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minix/kernel/arch/i386/protect.c
Tomas Hruby 62c666566e SMP - We boot APs 
- kernel detects CPUs by searching ACPI tables for local apic nodes

- each CPU has its own TSS that points to its own stack. All cpus boot
  on the same boot stack (in sequence) but switch to its private stack
  as soon as they can.

- final booting code in main() placed in bsp_finish_booting() which is
  executed only after the BSP switches to its final stack

- apic functions to send startup interrupts

- assembler functions to handle CPU features not needed for single cpu
  mode like memory barries, HT detection etc.

- new files kernel/smp.[ch], kernel/arch/i386/arch_smp.c and
  kernel/arch/i386/include/arch_smp.h

- 16-bit trampoline code for the APs. It is executed by each AP after
  receiving startup IPIs it brings up the CPUs to 32bit mode and let
  them spin in an infinite loop so they don't do any damage.

- implementation of kernel spinlock

- CONFIG_SMP and CONFIG_MAX_CPUS set by the build system
2010-09-15 14:09:52 +00:00

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/* This file contains code for initialization of protected mode, to initialize
* code and data segment descriptors, and to initialize global descriptors
* for local descriptors in the process table.
*/
#include "kernel/kernel.h"
#include "kernel/proc.h"
#include "archconst.h"
#include "arch_proto.h"
#define INT_GATE_TYPE (INT_286_GATE | DESC_386_BIT)
#define TSS_TYPE (AVL_286_TSS | DESC_386_BIT)
struct desctableptr_s {
char limit[sizeof(u16_t)];
char base[sizeof(u32_t)]; /* really u24_t + pad for 286 */
};
struct gatedesc_s {
u16_t offset_low;
u16_t selector;
u8_t pad; /* |000|XXXXX| ig & trpg, |XXXXXXXX| task g */
u8_t p_dpl_type; /* |P|DL|0|TYPE| */
u16_t offset_high;
};
PUBLIC struct segdesc_s gdt[GDT_SIZE]= /* used in klib.s and mpx.s */
{ {0},
{0,0,0,0}, /* GDT descriptor */
{0,0,0,0}, /* IDT descriptor */
{0xffff,0,0,0x92,0x4f,0}, /* kernel DS */
{0xffff,0,0,0x92,0xcf,0}, /* kernel ES (386: flag 4 Gb at startup) */
{0xffff,0,0,0x92,0x4f,0}, /* kernel SS (386: monitor SS at startup) */
{0xffff,0,0,0x9a,0x4f,0}, /* kernel CS */
{0xffff,0,0,0x9a,0x0f,0}, /* temp for BIOS (386: monitor CS at startup) */
};
PRIVATE struct gatedesc_s idt[IDT_SIZE]; /* zero-init so none present */
PUBLIC struct tss_s tss[CONFIG_MAX_CPUS]; /* zero init */
FORWARD _PROTOTYPE( void sdesc, (struct segdesc_s *segdp, phys_bytes base,
vir_bytes size) );
/*===========================================================================*
* enable_iop *
*===========================================================================*/
PUBLIC void enable_iop(struct proc *pp)
{
/* Allow a user process to use I/O instructions. Change the I/O Permission
* Level bits in the psw. These specify least-privileged Current Permission
* Level allowed to execute I/O instructions. Users and servers have CPL 3.
* You can't have less privilege than that. Kernel has CPL 0, tasks CPL 1.
*/
pp->p_reg.psw |= 0x3000;
}
/*===========================================================================*
* seg2phys *
