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minix/kernel/arch/i386/klib386.S
Tomas Hruby 8451a86f0a Interrupts hadling while idle 
- When the cpu halts, the interrupts are enable so the cpu may be
  woken up. When the interrupt handler returns but another interrupt
  is available it is also serviced immediately. This is not a problem
  per-se. It only slightly breaks time accounting as idle accounted is
  for the kernel time in the interrupt handler.
  
  
-  As the big kernel lock is lock/unlocked in the smp branch in the
   time acounting functions as they are called exactly at the places
   we need to take the lock) this leads to a deadlock.

- we make sure that once the interrupt handler returns from the nested
  trap, the interrupts are disabled. This means that only one
  interrupt is serviced after idle is interrupted.

- this requires the loop in apic timer calibration to keep reenabling
  the interrupts. I admit it is a little bit hackish (one line),
  however, this code is a stupid corner case at the boot time.
  Hopefully it does not matter too much.
2010-03-23 13:35:01 +00:00

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/* sections */
#include <minix/config.h>
#include <minix/const.h>
#include <machine/interrupt.h>
#include "archconst.h"
#include "../../const.h"
#include "sconst.h"
/*
* This file contains a number of assembly code utility routines needed by the
* kernel. They are:
*/
.globl monitor /* exit Minix and return to the monitor */
.globl int86 /* let the monitor make an 8086 interrupt call */
.globl exit /* dummy for library routines */
.globl _exit /* dummy for library routines */
.globl __exit /* dummy for library routines */
.globl __main /* dummy for GCC */
.globl phys_insw /* transfer data from (disk controller) port to memory */
.globl phys_insb /* likewise byte by byte */
.globl phys_outsw /* transfer data from memory to (disk controller) port */
.globl phys_outsb /* likewise byte by byte */
.globl phys_copy /* copy data from anywhere to anywhere in memory */
.globl phys_copy_fault /* phys_copy pagefault */
.globl phys_copy_fault_in_kernel /* phys_copy pagefault in kernel */
.globl phys_memset /* write pattern anywhere in memory */
.globl mem_rdw /* copy one word from [segment:offset] */
.globl reset /* reset the system */
.globl halt_cpu/* halts the current cpu when idle */
.globl read_cpu_flags /* read the cpu flags */
.globl read_cr0 /* read cr0 */
.globl read_cr2 /* read cr2 */
.globl getcr3val
.globl write_cr0 /* write a value in cr0 */
.globl read_cr3
.globl read_cr4
.globl write_cr4
.globl catch_pagefaults
.globl read_ds
.globl read_cs
.globl read_ss
.globl idt_reload /* reload idt when returning to monitor. */
.globl fninit /* non-waiting FPU initialization */
.globl fnstsw /* store status word (non-waiting) */
.globl fnstcw /* store control word (non-waiting) */
/*
* The routines only guarantee to preserve the registers the C compiler
* expects to be preserved (ebx, esi, edi, ebp, esp, segment registers, and
* direction bit in the flags).
