1 // SPDX-License-Identifier: GPL-2.0-only
8  *  X86-64 port
11  *	CPU hotplug support - ashok.raj@intel.com
15  * This file handles the architecture-dependent parts of process handling..
75 	if (regs->orig_ax != -1)  in __show_regs()
76 		pr_cont(" ORIG_RAX: %016lx\n", regs->orig_ax);  in __show_regs()
81 	       log_lvl, regs->ax, regs->bx, regs->cx);  in __show_regs()
83 	       log_lvl, regs->dx, regs->si, regs->di);  in __show_regs()
85 	       log_lvl, regs->bp, regs->r8, regs->r9);  in __show_regs()
87 	       log_lvl, regs->r10, regs->r11, regs->r12);  in __show_regs()
89 	       log_lvl, regs->r13, regs->r14, regs->r15);  in __show_regs()
119 		log_lvl, regs->cs, ds, es, cr0);  in __show_regs()
130 	/* Only print out debug registers if they are in their non-default state. */  in __show_regs()
145 	WARN_ON(dead_task->mm);  in release_thread()
205  * not available.  The goal is to be reasonably fast on non-FSGSBASE systems.
216 		 * be the pre-existing saved base or it could be zero.  On AMD  in save_base_legacy()
221 		 * context switch between 64-bit programs), and avoiding  in save_base_legacy()
226 		 * To avoid leaking state, on non-X86_BUG_NULL_SEG CPUs, if we  in save_base_legacy()
242 			prev_p->thread.fsbase = 0;  in save_base_legacy()
244 			prev_p->thread.gsbase = 0;  in save_base_legacy()
250 	savesegment(fs, task->thread.fsindex);  in save_fsgs()
251 	savesegment(gs, task->thread.gsindex);  in save_fsgs()
258 		task->thread.fsbase = rdfsbase();  in save_fsgs()
259 		task->thread.gsbase = __rdgsbase_inactive();  in save_fsgs()
261 		save_base_legacy(task, task->thread.fsindex, FS);  in save_fsgs()
262 		save_base_legacy(task, task->thread.gsindex, GS);  in save_fsgs()
267  * While a process is running,current->thread.fsbase and current->thread.gsbase
300 		 * The next task is using 64-bit TLS, is not using this  in load_seg_legacy()
322 				 * Intel-style CPUs.)  in load_seg_legacy()
347 		if (unlikely(prev->fsindex || next->fsindex))  in x86_fsgsbase_load()
348 			loadseg(FS, next->fsindex);  in x86_fsgsbase_load()
349 		if (unlikely(prev->gsindex || next->gsindex))  in x86_fsgsbase_load()
350 			loadseg(GS, next->gsindex);  in x86_fsgsbase_load()
353 		wrfsbase(next->fsbase);  in x86_fsgsbase_load()
354 		__wrgsbase_inactive(next->gsbase);  in x86_fsgsbase_load()
356 		load_seg_legacy(prev->fsindex, prev->fsbase,  in x86_fsgsbase_load()
357 				next->fsindex, next->fsbase, FS);  in x86_fsgsbase_load()
358 		load_seg_legacy(prev->gsindex, prev->gsbase,  in x86_fsgsbase_load()
359 				next->gsindex, next->gsbase, GS);  in x86_fsgsbase_load()
380 		idx -= GDT_ENTRY_TLS_MIN;  in x86_fsgsbase_read_task()
381 		base = get_desc_base(&task->thread.tls_array[idx]);  in x86_fsgsbase_read_task()
387 		 * If performance here mattered, we could protect the LDT  in x86_fsgsbase_read_task()
391 		mutex_lock(&task->mm->context.lock);  in x86_fsgsbase_read_task()
392 		ldt = task->mm->context.ldt;  in x86_fsgsbase_read_task()
393 		if (unlikely(!ldt || idx >= ldt->nr_entries))  in x86_fsgsbase_read_task()
396 			base = get_desc_base(ldt->entries + idx);  in x86_fsgsbase_read_task()
397 		mutex_unlock(&task->mm->context.lock);  in x86_fsgsbase_read_task()
443 		 (task->thread.fsindex == 0))  in x86_fsbase_read_task()
444 		fsbase = task->thread.fsbase;  in x86_fsbase_read_task()
446 		fsbase = x86_fsgsbase_read_task(task, task->thread.fsindex);  in x86_fsbase_read_task()
458 		 (task->thread.gsindex == 0))  in x86_gsbase_read_task()
459 		gsbase = task->thread.gsbase;  in x86_gsbase_read_task()
461 		gsbase = x86_fsgsbase_read_task(task, task->thread.gsindex);  in x86_gsbase_read_task()
470 	task->thread.fsbase = fsbase;  in x86_fsbase_write_task()
477 	task->thread.gsbase = gsbase;  in x86_gsbase_write_task()
498 	regs->ip		= new_ip;  in start_thread_common()
499 	regs->sp		= new_sp;  in start_thread_common()
500 	regs->cs		= _cs;  in start_thread_common()
501 	regs->ss		= _ss;  in start_thread_common()
502 	regs->flags		= X86_EFLAGS_IF;  in start_thread_common()
527  * - fold all the options into a flag word and test it with a single test.
