Skip to content

Commit

Permalink
x86/fpu: Reorganize fpu/internal.h
Browse files Browse the repository at this point in the history 
fpu/internal.h has grown organically, with not much high level structure,
which hurts its readability.

Organize the various definitions into 5 sections:

 - high level FPU state functions
 - FPU/CPU feature flag helpers
 - fpstate handling functions
 - FPU context switching helpers
 - misc helper functions

Other related changes:

 - Move MXCSR_DEFAULT to fpu/types.h.
 - drop the unused X87_FSW_ES define

No change in functionality.

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>
  • Loading branch information
Ingo Molnar committed May 19, 2015
1 parent e97131a commit b1b64dc
Show file tree
Hide file tree
Showing 2 changed files with 87 additions and 75 deletions.
159 changes: 84 additions & 75 deletions arch/x86/include/asm/fpu/internal.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,32 +18,6 @@
#include <asm/fpu/api.h>
#include <asm/fpu/xstate.h>

#define MXCSR_DEFAULT 0x1f80

extern unsigned int mxcsr_feature_mask;

extern union fpregs_state init_fpstate;

extern void fpu__init_cpu(void);
extern void fpu__init_system_xstate(void);
extern void fpu__init_cpu_xstate(void);
extern void fpu__init_system(struct cpuinfo_x86 *c);

extern void fpstate_init(union fpregs_state *state);
#ifdef CONFIG_MATH_EMULATION
extern void fpstate_init_soft(struct swregs_state *soft);
#else
static inline void fpstate_init_soft(struct swregs_state *soft) {}
#endif
static inline void fpstate_init_fxstate(struct fxregs_state *fx)
{
fx->cwd = 0x37f;
fx->mxcsr = MXCSR_DEFAULT;
}

extern int dump_fpu(struct pt_regs *, struct user_i387_struct *);
extern int fpu__exception_code(struct fpu *fpu, int trap_nr);

/*
* High level FPU state handling functions:
*/
Expand All @@ -55,7 +29,16 @@ extern int fpu__restore_sig(void __user *buf, int ia32_frame);
extern void fpu__drop(struct fpu *fpu);
extern int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu);
extern void fpu__clear(struct fpu *fpu);
extern int fpu__exception_code(struct fpu *fpu, int trap_nr);
extern int dump_fpu(struct pt_regs *ptregs, struct user_i387_struct *fpstate);

/*
* Boot time FPU initialization functions:
*/
extern void fpu__init_cpu(void);
extern void fpu__init_system_xstate(void);
extern void fpu__init_cpu_xstate(void);
extern void fpu__init_system(struct cpuinfo_x86 *c);
extern void fpu__init_check_bugs(void);
extern void fpu__resume_cpu(void);

Expand All @@ -68,27 +51,9 @@ extern void fpu__resume_cpu(void);
# define WARN_ON_FPU(x) ({ 0; })
#endif

DECLARE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx);

/*
* Must be run with preemption disabled: this clears the fpu_fpregs_owner_ctx,
* on this CPU.
*
* This will disable any lazy FPU state restore of the current FPU state,
* but if the current thread owns the FPU, it will still be saved by.
* FPU related CPU feature flag helper routines:
*/
static inline void __cpu_disable_lazy_restore(unsigned int cpu)
{
per_cpu(fpu_fpregs_owner_ctx, cpu) = NULL;
}

static inline int fpu_want_lazy_restore(struct fpu *fpu, unsigned int cpu)
{
return fpu == this_cpu_read_stable(fpu_fpregs_owner_ctx) && cpu == fpu->last_cpu;
}

#define X87_FSW_ES (1 << 7) /* Exception Summary */

static __always_inline __pure bool use_eager_fpu(void)
{
return static_cpu_has_safe(X86_FEATURE_EAGER_FPU);
Expand All @@ -109,6 +74,23 @@ static __always_inline __pure bool use_fxsr(void)
return static_cpu_has_safe(X86_FEATURE_FXSR);
}

/*
* fpstate handling functions:
*/

extern union fpregs_state init_fpstate;

extern void fpstate_init(union fpregs_state *state);
#ifdef CONFIG_MATH_EMULATION
extern void fpstate_init_soft(struct swregs_state *soft);
#else
static inline void fpstate_init_soft(struct swregs_state *soft) {}
#endif
static inline void fpstate_init_fxstate(struct fxregs_state *fx)
{
fx->cwd = 0x37f;
fx->mxcsr = MXCSR_DEFAULT;
}
extern void fpstate_sanitize_xstate(struct fpu *fpu);