*/
.text
/*===========================================================================*/
/* monitor */
/*===========================================================================*/
/* PUBLIC void monitor(); */
/* Return to the monitor. */
monitor:
movl mon_sp, %esp /* restore monitor stack pointer */
movw $SS_SELECTOR, %dx /* monitor data segment */
mov %dx, %ds
mov %dx, %es
mov %dx, %fs
mov %dx, %gs
mov %dx, %ss
pop %edi
pop %esi
pop %ebp
lretw /* return to the monitor */
/*===========================================================================*/
/* int86 */
/*===========================================================================*/
/* PUBLIC void int86(); */
int86:
cmpb $0, mon_return /* is the monitor there? */
jne 0f
movb $0x01, %ah /* an int 13 error seems appropriate */
movb %ah, reg86+0 /* reg86.w.f = 1 (set carry flag) */
movb %ah, reg86+13 /* reg86.b.ah = 0x01 = "invalid command" */
ret
0:
push %ebp /* save C registers */
push %esi
push %edi
push %ebx
pushf /* save flags */
cli /* no interruptions */
inb $INT2_CTLMASK
movb %al, %ah
inb $INT_CTLMASK
push %eax /* save interrupt masks */
movl irq_use, %eax /* map of in-use IRQ's */
and $~(1<<CLOCK_IRQ), %eax /* keep the clock ticking */
outb $INT_CTLMASK /* enable all unused IRQ's and vv. */
movb %ah, %al
outb $INT2_CTLMASK
mov $SS_SELECTOR, %eax /* monitor data segment */
mov %ax, %ss
xchgl mon_sp, %esp /* switch stacks */
push reg86+36 /* parameters used in INT call */
push reg86+32
push reg86+28
push reg86+24
push reg86+20
push reg86+16
push reg86+12
push reg86+8
push reg86+4
push reg86+0
mov %ax, %ds /* remaining data selectors */
mov %ax, %es
mov %ax, %fs
mov %ax, %gs
push %cs
push $return /* kernel return address and selector */
ljmpw *20+2*4+10*4+2*4(%esp)
return:
pop reg86+0
pop reg86+4
pop reg86+8
pop reg86+12
pop reg86+16
pop reg86+20
pop reg86+24
pop reg86+28
pop reg86+32
pop reg86+36
lgdt gdt+GDT_SELECTOR /* reload global descriptor table */
ljmp $CS_SELECTOR, $csinit
csinit:
mov $DS_SELECTOR, %eax
mov %ax, %ds
mov %ax, %es
mov %ax, %fs
mov %ax, %gs
mov %ax, %ss
xchgl mon_sp, %esp /* unswitch stacks */
lidt gdt+IDT_SELECTOR /* reload interrupt descriptor table */
#ifdef CONFIG_APIC
cmpl $0x0, lapic_addr
jne 3f
mov $0, %ebx
jmp 4f
3:
mov $FLAT_DS_SELECTOR, %ebx
mov %bx, %fs
movl lapic_addr, %eax
add $0x20, %eax
.byte 0x64; mov (%eax), %ebx
and $0xFF000000, %ebx
shr $24, %ebx
movzb %bl, %ebx
4:
add $apicid2cpuid, %ebx
movzb (%ebx), %eax
shl $3, %eax
mov %eax, %ebx
add $TSS_SELECTOR, %eax
addl gdt+DESC_ACCESS, %eax
and $~0x02, %eax
ltr %bx /* set TSS register */
mov $DS_SELECTOR, %eax
mov %ax, %fs
#endif /* CONFIG_APIC */
pop %eax
outb $INT_CTLMASK /* restore interrupt masks */
movb %ah, %al
outb $INT2_CTLMASK
6:
addl %ecx, lost_ticks /* record lost clock ticks */
popf /* restore flags */
pop %ebx /* restore C registers */
pop %edi
pop %esi
pop %ebp
ret
/*===========================================================================*/
/* exit */
/*===========================================================================*/
/*
* PUBLIC void exit();
* Some library routines use exit, so provide a dummy version.
* Actual calls to exit cannot occur in the kernel.
* GNU CC likes to call ___main from main() for nonobvious reasons.
*/
exit:
_exit:
__exit:
sti
jmp __exit
__main:
ret
/*===========================================================================*/
/* phys_insw */
/*===========================================================================*/
/*
* PUBLIC void phys_insw(Port_t port, phys_bytes buf, size_t count);
* Input an array from an I/O port. Absolute address version of insw().
