The functions save_init_fpu and unlazy_fpu do essentially the same thing: save the fpu context to memory, and call __thread_fpu_end, which most of the callers do not need or want.
Get rid of the function unlazy_fpu and make sure save_init_fpu does what unlazy_fpu does today, including preemption safe state saving in potentially unusual conditions. Callers of init_fpu do want __thread_fpu_end, so move the call to __thread_fpu_end into init_fpu. I am not sure whether math_error requires __thread_fpu_end. One would think that it would require that in order to sanitize the math state, before do_device_not_available and math_state_restore restore it, but those do not currently seem to do that. I am not sure how a task that catches SIGFPE is supposed to recover and continue... Signed-off-by: Rik van Riel <[email protected]> --- arch/x86/include/asm/fpu-internal.h | 18 ++++++++---------- arch/x86/include/asm/i387.h | 2 -- arch/x86/kernel/i387.c | 18 ++++-------------- arch/x86/kernel/traps.c | 1 + 4 files changed, 13 insertions(+), 26 deletions(-) diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h index 0dbc08282291..c7e440ddd269 100644 --- a/arch/x86/include/asm/fpu-internal.h +++ b/arch/x86/include/asm/fpu-internal.h @@ -524,16 +524,14 @@ static inline void __save_fpu(struct task_struct *tsk) */ static inline void save_init_fpu(struct task_struct *tsk) { - WARN_ON_ONCE(!__thread_has_fpu(tsk)); - - if (use_eager_fpu()) { - __save_fpu(tsk); - return; - } - preempt_disable(); - __save_init_fpu(tsk); - __thread_fpu_end(tsk); + if (__thread_has_fpu(tsk)) { + if (use_eager_fpu()) + __save_fpu(tsk); + else + __save_init_fpu(tsk); + } else if (!use_eager_fpu()) + tsk->thread.fpu_counter = 0; preempt_enable(); } @@ -600,7 +598,7 @@ static inline void fpu_copy(struct task_struct *dst, struct task_struct *src) struct fpu *dfpu = &dst->thread.fpu; struct fpu *sfpu = &src->thread.fpu; - unlazy_fpu(src); + save_init_fpu(src); memcpy(dfpu->state, sfpu->state, xstate_size); } } diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h index 6eb6fcb83f63..07836671acfb 100644 --- a/arch/x86/include/asm/i387.h +++ b/arch/x86/include/asm/i387.h @@ -101,8 +101,6 @@ static inline int user_has_fpu(void) return current->thread.fpu.has_fpu; } -extern void unlazy_fpu(struct task_struct *tsk); - #endif /* __ASSEMBLY__ */ #endif /* _ASM_X86_I387_H */ diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index 47348653503a..3afc4e73b07f 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -116,18 +116,6 @@ void __kernel_fpu_end(void) } EXPORT_SYMBOL(__kernel_fpu_end); -void unlazy_fpu(struct task_struct *tsk) -{ - preempt_disable(); - if (__thread_has_fpu(tsk)) { - __save_init_fpu(tsk); - __thread_fpu_end(tsk); - } else - tsk->thread.fpu_counter = 0; - preempt_enable(); -} -EXPORT_SYMBOL(unlazy_fpu); - unsigned int mxcsr_feature_mask __read_mostly = 0xffffffffu; unsigned int xstate_size; EXPORT_SYMBOL_GPL(xstate_size); @@ -245,8 +233,10 @@ int init_fpu(struct task_struct *tsk) int ret; if (tsk_used_math(tsk)) { - if (cpu_has_fpu && tsk == current) - unlazy_fpu(tsk); + if (cpu_has_fpu && tsk == current) { + save_init_fpu(tsk); + __thread_fpu_end(tsk); + } tsk->thread.fpu.last_cpu = ~0; return 0; } diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index fb4cb6adf225..201522fd2c96 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -664,6 +664,7 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr) * Save the info for the exception handler and clear the error. */ save_init_fpu(task); + __thread_fpu_end(task); task->thread.trap_nr = trapnr; task->thread.error_code = error_code; info.si_signo = SIGFPE; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