*===========================================================================*/
PUBLIC phys_bytes seg2phys(const u16_t seg)
{
/* Return the base address of a segment, with seg being a
* register, or a 286/386 segment selector.
*/
phys_bytes base;
struct segdesc_s *segdp;
segdp = &gdt[seg >> 3];
base = ((u32_t) segdp->base_low << 0)
| ((u32_t) segdp->base_middle << 16)
| ((u32_t) segdp->base_high << 24);
return base;
}
/*===========================================================================*
* phys2seg *
*===========================================================================*/
PRIVATE void phys2seg(u16_t *seg, vir_bytes *off, phys_bytes phys)
{
/* Return a segment selector and offset that can be used to reach a physical
* address, for use by a driver doing memory I/O in the A0000 - DFFFF range.
*/
*seg = FLAT_DS_SELECTOR;
*off = (vir_bytes) phys;
}
/*===========================================================================*
* init_dataseg *
*===========================================================================*/
PUBLIC void init_dataseg(register struct segdesc_s *segdp,
phys_bytes base, vir_bytes size, const int privilege)
{
/* Build descriptor for a data segment. */
sdesc(segdp, base, size);
segdp->access = (privilege << DPL_SHIFT) | (PRESENT | SEGMENT |
WRITEABLE);
/* EXECUTABLE = 0, EXPAND_DOWN = 0, ACCESSED = 0 */
}
/*===========================================================================*
* init_codeseg *
*===========================================================================*/
PRIVATE void init_codeseg(register struct segdesc_s *segdp, phys_bytes base,
vir_bytes size, int privilege)
{
/* Build descriptor for a code segment. */
sdesc(segdp, base, size);
segdp->access = (privilege << DPL_SHIFT)
| (PRESENT | SEGMENT | EXECUTABLE | READABLE);
/* CONFORMING = 0, ACCESSED = 0 */
}
PUBLIC struct gate_table_s gate_table_pic[] = {
{ hwint00, VECTOR( 0), INTR_PRIVILEGE },
{ hwint01, VECTOR( 1), INTR_PRIVILEGE },
{ hwint02, VECTOR( 2), INTR_PRIVILEGE },
{ hwint03, VECTOR( 3), INTR_PRIVILEGE },
{ hwint04, VECTOR( 4), INTR_PRIVILEGE },
{ hwint05, VECTOR( 5), INTR_PRIVILEGE },
{ hwint06, VECTOR( 6), INTR_PRIVILEGE },
{ hwint07, VECTOR( 7), INTR_PRIVILEGE },
{ hwint08, VECTOR( 8), INTR_PRIVILEGE },
{ hwint09, VECTOR( 9), INTR_PRIVILEGE },
{ hwint10, VECTOR(10), INTR_PRIVILEGE },
{ hwint11, VECTOR(11), INTR_PRIVILEGE },
{ hwint12, VECTOR(12), INTR_PRIVILEGE },
{ hwint13, VECTOR(13), INTR_PRIVILEGE },
{ hwint14, VECTOR(14), INTR_PRIVILEGE },
{ hwint15, VECTOR(15), INTR_PRIVILEGE },
{ NULL, 0, 0}
};
PUBLIC void tss_init(unsigned cpu, void * kernel_stack)
{
struct tss_s * t = &tss[cpu];
t->ss0 = DS_SELECTOR;
init_dataseg(&gdt[TSS_INDEX(cpu)], vir2phys(t),
sizeof(struct tss_s), INTR_PRIVILEGE);
gdt[TSS_INDEX(cpu)].access = PRESENT |
(INTR_PRIVILEGE << DPL_SHIFT) | TSS_TYPE;
/* Complete building of main TSS. */
t->iobase = sizeof(struct tss_s); /* empty i/o permissions map */
/*
* make space for process pointer and cpu id and point to the first
* usable word
*/
t->sp0 = ((unsigned) kernel_stack) - X86_STACK_TOP_RESERVED;
/*
* set the cpu id at the top of the stack so we know on which cpu is