*/
phys_insw:
push %ebp
mov %esp, %ebp
cld
push %edi
push %es
mov $FLAT_DS_SELECTOR, %ecx
mov %cx, %es
mov 8(%ebp), %edx /* port to read from */
mov 12(%ebp), %edi /* destination addr */
mov 16(%ebp), %ecx /* byte count */
shr $1, %ecx /* word count */
rep insw /* input many words */
pop %es
pop %edi
pop %ebp
ret
/*===========================================================================*/
/* phys_insb */
/*===========================================================================*/
/*
* PUBLIC void phys_insb(Port_t port, phys_bytes buf, size_t count);
* Input an array from an I/O port. Absolute address version of insb().
*/
phys_insb:
push %ebp
mov %esp, %ebp
cld
push %edi
push %es
mov $FLAT_DS_SELECTOR, %ecx
mov %cx, %es
mov 8(%ebp), %edx /* port to read from */
mov 12(%ebp), %edi /* destination addr */
mov 16(%ebp), %ecx /* byte count */
rep insb /* input many bytes */
pop %es
pop %edi
pop %ebp
ret
/*===========================================================================*/
/* phys_outsw */
/*===========================================================================*/
/*
* PUBLIC void phys_outsw(Port_t port, phys_bytes buf, size_t count);
* Output an array to an I/O port. Absolute address version of outsw().
*/
.balign 16
phys_outsw:
push %ebp
mov %esp, %ebp
cld
push %esi
push %ds
mov $FLAT_DS_SELECTOR, %ecx
mov %cx, %ds
mov 8(%ebp), %edx /* port to write to */
mov 12(%ebp), %esi /* source addr */
mov 16(%ebp), %ecx /* byte count */
shr $1, %ecx /* word count */
rep outsw /* output many words */
pop %ds
pop %esi
pop %ebp
ret
/*===========================================================================*/
/* phys_outsb */
/*===========================================================================*/
/*
* PUBLIC void phys_outsb(Port_t port, phys_bytes buf, size_t count);
* Output an array to an I/O port. Absolute address version of outsb().
*/
.balign 16
phys_outsb:
push %ebp
mov %esp, %ebp
cld
push %esi
push %ds
mov $FLAT_DS_SELECTOR, %ecx
mov %cx, %ds
mov 8(%ebp), %edx /* port to write to */
mov 12(%ebp), %esi /* source addr */
mov 16(%ebp), %ecx /* byte count */
rep outsb /* output many bytes */
pop %ds
pop %esi
pop %ebp
ret
/*===========================================================================*/
/* phys_copy */
/*===========================================================================*/
/*
* PUBLIC phys_bytes phys_copy(phys_bytes source, phys_bytes destination,
* phys_bytes bytecount);
* Copy a block of physical memory.
*/
PC_ARGS = 4+4+4+4 /* 4 + 4 + 4 */
/* es edi esi eip src dst len */
.balign 16
phys_copy:
cld
push %esi
push %edi
push %es
mov $FLAT_DS_SELECTOR, %eax
mov %ax, %es
mov PC_ARGS(%esp), %esi
mov PC_ARGS+4(%esp), %edi
mov PC_ARGS+4+4(%esp), %eax
cmp $10, %eax /* avoid align overhead for small counts */
jb pc_small
mov %esi, %ecx /* align source, hope target is too */
neg %ecx
and $3, %ecx /* count for alignment */
sub %ecx, %eax
rep movsb %es:(%esi), %es:(%edi)
mov %eax, %ecx
shr $2, %ecx /* count of dwords */
rep movsl %es:(%esi), %es:(%edi)
and $3, %eax
pc_small:
xchg %eax, %ecx /* remainder */
rep movsb %es:(%esi), %es:(%edi)
mov $0, %eax /* 0 means: no fault */
phys_copy_fault: /* kernel can send us here */
pop %es
pop %edi
pop %esi
ret
phys_copy_fault_in_kernel: /* kernel can send us here */
pop %es
pop %edi
pop %esi
mov %cr2, %eax
ret
/*===========================================================================*/
/* copy_msg_from_user */
/*===========================================================================*/
/*
* int copy_msg_from_user(struct proc * p, message * user_mbuf, message * dst);
*
* Copies a message of 36 bytes from user process space to a kernel buffer. This
* function assumes that the process address space is installed (cr3 loaded) and
* the local descriptor table of this process is loaded too.
