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x86/fpu: Rename fpu::fpstate_active to fpu::initialized

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The x86 FPU code used to have a complex state machine where both the FPU
registers and the FPU state context could be 'active' (or inactive)
independently of each other - which enabled features like lazy FPU restore.

Much of this complexity is gone in the current code: now we basically can
have FPU-less tasks (kernel threads) that don't use (and save/restore) FPU
state at all, plus full FPU users that save/restore directly with no laziness
whatsoever.

But the fpu::fpstate_active still carries bits of the old complexity - meanwhile
this flag has become a simple flag that shows whether the FPU context saving
area in the thread struct is initialized and used, or not.

Rename it to fpu::initialized to express this simplicity in the name as well.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-30-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar
2017-09-26 09:43:36 +02:00
parent 685c930d6e
commit e4a81bfcaa
11 changed files with 35 additions and 35 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
arch/x86/kernel/fpu/signal.c
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@@ -171,7 +171,7 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
sizeof(struct user_i387_ia32_struct), NULL,
(struct _fpstate_32 __user *) buf) ? -1 : 1;
if (fpu->fpstate_active || using_compacted_format()) {
if (fpu->initialized || using_compacted_format()) {
/* Save the live register state to the user directly. */
if (copy_fpregs_to_sigframe(buf_fx))
return -1;
@@ -315,12 +315,12 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
int err = 0;
/*
* Drop the current fpu which clears fpu->fpstate_active. This ensures
* Drop the current fpu which clears fpu->initialized. This ensures
* that any context-switch during the copy of the new state,
* avoids the intermediate state from getting restored/saved.
* Thus avoiding the new restored state from getting corrupted.
* We will be ready to restore/save the state only after
* fpu->fpstate_active is again set.
* fpu->initialized is again set.
*/
fpu__drop(fpu);
@@ -342,7 +342,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
sanitize_restored_xstate(tsk, &env, xfeatures, fx_only);
}
fpu->fpstate_active = 1;
fpu->initialized = 1;
preempt_disable();
fpu__restore(fpu);
preempt_enable();