diff options
Diffstat (limited to 'arch/x86/include/asm/i387.h')
| -rw-r--r-- | arch/x86/include/asm/i387.h | 400 |
1 files changed, 400 insertions, 0 deletions
diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h new file mode 100644 index 00000000000..9ba862a4eac --- /dev/null +++ b/arch/x86/include/asm/i387.h @@ -0,0 +1,400 @@ +/* + * 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 <linux/hardirq.h> +#include <asm/asm.h> +#include <asm/processor.h> +#include <asm/sigcontext.h> +#include <asm/user.h> +#include <asm/uaccess.h> +#include <asm/xsave.h> + +extern unsigned int sig_xstate_size; +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 int dump_fpu(struct pt_regs *, struct user_i387_struct *); + +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; + +extern struct _fpx_sw_bytes fx_sw_reserved; +#ifdef CONFIG_IA32_EMULATION +extern unsigned int sig_xstate_ia32_size; +extern struct _fpx_sw_bytes fx_sw_reserved_ia32; +struct _fpstate_ia32; +struct _xstate_ia32; +extern int save_i387_xstate_ia32(void __user *buf); +extern int restore_i387_xstate_ia32(void __user *buf); +#endif + +#define X87_FSW_ES (1 << 7) /* Exception Summary */ + +#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 fxrstor_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 + return err; +} + +static inline int restore_fpu_checking(struct task_struct *tsk) +{ + if (task_thread_info(tsk)->status & TS_XSAVE) + return xrstor_checking(&tsk->thread.xstate->xsave); + else + return fxrstor_checking(&tsk->thread.xstate->fxsave); +} + +/* 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 task_struct *tsk) +{ + struct xsave_struct *xstate = &tsk->thread.xstate->xsave; + struct i387_fxsave_struct *fx = &tsk->thread.xstate->fxsave; + + /* + * xsave header may indicate the init state of the FP. + */ + if ((task_thread_info(tsk)->status & TS_XSAVE) && + !(xstate->xsave_hdr.xstate_bv & XSTATE_FP)) + return; + + 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 fxsave_user(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 fxsave(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 +} + +static inline void __save_init_fpu(struct task_struct *tsk) +{ + if (task_thread_info(tsk)->status & TS_XSAVE) + xsave(tsk); + else + fxsave(tsk); + + clear_fpu_state(tsk); + task_thread_info(tsk)->status &= ~TS_USEDFPU; +} + +#else /* CONFIG_X86_32 */ + +extern void finit(void); + +static inline void tolerant_fwait(void) +{ + asm volatile("fnclex ; fwait"); +} + +static inline void restore_fpu(struct task_struct *tsk) +{ + if (task_thread_info(tsk)->status & TS_XSAVE) { + xrstor_checking(&tsk->thread.xstate->xsave); + return; + } + /* + * 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) +{ + if (task_thread_info(tsk)->status & TS_XSAVE) { + struct xsave_struct *xstate = &tsk->thread.xstate->xsave; + struct i387_fxsave_struct *fx = &tsk->thread.xstate->fxsave; + + xsave(tsk); + + /* + * xsave header may indicate the init state of the FP. + */ + if (!(xstate->xsave_hdr.xstate_bv & XSTATE_FP)) + goto end; + + if (unlikely(fx->swd & X87_FSW_ES)) + asm volatile("fnclex"); + + /* + * we can do a simple return here or be paranoid :) + */ + goto clear_state; + } + + /* 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"); +clear_state: + /* 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)); +end: + task_thread_info(tsk)->status &= ~TS_USEDFPU; +} + +#endif /* CONFIG_X86_64 */ + +/* + * Signal frame handlers... + */ +extern int save_i387_xstate(void __user *buf); +extern int restore_i387_xstate(void __user *buf); + +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(); +} + +/* + * Some instructions like VIA's padlock instructions generate a spurious + * DNA fault but don't modify SSE registers. And these instructions + * get used from interrupt context aswell. To prevent these kernel instructions + * in interrupt context interact wrongly with other user/kernel fpu usage, we + * should use them only in the context of irq_ts_save/restore() + */ +static inline int irq_ts_save(void) +{ + /* + * If we are in process context, we are ok to take a spurious DNA fault. + * Otherwise, doing clts() in process context require pre-emption to + * be disabled or some heavy lifting like kernel_fpu_begin() + */ + if (!in_interrupt()) + return 0; + + if (read_cr0() & X86_CR0_TS) { + clts(); + return 1; + } + + return 0; +} + +static inline void irq_ts_restore(int TS_state) +{ + if (TS_state) + stts(); +} + +#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 */ |