*
* The %gs segment register is used to access the userspace memory. We load the
* process' data segment in this register.
*
* This function from the callers point of view either succeeds or returns an
* error which gives the caller a chance to respond accordingly. In fact it
* either succeeds or if it generates a pagefault, general protection or other
* exception, the trap handler has to redirect the execution to
* __user_copy_msg_pointer_failure where the error is reported to the caller
* without resolving the pagefault. It is not kernel's problem to deal with
* wrong pointers from userspace and the caller should return an error to
* userspace as if wrong values or request were passed to the kernel
*/
.balign 16
.globl copy_msg_from_user
copy_msg_from_user:
push %gs
mov 8(%esp), %eax
movw DSREG(%eax), %gs
/* load the source pointer */
mov 12(%esp), %ecx
/* load the destination pointer */
mov 16(%esp), %edx
mov %gs:0*4(%ecx), %eax
mov %eax, 0*4(%edx)
mov %gs:1*4(%ecx), %eax
mov %eax, 1*4(%edx)
mov %gs:2*4(%ecx), %eax
mov %eax, 2*4(%edx)
mov %gs:3*4(%ecx), %eax
mov %eax, 3*4(%edx)
mov %gs:4*4(%ecx), %eax
mov %eax, 4*4(%edx)
mov %gs:5*4(%ecx), %eax
mov %eax, 5*4(%edx)
mov %gs:6*4(%ecx), %eax
mov %eax, 6*4(%edx)
mov %gs:7*4(%ecx), %eax
mov %eax, 7*4(%edx)
mov %gs:8*4(%ecx), %eax
mov %eax, 8*4(%edx)
.globl __copy_msg_from_user_end
__copy_msg_from_user_end:
pop %gs
movl $0, %eax
ret
/*===========================================================================*/
/* copy_msg_to_user */
/*===========================================================================*/
/*
* void copy_msg_to_user(struct proc * p, message * src, message * user_mbuf);
*
* Copies a message of 36 bytes to user process space from a kernel buffer. This
* function assumes that the process address space is installed (cr3 loaded) and
* the local descriptor table of this process is loaded too.
*
* All the other copy_msg_from_user() comments apply here as well!
*/
.balign 16
.globl copy_msg_to_user
copy_msg_to_user:
push %gs
mov 8(%esp), %eax
movw DSREG(%eax), %gs
/* load the source pointer */
mov 12(%esp), %ecx
/* load the destination pointer */
mov 16(%esp), %edx
mov 0*4(%ecx), %eax
mov %eax, %gs:0*4(%edx)
mov 1*4(%ecx), %eax
mov %eax, %gs:1*4(%edx)
mov 2*4(%ecx), %eax
mov %eax, %gs:2*4(%edx)
mov 3*4(%ecx), %eax
mov %eax, %gs:3*4(%edx)
mov 4*4(%ecx), %eax
mov %eax, %gs:4*4(%edx)
mov 5*4(%ecx), %eax
mov %eax, %gs:5*4(%edx)
mov 6*4(%ecx), %eax
mov %eax, %gs:6*4(%edx)
mov 7*4(%ecx), %eax
mov %eax, %gs:7*4(%edx)
mov 8*4(%ecx), %eax
mov %eax, %gs:8*4(%edx)
.globl __copy_msg_to_user_end
__copy_msg_to_user_end:
pop %gs
movl $0, %eax
ret
/*
* if a function from a selected set of copies from or to userspace fails, it is
* because of a wrong pointer supplied by the userspace. We have to clean up and
* and return -1 to indicated that something wrong has happend. The place it was
* called from has to handle this situation. The exception handler redirect us
* here to continue, clean up and report the error
*/
.balign 16
.globl __user_copy_msg_pointer_failure
__user_copy_msg_pointer_failure:
pop %gs
movl $-1, %eax
ret
/*===========================================================================*/
/* phys_memset */
/*===========================================================================*/
/*
* PUBLIC void phys_memset(phys_bytes source, unsigned long pattern,
* phys_bytes bytecount);
* Fill a block of physical memory with pattern.