528  * - could test fs/gs bitsliced
536 	struct thread_struct *prev = &prev_p->thread;  in __switch_to()
537 	struct thread_struct *next = &next_p->thread;  in __switch_to()
538 	struct fpu *prev_fpu = &prev->fpu;  in __switch_to()
539 	struct fpu *next_fpu = &next->fpu;  in __switch_to()
543 		     this_cpu_read(irq_count) != -1);  in __switch_to()
582 	savesegment(es, prev->es);  in __switch_to()
583 	if (unlikely(next->es | prev->es))  in __switch_to()
584 		loadsegment(es, next->es);  in __switch_to()
586 	savesegment(ds, prev->ds);  in __switch_to()
587 	if (unlikely(next->ds | prev->ds))  in __switch_to()
588 		loadsegment(ds, next->ds);  in __switch_to()
617 		 * SS, so the only way to get NULL is to re-enter the kernel  in __switch_to()
625 		 * it previously had a different non-NULL value.  in __switch_to()
648 	task_pt_regs(current)->orig_ax = __NR_execve;  in set_personality_64bit()
649 	current_thread_info()->status &= ~TS_COMPAT;  in set_personality_64bit()
652 	if (current->mm)  in set_personality_64bit()
653 		current->mm->context.ia32_compat = 0;  in set_personality_64bit()
659 	current->personality &= ~READ_IMPLIES_EXEC;  in set_personality_64bit()
667 	if (current->mm)  in __set_personality_x32()
668 		current->mm->context.ia32_compat = TIF_X32;  in __set_personality_x32()
669 	current->personality &= ~READ_IMPLIES_EXEC;  in __set_personality_x32()
674 	 * in_32bit_syscall() work during exec().  in __set_personality_x32()
678 	task_pt_regs(current)->orig_ax = __NR_x32_execve | __X32_SYSCALL_BIT;  in __set_personality_x32()
679 	current_thread_info()->status &= ~TS_COMPAT;  in __set_personality_x32()
688 	if (current->mm)  in __set_personality_ia32()
689 		current->mm->context.ia32_compat = TIF_IA32;  in __set_personality_ia32()
690 	current->personality |= force_personality32;  in __set_personality_ia32()
692 	task_pt_regs(current)->orig_ax = __NR_ia32_execve;  in __set_personality_ia32()
693 	current_thread_info()->status |= TS_COMPAT;  in __set_personality_ia32()
718 	return (long)image->size;  in prctl_map_vdso()
729 			return -EPERM;  in do_arch_prctl_64()
743 			 * On non-FSGSBASE systems, save_base_legacy() expects  in do_arch_prctl_64()
746 			task->thread.gsbase = arg2;  in do_arch_prctl_64()
749 			task->thread.gsindex = 0;  in do_arch_prctl_64()
761 			return -EPERM;  in do_arch_prctl_64()
773 			 * On non-FSGSBASE systems, save_base_legacy() expects  in do_arch_prctl_64()
776 			task->thread.fsbase = arg2;  in do_arch_prctl_64()
778 			task->thread.fsindex = 0;  in do_arch_prctl_64()
811 		ret = -EINVAL;  in do_arch_prctl_64()
823 	if (ret == -EINVAL)  in SYSCALL_DEFINE2()
838 	return task_pt_regs(task)->sp;  in KSTK_ESP()