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提交 a4b213cf 创建 作者: Frans Kaashoek's avatar Frans Kaashoek
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Avoid "boot" in xv6

上级 94496468
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Makefile
浏览文件 @ a4b213cf
...@@ -110,7 +110,7 @@ initcode: initcode.S ...@@ -110,7 +110,7 @@ initcode: initcode.S
$(OBJDUMP) -S initcode.o > initcode.asm $(OBJDUMP) -S initcode.o > initcode.asm
kernel: $(OBJS) entry.o data.o entryother initcode kernel: $(OBJS) entry.o data.o entryother initcode
$(LD) $(LDFLAGS) -T kernel.ld -e multiboot_entry -o kernel entry.o data.o $(OBJS) -b binary initcode entryother $(LD) $(LDFLAGS) -T kernel.ld -e entry -o kernel entry.o data.o $(OBJS) -b binary initcode entryother
$(OBJDUMP) -S kernel > kernel.asm $(OBJDUMP) -S kernel > kernel.asm
$(OBJDUMP) -t kernel | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > kernel.sym $(OBJDUMP) -t kernel | sed '1,/SYMBOL TABLE/d; s/ .* / /; /^$$/d' > kernel.sym
......
defs.h
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...@@ -62,7 +62,7 @@ extern uchar ioapicid; ...@@ -62,7 +62,7 @@ extern uchar ioapicid;
void ioapicinit(void); void ioapicinit(void);
// kalloc.c // kalloc.c
char* boot_alloc(void); char* enter_alloc(void);
char* kalloc(void); char* kalloc(void);
void kfree(char*); void kfree(char*);
void kinit(void); void kinit(void);
......
entry.S
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...@@ -34,17 +34,17 @@ multiboot_header: ...@@ -34,17 +34,17 @@ multiboot_header:
.long multiboot_header .long multiboot_header
.long edata .long edata
.long end .long end
.long multiboot_entry .long entry
# Multiboot entry point. Machine is mostly set up. # Entering xv6 on boot processor. Machine is mostly set up.
.globl multiboot_entry .globl entry
multiboot_entry: entry:
# Turn on page size extension for 4Mbyte pages # Turn on page size extension for 4Mbyte pages
movl %cr4, %eax movl %cr4, %eax
orl $(CR4_PSE), %eax orl $(CR4_PSE), %eax
movl %eax, %cr4 movl %eax, %cr4
# Set page directory # Set page directory
movl $(V2P_WO(bootpgdir)), %eax movl $(V2P_WO(enterpgdir)), %eax
movl %eax, %cr3 movl %eax, %cr3
# Turn on paging. # Turn on paging.
movl %cr0, %eax movl %cr0, %eax
......
entryother.S
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...@@ -14,8 +14,8 @@ ...@@ -14,8 +14,8 @@
# Bootothers (in main.c) sends the STARTUPs one at a time. # Bootothers (in main.c) sends the STARTUPs one at a time.
# It copies this code (start) at 0x7000. # It copies this code (start) at 0x7000.
# It puts the address of a newly allocated per-core stack in start-4, # It puts the address of a newly allocated per-core stack in start-4,
# the address of the place to jump to (mpboot) in start-8, and the physical # the address of the place to jump to (mpenter) in start-8, and the physical
# address of bootpgdir in start-12. # address of enterpgdir in start-12.
# #
# #
# This code is identical to bootasm.S except: # This code is identical to bootasm.S except:
...@@ -54,7 +54,7 @@ start32: ...@@ -54,7 +54,7 @@ start32:
movl %cr4, %eax movl %cr4, %eax
orl $(CR4_PSE), %eax orl $(CR4_PSE), %eax
movl %eax, %cr4 movl %eax, %cr4
# Use bootpgdir as our initial page table # Use enterpgdir as our initial page table
movl (start-12), %eax movl (start-12), %eax
movl %eax, %cr3 movl %eax, %cr3
# Turn on paging. # Turn on paging.
...@@ -62,9 +62,9 @@ start32: ...@@ -62,9 +62,9 @@ start32:
orl $(CR0_PE|CR0_PG|CR0_WP), %eax orl $(CR0_PE|CR0_PG|CR0_WP), %eax
movl %eax, %cr0 movl %eax, %cr0
# Switch to the stack allocated by enterothers() # Switch to the stack allocated by startothers()
movl (start-4), %esp movl (start-4), %esp
# Call mpboot() # Call mpenter()
call *(start-8) call *(start-8)
movw $0x8a00, %ax movw $0x8a00, %ax
......
kalloc.c
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...@@ -21,15 +21,15 @@ struct { ...@@ -21,15 +21,15 @@ struct {
extern char end[]; // first address after kernel loaded from ELF file extern char end[]; // first address after kernel loaded from ELF file
char *newend; char *newend;
// simple page allocator to get off the ground during boot // simple page allocator to get off the ground during entry
char * char *
boot_alloc(void) enter_alloc(void)
{ {
if (newend == 0) if (newend == 0)
newend = end; newend = end;
if ((uint) newend >= KERNBASE + 0x400000) if ((uint) newend >= KERNBASE + 0x400000)
panic("only first 4Mbyte are mapped during boot"); panic("only first 4Mbyte are mapped during entry");
void *p = (void*)PGROUNDUP((uint)newend); void *p = (void*)PGROUNDUP((uint)newend);
memset(p, 0, PGSIZE); memset(p, 0, PGSIZE);
newend = newend + PGSIZE; newend = newend + PGSIZE;
......
lapic.c
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...@@ -132,7 +132,7 @@ microdelay(int us) ...@@ -132,7 +132,7 @@ microdelay(int us)
#define IO_RTC 0x70 #define IO_RTC 0x70
// Start additional processor running bootstrap code at addr. // Start additional processor running entry code at addr.
