test_ti_thread_flag(current_thread_info(), flag)
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#define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED)
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#ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES
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static inline int arch_within_stack_frames(const void * const stack,
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const void * const stackend,
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const void *obj, unsigned long len)
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{
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return 0;
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}
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#endif
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#ifdef CONFIG_HARDENED_USERCOPY
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extern void __check_object_size(const void *ptr, unsigned long n,
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bool to_user);
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static __always_inline void check_object_size(const void *ptr, unsigned long n,
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bool to_user)
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{
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if (!__builtin_constant_p(n))
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__check_object_size(ptr, n, to_user);
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}
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#else
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static inline void check_object_size(const void *ptr, unsigned long n,
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bool to_user)
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{ }
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#endif /* CONFIG_HARDENED_USERCOPY */
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#ifndef arch_setup_new_exec
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static inline void arch_setup_new_exec(void) { }
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#endif
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#endif /* __KERNEL__ */
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#endif /* _LINUX_THREAD_INFO_H */
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