/*-
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_isa.h"
#include "opt_cpu.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/procctl.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/unistd.h>
#include <sys/vnode.h>
#include <sys/vmmeter.h>
#include <sys/wait.h>
#include <machine/cpu.h>
#include <machine/md_var.h>
#include <machine/pcb.h>
#include <machine/smp.h>
#include <machine/specialreg.h>
#include <machine/tss.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_param.h>
_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 for user processes. */
if ((td2->td_pflags & TDP_KTHREAD) == 0) {
MPASS(td1 == curthread);
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);
/* Kernel processes start with clean FPU and segment bases. */
if ((td2->td_pflags & TDP_KTHREAD) != 0) {
pcb2->pcb_fsbase = 0;
pcb2->pcb_gsbase = 0;
clear_pcb_flags(pcb2, PCB_FPUINITDONE | PCB_USERFPUINITDONE |
PCB_KERNFPU | PCB_KERNFPU_THR);
} else {
MPASS((pcb2->pcb_flags & (PCB_KERNFPU | PCB_KERNFPU_THR)) == 0);
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));
/*
* 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;
/* Ensure that td0's pcb is up to date for user threads. */
if ((td->td_pflags & TDP_KTHREAD) == 0) {
MPASS(td0 == curthread);
fpuexit(td0);
update_pcb_bases(td0->td_pcb);
}
/*
* Copy the upcall pcb. This loads kernel regs.
* Those not loaded individually below get their default
* values here.
*/
bcopy(td0->td_pcb, pcb2, sizeof(*pcb2));
pcb2->pcb_save = get_pcb_user_save_pcb(pcb2);
/* Kernel threads start with clean FPU and segment bases. */
if ((td->td_pflags & TDP_KTHREAD) != 0) {
pcb2->pcb_fsbase = 0;
pcb2->pcb_gsbase = 0;
clear_pcb_flags(pcb2, PCB_FPUINITDONE | PCB_USERFPUINITDONE |
PCB_KERNFPU | PCB_KERNFPU_THR);
} else {
MPASS((pcb2->pcb_flags & (PCB_KERNFPU | PCB_KERNFPU_THR)) == 0);
bcopy(get_pcb_user_save_td(td0), pcb2->pcb_save,
cpu_max_ext_state_size);
}
set_pcb_flags_raw(pcb2, PCB_FULL_IRET);
/*
* Copy user general-purpose registers.
*
* Some of these registers are rewritten by cpu_set_upcall()
* and linux_set_upcall_kse().
*/
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;
}
