diff options
| author | Ingo Molnar <mingo@kernel.org> | 2015-04-22 16:52:03 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-05-19 15:47:21 +0200 |
| commit | 085cc281a04633761bac361f26dcee2800d58077 (patch) | |
| tree | 7f13fc90dbd271e254b0f7fc8626c0a39482aa55 /arch | |
| parent | x86/fpu: Add debug check to kernel_fpu_disable() (diff) | |
| download | linux-085cc281a04633761bac361f26dcee2800d58077.tar.xz linux-085cc281a04633761bac361f26dcee2800d58077.zip | |
x86/fpu: Add kernel_fpu_disabled()
Instead of open-coded in_kernel_fpu access, Use kernel_fpu_disabled() in
interrupted_kernel_fpu_idle(), matching the other kernel_fpu_*() methods.
Also add some documentation for in_kernel_fpu.
Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/fpu/core.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 9bc573a5c9db..e898e83afa0a 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -7,6 +7,17 @@ */ #include <asm/fpu-internal.h> +/* + * Track whether the kernel is using the FPU state + * currently. + * + * This flag is used: + * + * - by IRQ context code to potentially use the FPU + * if it's unused. + * + * - to debug kernel_fpu_begin()/end() correctness + */ static DEFINE_PER_CPU(bool, in_kernel_fpu); static void kernel_fpu_disable(void) @@ -21,6 +32,11 @@ static void kernel_fpu_enable(void) this_cpu_write(in_kernel_fpu, false); } +static bool kernel_fpu_disabled(void) +{ + return this_cpu_read(in_kernel_fpu); +} + /* * Were we in an interrupt that interrupted kernel mode? * @@ -35,7 +51,7 @@ static void kernel_fpu_enable(void) */ static bool interrupted_kernel_fpu_idle(void) { - if (this_cpu_read(in_kernel_fpu)) + if (kernel_fpu_disabled()) return false; if (use_eager_fpu()) |