From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- arch/x86/include/asm/switch_to.h | 91 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 arch/x86/include/asm/switch_to.h (limited to 'arch/x86/include/asm/switch_to.h') diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h new file mode 100644 index 000000000..c08eb0fdd --- /dev/null +++ b/arch/x86/include/asm/switch_to.h @@ -0,0 +1,91 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_SWITCH_TO_H +#define _ASM_X86_SWITCH_TO_H + +#include + +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 + /* Xen PV enters the kernel on the thread stack. */ + 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, + int (*fun)(void *), void *arg) +{ + frame->bx = (unsigned long)fun; +#ifdef CONFIG_X86_32 + frame->di = (unsigned long)arg; +#else + frame->r12 = (unsigned long)arg; +#endif +} + +#endif /* _ASM_X86_SWITCH_TO_H */ -- cgit v1.2.3