diff options
Diffstat (limited to 'arch/x86/kernel/i387.c')
| -rw-r--r-- | arch/x86/kernel/i387.c | 81 |
1 files changed, 49 insertions, 32 deletions
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index 86cef6b32253..58bb239a2fd7 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -40,6 +40,7 @@ static unsigned int mxcsr_feature_mask __read_mostly = 0xffffffffu; unsigned int xstate_size; +EXPORT_SYMBOL_GPL(xstate_size); unsigned int sig_xstate_ia32_size = sizeof(struct _fpstate_ia32); static struct i387_fxsave_struct fx_scratch __cpuinitdata; @@ -59,62 +60,68 @@ void __cpuinit mxcsr_feature_mask_init(void) stts(); } -void __cpuinit init_thread_xstate(void) +static void __cpuinit init_thread_xstate(void) { + /* + * Note that xstate_size might be overwriten later during + * xsave_init(). + */ + if (!HAVE_HWFP) { + /* + * Disable xsave as we do not support it if i387 + * emulation is enabled. + */ + setup_clear_cpu_cap(X86_FEATURE_XSAVE); + setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT); xstate_size = sizeof(struct i387_soft_struct); return; } - if (cpu_has_xsave) { - xsave_cntxt_init(); - return; - } - if (cpu_has_fxsr) xstate_size = sizeof(struct i387_fxsave_struct); -#ifdef CONFIG_X86_32 else xstate_size = sizeof(struct i387_fsave_struct); -#endif } -#ifdef CONFIG_X86_64 /* * Called at bootup to set up the initial FPU state that is later cloned * into all processes. */ + void __cpuinit fpu_init(void) { - unsigned long oldcr0 = read_cr0(); + unsigned long cr0; + unsigned long cr4_mask = 0; - set_in_cr4(X86_CR4_OSFXSR); - set_in_cr4(X86_CR4_OSXMMEXCPT); - - write_cr0(oldcr0 & ~(X86_CR0_TS|X86_CR0_EM)); /* clear TS and EM */ + if (cpu_has_fxsr) + cr4_mask |= X86_CR4_OSFXSR; + if (cpu_has_xmm) + cr4_mask |= X86_CR4_OSXMMEXCPT; + if (cr4_mask) + set_in_cr4(cr4_mask); + + cr0 = read_cr0(); + cr0 &= ~(X86_CR0_TS|X86_CR0_EM); /* clear TS and EM */ + if (!HAVE_HWFP) + cr0 |= X86_CR0_EM; + write_cr0(cr0); - /* - * Boot processor to setup the FP and extended state context info. - */ if (!smp_processor_id()) init_thread_xstate(); - xsave_init(); mxcsr_feature_mask_init(); /* clean state in init */ current_thread_info()->status = 0; clear_used_math(); } -#endif /* CONFIG_X86_64 */ -static void fpu_finit(struct fpu *fpu) +void fpu_finit(struct fpu *fpu) { -#ifdef CONFIG_X86_32 if (!HAVE_HWFP) { finit_soft_fpu(&fpu->state->soft); return; } -#endif if (cpu_has_fxsr) { struct i387_fxsave_struct *fx = &fpu->state->fxsave; @@ -132,6 +139,7 @@ static void fpu_finit(struct fpu *fpu) fp->fos = 0xffff0000u; } } +EXPORT_SYMBOL_GPL(fpu_finit); /* * The _current_ task is using the FPU for the first time @@ -190,6 +198,8 @@ int xfpregs_get(struct task_struct *target, const struct user_regset *regset, if (ret) return ret; + sanitize_i387_state(target); + return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &target->thread.fpu.state->fxsave, 0, -1); } @@ -207,6 +217,8 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset, if (ret) return ret; + sanitize_i387_state(target); + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &target->thread.fpu.state->fxsave, 0, -1); @@ -374,19 +386,17 @@ convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk) #ifdef CONFIG_X86_64 env->fip = fxsave->rip; env->foo = fxsave->rdp; + /* + * should be actually ds/cs at fpu exception time, but + * that information is not available in 64bit mode. + */ + env->fcs = task_pt_regs(tsk)->cs; if (tsk == current) { - /* - * should be actually ds/cs at fpu exception time, but - * that information is not available in 64bit mode. - */ - asm("mov %%ds, %[fos]" : [fos] "=r" (env->fos)); - asm("mov %%cs, %[fcs]" : [fcs] "=r" (env->fcs)); + savesegment(ds, env->fos); } else { - struct pt_regs *regs = task_pt_regs(tsk); - - env->fos = 0xffff0000 | tsk->thread.ds; - env->fcs = regs->cs; + env->fos = tsk->thread.ds; } + env->fos |= 0xffff0000; #else env->fip = fxsave->fip; env->fcs = (u16) fxsave->fcs | ((u32) fxsave->fop << 16); @@ -446,6 +456,8 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset, -1); } + sanitize_i387_state(target); + if (kbuf && pos == 0 && count == sizeof(env)) { convert_from_fxsr(kbuf, target); return 0; @@ -467,6 +479,8 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset, if (ret) return ret; + sanitize_i387_state(target); + if (!HAVE_HWFP) return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf); @@ -533,6 +547,9 @@ static int save_i387_xsave(void __user *buf) struct _fpstate_ia32 __user *fx = buf; int err = 0; + + sanitize_i387_state(tsk); + /* * For legacy compatible, we always set FP/SSE bits in the bit * vector while saving the state to the user context. |