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Groups > linux.kernel > #1738002

[PATCH 15/33] x86/fpu: Simplify fpu->fpregs_active use

From Ingo Molnar <mingo@kernel.org>
Newsgroups linux.kernel
Subject [PATCH 15/33] x86/fpu: Simplify fpu->fpregs_active use
Date 2017-09-23 15:10 +0200
Message-ID <usSlX-3wU-13@gated-at.bofh.it> (permalink)
References <usSlX-3wU-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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The fpregs_active() inline function is pretty pointless - in almost
all the callsites it can be replaced with a direct fpu->fpregs_active
access.

Do so and eliminate the extra layer of obfuscation.

Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/include/asm/fpu/internal.h | 17 +----------------
 arch/x86/kernel/fpu/core.c          |  2 +-
 arch/x86/kernel/fpu/signal.c        |  9 +++++----
 arch/x86/mm/pkeys.c                 |  2 +-
 4 files changed, 8 insertions(+), 22 deletions(-)

diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 554cdb205d17..b223c57dd5dc 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -543,21 +543,6 @@ static inline void fpregs_activate(struct fpu *fpu)
 }
 
 /*
- * The question "does this thread have fpu access?"
- * is slightly racy, since preemption could come in
- * and revoke it immediately after the test.
- *
- * However, even in that very unlikely scenario,
- * we can just assume we have FPU access - typically
- * to save the FP state - we'll just take a #NM
- * fault and get the FPU access back.
- */
-static inline int fpregs_active(void)
-{
-	return current->thread.fpu.fpregs_active;
-}
-
-/*
  * FPU state switching for scheduling.
  *
  * This is a two-stage process:
@@ -617,7 +602,7 @@ static inline void user_fpu_begin(void)
 	struct fpu *fpu = &current->thread.fpu;
 
 	preempt_disable();
-	if (!fpregs_active())
+	if (!fpu->fpregs_active)
 		fpregs_activate(fpu);
 	preempt_enable();
 }
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index e1114f070c2d..bad57248e5a0 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -367,7 +367,7 @@ void fpu__current_fpstate_write_end(void)
 	 * registers may still be out of date.  Update them with
 	 * an XRSTOR if they are active.
 	 */
-	if (fpregs_active())
+	if (fpu->fpregs_active)
 		copy_kernel_to_fpregs(&fpu->state);
 
 	/*
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 2d682dac35d4..684025654d0c 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -155,7 +155,8 @@ static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf)
  */
 int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
 {
-	struct xregs_state *xsave = &current->thread.fpu.state.xsave;
+	struct fpu *fpu = &current->thread.fpu;
+	struct xregs_state *xsave = &fpu->state.xsave;
 	struct task_struct *tsk = current;
 	int ia32_fxstate = (buf != buf_fx);
 
@@ -170,13 +171,13 @@ 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 (fpregs_active() || using_compacted_format()) {
+	if (fpu->fpregs_active || using_compacted_format()) {
 		/* Save the live register state to the user directly. */
 		if (copy_fpregs_to_sigframe(buf_fx))
 			return -1;
 		/* Update the thread's fxstate to save the fsave header. */
 		if (ia32_fxstate)
-			copy_fxregs_to_kernel(&tsk->thread.fpu);
+			copy_fxregs_to_kernel(fpu);
 	} else {
 		/*
 		 * It is a *bug* if kernel uses compacted-format for xsave
@@ -189,7 +190,7 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
 			return -1;
 		}
 
-		fpstate_sanitize_xstate(&tsk->thread.fpu);
+		fpstate_sanitize_xstate(fpu);
 		if (__copy_to_user(buf_fx, xsave, fpu_user_xstate_size))
 			return -1;
 	}
diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index 2dab69a706ec..e2c23472233e 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -45,7 +45,7 @@ int __execute_only_pkey(struct mm_struct *mm)
 	 */
 	preempt_disable();
 	if (!need_to_set_mm_pkey &&
-	    fpregs_active() &&
+	    current->thread.fpu.fpregs_active &&
 	    !__pkru_allows_read(read_pkru(), execute_only_pkey)) {
 		preempt_enable();
 		return execute_only_pkey;
-- 
2.11.0