#define user_insn(insn, output, input...) \
Expand Down Expand Up @@ -285,6 +267,32 @@ static inline int copy_fpstate_to_fpregs(struct fpu *fpu)
return __copy_fpstate_to_fpregs(fpu);
}

extern int copy_fpstate_to_sigframe(void __user *buf, void __user *fx, int size);

/*
* FPU context switch related helper methods:
*/

DECLARE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx);

/*
* Must be run with preemption disabled: this clears the fpu_fpregs_owner_ctx,
* on this CPU.
*
* This will disable any lazy FPU state restore of the current FPU state,
* but if the current thread owns the FPU, it will still be saved by.
*/
static inline void __cpu_disable_lazy_restore(unsigned int cpu)
{
per_cpu(fpu_fpregs_owner_ctx, cpu) = NULL;
}

static inline int fpu_want_lazy_restore(struct fpu *fpu, unsigned int cpu)
{
return fpu == this_cpu_read_stable(fpu_fpregs_owner_ctx) && cpu == fpu->last_cpu;
}


/*
* Wrap lazy FPU TS handling in a 'hw fpregs activation/deactivation'
* idiom, which is then paired with the sw-flag (fpregs_active) later on:
Expand Down Expand Up @@ -354,31 +362,6 @@ static inline void fpregs_deactivate(struct fpu *fpu)
__fpregs_deactivate_hw();
}

/*
* Definitions for the eXtended Control Register instructions
*/

#define XCR_XFEATURE_ENABLED_MASK 0x00000000

static inline u64 xgetbv(u32 index)
{
u32 eax, edx;

asm volatile(".byte 0x0f,0x01,0xd0" /* xgetbv */
: "=a" (eax), "=d" (edx)
: "c" (index));
return eax + ((u64)edx << 32);
}

static inline void xsetbv(u32 index, u64 value)
{
u32 eax = value;
u32 edx = value >> 32;

asm volatile(".byte 0x0f,0x01,0xd1" /* xsetbv */
: : "a" (eax), "d" (edx), "c" (index));
}

/*
* FPU state switching for scheduling.
*
Expand Down Expand Up @@ -437,6 +420,10 @@ switch_fpu_prepare(struct fpu *old_fpu, struct fpu *new_fpu, int cpu)
return fpu;
}

/*
* Misc helper functions:
*/

/*
* By the time this gets called, we've already cleared CR0.TS and
* given the process the FPU if we are going to preload the FPU
Expand All @@ -453,11 +440,6 @@ static inline void switch_fpu_finish(struct fpu *new_fpu, fpu_switch_t fpu_switc
}
}

/*
* Signal frame handlers...
*/
extern int copy_fpstate_to_sigframe(void __user *buf, void __user *fx, int size);

/*
* Needs to be preemption-safe.
*
Expand All @@ -476,4 +458,31 @@ static inline void user_fpu_begin(void)
preempt_enable();
}

/*
* MXCSR and XCR definitions:
*/

extern unsigned int mxcsr_feature_mask;

#define XCR_XFEATURE_ENABLED_MASK 0x00000000

static inline u64 xgetbv(u32 index)
{
u32 eax, edx;

asm volatile(".byte 0x0f,0x01,0xd0" /* xgetbv */
: "=a" (eax), "=d" (edx)
: "c" (index));
return eax + ((u64)edx << 32);
}

static inline void xsetbv(u32 index, u64 value)
{
u32 eax = value;
u32 edx = value >> 32;

asm volatile(".byte 0x0f,0x01,0xd1" /* xsetbv */
: : "a" (eax), "d" (edx), "c" (index));
}

#endif /* _ASM_X86_FPU_INTERNAL_H */
3 changes: 3 additions & 0 deletions arch/x86/include/asm/fpu/types.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -65,6 +65,9 @@ struct fxregs_state {

} __attribute__((aligned(16)));

/* Default value for fxregs_state.mxcsr: */
#define MXCSR_DEFAULT 0x1f80

/*
* Software based FPU emulation state. This is arbitrary really,
* it matches the x87 format to make it easier to understand:
Expand Down

0 comments on commit b1b64dc

Please sign in to comment.