diff options
Diffstat (limited to 'arch/arm64/kernel/fpsimd.c')
| -rw-r--r-- | arch/arm64/kernel/fpsimd.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index d7e5f8a2d4f5..bcde88e2d981 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -21,12 +21,15 @@ #include <linux/cpu_pm.h> #include <linux/kernel.h> #include <linux/init.h> +#include <linux/preempt.h> #include <linux/sched/signal.h> #include <linux/signal.h> #include <linux/hardirq.h> #include <asm/fpsimd.h> #include <asm/cputype.h> +#include <asm/neon.h> +#include <asm/simd.h> #define FPEXC_IOF (1 << 0) #define FPEXC_DZF (1 << 1) @@ -276,6 +279,55 @@ void kernel_neon_end(void) } EXPORT_SYMBOL(kernel_neon_end); +DEFINE_PER_CPU(struct fpsimd_state, efi_fpsimd_state); +DEFINE_PER_CPU(bool, efi_fpsimd_state_used); + +/* + * EFI runtime services support functions + * + * The ABI for EFI runtime services allows EFI to use FPSIMD during the call. + * This means that for EFI (and only for EFI), we have to assume that FPSIMD + * is always used rather than being an optional accelerator. + * + * These functions provide the necessary support for ensuring FPSIMD + * save/restore in the contexts from which EFI is used. + * + * Do not use them for any other purpose -- if tempted to do so, you are + * either doing something wrong or you need to propose some refactoring. + */ + +/* + * __efi_fpsimd_begin(): prepare FPSIMD for making an EFI runtime services call + */ +void __efi_fpsimd_begin(void) +{ + if (!system_supports_fpsimd()) + return; + + WARN_ON(preemptible()); + + if (may_use_simd()) + kernel_neon_begin(); + else { + fpsimd_save_state(this_cpu_ptr(&efi_fpsimd_state)); + __this_cpu_write(efi_fpsimd_state_used, true); + } +} + +/* + * __efi_fpsimd_end(): clean up FPSIMD after an EFI runtime services call + */ +void __efi_fpsimd_end(void) +{ + if (!system_supports_fpsimd()) + return; + + if (__this_cpu_xchg(efi_fpsimd_state_used, false)) + fpsimd_load_state(this_cpu_ptr(&efi_fpsimd_state)); + else + kernel_neon_end(); +} + #endif /* CONFIG_KERNEL_MODE_NEON */ #ifdef CONFIG_CPU_PM |