/*- * SPDX-License-Identifier: BSD-4-Clause * * Copyright (c) 1982, 1986 The Regents of the University of California. * Copyright (c) 1989, 1990 William Jolitz * Copyright (c) 1994 John Dyson * All rights reserved. * * This code is derived from software contributed to Berkeley by * the Systems Programming Group of the University of Utah Computer * Science Department, and William Jolitz. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from: @(#)vm_machdep.c 7.3 (Berkeley) 5/13/91 * Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$ */ #include __FBSDID("$FreeBSD$"); #include "opt_isa.h" #include "opt_cpu.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include _Static_assert(OFFSETOF_MONITORBUF == offsetof(struct pcpu, pc_monitorbuf), "OFFSETOF_MONITORBUF does not correspond with offset of pc_monitorbuf."); void set_top_of_stack_td(struct thread *td) { td->td_md.md_stack_base = td->td_kstack + td->td_kstack_pages * PAGE_SIZE - roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN); } struct savefpu * get_pcb_user_save_td(struct thread *td) { vm_offset_t p; p = td->td_md.md_stack_base; KASSERT((p % XSAVE_AREA_ALIGN) == 0, ("Unaligned pcb_user_save area ptr %#lx td %p", p, td)); return ((struct savefpu *)p); } struct pcb * get_pcb_td(struct thread *td) { return (&td->td_md.md_pcb); } struct savefpu * get_pcb_user_save_pcb(struct pcb *pcb) { struct thread *td; td = __containerof(pcb, struct thread, td_md.md_pcb); return (get_pcb_user_save_td(td)); } void * alloc_fpusave(int flags) { void *res; struct savefpu_ymm *sf; res = malloc(cpu_max_ext_state_size, M_DEVBUF, flags); if (use_xsave) { sf = (struct savefpu_ymm *)res; bzero(&sf->sv_xstate.sx_hd, sizeof(sf->sv_xstate.sx_hd)); sf->sv_xstate.sx_hd.xstate_bv = xsave_mask; } return (res); } /* * Finish a fork operation, with process p2 nearly set up. * Copy and update the pcb, set up the stack so that the child * ready to run and return to user mode. */ void cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags) { struct proc *p1; struct pcb *pcb2; struct mdproc *mdp1, *mdp2; struct proc_ldt *pldt; p1 = td1->td_proc; if ((flags & RFPROC) == 0) { if ((flags & RFMEM) == 0) { /* unshare user LDT */ mdp1 = &p1->p_md; mtx_lock(&dt_lock); if ((pldt = mdp1->md_ldt) != NULL && pldt->ldt_refcnt > 1 && user_ldt_alloc(p1, 1) == NULL) panic("could not copy LDT"); mtx_unlock(&dt_lock); } return; } /* Ensure that td1's pcb is up to date. */ fpuexit(td1); update_pcb_bases(td1->td_pcb); /* Point the stack and pcb to the actual location */ set_top_of_stack_td(td2); td2->td_pcb = pcb2 = get_pcb_td(td2); /* Copy td1's pcb */ bcopy(td1->td_pcb, pcb2, sizeof(*pcb2)); /* Properly initialize pcb_save */ pcb2->pcb_save = get_pcb_user_save_pcb(pcb2); bcopy(get_pcb_user_save_td(td1), get_pcb_user_save_pcb(pcb2), cpu_max_ext_state_size); /* Point mdproc and then copy over td1's contents */ mdp2 = &p2->p_md; bcopy(&p1->p_md, mdp2, sizeof(*mdp2)); /* * Create a new fresh stack for the new process. * Copy the trap frame for the return to user mode as if from a * syscall. This copies most of the user mode register values. */ td2->td_frame = (struct