mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-30 14:16:41 +07:00
c41bf8fa5e
There are two callers of __unlazy_fpu, unlazy_fpu and __switch_to, and none of them appear to require additional preempt_disable/enable here. Let's open-code save_init_fpu in __unlazy_fpu to save a few ops. Signed-off-by: Jan Kiszka <jan.kiszka@web.de> Signed-off-by: Andi Kleen <ak@suse.de>
152 lines
3.8 KiB
C
152 lines
3.8 KiB
C
/*
|
|
* include/asm-i386/i387.h
|
|
*
|
|
* Copyright (C) 1994 Linus Torvalds
|
|
*
|
|
* Pentium III FXSR, SSE support
|
|
* General FPU state handling cleanups
|
|
* Gareth Hughes <gareth@valinux.com>, May 2000
|
|
*/
|
|
|
|
#ifndef __ASM_I386_I387_H
|
|
#define __ASM_I386_I387_H
|
|
|
|
#include <linux/sched.h>
|
|
#include <linux/init.h>
|
|
#include <linux/kernel_stat.h>
|
|
#include <asm/processor.h>
|
|
#include <asm/sigcontext.h>
|
|
#include <asm/user.h>
|
|
|
|
extern void mxcsr_feature_mask_init(void);
|
|
extern void init_fpu(struct task_struct *);
|
|
|
|
/*
|
|
* FPU lazy state save handling...
|
|
*/
|
|
|
|
/*
|
|
* The "nop" is needed to make the instructions the same
|
|
* length.
|
|
*/
|
|
#define restore_fpu(tsk) \
|
|
alternative_input( \
|
|
"nop ; frstor %1", \
|
|
"fxrstor %1", \
|
|
X86_FEATURE_FXSR, \
|
|
"m" ((tsk)->thread.i387.fxsave))
|
|
|
|
extern void kernel_fpu_begin(void);
|
|
#define kernel_fpu_end() do { stts(); preempt_enable(); } while(0)
|
|
|
|
/* We need a safe address that is cheap to find and that is already
|
|
in L1 during context switch. The best choices are unfortunately
|
|
different for UP and SMP */
|
|
#ifdef CONFIG_SMP
|
|
#define safe_address (__per_cpu_offset[0])
|
|
#else
|
|
#define safe_address (kstat_cpu(0).cpustat.user)
|
|
#endif
|
|
|
|
/*
|
|
* These must be called with preempt disabled
|
|
*/
|
|
static inline void __save_init_fpu( struct task_struct *tsk )
|
|
{
|
|
/* Use more nops than strictly needed in case the compiler
|
|
varies code */
|
|
alternative_input(
|
|
"fnsave %[fx] ;fwait;" GENERIC_NOP8 GENERIC_NOP4,
|
|
"fxsave %[fx]\n"
|
|
"bt $7,%[fsw] ; jnc 1f ; fnclex\n1:",
|
|
X86_FEATURE_FXSR,
|
|
[fx] "m" (tsk->thread.i387.fxsave),
|
|
[fsw] "m" (tsk->thread.i387.fxsave.swd) : "memory");
|
|
/* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception
|
|
is pending. Clear the x87 state here by setting it to fixed
|
|
values. safe_address is a random variable that should be in L1 */
|
|
alternative_input(
|
|
GENERIC_NOP8 GENERIC_NOP2,
|
|
"emms\n\t" /* clear stack tags */
|
|
"fildl %[addr]", /* set F?P to defined value */
|
|
X86_FEATURE_FXSAVE_LEAK,
|
|
[addr] "m" (safe_address));
|
|
task_thread_info(tsk)->status &= ~TS_USEDFPU;
|
|
}
|
|
|
|
#define __unlazy_fpu( tsk ) do { \
|
|
if (task_thread_info(tsk)->status & TS_USEDFPU) { \
|
|
__save_init_fpu(tsk); \
|
|
stts(); \
|
|
} else \
|
|
tsk->fpu_counter = 0; \
|
|
} while (0)
|
|
|
|
#define __clear_fpu( tsk ) \
|
|
do { \
|
|
if (task_thread_info(tsk)->status & TS_USEDFPU) { \
|
|
asm volatile("fnclex ; fwait"); \
|
|
task_thread_info(tsk)->status &= ~TS_USEDFPU; \
|
|
stts(); \
|
|
} \
|
|
} while (0)
|
|
|
|
|
|
/*
|
|
* These disable preemption on their own and are safe
|
|
*/
|
|
static inline void save_init_fpu( struct task_struct *tsk )
|
|
{
|
|
preempt_disable();
|
|
__save_init_fpu(tsk);
|
|
stts();
|
|
preempt_enable();
|
|
}
|
|
|
|
#define unlazy_fpu( tsk ) do { \
|
|
preempt_disable(); \
|
|
__unlazy_fpu(tsk); \
|
|
preempt_enable(); \
|
|
} while (0)
|
|
|
|
#define clear_fpu( tsk ) do { \
|
|
preempt_disable(); \
|
|
__clear_fpu( tsk ); \
|
|
preempt_enable(); \
|
|
} while (0)
|
|
|
|
/*
|
|
* FPU state interaction...
|
|
*/
|
|
extern unsigned short get_fpu_cwd( struct task_struct *tsk );
|
|
extern unsigned short get_fpu_swd( struct task_struct *tsk );
|
|
extern unsigned short get_fpu_mxcsr( struct task_struct *tsk );
|
|
extern asmlinkage void math_state_restore(void);
|
|
|
|
/*
|
|
* Signal frame handlers...
|
|
*/
|
|
extern int save_i387( struct _fpstate __user *buf );
|
|
extern int restore_i387( struct _fpstate __user *buf );
|
|
|
|
/*
|
|
* ptrace request handers...
|
|
*/
|
|
extern int get_fpregs( struct user_i387_struct __user *buf,
|
|
struct task_struct *tsk );
|
|
extern int set_fpregs( struct task_struct *tsk,
|
|
struct user_i387_struct __user *buf );
|
|
|
|
extern int get_fpxregs( struct user_fxsr_struct __user *buf,
|
|
struct task_struct *tsk );
|
|
extern int set_fpxregs( struct task_struct *tsk,
|
|
struct user_fxsr_struct __user *buf );
|
|
|
|
/*
|
|
* FPU state for core dumps...
|
|
*/
|
|
extern int dump_fpu( struct pt_regs *regs,
|
|
struct user_i387_struct *fpu );
|
|
|
|
#endif /* __ASM_I386_I387_H */
|