The following commit has been merged into the x86/fpu branch of tip: Commit-ID: 23686ef25d4ae81bc12fe3994d1905191fcf71f8 Gitweb: https://git.kernel.org/tip/23686ef25d4ae81bc12fe3994d1905191fcf71f8 Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Thu, 21 Oct 2021 15:55:11 -07:00 Committer: Borislav Petkov <bp@xxxxxxx> CommitterDate: Tue, 26 Oct 2021 10:18:09 +02:00 x86/fpu: Add basic helpers for dynamically enabled features To allow building up the infrastructure required to support dynamically enabled FPU features, add: - XFEATURES_MASK_DYNAMIC This constant will hold xfeatures which can be dynamically enabled. - fpu_state_size_dynamic() A static branch for 64-bit and a simple 'return false' for 32-bit. This helper allows to add dynamic-feature-specific changes to common code which is shared between 32-bit and 64-bit without #ifdeffery. Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Chang S. Bae <chang.seok.bae@xxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Link: https://lkml.kernel.org/r/20211021225527.10184-8-chang.seok.bae@xxxxxxxxx --- arch/x86/include/asm/fpu/xstate.h | 21 +++++++++++++++++++++ arch/x86/kernel/fpu/core.c | 4 ++++ 2 files changed, 25 insertions(+) diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index 43ae89d..cf28546 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -43,6 +43,9 @@ #define XFEATURE_MASK_USER_RESTORE \ (XFEATURE_MASK_USER_SUPPORTED & ~XFEATURE_MASK_PKRU) +/* Features which are dynamically enabled for a process on request */ +#define XFEATURE_MASK_USER_DYNAMIC 0ULL + /* All currently supported supervisor features */ #define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID) @@ -96,4 +99,22 @@ int xfeature_size(int xfeature_nr); void xsaves(struct xregs_state *xsave, u64 mask); void xrstors(struct xregs_state *xsave, u64 mask); +#ifdef CONFIG_X86_64 +DECLARE_STATIC_KEY_FALSE(__fpu_state_size_dynamic); +#endif + +#ifdef CONFIG_X86_64 +DECLARE_STATIC_KEY_FALSE(__fpu_state_size_dynamic); + +static __always_inline __pure bool fpu_state_size_dynamic(void) +{ + return static_branch_unlikely(&__fpu_state_size_dynamic); +} +#else +static __always_inline __pure bool fpu_state_size_dynamic(void) +{ + return false; +} +#endif + #endif diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index b05f6a3..4018083 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -25,6 +25,10 @@ #define CREATE_TRACE_POINTS #include <asm/trace/fpu.h> +#ifdef CONFIG_X86_64 +DEFINE_STATIC_KEY_FALSE(__fpu_state_size_dynamic); +#endif + /* The FPU state configuration data for kernel and user space */ struct fpu_state_config fpu_kernel_cfg __ro_after_init; struct fpu_state_config fpu_user_cfg __ro_after_init;
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