| /* |
| * Copyright (C) 1994 Linus Torvalds |
| * |
| * Pentium III FXSR, SSE support |
| * General FPU state handling cleanups |
| * Gareth Hughes <gareth@valinux.com>, May 2000 |
| * x86-64 work by Andi Kleen 2002 |
| */ |
| |
| #ifndef _ASM_X86_I387_H |
| #define _ASM_X86_I387_H |
| |
| #include <linux/sched.h> |
| #include <linux/kernel_stat.h> |
| #include <linux/regset.h> |
| #include <asm/asm.h> |
| #include <asm/processor.h> |
| #include <asm/sigcontext.h> |
| #include <asm/user.h> |
| #include <asm/uaccess.h> |
| |
| extern void fpu_init(void); |
| extern void mxcsr_feature_mask_init(void); |
| extern int init_fpu(struct task_struct *child); |
| extern asmlinkage void math_state_restore(void); |
| extern void init_thread_xstate(void); |
| |
| extern user_regset_active_fn fpregs_active, xfpregs_active; |
| extern user_regset_get_fn fpregs_get, xfpregs_get, fpregs_soft_get; |
| extern user_regset_set_fn fpregs_set, xfpregs_set, fpregs_soft_set; |
| |
| #ifdef CONFIG_IA32_EMULATION |
| struct _fpstate_ia32; |
| extern int save_i387_ia32(struct _fpstate_ia32 __user *buf); |
| extern int restore_i387_ia32(struct _fpstate_ia32 __user *buf); |
| #endif |
| |
| #ifdef CONFIG_X86_64 |
| |
| /* Ignore delayed exceptions from user space */ |
| static inline void tolerant_fwait(void) |
| { |
| asm volatile("1: fwait\n" |
| "2:\n" |
| _ASM_EXTABLE(1b, 2b)); |
| } |
| |
| static inline int restore_fpu_checking(struct i387_fxsave_struct *fx) |
| { |
| int err; |
| |
| asm volatile("1: rex64/fxrstor (%[fx])\n\t" |
| "2:\n" |
| ".section .fixup,\"ax\"\n" |
| "3: movl $-1,%[err]\n" |
| " jmp 2b\n" |
| ".previous\n" |
| _ASM_EXTABLE(1b, 3b) |
| : [err] "=r" (err) |
| #if 0 /* See comment in __save_init_fpu() below. */ |
| : [fx] "r" (fx), "m" (*fx), "0" (0)); |
| #else |
| : [fx] "cdaSDb" (fx), "m" (*fx), "0" (0)); |
| #endif |
| if (unlikely(err)) |
| init_fpu(current); |
| return err; |
| } |
| |
| #define X87_FSW_ES (1 << 7) /* Exception Summary */ |
| |
| /* AMD CPUs don't save/restore FDP/FIP/FOP unless an exception |
| is pending. Clear the x87 state here by setting it to fixed |
| values. The kernel data segment can be sometimes 0 and sometimes |
| new user value. Both should be ok. |
| Use the PDA as safe address because it should be already in L1. */ |
| static inline void clear_fpu_state(struct i387_fxsave_struct *fx) |
| { |
| if (unlikely(fx->swd & X87_FSW_ES)) |
| asm volatile("fnclex"); |
| alternative_input(ASM_NOP8 ASM_NOP2, |
| " emms\n" /* clear stack tags */ |
| " fildl %%gs:0", /* load to clear state */ |
| X86_FEATURE_FXSAVE_LEAK); |
| } |
| |
| static inline int save_i387_checking(struct i387_fxsave_struct __user *fx) |
| { |
| int err; |
| |
| asm volatile("1: rex64/fxsave (%[fx])\n\t" |
| "2:\n" |
| ".section .fixup,\"ax\"\n" |
| "3: movl $-1,%[err]\n" |
| " jmp 2b\n" |
| ".previous\n" |
| _ASM_EXTABLE(1b, 3b) |
| : [err] "=r" (err), "=m" (*fx) |
| #if 0 /* See comment in __fxsave_clear() below. */ |
| : [fx] "r" (fx), "0" (0)); |
| #else |
| : [fx] "cdaSDb" (fx), "0" (0)); |
| #endif |
| if (unlikely(err) && |
| __clear_user(fx, sizeof(struct i387_fxsave_struct))) |
| err = -EFAULT; |
| /* No need to clear here because the caller clears USED_MATH */ |
| return err; |
| } |
| |
| static inline void __save_init_fpu(struct task_struct *tsk) |