trapframe *)td2->td_md.md_stack_base - 1; bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe)); td2->td_frame->tf_rax = 0; /* Child returns zero */ td2->td_frame->tf_rflags &= ~PSL_C; /* success */ td2->td_frame->tf_rdx = 1; /* * If the parent process has the trap bit set (i.e. a debugger * had single stepped the process to the system call), we need * to clear the trap flag from the new frame. */ td2->td_frame->tf_rflags &= ~PSL_T; /* * Set registers for trampoline to user mode. Leave space for the * return address on stack. These are the kernel mode register values. */ pcb2->pcb_r12 = (register_t)fork_return; /* fork_trampoline argument */ pcb2->pcb_rbp = 0; pcb2->pcb_rsp = (register_t)td2->td_frame - sizeof(void *); pcb2->pcb_rbx = (register_t)td2; /* fork_trampoline argument */ pcb2->pcb_rip = (register_t)fork_trampoline; /*- * pcb2->pcb_dr*: cloned above. * pcb2->pcb_savefpu: cloned above. * pcb2->pcb_flags: cloned above. * pcb2->pcb_onfault: cloned above (always NULL here?). * pcb2->pcb_[fg]sbase: cloned above */ /* Setup to release spin count in fork_exit(). */ td2->td_md.md_spinlock_count = 1; td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I; pmap_thread_init_invl_gen(td2); /* As an i386, do not copy io permission bitmap. */ pcb2->pcb_tssp = NULL; /* New segment registers. */ set_pcb_flags_raw(pcb2, PCB_FULL_IRET); /* Copy the LDT, if necessary. */ mdp1 = &td1->td_proc->p_md; mdp2 = &p2->p_md; if (mdp1->md_ldt == NULL) { mdp2->md_ldt = NULL; return; } mtx_lock(&dt_lock); if (mdp1->md_ldt != NULL) { if (flags & RFMEM) { mdp1->md_ldt->ldt_refcnt++; mdp2->md_ldt = mdp1->md_ldt; bcopy(&mdp1->md_ldt_sd, &mdp2->md_ldt_sd, sizeof(struct system_segment_descriptor)); } else { mdp2->md_ldt = NULL; mdp2->md_ldt = user_ldt_alloc(p2, 0); if (mdp2->md_ldt == NULL) panic("could not copy LDT"); amd64_set_ldt_data(td2, 0, max_ldt_segment, (struct user_segment_descriptor *) mdp1->md_ldt->ldt_base); } } else mdp2->md_ldt = NULL; mtx_unlock(&dt_lock); /* * Now, cpu_switch() can schedule the new process. * pcb_rsp is loaded pointing to the cpu_switch() stack frame * containing the return address when exiting cpu_switch. * This will normally be to fork_trampoline(), which will have * %ebx loaded with the new proc's pointer. fork_trampoline() * will set up a stack to call fork_return(p, frame); to complete * the return to user-mode. */ } /* * Intercept the return address from a freshly forked process that has NOT * been scheduled yet. * * This is needed to make kernel threads stay in kernel mode. */ void cpu_fork_kthread_handler(struct thread *td, void (*func)(void *), void *arg) { /* * Note that the trap frame follows the args, so the function * is really called like this: func(arg, frame); */ td->td_pcb->pcb_r12 = (long) func; /* function */ td->td_pcb->pcb_rbx = (long) arg; /* first arg */ } void cpu_exit(struct thread *td) { /* * If this process has a custom LDT, release it. */ if (td->td_proc->p_md.md_ldt != NULL) user_ldt_free(td); } void cpu_thread_exit(struct thread *td) { struct pcb *pcb; critical_enter(); if (td == PCPU_GET(fpcurthread)) fpudrop(); critical_exit(); pcb = td->td_pcb; /* Disable any hardware breakpoints. */ if (pcb->pcb_flags & PCB_DBREGS) { reset_dbregs(); clear_pcb_flags(pcb, PCB_DBREGS); } } void cpu_thread_clean(struct thread *td) { struct pcb *pcb; pcb = td->td_pcb; /* * Clean TSS/iomap */ if (pcb->pcb_tssp != NULL) { pmap_pti_remove_kva((vm_offset_t)pcb->pcb_tssp, (vm_offset_t)pcb->pcb_tssp + ctob(IOPAGES + 1)); kmem_free((vm_offset_t)pcb->pcb_tssp, ctob(IOPAGES + 1)); pcb->pcb_tssp = NULL; } } void cpu_thread_swapin(struct thread *td) { } void cpu_thread_swapout(struct thread *td) { } void cpu_thread_alloc(struct thread *td) { struct pcb *pcb; struct xstate_hdr *xhdr; set_top_of_stack_td(td); td->td_pcb = pcb = get_pcb_td(td); td->td_frame = (struct trapframe *)td->td_md.md_stack_base - 1; pcb->pcb_save = get_pcb_user_save_pcb(pcb); if (use_xsave) { xhdr = (struct xstate_hdr *)(pcb->pcb_save + 1); bzero(xhdr, sizeof(*xhdr)); xhdr->xstate_bv = xsave_mask; } } void cpu_thread_free(struct thread *td) { cpu_thread_clean(td); } bool cpu_exec_vmspace_reuse(struct proc *p, vm_map_t map) { return (((curproc->p_md.md_flags & P_MD_KPTI) != 0) == (vm_map_pmap(map)->pm_ucr3 != PMAP_NO_CR3)); } static void cpu_procctl_kpti_ctl(struct proc *p, int val) { if (pti && val == PROC_KPTI_CTL_ENABLE_ON_EXEC) p->p_md.md_flags |= P_MD_KPTI; if (val == PROC_KPTI_CTL_DISABLE_ON_EXEC) p->p_md.md_flags &= ~P_MD_KPTI; } static void cpu_procctl_kpti_status(struct proc *p, int *val) { *val = (p->p_md.md_flags & P_MD_KPTI) != 0 ? PROC_KPTI_CTL_ENABLE_ON_EXEC: PROC_KPTI_CTL_DISABLE_ON_EXEC; if (vmspace_pmap(p->p_vmspace)->pm_ucr3 != PMAP_NO_CR3) *val |= PROC_KPTI_STATUS_ACTIVE; } static int cpu_procctl_la_ctl(struct proc *p, int val) { int error; error = 0; switch (val) { case PROC_LA_CTL_LA48_ON_EXEC: p->p_md.md_flags |= P_MD_LA48; p->p_md.md_flags &= ~P_MD_LA57; break; case PROC_LA_CTL_LA57_ON_EXEC: if (la57) { p->p_md.md_flags &= ~P_MD_LA48; p->p_md.md_flags |= P_MD_LA57; } else { error = ENOTSUP; } break; case PROC_LA_CTL_DEFAULT_ON_EXEC: p->p_md.md_flags &= ~(P_MD_LA48 | P_MD_LA57); break; } return (error); } static void cpu_procctl_la_status(struct proc *p, int *val) { int res; if ((p->p_md.md_flags & P_MD_LA48) != 0) res = PROC_LA_CTL_LA48_ON_EXEC; else if ((p->p_md.md_flags & P_MD_LA57) != 0) res = PROC_LA_CTL_LA57_ON_EXEC; else res = PROC_LA_CTL_DEFAULT_ON_EXEC; if (p->p_sysent->sv_maxuser == VM_MAXUSER_ADDRESS_LA48) res |= PROC_LA_STATUS_LA48; else res |= PROC_LA_STATUS_LA57; *val = res; } int cpu_procctl(struct thread *td, int idtype, id_t id, int com, void *data) { struct proc *p; int error, val; switch (com) { case PROC_KPTI_CTL: case PROC_KPTI_STATUS: case PROC_LA_CTL: case PROC_LA_STATUS: if (idtype != P_PID) { error = EINVAL; break; } if (com == PROC_KPTI_CTL) { /* sad but true and not a joke */ error = priv_check(td, PRIV_IO); if (error != 0) break; } if (com == PROC_KPTI_CTL || com == PROC_LA_CTL) { error = copyin(data, &val, sizeof(val)); if (error != 0) break; } if (com == PROC_KPTI_CTL && val != PROC_KPTI_CTL_ENABLE_ON_EXEC && val != PROC_KPTI_CTL_DISABLE_ON_EXEC) { error = EINVAL; break; } if (com == PROC_LA_CTL && val != PROC_LA_CTL_LA48_ON_EXEC && val != PROC_LA_CTL_LA57_ON_EXEC && val != PROC_LA_CTL_DEFAULT_ON_EXEC) { error = EINVAL; break; } error = pget(id, PGET_CANSEE | PGET_NOTWEXIT | PGET_NOTID, &p); if (error != 0) break; switch (com) { case PROC_KPTI_CTL: cpu_procctl_kpti_ctl(p, val); break; case PROC_KPTI_STATUS: cpu_procctl_kpti_status(p, &val); break; case PROC_LA_CTL: error = cpu_procctl_la_ctl(p, val); break; case PROC_LA_STATUS: cpu_procctl_la_status(p, &val); break; } PROC_UNLOCK(p); if (com == PROC_KPTI_STATUS || com == PROC_LA_STATUS) error = copyout(&val, data, sizeof(val)); break; default: error = EINVAL; break; } return (error); } void cpu_set_syscall_retval(struct thread *td, int error) { struct trapframe *frame; frame = td->td_frame; if (__predict_true(error == 0)) { frame->tf_rax = td->td_retval[0]; frame->tf_rdx = td->td_retval[1]; frame->tf_rflags &= ~PSL_C; return; } switch (error) { case ERESTART: /* * Reconstruct pc, we know that 'syscall' is 2 bytes, * lcall $X,y is 7 bytes, int 0x80 is 2 bytes. * We saved this in tf_err. * %r10 (which was holding the value of %rcx) is restored * for the next iteration. * %r10 restore is only required for freebsd/amd64 processes, * but shall be innocent for any ia32 ABI. * * Require full context restore to get the arguments * in the registers reloaded at return to usermode. */ frame->tf_rip -= frame->tf_err; frame->tf_r10 = frame->tf_rcx; set_pcb_flags(td->td_pcb, PCB_FULL_IRET); break; case EJUSTRETURN: break; default: frame->tf_rax = error; frame->tf_rflags |= PSL_C; break; } } /* * Initialize machine state, mostly pcb and trap frame for a new * thread, about to return to userspace. Put enough state in the new * thread's PCB to get it to go back to the fork_return(), which * finalizes the thread state and handles peculiarities of the first * return to userspace for the new thread. */ void cpu_copy_thread(struct thread *td, struct thread *td0) { struct pcb *pcb2; pcb2 = td->td_pcb; /* * Copy the upcall pcb. This loads kernel regs. * Those not loaded individually below get their default * values here. */ update_pcb_bases(td0->td_pcb); bcopy(td0->td_pcb, pcb2, sizeof(*pcb2)); clear_pcb_flags(pcb2, PCB_FPUINITDONE | PCB_USERFPUINITDONE | PCB_KERNFPU); pcb2->pcb_save = get_pcb_user_save_pcb(pcb2); bcopy(get_pcb_user_save_td(td0), pcb2->pcb_save, cpu_max_ext_state_size); set_pcb_flags_raw(pcb2, PCB_FULL_IRET); /* * Create a new fresh stack for the new thread. */ bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe)); /* If the current thread has the trap bit set (i.e. a debugger had * single stepped the process to the system call), we need to clear * the trap flag from the new frame. Otherwise, the new thread will * receive a (likely unexpected) SIGTRAP when it executes the first * instruction after returning to userland. */ td->td_frame->tf_rflags &= ~PSL_T; /* * Set registers for trampoline to user mode. Leave space for the * return address on stack. These are the kernel mode register values. */ pcb2->pcb_r12 = (register_t)fork_return; /* trampoline arg */ pcb2->pcb_rbp = 0; pcb2->pcb_rsp = (register_t)td->td_frame - sizeof(void *); /* trampoline arg */ pcb2->pcb_rbx = (register_t)td; /* trampoline arg */ pcb2->pcb_rip = (register_t)fork_trampoline; /* * If we didn't copy the pcb, we'd need to do the following registers: * pcb2->pcb_dr*: cloned above. * pcb2->pcb_savefpu: cloned above. * pcb2->pcb_onfault: cloned above (always NULL here?). * pcb2->pcb_[fg]sbase: cloned above */ /* Setup to release spin count in fork_exit(). */ td->td_md.md_spinlock_count = 1; td->td_md.md_saved_flags = PSL_KERNEL | PSL_I; pmap_thread_init_invl_gen(td); } /* * Set that machine state for performing an upcall that starts * the entry function with the given argument. */ void cpu_set_upcall(struct thread *td, void (*entry)(void *), void *arg, stack_t *stack) { /* * Do any extra cleaning that needs to be done. * The thread may have optional components * that are not present in a fresh thread. * This may be a recycled thread so make it look * as though it's newly allocated. */ cpu_thread_clean(td); #ifdef COMPAT_FREEBSD32 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) { /* * Set the trap frame to point at the beginning of the entry * function. */ td->td_frame->tf_rbp = 0; td->td_frame->tf_rsp = (((uintptr_t)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4; td->td_frame->tf_rip = (uintptr_t)entry; /* Return address sentinel value to stop stack unwinding. */ suword32((void *)td->td_frame->tf_rsp, 0); /* Pass the argument to the entry point. */ suword32((void *)(td->td_frame->tf_rsp + sizeof(int32_t)), (uint32_t)(uintptr_t)arg); return; } #endif /* * Set the trap frame to point at the beginning of the uts * function. */ td->td_frame->tf_rbp = 0; td->td_frame->tf_rsp = ((register_t)stack->ss_sp + stack->ss_size) & ~0x0f; td->td_frame->tf_rsp -= 8; td->td_frame->tf_rip = (register_t)entry; td->td_frame->tf_ds = _udatasel; td->td_frame->tf_es = _udatasel; td->td_frame->tf_fs = _ufssel; td->td_frame->tf_gs = _ugssel; td->td_frame->tf_flags = TF_HASSEGS; /* Return address sentinel value to stop stack unwinding. */ suword((void *)td->td_frame->tf_rsp, 0); /* Pass the argument to the entry point. */ td->td_frame->tf_rdi = (register_t)arg; } int cpu_set_user_tls(struct thread *td, void *tls_base) { struct pcb *pcb; if ((u_int64_t)tls_base >= VM_MAXUSER_ADDRESS) return (EINVAL); pcb = td->td_pcb; set_pcb_flags(pcb, PCB_FULL_IRET); #ifdef COMPAT_FREEBSD32 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) { pcb->pcb_gsbase = (register_t)tls_base; return (0); } #endif pcb->pcb_fsbase = (register_t)tls_base; return (0); } /* * Software interrupt handler for queued VM system processing. */ void swi_vm(void *dummy) { if (busdma_swi_pending != 0) busdma_swi(); } /* * Tell whether this address is in some physical memory region. * Currently used by the kernel coredump code in order to avoid * dumping the ``ISA memory hole'' which could cause indefinite hangs, * or other unpredictable behaviour. */ int is_physical_memory(vm_paddr_t addr) { #ifdef DEV_ISA /* The ISA ``memory hole''. */ if (addr >= 0xa0000 && addr < 0x100000) return 0; #endif /* * stuff other tests for known memory-mapped devices (PCI?) * here */ return 1; }