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|
/*
* Mach Operating System
* Copyright (c) 1991,1990 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie Mellon
* the rights to redistribute these changes.
*/
#include <cpus.h>
#include <mach_debug.h>
#include <mach/std_types.h>
#include <mach/kern_return.h>
#include <mach/thread_status.h>
#include <mach/exec/exec.h>
#include "vm_param.h"
#include <kern/counters.h>
#include <kern/mach_param.h>
#include <kern/thread.h>
#include <kern/sched_prim.h>
#include <vm/vm_kern.h>
#include <vm/pmap.h>
#include <i386/thread.h>
#include <i386/proc_reg.h>
#include <i386/seg.h>
#include <i386/tss.h>
#include <i386/user_ldt.h>
#include <i386/fpu.h>
#include "eflags.h"
#include "gdt.h"
#include "ldt.h"
#include "ktss.h"
#if NCPUS > 1
#include <i386/mp_desc.h>
#endif
extern thread_t Switch_context();
extern void Thread_continue();
extern iopb_tss_t iopb_create();
extern void iopb_destroy();
extern void user_ldt_free();
zone_t pcb_zone;
vm_offset_t kernel_stack[NCPUS]; /* top of active_stack */
/*
* stack_attach:
*
* Attach a kernel stack to a thread.
*/
void stack_attach(thread, stack, continuation)
register thread_t thread;
register vm_offset_t stack;
void (*continuation)();
{
counter(if (++c_stacks_current > c_stacks_max)
c_stacks_max = c_stacks_current);
thread->kernel_stack = stack;
/*
* We want to run continuation, giving it as an argument
* the return value from Load_context/Switch_context.
* Thread_continue takes care of the mismatch between
* the argument-passing/return-value conventions.
* This function will not return normally,
* so we don`t have to worry about a return address.
*/
STACK_IKS(stack)->k_eip = (int) Thread_continue;
STACK_IKS(stack)->k_ebx = (int) continuation;
STACK_IKS(stack)->k_esp = (int) STACK_IEL(stack);
/*
* Point top of kernel stack to user`s registers.
*/
STACK_IEL(stack)->saved_state = &thread->pcb->iss;
}
/*
* stack_detach:
*
* Detaches a kernel stack from a thread, returning the old stack.
*/
vm_offset_t stack_detach(thread)
register thread_t thread;
{
register vm_offset_t stack;
counter(if (--c_stacks_current < c_stacks_min)
c_stacks_min = c_stacks_current);
stack = thread->kernel_stack;
thread->kernel_stack = 0;
return stack;
}
#if NCPUS > 1
#define curr_gdt(mycpu) (mp_gdt[mycpu])
#define curr_ktss(mycpu) (mp_ktss[mycpu])
#else
#define curr_gdt(mycpu) (gdt)
#define curr_ktss(mycpu) (&ktss)
#endif
#define gdt_desc_p(mycpu,sel) \
((struct real_descriptor *)&curr_gdt(mycpu)[sel_idx(sel)])
void switch_ktss(pcb)
register pcb_t pcb;
{
int mycpu = cpu_number();
{
register iopb_tss_t tss = pcb->ims.io_tss;
vm_offset_t pcb_stack_top;
/*
* Save a pointer to the top of the "kernel" stack -
* actually the place in the PCB where a trap into
* kernel mode will push the registers.
* The location depends on V8086 mode. If we are
* not in V8086 mode, then a trap into the kernel
* won`t save the v86 segments, so we leave room.
*/
pcb_stack_top = (pcb->iss.efl & EFL_VM)
? (int) (&pcb->iss + 1)
: (int) (&pcb->iss.v86_segs);
if (tss == 0) {
/*
* No per-thread IO permissions.
* Use standard kernel TSS.