*/
.balign 16
phys_memset:
push %ebp
mov %esp, %ebp
push %esi
push %ebx
push %ds
mov 8(%ebp), %esi
mov 16(%ebp), %eax
mov $FLAT_DS_SELECTOR, %ebx
mov %bx, %ds
mov 12(%ebp), %ebx
shr $2, %eax
fill_start:
mov %ebx, (%esi)
add $4, %esi
dec %eax
jne fill_start
/* Any remaining bytes? */
mov 16(%ebp), %eax
and $3, %eax
remain_fill:
cmp $0, %eax
je fill_done
movb 12(%ebp), %bl
movb %bl, (%esi)
add $1, %esi
inc %ebp
dec %eax
jmp remain_fill
fill_done:
pop %ds
pop %ebx
pop %esi
pop %ebp
ret
/*===========================================================================*/
/* mem_rdw */
/*===========================================================================*/
/*
* PUBLIC u16_t mem_rdw(U16_t segment, u16_t *offset);
* Load and return word at far pointer segment:offset.
*/
.balign 16
mem_rdw:
mov %ds, %cx
mov 4(%esp), %ds
mov 4+4(%esp), %eax /* offset */
movzwl (%eax), %eax /* word to return */
mov %cx, %ds
ret
/*===========================================================================*/
/* reset */
/*===========================================================================*/
/*
* PUBLIC void reset();
* Reset the system by loading IDT with offset 0 and interrupting.
*/
reset:
lidt idt_zero
int $3 /* anything goes, the 386 will not like it */
.data
idt_zero:
.long 0, 0
.text
/*===========================================================================*/
/* halt_cpu */
/*===========================================================================*/
/*
* PUBLIC void halt_cpu(void);
* reanables interrupts and puts the cpu in the halts state. Once an interrupt
* is handled the execution resumes by disabling interrupts and continues
*/
halt_cpu:
sti
hlt /* interrupts enabled only after this instruction is executed! */
/*
* interrupt handlers make sure that the interrupts are disabled when we
* get here so we take only _one_ interrupt after halting the CPU
*/
ret
/*===========================================================================*/
/* read_flags */
/*===========================================================================*/
/*
* PUBLIC unsigned long read_cpu_flags(void);
* Read CPU status flags from C.
*/
.balign 16
read_cpu_flags:
pushf
mov (%esp), %eax
add $4, %esp
ret
read_ds:
mov $0, %eax
mov %ds, %ax
ret
read_cs:
mov $0, %eax
mov %cs, %ax
ret
read_ss:
mov $0, %eax
mov %ss, %ax
ret
/*===========================================================================*/
/* fpu_routines */
/*===========================================================================*/
fninit:
fninit
ret
fnstsw:
xor %eax, %eax
/* DO NOT CHANGE THE OPERAND!!! gas2ack does not handle it yet */
fnstsw %ax
ret
fnstcw:
push %eax
mov 8(%esp), %eax
/* DO NOT CHANGE THE OPERAND!!! gas2ack does not handle it yet */
fnstcw (%eax)
pop %eax
ret
/*===========================================================================*/
/* read_cr0 */
/*===========================================================================*/
/* PUBLIC unsigned long read_cr0(void); */
read_cr0:
push %ebp
mov %esp, %ebp
mov %cr0, %eax
pop %ebp
ret
/*===========================================================================*/
/* write_cr0 */
/*===========================================================================*/
/* PUBLIC void write_cr0(unsigned long value); */
write_cr0:
push %ebp
mov %esp, %ebp
mov 8(%ebp), %eax
mov %eax, %cr0
jmp 0f /* A jump is required for some flags */
0:
pop %ebp
ret
/*===========================================================================*/