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[PATCH 00/33] x86 FPU fixes and cleanups for v4.14 Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
  [PATCH 19/33] x86/fpu: Decouple fpregs_activate()/fpregs_deactivate() from fpu->fpregs_active Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Decouple  fpregs_activate()/fpregs_deactivate() from fpu->fpregs_active tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 15/33] x86/fpu: Simplify fpu->fpregs_active use Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Simplify fpu->fpregs_active use tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 26/33] x86/fpu: Reinitialize FPU registers if restoring FPU state fails Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Reinitialize FPU registers if restoring FPU  state fails tip-bot for Eric Biggers <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 32/33] x86/fpu: Rename fpu__activate_curr() to fpu__initialize() Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Rename fpu__activate_curr() to  fpu__initialize() tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:50 +0200
  [PATCH 31/33] x86/fpu: Simplify and speed up fpu__copy() Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Simplify and speed up fpu__copy() tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:50 +0200
  [PATCH 21/33] x86/fpu: Add FPU state copying quirk to handle XRSTOR failure on Intel Skylake CPUs Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Add FPU state copying quirk to handle XRSTOR  failure on Intel Skylake CPUs tip-bot for Rik van Riel <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 13/33] x86/fpu: Remove 'kbuf' parameter from the copy_user_to_xstate() API Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Remove 'kbuf' parameter from the  copy_user_to_xstate() API tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 33/33] x86/fpu: Rename fpu__activate_fpstate_read/write() to fpu__read/write() Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
  [PATCH 02/33] x86/fpu: Split copy_xstate_to_user() into copy_xstate_to_kernel() & copy_xstate_to_user() Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Split copy_xstate_to_user() into  copy_xstate_to_kernel() & copy_xstate_to_user() tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:30 +0200
  [PATCH 16/33] x86/fpu: Make the fpu state change in fpu__clear() scheduler-atomic Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Make the fpu state change in fpu__clear()  scheduler-atomic tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 14/33] x86/fpu: Flip the parameter order in copy_*_to_xstate() Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Flip the parameter order in  copy_*_to_xstate() tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 11/33] x86/fpu: Split copy_user_to_xstate() into copy_kernel_to_xstate() & copy_user_to_xstate() Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Split copy_user_to_xstate() into  copy_kernel_to_xstate() & copy_user_to_xstate() tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 07/33] x86/fpu: Remove the 'start_pos' parameter from the __copy_xstate_to_*() functions Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Remove the 'start_pos' parameter from the  __copy_xstate_to_*() functions tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 01/33] x86/fpu: Rename copyin_to_xsaves()/copyout_from_xsaves() to copy_user_to_xstate()/copy_xstate_to_user() Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Rename  copyin_to_xsaves()/copyout_from_xsaves() to  copy_user_to_xstate()/copy_xstate_to_user() tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:30 +0200
  [PATCH 29/33] x86/fpu: Rename fpu::fpstate_active to fpu::initialized Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Rename fpu::fpstate_active to  fpu::initialized tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:50 +0200
  [PATCH 17/33] x86/fpu: Split the state handling in fpu__drop() Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Split the state handling in fpu__drop() tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 09/33] x86/fpu: Change 'size_total' parameter to unsigned and standardize the size checks in copy_xstate_to_*() Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Change 'size_total' parameter to unsigned  and standardize the size checks in copy_xstate_to_*() tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 30/33] x86/fpu: Fix stale comments about lazy FPU logic Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Fix stale comments about lazy FPU logic tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:50 +0200
  [PATCH 08/33] x86/fpu: Clarify parameter names in the copy_xstate_to_*() methods Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    Re: [PATCH 08/33] x86/fpu: Clarify parameter names in the  copy_xstate_to_*() methods Thomas Gleixner <tglx@linutronix.de> - 2017-09-25 22:00 +0200
      Re: [PATCH 08/33] x86/fpu: Clarify parameter names in the  copy_xstate_to_*() methods Thomas Gleixner <tglx@linutronix.de> - 2017-09-25 22:10 +0200
    [tip:x86/fpu] x86/fpu: Clarify parameter names in the  copy_xstate_to_*() methods tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 20/33] x86/fpu: Remove struct fpu::fpregs_active Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Remove struct fpu::fpregs_active tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 03/33] x86/fpu: Remove 'ubuf' parameter from the copy_xstate_to_kernel() APIs Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Remove 'ubuf' parameter from the  copy_xstate_to_kernel() APIs tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:30 +0200
  [PATCH 23/33] x86/fpu: Turn WARN_ON() in context switch into WARN_ON_FPU() Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Turn WARN_ON() in context switch into  WARN_ON_FPU() tip-bot for Andi Kleen <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 22/33] x86/fpu: Fix boolreturn.cocci warnings Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Fix boolreturn.cocci warnings tip-bot for kbuild test robot <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 06/33] x86/fpu: Clean up the parameter definitions of copy_xstate_to_*() Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Clean up the parameter definitions of  copy_xstate_to_*() tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 04/33] x86/fpu: Remove 'kbuf' parameter from the copy_xstate_to_user() APIs Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Remove 'kbuf' parameter from the  copy_xstate_to_user() APIs tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 05/33] x86/fpu: Clean up parameter order in the copy_xstate_to_*() APIs Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Clean up parameter order in the  copy_xstate_to_*() APIs tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 24/33] x86/fpu: Don't let userspace set bogus xcomp_bv Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Don't let userspace set bogus xcomp_bv tip-bot for Eric Biggers <tipbot@zytor.com> - 2017-09-26 10:50 +0200
  [PATCH 18/33] x86/fpu: Change fpu->fpregs_active users to fpu->fpstate_active Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Change fpu->fpregs_active users to  fpu->fpstate_active tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 27/33] x86/fpu: Simplify fpu__activate_fpstate_read() Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Fix fpu__activate_fpstate_read() and update  comments tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 12/33] x86/fpu: Remove 'ubuf' parameter from the copy_kernel_to_xstate() API Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Remove 'ubuf' parameter from the  copy_kernel_to_xstate() API tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  [PATCH 25/33] x86/fpu: Tighten validation of user-supplied xstate_header Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
  [PATCH 28/33] x86/fpu: Remove fpu__current_fpstate_write_begin/end() Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    [tip:x86/fpu] x86/fpu: Remove  fpu__current_fpstate_write_begin/end() tip-bot for Ingo Molnar <tipbot@zytor.com> - 2017-09-26 10:40 +0200
  Re: [PATCH 00/33] x86 FPU fixes and cleanups for v4.14 Ingo Molnar <mingo@kernel.org> - 2017-09-23 15:10 +0200
    Re: [PATCH 00/33] x86 FPU fixes and cleanups for v4.14 Juergen Gross <jgross@suse.com> - 2017-09-23 17:10 +0200
      Re: [PATCH 00/33] x86 FPU fixes and cleanups for v4.14 Ingo Molnar <mingo@kernel.org> - 2017-09-24 01:30 +0200

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