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author | Suresh Siddha <suresh.b.siddha@intel.com> | 2008-03-10 22:28:04 (GMT) |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2008-04-19 17:19:55 (GMT) |
commit | 61c4628b538608c1a85211ed8438136adfeb9a95 (patch) | |
tree | 290a695299a363153bc692e6d705ac680d64359e /arch/x86/kernel/i387.c | |
parent | fa5c4639419668cbb18ca3d20c1253559a3b43ae (diff) | |
download | linux-fsl-qoriq-61c4628b538608c1a85211ed8438136adfeb9a95.tar.xz |
x86, fpu: split FPU state from task struct - v5
Split the FPU save area from the task struct. This allows easy migration
of FPU context, and it's generally cleaner. It also allows the following
two optimizations:
1) only allocate when the application actually uses FPU, so in the first
lazy FPU trap. This could save memory for non-fpu using apps. Next patch
does this lazy allocation.
2) allocate the right size for the actual cpu rather than 512 bytes always.
Patches enabling xsave/xrstor support (coming shortly) will take advantage
of this.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/kernel/i387.c')
-rw-r--r-- | arch/x86/kernel/i387.c | 80 |
1 files changed, 46 insertions, 34 deletions
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index 8f8102d..baf632b 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -8,6 +8,7 @@ #include <linux/module.h> #include <linux/regset.h> #include <linux/sched.h> +#include <linux/bootmem.h> #include <asm/sigcontext.h> #include <asm/processor.h> @@ -35,17 +36,18 @@ #endif static unsigned int mxcsr_feature_mask __read_mostly = 0xffffffffu; +unsigned int xstate_size; +static struct i387_fxsave_struct fx_scratch __cpuinitdata; -void mxcsr_feature_mask_init(void) +void __cpuinit mxcsr_feature_mask_init(void) { unsigned long mask = 0; clts(); if (cpu_has_fxsr) { - memset(¤t->thread.i387.fxsave, 0, - sizeof(struct i387_fxsave_struct)); - asm volatile("fxsave %0" : : "m" (current->thread.i387.fxsave)); - mask = current->thread.i387.fxsave.mxcsr_mask; + memset(&fx_scratch, 0, sizeof(struct i387_fxsave_struct)); + asm volatile("fxsave %0" : : "m" (fx_scratch)); + mask = fx_scratch.mxcsr_mask; if (mask == 0) mask = 0x0000ffbf; } @@ -53,6 +55,17 @@ void mxcsr_feature_mask_init(void) stts(); } +void __init init_thread_xstate(void) +{ + if (cpu_has_fxsr) + xstate_size = sizeof(struct i387_fxsave_struct); +#ifdef CONFIG_X86_32 + else + xstate_size = sizeof(struct i387_fsave_struct); +#endif + init_task.thread.xstate = alloc_bootmem(xstate_size); +} + #ifdef CONFIG_X86_64 /* * Called at bootup to set up the initial FPU state that is later cloned @@ -61,10 +74,6 @@ void mxcsr_feature_mask_init(void) void __cpuinit fpu_init(void) { unsigned long oldcr0 = read_cr0(); - extern void __bad_fxsave_alignment(void); - - if (offsetof(struct task_struct, thread.i387.fxsave) & 15) - __bad_fxsave_alignment(); set_in_cr4(X86_CR4_OSFXSR); set_in_cr4(X86_CR4_OSXMMEXCPT); @@ -93,18 +102,19 @@ void init_fpu(struct task_struct *tsk) } if (cpu_has_fxsr) { - memset(&tsk->thread.i387.fxsave, 0, - sizeof(struct i387_fxsave_struct)); - tsk->thread.i387.fxsave.cwd = 0x37f; + struct i387_fxsave_struct *fx = &tsk->thread.xstate->fxsave; + + memset(fx, 0, xstate_size); + fx->cwd = 0x37f; if (cpu_has_xmm) - tsk->thread.i387.fxsave.mxcsr = MXCSR_DEFAULT; + fx->mxcsr = MXCSR_DEFAULT; } else { - memset(&tsk->thread.i387.fsave, 0, - sizeof(struct i387_fsave_struct)); - tsk->thread.i387.fsave.cwd = 0xffff037fu; - tsk->thread.i387.fsave.swd = 0xffff0000u; - tsk->thread.i387.fsave.twd = 0xffffffffu; - tsk->thread.i387.fsave.fos = 0xffff0000u; + struct i387_fsave_struct *fp = &tsk->thread.xstate->fsave; + memset(fp, 0, xstate_size); + fp->cwd = 0xffff037fu; + fp->swd = 0xffff0000u; + fp->twd = 0xffffffffu; + fp->fos = 0xffff0000u; } /* * Only the device not available exception or ptrace can call init_fpu. @@ -132,7 +142,7 @@ int xfpregs_get(struct task_struct *target, const struct user_regset *regset, init_fpu(target); return user_regset_copyout(&pos, &count, &kbuf, &ubuf, - &target->thread.i387.fxsave, 0, -1); + &target->thread.xstate->fxsave, 