*/
if (!(gdt_desc_p(mycpu,KERNEL_TSS)->access & ACC_TSS_BUSY))
set_tr(KERNEL_TSS);
curr_ktss(mycpu)->esp0 = pcb_stack_top;
}
else {
/*
* Set the IO permissions. Use this thread`s TSS.
*/
*gdt_desc_p(mycpu,USER_TSS)
= *(struct real_descriptor *)tss->iopb_desc;
tss->tss.esp0 = pcb_stack_top;
set_tr(USER_TSS);
gdt_desc_p(mycpu,KERNEL_TSS)->access &= ~ ACC_TSS_BUSY;
}
}
{
register user_ldt_t ldt = pcb->ims.ldt;
/*
* Set the thread`s LDT.
*/
if (ldt == 0) {
/*
* Use system LDT.
*/
set_ldt(KERNEL_LDT);
}
else {
/*
* Thread has its own LDT.
*/
*gdt_desc_p(mycpu,USER_LDT) = ldt->desc;
set_ldt(USER_LDT);
}
}
/*
* Load the floating-point context, if necessary.
*/
fpu_load_context(pcb);
}
/*
* stack_handoff:
*
* Move the current thread's kernel stack to the new thread.
*/
void stack_handoff(old, new)
register thread_t old;
register thread_t new;
{
register int mycpu = cpu_number();
register vm_offset_t stack;
/*
* Save FP registers if in use.
*/
fpu_save_context(old);
/*
* Switch address maps if switching tasks.
*/
{
task_t old_task, new_task;
if ((old_task = old->task) != (new_task = new->task)) {
PMAP_DEACTIVATE_USER(vm_map_pmap(old_task->map),
old, mycpu);
PMAP_ACTIVATE_USER(vm_map_pmap(new_task->map),
new, mycpu);
}
}
/*
* Load the rest of the user state for the new thread
*/
switch_ktss(new->pcb);
/*
* Switch to new thread
*/
stack = current_stack();
old->kernel_stack = 0;
new->kernel_stack = stack;
active_threads[mycpu] = new;
/*
* Switch exception link to point to new
* user registers.
*/
STACK_IEL(stack)->saved_state = &new->pcb->iss;
}
/*
* Switch to the first thread on a CPU.
*/
void load_context(new)
register thread_t new;
{
switch_ktss(new->pcb);
Load_context(new);
}
/*
* Switch to a new thread.
* Save the old thread`s kernel state or continuation,
* and return it.
*/
thread_t switch_context(old, continuation, new)
register thread_t old;
void (*continuation)();
register thread_t new;
{
/*
* Save FP registers if in use.
*/
fpu_save_context(old);
/*
* Switch address maps if switching tasks.
*/
{
task_t old_task, new_task;
int mycpu = cpu_number();
if ((old_task = old->task) != (new_task = new->task)) {
PMAP_DEACTIVATE_USER(vm_map_pmap(old_task->map),
old, mycpu);
PMAP_ACTIVATE_USER(vm_map_pmap(new_task->map),
new, mycpu);
}
}
/*
* Load the rest of the user state for the new thread
*/
switch_ktss(new->pcb);
return Switch_context(old, continuation, new);
}
void pcb_module_init()
{
pcb_zone = zinit(sizeof(struct pcb),
THREAD_MAX * sizeof(struct pcb),
THREAD_CHUNK * sizeof(struct pcb),
0, "i386 pcb state");
fpu_module_init();
iopb_init();
}
void pcb_init(thread)
register thread_t thread;
{
register pcb_t pcb;
pcb = (pcb_t) zalloc(pcb_zone);
if (pcb == 0)
panic("pcb_init");
counter(if (++c_threads_current > c_threads_max)
c_threads_max = c_threads_current);
/*
* We can't let random values leak out to the user.
*/
bzero((char *) pcb, sizeof *pcb);
simple_lock_init(&pcb->lock);
/*
* Guarantee that the bootstrapped thread will be in user
* mode.