// See Appendix B of MultiProcessor Specification. // See Appendix B of MultiProcessor Specification.
void void
...@@ -158,7 +158,7 @@ lapicstartap(uchar apicid, uint addr) ...@@ -158,7 +158,7 @@ lapicstartap(uchar apicid, uint addr)
lapicw(ICRLO, INIT | LEVEL); lapicw(ICRLO, INIT | LEVEL);
microdelay(100); // should be 10ms, but too slow in Bochs! microdelay(100); // should be 10ms, but too slow in Bochs!
// Send startup IPI (twice!) to enter bootstrap code. // Send startup IPI (twice!) to enter code.
// Regular hardware is supposed to only accept a STARTUP // Regular hardware is supposed to only accept a STARTUP
// when it is in the halted state due to an INIT. So the second // when it is in the halted state due to an INIT. So the second
// should be ignored, but it is part of the official Intel algorithm. // should be ignored, but it is part of the official Intel algorithm.
......
main.c
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...@@ -6,7 +6,7 @@ ...@@ -6,7 +6,7 @@
#include "proc.h" #include "proc.h"
#include "x86.h" #include "x86.h"
static void enterothers(void); static void startothers(void);
static void mpmain(void) __attribute__((noreturn)); static void mpmain(void) __attribute__((noreturn));
extern pde_t *kpgdir; extern pde_t *kpgdir;
...@@ -33,7 +33,7 @@ main(void) ...@@ -33,7 +33,7 @@ main(void)
ideinit(); // disk ideinit(); // disk
if(!ismp) if(!ismp)
timerinit(); // uniprocessor timer timerinit(); // uniprocessor timer
enterothers(); // start other processors (must come before kinit; must use boot_alloc) startothers(); // start other processors (must come before kinit; must use enter_alloc)
kinit(); // initialize memory allocator kinit(); // initialize memory allocator
userinit(); // first user process (must come after kinit) userinit(); // first user process (must come after kinit)
// Finish setting up this processor in mpmain. // Finish setting up this processor in mpmain.
...@@ -42,7 +42,7 @@ main(void) ...@@ -42,7 +42,7 @@ main(void)
// Other CPUs jump here from entryother.S. // Other CPUs jump here from entryother.S.
static void static void
mpboot(void) mpenter(void)
{ {
switchkvm(); switchkvm();
seginit(); seginit();
...@@ -56,22 +56,22 @@ mpmain(void) ...@@ -56,22 +56,22 @@ mpmain(void)
{ {
cprintf("cpu%d: starting\n", cpu->id); cprintf("cpu%d: starting\n", cpu->id);
idtinit(); // load idt register idtinit(); // load idt register
xchg(&cpu->booted, 1); // tell enterothers() we're up xchg(&cpu->started, 1); // tell startothers() we're up
scheduler(); // start running processes scheduler(); // start running processes
} }
pde_t bootpgdir[]; pde_t enterpgdir[];
// Start the non-boot processors. // Start the non-boot (AP) processors.
static void static void
enterothers(void) startothers(void)
{ {
extern uchar _binary_entryother_start[], _binary_entryother_size[]; extern uchar _binary_entryother_start[], _binary_entryother_size[];
uchar *code; uchar *code;
struct cpu *c; struct cpu *c;
char *stack; char *stack;
// Write bootstrap code to unused memory at 0x7000. // Write entry code to unused memory at 0x7000.
// The linker has placed the image of entryother.S in // The linker has placed the image of entryother.S in
// _binary_entryother_start. // _binary_entryother_start.
code = p2v(0x7000); code = p2v(0x7000);
...@@ -81,44 +81,36 @@ enterothers(void) ...@@ -81,44 +81,36 @@ enterothers(void)
if(c == cpus+cpunum()) // We've started already. if(c == cpus+cpunum()) // We've started already.
continue; continue;
// Tell entryother.S what stack to use, the address of mpboot and pgdir; // Tell entryother.S what stack to use, the address of mpenter and pgdir;
// We cannot use kpgdir yet, because the AP processor is running in low // We cannot use kpgdir yet, because the AP processor is running in low
// memory, so we use bootpgdir for the APs too. kalloc can return addresses // memory, so we use enterpgdir for the APs too. kalloc can return addresses
// above 4Mbyte (the machine may have much more physical memory than 4Mbyte), which // above 4Mbyte (the machine may have much more physical memory than 4Mbyte), which
// aren't mapped by bootpgdir, so we must allocate a stack using boot_alloc(); // aren't mapped by enterpgdir, so we must allocate a stack using enter_alloc();
// This introduces the constraint that xv6 cannot use kalloc until after these // This introduces the constraint that xv6 cannot use kalloc until after these
// last boot_alloc invocations. // last enter_alloc invocations.