0, -1); } int xfpregs_set(struct task_struct *target, const struct user_regset *regset, @@ -148,12 +158,12 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset, set_stopped_child_used_math(target); ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, - &target->thread.i387.fxsave, 0, -1); + &target->thread.xstate->fxsave, 0, -1); /* * mxcsr reserved bits must be masked to zero for security reasons. */ - target->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask; + target->thread.xstate->fxsave.mxcsr &= mxcsr_feature_mask; return ret; } @@ -233,7 +243,7 @@ static inline u32 twd_fxsr_to_i387(struct i387_fxsave_struct *fxsave) static void convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk) { - struct i387_fxsave_struct *fxsave = &tsk->thread.i387.fxsave; + struct i387_fxsave_struct *fxsave = &tsk->thread.xstate->fxsave; struct _fpreg *to = (struct _fpreg *) &env->st_space[0]; struct _fpxreg *from = (struct _fpxreg *) &fxsave->st_space[0]; int i; @@ -273,7 +283,7 @@ static void convert_to_fxsr(struct task_struct *tsk, const struct user_i387_ia32_struct *env) { - struct i387_fxsave_struct *fxsave = &tsk->thread.i387.fxsave; + struct i387_fxsave_struct *fxsave = &tsk->thread.xstate->fxsave; struct _fpreg *from = (struct _fpreg *) &env->st_space[0]; struct _fpxreg *to = (struct _fpxreg *) &fxsave->st_space[0]; int i; @@ -310,7 +320,8 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset, if (!cpu_has_fxsr) { return user_regset_copyout(&pos, &count, &kbuf, &ubuf, - &target->thread.i387.fsave, 0, -1); + &target->thread.xstate->fsave, 0, + -1); } if (kbuf && pos == 0 && count == sizeof(env)) { @@ -338,7 +349,7 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset, if (!cpu_has_fxsr) { return user_regset_copyin(&pos, &count, &kbuf, &ubuf, - &target->thread.i387.fsave, 0, -1); + &target->thread.xstate->fsave, 0, -1); } if (pos > 0 || count < sizeof(env)) @@ -358,11 +369,11 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset, static inline int save_i387_fsave(struct _fpstate_ia32 __user *buf) { struct task_struct *tsk = current; + struct i387_fsave_struct *fp = &tsk->thread.xstate->fsave; unlazy_fpu(tsk); - tsk->thread.i387.fsave.status = tsk->thread.i387.fsave.swd; - if (__copy_to_user(buf, &tsk->thread.i387.fsave, - sizeof(struct i387_fsave_struct))) + fp->status = fp->swd; + if (__copy_to_user(buf, fp, sizeof(struct i387_fsave_struct))) return -1; return 1; } @@ -370,6 +381,7 @@ static inline int save_i387_fsave(struct _fpstate_ia32 __user *buf) static int save_i387_fxsave(struct _fpstate_ia32 __user *buf) { struct task_struct *tsk = current; + struct i387_fxsave_struct *fx = &tsk->thread.xstate->fxsave; struct user_i387_ia32_struct env; int err = 0; @@ -379,12 +391,12 @@ static int save_i387_fxsave(struct _fpstate_ia32 __user *buf) if (__copy_to_user(buf, &env, sizeof(env))) return -1; - err |= __put_user(tsk->thread.i387.fxsave.swd, &buf->status); + err |= __put_user(fx->swd, &buf->status); err |= __put_user(X86_FXSR_MAGIC, &buf->magic); if (err) return -1; - if (__copy_to_user(&buf->_fxsr_env[0], &tsk->thread.i387.fxsave, + if (__copy_to_user(&buf->_fxsr_env[0], fx, sizeof(struct i387_fxsave_struct))) return -1; return 1; @@ -417,7 +429,7 @@ static inline int restore_i387_fsave(struct _fpstate_ia32 __user *buf) struct task_struct *tsk = current; clear_fpu(tsk); - return __copy_from_user(&tsk->thread.i387.fsave, buf, + return __copy_from_user(&tsk->thread.xstate->fsave, buf, sizeof(struct i387_fsave_struct)); } @@ -428,10 +440,10 @@ static int restore_i387_fxsave(struct _fpstate_ia32 __user *buf) int err; clear_fpu(tsk); - err = __copy_from_user(&tsk->thread.i387.fxsave, &buf->_fxsr_env[0], + err = __copy_from_user(&tsk->thread.xstate->fxsave, &buf->_fxsr_env[0], sizeof(struct i387_fxsave_struct)); /* mxcsr reserved bits must be masked to zero for security reasons */ - tsk->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask; + tsk->thread.xstate->fxsave.mxcsr &= mxcsr_feature_mask; if (err || __copy_from_user(&env, buf, sizeof(env))) return 1; convert_to_fxsr(tsk, &env); |