Commit-ID: 4ee91519e1dccc175665fe24bb20a47c6053575c Gitweb: https://git.kernel.org/tip/4ee91519e1dccc175665fe24bb20a47c6053575c Author: Rik van Riel <[email protected]> AuthorDate: Wed, 3 Apr 2019 18:41:38 +0200 Committer: Borislav Petkov <[email protected]> CommitDate: Wed, 10 Apr 2019 16:23:14 +0200
x86/fpu: Add an __fpregs_load_activate() internal helper Add a helper function that ensures the floating point registers for the current task are active. Use with preemption disabled. While at it, add fpregs_lock/unlock() helpers too, to be used in later patches. [ bp: Add a comment about its intended usage. ] Signed-off-by: Rik van Riel <[email protected]> Signed-off-by: Sebastian Andrzej Siewior <[email protected]> Signed-off-by: Borislav Petkov <[email protected]> Reviewed-by: Dave Hansen <[email protected]> Reviewed-by: Thomas Gleixner <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Aubrey Li <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Jann Horn <[email protected]> Cc: "Jason A. Donenfeld" <[email protected]> Cc: kvm ML <[email protected]> Cc: Paolo Bonzini <[email protected]> Cc: Radim Krčmář <[email protected]> Cc: Rik van Riel <[email protected]> Cc: x86-ml <[email protected]> Link: https://lkml.kernel.org/r/[email protected] --- arch/x86/include/asm/fpu/api.h | 11 +++++++++++ arch/x86/include/asm/fpu/internal.h | 22 ++++++++++++++-------- 2 files changed, 25 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h index b56d504af654..73e684160f35 100644 --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -10,6 +10,7 @@ #ifndef _ASM_X86_FPU_API_H #define _ASM_X86_FPU_API_H +#include <linux/preempt.h> /* * Use kernel_fpu_begin/end() if you intend to use FPU in kernel context. It @@ -22,6 +23,16 @@ extern void kernel_fpu_begin(void); extern void kernel_fpu_end(void); extern bool irq_fpu_usable(void); +static inline void fpregs_lock(void) +{ + preempt_disable(); +} + +static inline void fpregs_unlock(void) +{ + preempt_enable(); +} + /* * Query the presence of one or more xfeatures. Works on any legacy CPU as well. * diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 54f70cae2f15..3e0c2c496f2d 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -484,6 +484,18 @@ static inline void fpregs_activate(struct fpu *fpu) trace_x86_fpu_regs_activated(fpu); } +/* + * Internal helper, do not use directly. Use switch_fpu_return() instead. + */ +static inline void __fpregs_load_activate(struct fpu *fpu, int cpu) +{ + if (!fpregs_state_valid(fpu, cpu)) { + if (current->mm) + copy_kernel_to_fpregs(&fpu->state); + fpregs_activate(fpu); + } +} + /* * FPU state switching for scheduling. * @@ -522,14 +534,8 @@ switch_fpu_prepare(struct fpu *old_fpu, int cpu) */ static inline void switch_fpu_finish(struct fpu *new_fpu, int cpu) { - if (static_cpu_has(X86_FEATURE_FPU)) { - if (!fpregs_state_valid(new_fpu, cpu)) { - if (current->mm) - copy_kernel_to_fpregs(&new_fpu->state); - } - - fpregs_activate(new_fpu); - } + if (static_cpu_has(X86_FEATURE_FPU)) + __fpregs_load_activate(new_fpu, cpu); } /*