| { |
| /* Using "rex64; fxsave %0" is broken because, if the memory operand |
| uses any extended registers for addressing, a second REX prefix |
| will be generated (to the assembler, rex64 followed by semicolon |
| is a separate instruction), and hence the 64-bitness is lost. */ |
| #if 0 |
| /* Using "fxsaveq %0" would be the ideal choice, but is only supported |
| starting with gas 2.16. */ |
| __asm__ __volatile__("fxsaveq %0" |
| : "=m" (tsk->thread.xstate->fxsave)); |
| #elif 0 |
| /* Using, as a workaround, the properly prefixed form below isn't |
| accepted by any binutils version so far released, complaining that |
| the same type of prefix is used twice if an extended register is |
| needed for addressing (fix submitted to mainline 2005-11-21). */ |
| __asm__ __volatile__("rex64/fxsave %0" |
| : "=m" (tsk->thread.xstate->fxsave)); |
| #else |
| /* This, however, we can work around by forcing the compiler to select |
| an addressing mode that doesn't require extended registers. */ |
| __asm__ __volatile__("rex64/fxsave (%1)" |
| : "=m" (tsk->thread.xstate->fxsave) |
| : "cdaSDb" (&tsk->thread.xstate->fxsave)); |
| #endif |
| clear_fpu_state(&tsk->thread.xstate->fxsave); |
| task_thread_info(tsk)->status &= ~TS_USEDFPU; |
| } |
| |
| /* |
| * Signal frame handlers. |
| */ |
| |
| static inline int save_i387(struct _fpstate __user *buf) |
| { |
| struct task_struct *tsk = current; |
| int err = 0; |
| |
| BUILD_BUG_ON(sizeof(struct user_i387_struct) != |
| sizeof(tsk->thread.xstate->fxsave)); |
| |
| if ((unsigned long)buf % 16) |
| printk("save_i387: bad fpstate %p\n", buf); |
| |
| if (!used_math()) |
| return 0; |
| clear_used_math(); /* trigger finit */ |
| if (task_thread_info(tsk)->status & TS_USEDFPU) { |
| err = save_i387_checking((struct i387_fxsave_struct __user *) |
| buf); |
| if (err) |
| return err; |
| task_thread_info(tsk)->status &= ~TS_USEDFPU; |
| stts(); |
| } else { |
| if (__copy_to_user(buf, &tsk->thread.xstate->fxsave, |
| sizeof(struct i387_fxsave_struct))) |
| return -1; |
| } |
| return 1; |
| } |
| |
| /* |
| * This restores directly out of user space. Exceptions are handled. |
| */ |
| static inline int restore_i387(struct _fpstate __user *buf) |
| { |
| set_used_math(); |
| if (!(task_thread_info(current)->status & TS_USEDFPU)) { |
| clts(); |
| task_thread_info(current)->status |= TS_USEDFPU; |
| } |
| return restore_fpu_checking((__force struct i387_fxsave_struct *)buf); |
| } |
| |
| #else /* CONFIG_X86_32 */ |
| |
| static inline void tolerant_fwait(void) |
| { |
| asm volatile("fnclex ; fwait"); |
| } |
| |
| static inline void restore_fpu(struct task_struct *tsk) |
| { |
| /* |
| * The "nop" is needed to make the instructions the same |
| * length. |
| */ |
| alternative_input( |
| "nop ; frstor %1", |
| "fxrstor %1", |
| X86_FEATURE_FXSR, |
| "m" (tsk->thread.xstate->fxsave)); |
| } |
| |
| /* We need a safe address that is cheap to find and that is already |
| in L1 during context switch. The best choices are unfortunately |
| different for UP and SMP */ |
| #ifdef CONFIG_SMP |
| #define safe_address (__per_cpu_offset[0]) |
| #else |
| #define safe_address (kstat_cpu(0).cpustat.user) |
| #endif |
| |
| /* |
| * These must be called with preempt disabled |
| */ |
| static inline void __save_init_fpu(struct task_struct *tsk) |
