cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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switch_to.h (2368B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef _ASM_X86_SWITCH_TO_H
      3#define _ASM_X86_SWITCH_TO_H
      4
      5#include <linux/sched/task_stack.h>
      6
      7struct task_struct; /* one of the stranger aspects of C forward declarations */
      8
      9struct task_struct *__switch_to_asm(struct task_struct *prev,
     10				    struct task_struct *next);
     11
     12__visible struct task_struct *__switch_to(struct task_struct *prev,
     13					  struct task_struct *next);
     14
     15asmlinkage void ret_from_fork(void);
     16
     17/*
     18 * This is the structure pointed to by thread.sp for an inactive task.  The
     19 * order of the fields must match the code in __switch_to_asm().
     20 */
     21struct inactive_task_frame {
     22#ifdef CONFIG_X86_64
     23	unsigned long r15;
     24	unsigned long r14;
     25	unsigned long r13;
     26	unsigned long r12;
     27#else
     28	unsigned long flags;
     29	unsigned long si;
     30	unsigned long di;
     31#endif
     32	unsigned long bx;
     33
     34	/*
     35	 * These two fields must be together.  They form a stack frame header,
     36	 * needed by get_frame_pointer().
     37	 */
     38	unsigned long bp;
     39	unsigned long ret_addr;
     40};
     41
     42struct fork_frame {
     43	struct inactive_task_frame frame;
     44	struct pt_regs regs;
     45};
     46
     47#define switch_to(prev, next, last)					\
     48do {									\
     49	((last) = __switch_to_asm((prev), (next)));			\
     50} while (0)
     51
     52#ifdef CONFIG_X86_32
     53static inline void refresh_sysenter_cs(struct thread_struct *thread)
     54{
     55	/* Only happens when SEP is enabled, no need to test "SEP"arately: */
     56	if (unlikely(this_cpu_read(cpu_tss_rw.x86_tss.ss1) == thread->sysenter_cs))
     57		return;
     58
     59	this_cpu_write(cpu_tss_rw.x86_tss.ss1, thread->sysenter_cs);
     60	wrmsr(MSR_IA32_SYSENTER_CS, thread->sysenter_cs, 0);
     61}
     62#endif
     63
     64/* This is used when switching tasks or entering/exiting vm86 mode. */
     65static inline void update_task_stack(struct task_struct *task)
     66{
     67	/* sp0 always points to the entry trampoline stack, which is constant: */
     68#ifdef CONFIG_X86_32
     69	if (static_cpu_has(X86_FEATURE_XENPV))
     70		load_sp0(task->thread.sp0);
     71	else
     72		this_cpu_write(cpu_tss_rw.x86_tss.sp1, task->thread.sp0);
     73#else
     74	/* Xen PV enters the kernel on the thread stack. */
     75	if (static_cpu_has(X86_FEATURE_XENPV))
     76		load_sp0(task_top_of_stack(task));
     77#endif
     78}
     79
     80static inline void kthread_frame_init(struct inactive_task_frame *frame,
     81				      int (*fun)(void *), void *arg)
     82{
     83	frame->bx = (unsigned long)fun;
     84#ifdef CONFIG_X86_32
     85	frame->di = (unsigned long)arg;
     86#else
     87	frame->r12 = (unsigned long)arg;
     88#endif
     89}
     90
     91#endif /* _ASM_X86_SWITCH_TO_H */