*/
pcb->iss.cs = USER_CS;
pcb->iss.ss = USER_DS;
pcb->iss.ds = USER_DS;
pcb->iss.es = USER_DS;
pcb->iss.fs = USER_DS;
pcb->iss.gs = USER_DS;
pcb->iss.efl = EFL_USER_SET;
thread->pcb = pcb;
}
void pcb_terminate(thread)
register thread_t thread;
{
register pcb_t pcb = thread->pcb;
counter(if (--c_threads_current < c_threads_min)
c_threads_min = c_threads_current);
if (pcb->ims.io_tss != 0)
iopb_destroy(pcb->ims.io_tss);
if (pcb->ims.ifps != 0)
fp_free(pcb->ims.ifps);
if (pcb->ims.ldt != 0)
user_ldt_free(pcb->ims.ldt);
zfree(pcb_zone, (vm_offset_t) pcb);
thread->pcb = 0;
}
/*
* pcb_collect:
*
* Attempt to free excess pcb memory.
*/
void pcb_collect(thread)
thread_t thread;
{
}
/*
* thread_setstatus:
*
* Set the status of the specified thread.
*/
kern_return_t thread_setstatus(thread, flavor, tstate, count)
thread_t thread;
int flavor;
thread_state_t tstate;
unsigned int count;
{
switch (flavor) {
case i386_THREAD_STATE:
case i386_REGS_SEGS_STATE:
{
register struct i386_thread_state *state;
register struct i386_saved_state *saved_state;
if (count < i386_THREAD_STATE_COUNT) {
return(KERN_INVALID_ARGUMENT);
}
if (flavor == i386_REGS_SEGS_STATE) {
/*
* Code and stack selectors must not be null,
* and must have user protection levels.
* Only the low 16 bits are valid.
*/
state->cs &= 0xffff;
state->ss &= 0xffff;
state->ds &= 0xffff;
state->es &= 0xffff;
state->fs &= 0xffff;
state->gs &= 0xffff;
if (state->cs == 0 || (state->cs & SEL_PL) != SEL_PL_U
|| state->ss == 0 || (state->ss & SEL_PL) != SEL_PL_U)
return KERN_INVALID_ARGUMENT;
}
state = (struct i386_thread_state *) tstate;
saved_state = USER_REGS(thread);
/*
* General registers
*/
saved_state->edi = state->edi;
saved_state->esi = state->esi;
saved_state->ebp = state->ebp;
saved_state->uesp = state->uesp;
saved_state->ebx = state->ebx;
saved_state->edx = state->edx;
saved_state->ecx = state->ecx;
saved_state->eax = state->eax;
saved_state->eip = state->eip;
saved_state->efl = (state->efl & ~EFL_USER_CLEAR)
| EFL_USER_SET;
/*
* Segment registers. Set differently in V8086 mode.
*/
if (state->efl & EFL_VM) {
/*
* Set V8086 mode segment registers.
*/
saved_state->cs = state->cs & 0xffff;
saved_state->ss = state->ss & 0xffff;
saved_state->v86_segs.v86_ds = state->ds & 0xffff;
saved_state->v86_segs.v86_es = state->es & 0xffff;
saved_state->v86_segs.v86_fs = state->fs & 0xffff;
saved_state->v86_segs.v86_gs = state->gs & 0xffff;
/*
* Zero protected mode segment registers.
*/
saved_state->ds = 0;
saved_state->es = 0;
saved_state->fs = 0;
saved_state->gs = 0;
if (thread->pcb->ims.v86s.int_table) {
/*
* Hardware assist on.
*/
thread->pcb->ims.v86s.flags =
state->efl & (EFL_TF | EFL_IF);
}
}
else if (flavor == i386_THREAD_STATE) {
/*
* 386 mode. Set segment registers for flat
* 32-bit address space.
*/
saved_state->cs = USER_CS;
saved_state->ss = USER_DS;
saved_state->ds = USER_DS;
saved_state->es = USER_DS;
saved_state->fs = USER_DS;
saved_state->gs = USER_DS;
}
else {
/*
* User setting segment registers.
