97 lines
2.4 KiB
C
97 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _ASM_X86_SWITCH_TO_H
|
|
#define _ASM_X86_SWITCH_TO_H
|
|
|
|
#include <linux/sched/task_stack.h>
|
|
|
|
struct task_struct; /* one of the stranger aspects of C forward declarations */
|
|
|
|
struct task_struct *__switch_to_asm(struct task_struct *prev,
|
|
struct task_struct *next);
|
|
|
|
__visible struct task_struct *__switch_to(struct task_struct *prev,
|
|
struct task_struct *next);
|
|
|
|
asmlinkage void ret_from_fork(void);
|
|
|
|
/*
|
|
* This is the structure pointed to by thread.sp for an inactive task. The
|
|
* order of the fields must match the code in __switch_to_asm().
|
|
*/
|
|
struct inactive_task_frame {
|
|
#ifdef CONFIG_X86_64
|
|
unsigned long r15;
|
|
unsigned long r14;
|
|
unsigned long r13;
|
|
unsigned long r12;
|
|
#else
|
|
unsigned long flags;
|
|
unsigned long si;
|
|
unsigned long di;
|
|
#endif
|
|
unsigned long bx;
|
|
|
|
/*
|
|
* These two fields must be together. They form a stack frame header,
|
|
* needed by get_frame_pointer().
|
|
*/
|
|
unsigned long bp;
|
|
unsigned long ret_addr;
|
|
};
|
|
|
|
struct fork_frame {
|
|
struct inactive_task_frame frame;
|
|
struct pt_regs regs;
|
|
};
|
|
|
|
#define switch_to(prev, next, last) \
|
|
do { \
|
|
((last) = __switch_to_asm((prev), (next))); \
|
|
} while (0)
|
|
|
|
#ifdef CONFIG_X86_32
|
|
static inline void refresh_sysenter_cs(struct thread_struct *thread)
|
|
{
|
|
/* Only happens when SEP is enabled, no need to test "SEP"arately: */
|
|
if (unlikely(this_cpu_read(cpu_tss_rw.x86_tss.ss1) == thread->sysenter_cs))
|
|
return;
|
|
|
|
this_cpu_write(cpu_tss_rw.x86_tss.ss1, thread->sysenter_cs);
|
|
wrmsr(MSR_IA32_SYSENTER_CS, thread->sysenter_cs, 0);
|
|
}
|
|
#endif
|
|
|
|
/* This is used when switching tasks or entering/exiting vm86 mode. */
|
|
static inline void update_task_stack(struct task_struct *task)
|
|
{
|
|
/* sp0 always points to the entry trampoline stack, which is constant: */
|
|
#ifdef CONFIG_X86_32
|
|
if (static_cpu_has(X86_FEATURE_XENPV))
|
|
load_sp0(task->thread.sp0);
|
|
else
|
|
this_cpu_write(cpu_tss_rw.x86_tss.sp1, task->thread.sp0);
|
|
#else
|
|
/*
|
|
* x86-64 updates x86_tss.sp1 via cpu_current_top_of_stack. That
|
|
* doesn't work on x86-32 because sp1 and
|
|
* cpu_current_top_of_stack have different values (because of
|
|
* the non-zero stack-padding on 32bit).
|
|
*/
|
|
if (static_cpu_has(X86_FEATURE_XENPV))
|
|
load_sp0(task_top_of_stack(task));
|
|
#endif
|
|
}
|
|
|
|
static inline void kthread_frame_init(struct inactive_task_frame *frame,
|
|
unsigned long fun, unsigned long arg)
|
|
{
|
|
frame->bx = fun;
|
|
#ifdef CONFIG_X86_32
|
|
frame->di = arg;
|
|
#else
|
|
frame->r12 = arg;
|
|
#endif
|
|
}
|
|
|
|
#endif /* _ASM_X86_SWITCH_TO_H */
|