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x86/fpu: Add CONFIG_X86_DEBUG_FPU=y FPU debugging code

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There are various internal FPU state debugging checks that never
trigger in practice, but which are useful for FPU code development.

Separate these out into CONFIG_X86_DEBUG_FPU=y, and also add a
couple of new ones.

The size difference is about 0.5K of code on defconfig:

   text        data     bss          filename
   15028906    2578816  1638400      vmlinux
   15029430    2578816  1638400      vmlinux

( Keep this enabled by default until the new FPU code is debugged. )

Cc: Andy Lutomirski <luto@amacapital.net>
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: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar
2015-05-05 11:34:49 +02:00
parent d364a7656c
commit e97131a839
5 changed files with 58 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
arch/x86/include/asm/fpu/internal.h
View File

@@ -59,6 +59,15 @@ extern void fpu__clear(struct fpu *fpu);
extern void fpu__init_check_bugs(void);
extern void fpu__resume_cpu(void);
/*
* Debugging facility:
*/
#ifdef CONFIG_X86_DEBUG_FPU
# define WARN_ON_FPU(x) WARN_ON_ONCE(x)
#else
# define WARN_ON_FPU(x) ({ 0; })
#endif
DECLARE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx);
/*
@@ -296,6 +305,8 @@ static inline void __fpregs_deactivate_hw(void)
/* Must be paired with an 'stts' (fpregs_deactivate_hw()) after! */
static inline void __fpregs_deactivate(struct fpu *fpu)
{
WARN_ON_FPU(!fpu->fpregs_active);
fpu->fpregs_active = 0;
this_cpu_write(fpu_fpregs_owner_ctx, NULL);
}
@@ -303,6 +314,8 @@ static inline void __fpregs_deactivate(struct fpu *fpu)
/* Must be paired with a 'clts' (fpregs_activate_hw()) before! */
static inline void __fpregs_activate(struct fpu *fpu)
{
WARN_ON_FPU(fpu->fpregs_active);
fpu->fpregs_active = 1;
this_cpu_write(fpu_fpregs_owner_ctx, fpu);
}
@@ -433,8 +446,10 @@ switch_fpu_prepare(struct fpu *old_fpu, struct fpu *new_fpu, int cpu)
static inline void switch_fpu_finish(struct fpu *new_fpu, fpu_switch_t fpu_switch)
{
if (fpu_switch.preload) {
if (unlikely(copy_fpstate_to_fpregs(new_fpu)))
if (unlikely(copy_fpstate_to_fpregs(new_fpu))) {
WARN_ON_FPU(1);
fpu__clear(new_fpu);
}
}
}