* Code and stack selectors have already been
* checked. Others will be reset by 'iret'
* if they are not valid.
*/
saved_state->cs = state->cs;
saved_state->ss = state->ss;
saved_state->ds = state->ds;
saved_state->es = state->es;
saved_state->fs = state->fs;
saved_state->gs = state->gs;
}
break;
}
case i386_FLOAT_STATE: {
if (count < i386_FLOAT_STATE_COUNT)
return(KERN_INVALID_ARGUMENT);
return fpu_set_state(thread,
(struct i386_float_state *) tstate);
}
/*
* Temporary - replace by i386_io_map
*/
case i386_ISA_PORT_MAP_STATE: {
register struct i386_isa_port_map_state *state;
register iopb_tss_t tss;
if (count < i386_ISA_PORT_MAP_STATE_COUNT)
return(KERN_INVALID_ARGUMENT);
#if 0
/*
* If the thread has no ktss yet,
* we must allocate one.
*/
state = (struct i386_isa_port_map_state *) tstate;
tss = thread->pcb->ims.io_tss;
if (tss == 0) {
tss = iopb_create();
thread->pcb->ims.io_tss = tss;
}
bcopy((char *) state->pm,
(char *) tss->bitmap,
sizeof state->pm);
#endif
break;
}
case i386_V86_ASSIST_STATE:
{
register struct i386_v86_assist_state *state;
vm_offset_t int_table;
int int_count;
if (count < i386_V86_ASSIST_STATE_COUNT)
return KERN_INVALID_ARGUMENT;
state = (struct i386_v86_assist_state *) tstate;
int_table = state->int_table;
int_count = state->int_count;
if (int_table >= VM_MAX_ADDRESS ||
int_table +
int_count * sizeof(struct v86_interrupt_table)
> VM_MAX_ADDRESS)
return KERN_INVALID_ARGUMENT;
thread->pcb->ims.v86s.int_table = int_table;
thread->pcb->ims.v86s.int_count = int_count;
thread->pcb->ims.v86s.flags =
USER_REGS(thread)->efl & (EFL_TF | EFL_IF);
break;
}
default:
return(KERN_INVALID_ARGUMENT);
}
return(KERN_SUCCESS);
}
/*
* thread_getstatus:
*
* Get the status of the specified thread.
*/
kern_return_t thread_getstatus(thread, flavor, tstate, count)
register thread_t thread;
int flavor;
thread_state_t tstate; /* pointer to OUT array */
unsigned int *count; /* IN/OUT */
{
switch (flavor) {
case THREAD_STATE_FLAVOR_LIST:
if (*count < 4)
return (KERN_INVALID_ARGUMENT);
tstate[0] = i386_THREAD_STATE;
tstate[1] = i386_FLOAT_STATE;
tstate[2] = i386_ISA_PORT_MAP_STATE;
tstate[3] = i386_V86_ASSIST_STATE;
*count = 4;
break;
case i386_THREAD_STATE:
case i386_REGS_SEGS_STATE:
{
register struct i386_thread_state *state;
register struct i386_saved_state *saved_state;
if (*count < i386_THREAD_STATE_COUNT)
return(KERN_INVALID_ARGUMENT);
state = (struct i386_thread_state *) tstate;
saved_state = USER_REGS(thread);
/*
* General registers.
*/
state->edi = saved_state->edi;
state->esi = saved_state->esi;
state->ebp = saved_state->ebp;
state->ebx = saved_state->ebx;
state->edx = saved_state->edx;
state->ecx = saved_state->ecx;
state->eax = saved_state->eax;
state->eip = saved_state->eip;
state->efl = saved_state->efl;
state->uesp = saved_state->uesp;
state->cs = saved_state->cs;
state->ss = saved_state->ss;
if (saved_state->efl & EFL_VM) {
/*
* V8086 mode.
