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| author | Thomas Gleixner <tglx@linutronix.de> | 2021-10-22 00:55:11 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-10-26 10:18:09 +0200 |
| commit | 23686ef25d4ae81bc12fe3994d1905191fcf71f8 (patch) | |
| tree | 1df83e5f7ad25484ce845e6771185bde2421c065 | |
| parent | x86/arch_prctl: Add controls for dynamic XSTATE components (diff) | |
| download | linux-23686ef25d4ae81bc12fe3994d1905191fcf71f8.tar.xz linux-23686ef25d4ae81bc12fe3994d1905191fcf71f8.zip | |
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@linutronix.de>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211021225527.10184-8-chang.seok.bae@intel.com
| -rw-r--r-- | arch/x86/include/asm/fpu/xstate.h | 21 | ||||
| -rw-r--r-- | arch/x86/kernel/fpu/core.c | 4 |
2 files changed, 25 insertions, 0 deletions
diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index 43ae89d4bcd2..cf285464eabe 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 b05f6a3b2057..4018083c5b36 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; |