/* read_cr2 */
/*===========================================================================*/
/* PUBLIC reg_t read_cr2(void); */
read_cr2:
mov %cr2, %eax
ret
/*===========================================================================*/
/* read_cr3 */
/*===========================================================================*/
/* PUBLIC unsigned long read_cr3(void); */
read_cr3:
push %ebp
mov %esp, %ebp
/* DO NOT CHANGE THE OPERAND!!! gas2ack does not handle it yet */
mov %cr3, %eax
pop %ebp
ret
/*===========================================================================*/
/* read_cr4 */
/*===========================================================================*/
/* PUBLIC unsigned long read_cr4(void); */
read_cr4:
push %ebp
mov %esp, %ebp
/* DO NOT CHANGE THE OPERAND!!! gas2ack does not handle it yet */
mov %cr4, %eax
pop %ebp
ret
/*===========================================================================*/
/* write_cr4 */
/*===========================================================================*/
/* PUBLIC void write_cr4(unsigned long value); */
write_cr4:
push %ebp
mov %esp, %ebp
mov 8(%ebp), %eax
/* DO NOT CHANGE THE OPERAND!!! gas2ack does not handle it yet */
mov %eax, %cr4
jmp 0f
0:
pop %ebp
ret
/*===========================================================================*/
/* getcr3val */
/*===========================================================================*/
/* PUBLIC unsigned long getcr3val(void); */
getcr3val:
mov %cr3, %eax
ret
/*
* Read the Model Specific Register (MSR) of IA32 architecture
*
* void ia32_msr_read(u32_t reg, u32_t * hi, u32_t * lo)
*/
.globl ia32_msr_read
ia32_msr_read:
push %ebp
mov %esp, %ebp
mov 8(%ebp), %ecx
rdmsr
mov 12(%ebp), %ecx
mov %edx, (%ecx)
mov 16(%ebp), %ecx
mov %eax, (%ecx)
pop %ebp
ret
/*
* Write the Model Specific Register (MSR) of IA32 architecture
*
* void ia32_msr_write(u32_t reg, u32_t hi, u32_t lo)
*/
.globl ia32_msr_write
ia32_msr_write:
push %ebp
mov %esp, %ebp
mov 12(%ebp), %edx
mov 16(%ebp), %eax
mov 8(%ebp), %ecx
wrmsr
pop %ebp
ret
/*===========================================================================*/
/* idt_reload */
/*===========================================================================*/
/* PUBLIC void idt_reload (void); */
.balign 16
idt_reload:
lidt gdt+IDT_SELECTOR /* reload interrupt descriptor table */
ret
/*
* void reload_segment_regs(void)
*/
#define RELOAD_SEG_REG(reg) \
mov reg, %ax ;\
mov %ax, reg ;
.globl reload_ds
reload_ds:
RELOAD_SEG_REG(%ds)
ret
/*===========================================================================*/
/* switch_address_space */
/*===========================================================================*/
/* PUBLIC void switch_address_space(struct proc *p)
*
* sets the %cr3 register to the supplied value if it is not already set to the
* same value in which case it would only result in an extra TLB flush which is
* not desirable
*/
.balign 16
.globl switch_address_space
switch_address_space:
/* read the process pointer */
mov 4(%esp), %edx
/* enable process' segment descriptors */
lldt P_LDT_SEL(%edx)
/* get the new cr3 value */
movl P_CR3(%edx), %eax
/* test if the new cr3 != NULL */
cmpl $0, %eax
je 0f
/*
* test if the cr3 is loaded with the current value to avoid unnecessary
* TLB flushes
*/
mov %cr3, %ecx
cmp %ecx, %eax
je 0f
mov %eax, %cr3
mov %edx, ptproc
0:
ret
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