*/
state->ds = saved_state->v86_segs.v86_ds & 0xffff;
state->es = saved_state->v86_segs.v86_es & 0xffff;
state->fs = saved_state->v86_segs.v86_fs & 0xffff;
state->gs = saved_state->v86_segs.v86_gs & 0xffff;
if (thread->pcb->ims.v86s.int_table) {
/*
* Hardware assist on
*/
if ((thread->pcb->ims.v86s.flags &
(EFL_IF|V86_IF_PENDING))
== 0)
state->efl &= ~EFL_IF;
}
}
else {
/*
* 386 mode.
*/
state->ds = saved_state->ds & 0xffff;
state->es = saved_state->es & 0xffff;
state->fs = saved_state->fs & 0xffff;
state->gs = saved_state->gs & 0xffff;
}
*count = i386_THREAD_STATE_COUNT;
break;
}
case i386_FLOAT_STATE: {
if (*count < i386_FLOAT_STATE_COUNT)
return(KERN_INVALID_ARGUMENT);
*count = i386_FLOAT_STATE_COUNT;
return fpu_get_state(thread,
(struct i386_float_state *)tstate);
}
/*
* Temporary - replace by i386_io_map
*/
case i386_ISA_PORT_MAP_STATE: {
register struct i386_isa_port_map_state *state;
register iopb_tss_t tss;
if (*count < i386_ISA_PORT_MAP_STATE_COUNT)
return(KERN_INVALID_ARGUMENT);
state = (struct i386_isa_port_map_state *) tstate;
tss = thread->pcb->ims.io_tss;
if (tss == 0) {
int i;
/*
* The thread has no ktss, so no IO permissions.
*/
for (i = 0; i < sizeof state->pm; i++)
state->pm[i] = 0xff;
} else {
/*
* The thread has its own ktss.
*/
bcopy((char *) tss->bitmap,
(char *) state->pm,
sizeof state->pm);
}
*count = i386_ISA_PORT_MAP_STATE_COUNT;
break;
}
case i386_V86_ASSIST_STATE:
{
register struct i386_v86_assist_state *state;
if (*count < i386_V86_ASSIST_STATE_COUNT)
return KERN_INVALID_ARGUMENT;
state = (struct i386_v86_assist_state *) tstate;
state->int_table = thread->pcb->ims.v86s.int_table;
state->int_count = thread->pcb->ims.v86s.int_count;
*count = i386_V86_ASSIST_STATE_COUNT;
break;
}
default:
return(KERN_INVALID_ARGUMENT);
}
return(KERN_SUCCESS);
}
/*
* Alter the thread`s state so that a following thread_exception_return
* will make the thread return 'retval' from a syscall.
*/
void
thread_set_syscall_return(thread, retval)
thread_t thread;
kern_return_t retval;
{
thread->pcb->iss.eax = retval;
}
/*
* Return prefered address of user stack.
* Always returns low address. If stack grows up,
* the stack grows away from this address;
* if stack grows down, the stack grows towards this
* address.
*/
vm_offset_t
user_stack_low(stack_size)
vm_size_t stack_size;
{
return (VM_MAX_ADDRESS - stack_size);
}
/*
* Allocate argument area and set registers for first user thread.
*/
vm_offset_t
set_user_regs(stack_base, stack_size, exec_info, arg_size)
vm_offset_t stack_base; /* low address */
vm_offset_t stack_size;
struct exec_info *exec_info;
vm_size_t arg_size;
{
vm_offset_t arg_addr;
register struct i386_saved_state *saved_state;
arg_size = (arg_size + sizeof(int) - 1) & ~(sizeof(int)-1);
arg_addr = stack_base + stack_size - arg_size;
saved_state = USER_REGS(current_thread());
saved_state->uesp = (int)arg_addr;
saved_state->eip = exec_info->entry;
return (arg_addr);
}
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