From cc927a25bd704448b18b095c658cbfdd79dab865 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Wed, 30 Jan 2008 13:31:49 +0100 Subject: [PATCH] x86: x86 i387 header cleanup This moves some code into asm-x86/i387_64.h in preparation for unifying this code between 32 and 64. The 32-bit versions of some things are copied in some existing names changed to match 32-bit names and share code. For 64, save_i387 is moved into an inline from i387_64.c; this matches restore_i387, which is already an inline, and makes sense since there is exactly one caller (in signal_64.c). The save_i387 function could use more cosmetic cleanup, but it is just moved verbatim in this patch. Signed-off-by: Roland McGrath Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/kernel/i387_64.c | 31 ---- include/asm-x86/i387_64.h | 315 ++++++++++++++++++++++++++++---------- 2 files changed, 233 insertions(+), 113 deletions(-) diff --git a/arch/x86/kernel/i387_64.c b/arch/x86/kernel/i387_64.c index bfaff28fb1..f335a76d7e 100644 --- a/arch/x86/kernel/i387_64.c +++ b/arch/x86/kernel/i387_64.c @@ -71,37 +71,6 @@ void init_fpu(struct task_struct *child) set_stopped_child_used_math(child); } -/* - * Signal frame handlers. - */ - -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.i387.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.i387.fxsave, - sizeof(struct i387_fxsave_struct))) - return -1; - } - return 1; -} - /* * ptrace request handlers. */ diff --git a/include/asm-x86/i387_64.h b/include/asm-x86/i387_64.h index 12edb9f2d7..4cea7373ac 100644 --- a/include/asm-x86/i387_64.h +++ b/include/asm-x86/i387_64.h @@ -7,33 +7,23 @@ * x86-64 work by Andi Kleen 2002 */ -#ifndef __ASM_X86_64_I387_H -#define __ASM_X86_64_I387_H +#ifndef _ASM_X86_I387_H +#define _ASM_X86_I387_H #include +#include #include #include #include -#include #include extern void fpu_init(void); extern unsigned int mxcsr_feature_mask; extern void mxcsr_feature_mask_init(void); extern void init_fpu(struct task_struct *child); -extern int save_i387(struct _fpstate __user *buf); extern asmlinkage void math_state_restore(void); -/* - * FPU lazy state save handling... - */ - -#define unlazy_fpu(tsk) do { \ - if (task_thread_info(tsk)->status & TS_USEDFPU) \ - save_init_fpu(tsk); \ - else \ - tsk->fpu_counter = 0; \ -} while (0) +#ifdef CONFIG_X86_64 /* Ignore delayed exceptions from user space */ static inline void tolerant_fwait(void) @@ -46,52 +36,8 @@ static inline void tolerant_fwait(void) " .previous\n"); } -#define clear_fpu(tsk) do { \ - if (task_thread_info(tsk)->status & TS_USEDFPU) { \ - tolerant_fwait(); \ - task_thread_info(tsk)->status &= ~TS_USEDFPU; \ - stts(); \ - } \ -} while (0) - -/* - * ptrace request handers... - */ -extern int get_fpregs(struct user_i387_struct __user *buf, - struct task_struct *tsk); -extern int set_fpregs(struct task_struct *tsk, - struct user_i387_struct __user *buf); - -/* - * i387 state interaction - */ -#define get_fpu_mxcsr(t) ((t)->thread.i387.fxsave.mxcsr) -#define get_fpu_cwd(t) ((t)->thread.i387.fxsave.cwd) -#define get_fpu_fxsr_twd(t) ((t)->thread.i387.fxsave.twd) -#define get_fpu_swd(t) ((t)->thread.i387.fxsave.swd) -#define set_fpu_cwd(t,val) ((t)->thread.i387.fxsave.cwd = (val)) -#define set_fpu_swd(t,val) ((t)->thread.i387.fxsave.swd = (val)) -#define set_fpu_fxsr_twd(t,val) ((t)->thread.i387.fxsave.twd = (val)) - -#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) +static inline int restore_fpu_checking(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 restore_fpu_checking(struct i387_fxsave_struct *fx) -{ int err; asm volatile("1: rex64/fxrstor (%[fx])\n\t" @@ -105,7 +51,7 @@ static inline int restore_fpu_checking(struct i387_fxsave_struct *fx) " .quad 1b,3b\n" ".previous" : [err] "=r" (err) -#if 0 /* See comment in __fxsave_clear() below. */ +#if 0 /* See comment in __save_init_fpu() below. */ : [fx] "r" (fx), "m" (*fx), "0" (0)); #else : [fx] "cdaSDb" (fx), "m" (*fx), "0" (0)); @@ -113,10 +59,27 @@ static inline int restore_fpu_checking(struct i387_fxsave_struct *fx) if (unlikely(err)) init_fpu(current); return err; -} +} -static inline int save_i387_checking(struct i387_fxsave_struct __user *fx) -{ +#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" @@ -139,9 +102,9 @@ static inline int save_i387_checking(struct i387_fxsave_struct __user *fx) err = -EFAULT; /* No need to clear here because the caller clears USED_MATH */ return err; -} +} -static inline void __fxsave_clear(struct task_struct *tsk) +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 @@ -169,18 +132,142 @@ static inline void __fxsave_clear(struct task_struct *tsk) thread.i387.fxsave))); #endif clear_fpu_state(&tsk->thread.i387.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.i387.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.i387.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.i387.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.i387.fxsave), + [fsw] "m" (tsk->thread.i387.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) { - __fxsave_clear(me->task); - me->status &= ~TS_USEDFPU; - return; - } - clts(); + if (me->status & TS_USEDFPU) + __save_init_fpu(me->task); + else + clts(); } static inline void kernel_fpu_end(void) @@ -189,24 +276,88 @@ static inline void kernel_fpu_end(void) preempt_enable(); } +#ifdef CONFIG_X86_64 + static inline void save_init_fpu(struct task_struct *tsk) { - __fxsave_clear(tsk); - task_thread_info(tsk)->status &= ~TS_USEDFPU; + __save_init_fpu(tsk); stts(); } -/* - * This restores directly out of user space. Exceptions are handled. +#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 int restore_i387(struct _fpstate __user *buf) +static inline void save_init_fpu(struct task_struct *tsk) { - set_used_math(); - if (!(task_thread_info(current)->status & TS_USEDFPU)) { - clts(); - task_thread_info(current)->status |= TS_USEDFPU; + 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 */ + +/* + * ptrace request handlers... + */ +extern int get_fpregs(struct user_i387_struct __user *buf, + struct task_struct *tsk); +extern int set_fpregs(struct task_struct *tsk, + struct user_i387_struct __user *buf); + +struct user_fxsr_struct; +extern int get_fpxregs(struct user_fxsr_struct __user *buf, + struct task_struct *tsk); +extern int set_fpxregs(struct task_struct *tsk, + struct user_fxsr_struct __user *buf); + +/* + * i387 state interaction + */ +static inline unsigned short get_fpu_cwd(struct task_struct *tsk) +{ + if (cpu_has_fxsr) { + return tsk->thread.i387.fxsave.cwd; + } else { + return (unsigned short)tsk->thread.i387.fsave.cwd; + } +} + +static inline unsigned short get_fpu_swd(struct task_struct *tsk) +{ + if (cpu_has_fxsr) { + return tsk->thread.i387.fxsave.swd; + } else { + return (unsigned short)tsk->thread.i387.fsave.swd; + } +} + +static inline unsigned short get_fpu_mxcsr(struct task_struct *tsk) +{ + if (cpu_has_xmm) { + return tsk->thread.i387.fxsave.mxcsr; + } else { + return MXCSR_DEFAULT; } - return restore_fpu_checking((__force struct i387_fxsave_struct *)buf); } -#endif /* __ASM_X86_64_I387_H */ +#endif /* _ASM_X86_I387_H */ -- 2.39.5