x86/fpu: Simplify fpu->fpregs_active use

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: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
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/20170923130016.21448-16-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 554cdb205d17586887e6b599c991b2fc090ba38a..b223c57dd5dc3d1dd20b4b309994fecf09fd1977 100644 (file)
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -542,21 +542,6 @@ static inline void fpregs_activate(struct fpu *fpu)
        trace_x86_fpu_regs_activated(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.
  *
@@ -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 e1114f070c2dfdedf9911cd587afb7cca1769785..bad57248e5a034559b6d23c6562d7a9f02e5c529 100644 (file)
--- 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         * registers may still be out of date.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 2d682dac35d4ce21ae258e0b9b4e1989f65a8271..684025654d0cc81ea0bbc133a311f5ed1b82a4dd 100644 (file)
--- 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 2dab69a706ec062affe14eb7d9f10fd8538a9018..e2c23472233e09ec0517d014c71b421bc960216d 100644 (file)
--- 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;