* this stak in use when we trap to kernel
*/
*((reg_t *)(t->sp0 + 1 * sizeof(reg_t))) = cpu;
}
/*===========================================================================*
* prot_init *
*===========================================================================*/
PUBLIC void prot_init(void)
{
/* Set up tables for protected mode.
* All GDT slots are allocated at compile time.
*/
struct desctableptr_s *dtp;
unsigned ldt_index;
register struct proc *rp;
/* Click-round kernel. */
if(kinfo.data_base % CLICK_SIZE)
panic("kinfo.data_base not aligned");
kinfo.data_size = (phys_bytes) (CLICK_CEIL(kinfo.data_size));
/* Build gdt and idt pointers in GDT where the BIOS expects them. */
dtp= (struct desctableptr_s *) &gdt[GDT_INDEX];
* (u16_t *) dtp->limit = (sizeof gdt) - 1;
* (u32_t *) dtp->base = vir2phys(gdt);
dtp= (struct desctableptr_s *) &gdt[IDT_INDEX];
* (u16_t *) dtp->limit = (sizeof idt) - 1;
* (u32_t *) dtp->base = vir2phys(idt);
/* Build segment descriptors for tasks and interrupt handlers. */
init_codeseg(&gdt[CS_INDEX],
kinfo.code_base, kinfo.code_size, INTR_PRIVILEGE);
init_dataseg(&gdt[DS_INDEX],
kinfo.data_base, kinfo.data_size, INTR_PRIVILEGE);
init_dataseg(&gdt[ES_INDEX], 0L, 0, INTR_PRIVILEGE);
/* Build local descriptors in GDT for LDT's in process table.
* The LDT's are allocated at compile time in the process table, and
* initialized whenever a process' map is initialized or changed.
*/
for (rp = BEG_PROC_ADDR, ldt_index = FIRST_LDT_INDEX;
rp < END_PROC_ADDR; ++rp, ldt_index++) {
init_dataseg(&gdt[ldt_index], vir2phys(rp->p_seg.p_ldt),
sizeof(rp->p_seg.p_ldt), INTR_PRIVILEGE);
gdt[ldt_index].access = PRESENT | LDT;
rp->p_seg.p_ldt_sel = ldt_index * DESC_SIZE;
}
/* Build boot TSS */
tss_init(0, &k_boot_stktop);
}
PUBLIC void idt_copy_vectors(struct gate_table_s * first)
{
struct gate_table_s *gtp;
for (gtp = first; gtp->gate; gtp++) {
int_gate(gtp->vec_nr, (vir_bytes) gtp->gate,
PRESENT | INT_GATE_TYPE |
(gtp->privilege << DPL_SHIFT));
}
}
/* Build descriptors for interrupt gates in IDT. */
PUBLIC void idt_init(void)
{
struct gate_table_s gate_table[] = {
{ divide_error, DIVIDE_VECTOR, INTR_PRIVILEGE },
{ single_step_exception, DEBUG_VECTOR, INTR_PRIVILEGE },
{ nmi, NMI_VECTOR, INTR_PRIVILEGE },
{ breakpoint_exception, BREAKPOINT_VECTOR, USER_PRIVILEGE },
{ overflow, OVERFLOW_VECTOR, USER_PRIVILEGE },
{ bounds_check, BOUNDS_VECTOR, INTR_PRIVILEGE },
{ inval_opcode, INVAL_OP_VECTOR, INTR_PRIVILEGE },
{ copr_not_available, COPROC_NOT_VECTOR, INTR_PRIVILEGE },
{ double_fault, DOUBLE_FAULT_VECTOR, INTR_PRIVILEGE },
{ copr_seg_overrun, COPROC_SEG_VECTOR, INTR_PRIVILEGE },
{ inval_tss, INVAL_TSS_VECTOR, INTR_PRIVILEGE },
{ segment_not_present, SEG_NOT_VECTOR, INTR_PRIVILEGE },
{ stack_exception, STACK_FAULT_VECTOR, INTR_PRIVILEGE },
{ general_protection, PROTECTION_VECTOR, INTR_PRIVILEGE },
{ page_fault, PAGE_FAULT_VECTOR, INTR_PRIVILEGE },
{ copr_error, COPROC_ERR_VECTOR, INTR_PRIVILEGE },
{ alignment_check, ALIGNMENT_CHECK_VECTOR, INTR_PRIVILEGE },
{ machine_check, MACHINE_CHECK_VECTOR, INTR_PRIVILEGE },
{ simd_exception, SIMD_EXCEPTION_VECTOR, INTR_PRIVILEGE },
