Both function names are a misnomer.
fpu__save() is actually about synchronizing the hardware register state
into the task's memory state so that either coredump or a math exception
handler can inspect the state at the time where the problem happens.
The function guarantees to preserve the register state, while "save" is a
common terminology for saving the current state so it can be modified and
restored later. This is clearly not the case here.
Rename it to fpu_sync_fpstate().
fpu__copy() is used to clone the current task's FPU state when duplicating
task_struct. While the register state is a copy the rest of the FPU state
is not.
Name it accordingly and remove the really pointless @src argument along
with the warning which comes along with it.
Nothing can ever copy the FPU state of a non-current task. It's clearly
just a consequence of arch_dup_task_struct(), but it makes no sense to
proliferate that further.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121455.196727450@linutronix.de
/*
* High level FPU state handling functions:
*/
/*
* High level FPU state handling functions:
*/
-extern void fpu__save(struct fpu *fpu);
extern int fpu__restore_sig(void __user *buf, int ia32_frame);
extern void fpu__drop(struct fpu *fpu);
extern int fpu__restore_sig(void __user *buf, int ia32_frame);
extern void fpu__drop(struct fpu *fpu);
-extern int fpu__copy(struct task_struct *dst, struct task_struct *src);
extern void fpu__clear_user_states(struct fpu *fpu);
extern void fpu__clear_all(struct fpu *fpu);
extern int fpu__exception_code(struct fpu *fpu, int trap_nr);
extern void fpu__clear_user_states(struct fpu *fpu);
extern void fpu__clear_all(struct fpu *fpu);
extern int fpu__exception_code(struct fpu *fpu, int trap_nr);
+extern void fpu_sync_fpstate(struct fpu *fpu);
+
+extern int fpu_clone(struct task_struct *dst);
+
/*
* Boot time FPU initialization functions:
*/
/*
* Boot time FPU initialization functions:
*/
EXPORT_SYMBOL_GPL(kernel_fpu_end);
/*
EXPORT_SYMBOL_GPL(kernel_fpu_end);
/*
- * Save the FPU state (mark it for reload if necessary):
- *
- * This only ever gets called for the current task.
+ * Sync the FPU register state to current's memory register state when the
+ * current task owns the FPU. The hardware register state is preserved.
-void fpu__save(struct fpu *fpu)
+void fpu_sync_fpstate(struct fpu *fpu)
{
WARN_ON_FPU(fpu != ¤t->thread.fpu);
{
WARN_ON_FPU(fpu != ¤t->thread.fpu);
}
EXPORT_SYMBOL_GPL(fpstate_init);
}
EXPORT_SYMBOL_GPL(fpstate_init);
-int fpu__copy(struct task_struct *dst, struct task_struct *src)
+/* Clone current's FPU state on fork */
+int fpu_clone(struct task_struct *dst)
+ struct fpu *src_fpu = ¤t->thread.fpu;
struct fpu *dst_fpu = &dst->thread.fpu;
struct fpu *dst_fpu = &dst->thread.fpu;
- struct fpu *src_fpu = &src->thread.fpu;
+ /* The new task's FPU state cannot be valid in the hardware. */
- if (!static_cpu_has(X86_FEATURE_FPU))
+ if (!cpu_feature_enabled(X86_FEATURE_FPU))
- WARN_ON_FPU(src_fpu != ¤t->thread.fpu);
-
/*
* Don't let 'init optimized' areas of the XSAVE area
* leak into the child task:
/*
* Don't let 'init optimized' areas of the XSAVE area
* leak into the child task:
static void sync_fpstate(struct fpu *fpu)
{
if (fpu == ¤t->thread.fpu)
static void sync_fpstate(struct fpu *fpu)
{
if (fpu == ¤t->thread.fpu)
#ifdef CONFIG_VM86
dst->thread.vm86 = NULL;
#endif
#ifdef CONFIG_VM86
dst->thread.vm86 = NULL;
#endif
-
- return fpu__copy(dst, src);
- * Save the info for the exception handler and clear the error.
+ * Synchronize the FPU register state to the memory register state
+ * if necessary. This allows the exception handler to inspect it.
task->thread.trap_nr = trapnr;
task->thread.error_code = 0;
task->thread.trap_nr = trapnr;
task->thread.error_code = 0;