| { |
| /* Use more nops than strictly needed in case the compiler |
| varies code */ |
| alternative_input( |
| "fnsave %[fx] ;fwait;" GENERIC_NOP8 GENERIC_NOP4, |
| "fxsave %[fx]\n" |
| "bt $7,%[fsw] ; jnc 1f ; fnclex\n1:", |
| X86_FEATURE_FXSR, |
| [fx] "m" (tsk->thread.xstate->fxsave), |
| [fsw] "m" (tsk->thread.xstate->fxsave.swd) : "memory"); |
| /* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception |
| is pending. Clear the x87 state here by setting it to fixed |
| values. safe_address is a random variable that should be in L1 */ |
| alternative_input( |
| GENERIC_NOP8 GENERIC_NOP2, |
| "emms\n\t" /* clear stack tags */ |
| "fildl %[addr]", /* set F?P to defined value */ |
| X86_FEATURE_FXSAVE_LEAK, |
| [addr] "m" (safe_address)); |
| task_thread_info(tsk)->status &= ~TS_USEDFPU; |
| } |
| |
| /* |
| * Signal frame handlers... |
| */ |
| extern int save_i387(struct _fpstate __user *buf); |
| extern int restore_i387(struct _fpstate __user *buf); |
| |
| #endif /* CONFIG_X86_64 */ |
| |
| static inline void __unlazy_fpu(struct task_struct *tsk) |
| { |
| if (task_thread_info(tsk)->status & TS_USEDFPU) { |
| __save_init_fpu(tsk); |
| stts(); |
| } else |
| tsk->fpu_counter = 0; |
| } |
| |
| static inline void __clear_fpu(struct task_struct *tsk) |
| { |
| if (task_thread_info(tsk)->status & TS_USEDFPU) { |
| tolerant_fwait(); |
| task_thread_info(tsk)->status &= ~TS_USEDFPU; |
| stts(); |
| } |
| } |
| |
| static inline void kernel_fpu_begin(void) |
| { |
| struct thread_info *me = current_thread_info(); |
| preempt_disable(); |
| if (me->status & TS_USEDFPU) |
| __save_init_fpu(me->task); |
| else |
| clts(); |
| } |
| |
| static inline void kernel_fpu_end(void) |
| { |
| stts(); |
| preempt_enable(); |
| } |
| |
| #ifdef CONFIG_X86_64 |
| |
| static inline void save_init_fpu(struct task_struct *tsk) |
| { |
| __save_init_fpu(tsk); |
| stts(); |
| } |
| |
| #define unlazy_fpu __unlazy_fpu |
| #define clear_fpu __clear_fpu |
| |
| #else /* CONFIG_X86_32 */ |
| |
| /* |
| * These disable preemption on their own and are safe |
| */ |
| static inline void save_init_fpu(struct task_struct *tsk) |
| { |
| preempt_disable(); |
| __save_init_fpu(tsk); |
| stts(); |
| preempt_enable(); |
| } |
| |
| static inline void unlazy_fpu(struct task_struct *tsk) |
| { |
| preempt_disable(); |
| __unlazy_fpu(tsk); |
| preempt_enable(); |
| } |
| |
| static inline void clear_fpu(struct task_struct *tsk) |
| { |
| preempt_disable(); |
| __clear_fpu(tsk); |
| preempt_enable(); |
| } |
| |
| #endif /* CONFIG_X86_64 */ |
| |
| /* |
| * i387 state interaction |
| */ |
| static inline unsigned short get_fpu_cwd(struct task_struct *tsk) |
| { |
| if (cpu_has_fxsr) { |
| return tsk->thread.xstate->fxsave.cwd; |
| } else { |
| return (unsigned short) tsk->thread.xstate->fsave.cwd; |
| } |
| } |
| |
| static inline unsigned short get_fpu_swd(struct task_struct *tsk) |
| { |
| if (cpu_has_fxsr) { |
| return tsk->thread.xstate->fxsave.swd; |
| } else { |
| return (unsigned short) tsk->thread.xstate->fsave.swd; |
| } |
| } |
| |
| static inline unsigned short get_fpu_mxcsr(struct task_struct *tsk) |
| { |
| if (cpu_has_xmm) { |
| return tsk->thread.xstate->fxsave.mxcsr; |
| } else { |
| return MXCSR_DEFAULT; |
| } |
| } |
| |
| #endif /* _ASM_X86_I387_H */ |