{ ipc_entry, IPC_VECTOR, USER_PRIVILEGE },
{ kernel_call_entry, KERN_CALL_VECTOR, USER_PRIVILEGE },
{ NULL, 0, 0}
};
idt_copy_vectors(gate_table);
idt_copy_vectors(gate_table_pic);
}
/*===========================================================================*
* sdesc *
*===========================================================================*/
PRIVATE void sdesc(segdp, base, size)
register struct segdesc_s *segdp;
phys_bytes base;
vir_bytes size;
{
/* Fill in the size fields (base, limit and granularity) of a descriptor. */
segdp->base_low = base;
segdp->base_middle = base >> BASE_MIDDLE_SHIFT;
segdp->base_high = base >> BASE_HIGH_SHIFT;
--size; /* convert to a limit, 0 size means 4G */
if (size > BYTE_GRAN_MAX) {
segdp->limit_low = size >> PAGE_GRAN_SHIFT;
segdp->granularity = GRANULAR | (size >>
(PAGE_GRAN_SHIFT + GRANULARITY_SHIFT));
} else {
segdp->limit_low = size;
segdp->granularity = size >> GRANULARITY_SHIFT;
}
segdp->granularity |= DEFAULT; /* means BIG for data seg */
}
/*===========================================================================*
* int_gate *
*===========================================================================*/
PUBLIC void int_gate(unsigned vec_nr, vir_bytes offset, unsigned dpl_type)
{
/* Build descriptor for an interrupt gate. */
register struct gatedesc_s *idp;
idp = &idt[vec_nr];
idp->offset_low = offset;
idp->selector = CS_SELECTOR;
idp->p_dpl_type = dpl_type;
idp->offset_high = offset >> OFFSET_HIGH_SHIFT;
}
/*===========================================================================*
* alloc_segments *
*===========================================================================*/
PUBLIC void alloc_segments(register struct proc *rp)
{
/* This is called at system initialization from main() and by do_newmap().
* The code has a separate function because of all hardware-dependencies.
*/
phys_bytes code_bytes;
phys_bytes data_bytes;
int privilege;
data_bytes = (phys_bytes) (rp->p_memmap[S].mem_vir +
rp->p_memmap[S].mem_len) << CLICK_SHIFT;
if (rp->p_memmap[T].mem_len == 0)
code_bytes = data_bytes; /* common I&D, poor protect */
else
code_bytes = (phys_bytes) rp->p_memmap[T].mem_len << CLICK_SHIFT;
privilege = USER_PRIVILEGE;
init_codeseg(&rp->p_seg.p_ldt[CS_LDT_INDEX],
(phys_bytes) rp->p_memmap[T].mem_phys << CLICK_SHIFT,
code_bytes, privilege);
init_dataseg(&rp->p_seg.p_ldt[DS_LDT_INDEX],
(phys_bytes) rp->p_memmap[D].mem_phys << CLICK_SHIFT,
data_bytes, privilege);
rp->p_reg.cs = (CS_LDT_INDEX * DESC_SIZE) | TI | privilege;
rp->p_reg.gs =
rp->p_reg.fs =
rp->p_reg.ss =
rp->p_reg.es =
rp->p_reg.ds = (DS_LDT_INDEX*DESC_SIZE) | TI | privilege;
}
/*===========================================================================*
* check_segments *
*===========================================================================*/
PRIVATE void check_segments(char *File, int line)
{
int checked = 0;
int fail = 0;
struct proc *rp;
for (rp = BEG_PROC_ADDR; rp < END_PROC_ADDR; ++rp) {
int privilege;
int cs, ds;
if (isemptyp(rp))
continue;
privilege = USER_PRIVILEGE;
cs = (CS_LDT_INDEX*DESC_SIZE) | TI | privilege;
ds = (DS_LDT_INDEX*DESC_SIZE) | TI | privilege;
