diff options
Diffstat (limited to 'include/asm-x86/i387.h')
| -rw-r--r-- | include/asm-x86/i387.h | 40 |
1 files changed, 35 insertions, 5 deletions
diff --git a/include/asm-x86/i387.h b/include/asm-x86/i387.h index b1733601df9..1ecdc3ed96e 100644 --- a/include/asm-x86/i387.h +++ b/include/asm-x86/i387.h @@ -7,12 +7,13 @@ * x86-64 work by Andi Kleen 2002 */ -#ifndef _ASM_X86_I387_H -#define _ASM_X86_I387_H +#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> @@ -63,8 +64,6 @@ static inline int restore_fpu_checking(struct i387_fxsave_struct *fx) #else : [fx] "cdaSDb" (fx), "m" (*fx), "0" (0)); #endif - if (unlikely(err)) - init_fpu(current); return err; } @@ -237,6 +236,37 @@ static inline void kernel_fpu_end(void) 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) @@ -307,4 +337,4 @@ static inline unsigned short get_fpu_mxcsr(struct task_struct *tsk) } } -#endif /* _ASM_X86_I387_H */ +#endif /* ASM_X86__I387_H */ |