stack = boot_alloc(); stack = enter_alloc();
*(void**)(code-4) = stack + KSTACKSIZE; *(void**)(code-4) = stack + KSTACKSIZE;
*(void**)(code-8) = mpboot; *(void**)(code-8) = mpenter;
*(int**)(code-12) = (void *) v2p(bootpgdir); *(int**)(code-12) = (void *) v2p(enterpgdir);
lapicstartap(c->id, v2p(code)); lapicstartap(c->id, v2p(code));
// wait for cpu to finish mpmain() // wait for cpu to finish mpmain()
while(c->booted == 0) while(c->started == 0)
; ;
} }
} }
// Boot page table used in multiboot.S and entryother.S. // Boot page table used in entry.S and entryother.S.
// Page directories (and page tables), must start on a page boundary, // Page directories (and page tables), must start on a page boundary,
// hence the "__aligned__" attribute. Also, because of restrictions // hence the "__aligned__" attribute.
// related to linking and static initializers, we use "x + PTE_P"
// here, rather than the more standard "x | PTE_P". Everywhere else
// you should use "|" to combine flags.
// Use PTE_PS in page directory entry to enable 4Mbyte pages. // Use PTE_PS in page directory entry to enable 4Mbyte pages.
pte_t dev_pgtable[NPTENTRIES];
pte_t entry_pgtable[NPTENTRIES];
__attribute__((__aligned__(PGSIZE))) __attribute__((__aligned__(PGSIZE)))
pde_t bootpgdir[NPDENTRIES] = { pde_t enterpgdir[NPDENTRIES] = {
// Map VA's [0, 4MB) to PA's [0, 4MB) // Map VA's [0, 4MB) to PA's [0, 4MB)
[0] [0] = (0) + PTE_P + PTE_W + PTE_PS,
= (0) + PTE_P + PTE_W + PTE_PS,
// Map VA's [KERNBASE, KERNBASE+4MB) to PA's [0, 4MB) // Map VA's [KERNBASE, KERNBASE+4MB) to PA's [0, 4MB)
[KERNBASE>>PDXSHIFT] [KERNBASE>>PDXSHIFT] = (0) + PTE_P + PTE_W + PTE_PS,
= (0) + PTE_P + PTE_W + PTE_PS,
}; };
//PAGEBREAK! //PAGEBREAK!
......
mp.c
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// Multiprocessor bootstrap. // Multiprocessor support
// Search memory for MP description structures. // Search memory for MP description structures.
// http://developer.intel.com/design/pentium/datashts/24201606.pdf // http://developer.intel.com/design/pentium/datashts/24201606.pdf
......
proc.h
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...@@ -7,7 +7,7 @@ struct cpu { ...@@ -7,7 +7,7 @@ struct cpu {
struct context *scheduler; // swtch() here to enter scheduler struct context *scheduler; // swtch() here to enter scheduler
struct taskstate ts; // Used by x86 to find stack for interrupt struct taskstate ts; // Used by x86 to find stack for interrupt
struct segdesc gdt[NSEGS]; // x86 global descriptor table struct segdesc gdt[NSEGS]; // x86 global descriptor table
volatile uint booted; // Has the CPU started? volatile uint started; // Has the CPU started?
int ncli; // Depth of pushcli nesting. int ncli; // Depth of pushcli nesting.
int intena; // Were interrupts enabled before pushcli? int intena; // Were interrupts enabled before pushcli?
......
sysproc.c
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...@@ -77,7 +77,7 @@ sys_sleep(void) ...@@ -77,7 +77,7 @@ sys_sleep(void)
} }
// return how many clock tick interrupts have occurred // return how many clock tick interrupts have occurred
// since boot. // since start.
int int
sys_uptime(void) sys_uptime(void)
{ {
......
vm.c
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...@@ -12,7 +12,7 @@ pde_t *kpgdir; // for use in scheduler() ...@@ -12,7 +12,7 @@ pde_t *kpgdir; // for use in scheduler()
struct segdesc gdt[NSEGS]; struct segdesc gdt[NSEGS];
// Set up CPU's kernel segment descriptors. // Set up CPU's kernel segment descriptors.
// Run once at boot time on each CPU. // Run once on entry on each CPU.
void void
seginit(void) seginit(void)
{ {
...@@ -146,7 +146,7 @@ setupkvm(char* (*alloc)(void)) ...@@ -146,7 +146,7 @@ setupkvm(char* (*alloc)(void))
void void
kvmalloc(void) kvmalloc(void)
{ {
kpgdir = setupkvm(boot_alloc); kpgdir = setupkvm(enter_alloc);
switchkvm(); switchkvm();
} }
......
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