#define CHECK(s1, s2) if(s1 != s2) { \
printf("%s:%d: " #s1 " != " #s2 " for ep %d\n", \
File, line, rp->p_endpoint); fail++; } checked++;
CHECK(rp->p_reg.cs, cs);
CHECK(rp->p_reg.gs, ds);
CHECK(rp->p_reg.fs, ds);
CHECK(rp->p_reg.ss, ds);
if(rp->p_endpoint != SYSTEM) {
CHECK(rp->p_reg.es, ds);
}
CHECK(rp->p_reg.ds, ds);
}
if(fail) {
printf("%d/%d checks failed\n", fail, checked);
panic("wrong: %d", fail);
}
}
/*===========================================================================*
* printseg *
*===========================================================================*/
PUBLIC void printseg(char *banner, const int iscs, struct proc *pr,
const u32_t selector)
{
u32_t base, limit, index, dpl;
struct segdesc_s *desc;
if(banner) { printf("%s", banner); }
index = selector >> 3;
printf("RPL %d, ind %d of ",
(selector & RPL_MASK), index);
if(selector & TI) {
printf("LDT");
if(index >= LDT_SIZE) {
printf("invalid index in ldt\n");
return;
}
if(!pr) {
printf("local selector but unknown process\n");
return;
}
desc = &pr->p_seg.p_ldt[index];
} else {
printf("GDT");
if(index >= GDT_SIZE) {
printf("invalid index in gdt\n");
return;
}
desc = &gdt[index];
}
limit = desc->limit_low |
(((u32_t) desc->granularity & LIMIT_HIGH) << GRANULARITY_SHIFT);
if(desc->granularity & GRANULAR) {
limit = (limit << PAGE_GRAN_SHIFT) + 0xfff;
}
base = desc->base_low |
((u32_t) desc->base_middle << BASE_MIDDLE_SHIFT) |
((u32_t) desc->base_high << BASE_HIGH_SHIFT);
printf(" -> base 0x%08lx size 0x%08lx ", base, limit+1);
if(iscs) {
if(!(desc->granularity & BIG))
printf("16bit ");
} else {
if(!(desc->granularity & BIG))
printf("not big ");
}
if(desc->granularity & 0x20) { /* reserved */
panic("granularity reserved field set");
}
if(!(desc->access & PRESENT))
printf("notpresent ");
if(!(desc->access & SEGMENT))
printf("system ");
if(desc->access & EXECUTABLE) {
printf(" exec ");
if(desc->access & CONFORMING) printf("conforming ");
if(!(desc->access & READABLE)) printf("non-readable ");
} else {
printf("nonexec ");
if(desc->access & EXPAND_DOWN) printf("non-expand-down ");
if(!(desc->access & WRITEABLE)) printf("non-writable ");
}
if(!(desc->access & ACCESSED)) {
printf("nonacc ");
}
dpl = ((u32_t) desc->access & DPL) >> DPL_SHIFT;
printf("DPL %d\n", dpl);
return;
}
/*===========================================================================*
* prot_set_kern_seg_limit *
*===========================================================================*/
PUBLIC int prot_set_kern_seg_limit(const vir_bytes limit)
{
struct proc *rp;
int orig_click;
int incr_clicks;
if(limit <= kinfo.data_base) {
printf("prot_set_kern_seg_limit: limit bogus\n");
return EINVAL;
}
/* Do actual increase. */
orig_click = kinfo.data_size / CLICK_SIZE;
kinfo.data_size = limit - kinfo.data_base;
incr_clicks = kinfo.data_size / CLICK_SIZE - orig_click;
prot_init();
/* Increase kernel processes too. */
for (rp = BEG_PROC_ADDR; rp < END_PROC_ADDR; ++rp) {
if (isemptyp(rp) || !iskernelp(rp))
continue;
rp->p_memmap[S].mem_len += incr_clicks;
alloc_segments(rp);
rp->p_memmap[S].mem_len -= incr_clicks;
}
return OK;
}
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