diff options
Diffstat (limited to 'arch/arm64/kernel/fpsimd.c')
| -rw-r--r-- | arch/arm64/kernel/fpsimd.c | 49 |
1 files changed, 47 insertions, 2 deletions
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index f995dae1c8fd..7950df171d86 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -20,6 +20,7 @@ #include <linux/cpu.h> #include <linux/cpu_pm.h> #include <linux/kernel.h> +#include <linux/module.h> #include <linux/init.h> #include <linux/sched.h> #include <linux/signal.h> @@ -27,6 +28,7 @@ #include <asm/fpsimd.h> #include <asm/cputype.h> +#include <asm/app_api.h> #define FPEXC_IOF (1 << 0) #define FPEXC_DZF (1 << 1) @@ -35,6 +37,8 @@ #define FPEXC_IXF (1 << 4) #define FPEXC_IDF (1 << 7) +#define FP_SIMD_BIT 31 + /* * In order to reduce the number of times the FPSIMD state is needlessly saved * and restored, we need to keep track of two things: @@ -88,14 +92,42 @@ * whatever is in the FPSIMD registers is not saved to memory, but discarded. */ static DEFINE_PER_CPU(struct fpsimd_state *, fpsimd_last_state); +static DEFINE_PER_CPU(int, fpsimd_stg_enable); + +static int fpsimd_settings = 0x1; /* default = 0x1 */ +module_param(fpsimd_settings, int, 0644); + +void fpsimd_settings_enable(void) +{ + set_app_setting_bit(FP_SIMD_BIT); +} + +void fpsimd_settings_disable(void) +{ + clear_app_setting_bit(FP_SIMD_BIT); +} /* * Trapped FP/ASIMD access. */ void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs) { - /* TODO: implement lazy context saving/restoring */ - WARN_ON(1); + if (!fpsimd_settings) + return; + + fpsimd_disable_trap(); + fpsimd_settings_disable(); + this_cpu_write(fpsimd_stg_enable, 0); +} + +void do_fpsimd_acc_compat(unsigned int esr, struct pt_regs *regs) +{ + if (!fpsimd_settings) + return; + + fpsimd_disable_trap(); + fpsimd_settings_enable(); + this_cpu_write(fpsimd_stg_enable, 1); } /* @@ -135,6 +167,11 @@ void fpsimd_thread_switch(struct task_struct *next) if (current->mm && !test_thread_flag(TIF_FOREIGN_FPSTATE)) fpsimd_save_state(¤t->thread.fpsimd_state); + if (fpsimd_settings && __this_cpu_read(fpsimd_stg_enable)) { + fpsimd_settings_disable(); + this_cpu_write(fpsimd_stg_enable, 0); + } + if (next->mm) { /* * If we are switching to a task whose most recent userland @@ -152,6 +189,14 @@ void fpsimd_thread_switch(struct task_struct *next) else set_ti_thread_flag(task_thread_info(next), TIF_FOREIGN_FPSTATE); + + if (!fpsimd_settings) + return; + + if (test_ti_thread_flag(task_thread_info(next), TIF_32BIT)) + fpsimd_enable_trap(); + else + fpsimd_disable_trap(); } } |