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CONFIG_LAZY_FP_SHARING¶
(No prompt – not directly user assignable.)
Type: bool
Help¶
This hidden option allows multiple threads to use the floating point registers, using logic to lazily save/restore the floating point register state on context switch.
On Intel Core procesors, may be vulnerable to exploits which allows malware to read the contents of all floating point registers, see CVE-2018-3665.
Direct dependencies¶
FLOAT && !EAGER_FP_SHARING && FP_SHARING && CPU_HAS_FPU && X86
(Includes any dependencies from if’s and menus.)
Defaults¶
- “y” if (
X86_NO_LAZY_FP|| !USERSPACE) &&FLOAT&& !EAGER_FP_SHARING&&FP_SHARING&&CPU_HAS_FPU&&X86
Kconfig definition¶
At arch/x86/Kconfig:197
Included via Kconfig:10 → Kconfig.zephyr:29 → arch/Kconfig:15
Menu path: (top menu) → X86 Architecture Options → Processor Capabilities → Architecture Floating Point Options
config LAZY_FP_SHARING
bool
default "y" if (X86_NO_LAZY_FP || !USERSPACE) && FLOAT && !EAGER_FP_SHARING && FP_SHARING && CPU_HAS_FPU && X86
depends on FLOAT && !EAGER_FP_SHARING && FP_SHARING && CPU_HAS_FPU && X86
help
This hidden option allows multiple threads to use the floating point
registers, using logic to lazily save/restore the floating point
register state on context switch.
On Intel Core procesors, may be vulnerable to exploits which allows
malware to read the contents of all floating point registers, see
CVE-2018-3665.
(Definitions include propagated dependencies, including from if’s and menus.)