diff options
| -rw-r--r-- | .cvsignore | 13 | ||||
| -rw-r--r-- | Makefile | 31 | ||||
| -rw-r--r-- | Notes | 2 | ||||
| -rw-r--r-- | console.c | 2 | ||||
| -rw-r--r-- | defs.h | 7 | ||||
| -rwxr-xr-x | dot-bochsrc | 2 | ||||
| -rw-r--r-- | main.c | 11 | ||||
| -rw-r--r-- | mp.c | 4 | ||||
| -rw-r--r-- | proc.c | 83 | ||||
| -rw-r--r-- | proc.h | 24 | ||||
| -rw-r--r-- | spinlock.c | 21 | ||||
| -rw-r--r-- | swtch.S | 37 | ||||
| -rw-r--r-- | syscall.c | 3 | ||||
| -rw-r--r-- | trap.c | 8 | ||||
| -rw-r--r-- | trapasm.S | 5 | ||||
| -rw-r--r-- | ulib.c | 56 | ||||
| -rw-r--r-- | userfs.c | 1 | ||||
| -rw-r--r-- | usys.S | 18 | ||||
| -rw-r--r-- | x86.h | 1 |
19 files changed, 199 insertions, 130 deletions
diff --git a/.cvsignore b/.cvsignore new file mode 100644 index 0000000..bc713b6 --- /dev/null +++ b/.cvsignore @@ -0,0 +1,13 @@ +*.asm +*.d +kernel +user1 +userfs +usertests +xv6.img +vectors.S +bochsout.txt +bootblock +bootother +bootother.out +parport.out @@ -1,11 +1,18 @@ OBJS = main.o console.o string.o kalloc.o proc.o trapasm.o trap.o vectors.o \ - syscall.o ide.o picirq.o mp.o spinlock.o fd.o pipe.o + syscall.o ide.o picirq.o mp.o spinlock.o fd.o pipe.o swtch.o -CC = i386-jos-elf-gcc -LD = i386-jos-elf-ld -OBJCOPY = i386-jos-elf-objcopy -OBJDUMP = i386-jos-elf-objdump +# Cross-compiling (e.g., on Mac OS X) +TOOLPREFIX = i386-jos-elf- + +# Using native tools (e.g., on X86 Linux) +# TOOLPREFIX = + +CC = $(TOOLPREFIX)gcc +LD = $(TOOLPREFIX)ld +OBJCOPY = $(TOOLPREFIX)objcopy +OBJDUMP = $(TOOLPREFIX)objdump CFLAGS = -nostdinc -I. -O2 -Wall -MD +AS = $(TOOLPREFIX)gas xv6.img : bootblock kernel dd if=/dev/zero of=xv6.img count=10000 @@ -31,19 +38,21 @@ kernel : $(OBJS) bootother.S user1 usertests userfs vectors.S : vectors.pl perl vectors.pl > vectors.S -user1 : user1.c ulib.o +ULIB = ulib.o usys.o + +user1 : user1.c $(ULIB) $(CC) -nostdinc -I. -c user1.c - $(LD) -N -e main -Ttext 0 -o user1 user1.o ulib.o + $(LD) -N -e main -Ttext 0 -o user1 user1.o $(ULIB) $(OBJDUMP) -S user1 > user1.asm -usertests : usertests.c ulib.o +usertests : usertests.c $(ULIB) $(CC) -nostdinc -I. -c usertests.c - $(LD) -N -e main -Ttext 0 -o usertests usertests.o ulib.o + $(LD) -N -e main -Ttext 0 -o usertests usertests.o $(ULIB) $(OBJDUMP) -S usertests > usertests.asm -userfs : userfs.c ulib.o +userfs : userfs.c $(ULIB) $(CC) -nostdinc -I. -c userfs.c - $(LD) -N -e main -Ttext 0 -o userfs userfs.o ulib.o + $(LD) -N -e main -Ttext 0 -o userfs userfs.o $(ULIB) $(OBJDUMP) -S userfs > userfs.asm ulib.o : ulib.c @@ -1,5 +1,7 @@ bochs 2.2.6: ./configure --enable-smp --enable-disasm --enable-debugger --enable-all-optimizations --enable-4meg-pages --enable-global-pages --enable-pae --disable-reset-on-triple-fault +bochs CVS after 2.2.6: +./configure --enable-smp --enable-disasm --enable-debugger --enable-all-optimizations --enable-4meg-pages --enable-global-pages --enable-pae bootmain.c doesn't work right if the ELF sections aren't sector-aligned. so you can't use ld -N. and the sections may also need @@ -106,7 +106,7 @@ cprintf(char *fmt, ...) if(c == 'd'){ printint(*ap, 10, 1); ap++; - } else if(c == 'x'){ + } else if(c == 'x' || c == 'p'){ printint(*ap, 16, 0); ap++; } else if(c == '%'){ @@ -10,11 +10,18 @@ void cons_putc(int); // proc.c struct proc; +struct jmpbuf; void setupsegs(struct proc *); struct proc * newproc(void); void swtch(void); void sleep(void *); void wakeup(void *); +void scheduler(void); + +// swtch.S +struct jmpbuf; +int setjmp(struct jmpbuf*); +void longjmp(struct jmpbuf*); // trap.c void tvinit(void); diff --git a/dot-bochsrc b/dot-bochsrc index 25f24fb..d8afbd6 100755 --- a/dot-bochsrc +++ b/dot-bochsrc @@ -107,7 +107,7 @@ romimage: file=$BXSHARE/BIOS-bochs-latest, address=0xf0000 # 650Mhz Athlon K-7 with Linux 2.4.4/egcs-2.91.66 2 to 2.5 Mips # 400Mhz Pentium II with Linux 2.0.36/egcs-1.0.3 1 to 1.8 Mips #======================================================================= -cpu: count=1, ips=10000000 +cpu: count=2, ips=10000000 #======================================================================= # MEGS @@ -28,8 +28,7 @@ main() acquire_spinlock(&kernel_lock); idtinit(); // CPU's idt lapic_init(cpu()); - curproc[cpu()] = &proc[0]; // XXX - swtch(); + scheduler(); } acpu = 1; // clear BSS @@ -45,7 +44,7 @@ main() // create fake process zero p = &proc[0]; - curproc[cpu()] = p; + memset(p, 0, sizeof *p); p->state = WAITING; p->sz = 4 * PAGE; p->mem = kalloc(p->sz); @@ -70,10 +69,10 @@ main() write_eflags(read_eflags() | FL_IF); p = newproc(); - // load_icode(p, _binary_usertests_start, (unsigned) _binary_usertests_size); + // load_icode(p, _binary_usertests_start, (unsigned) _binary_usertests_size); load_icode(p, _binary_userfs_start, (unsigned) _binary_userfs_size); - - swtch(); + cprintf("loaded userfs\n"); + scheduler(); return 0; } @@ -141,8 +141,8 @@ lapic_timerinit() cprintf("%d: init timer\n", cpu()); lapic_write(LAPIC_TDCR, LAPIC_X1); lapic_write(LAPIC_TIMER, LAPIC_CLKIN | LAPIC_PERIODIC | (IRQ_OFFSET + IRQ_TIMER)); - lapic_write(LAPIC_TCCR, 1000000); - lapic_write(LAPIC_TICR, 1000000); + lapic_write(LAPIC_TCCR, 10000000); + lapic_write(LAPIC_TICR, 10000000); } void @@ -48,8 +48,7 @@ struct proc * newproc() { struct proc *np; - struct proc *op = curproc[cpu()]; - unsigned *sp; + struct proc *op; int fd; for(np = &proc[1]; np < &proc[NPROC]; np++) @@ -58,6 +57,11 @@ newproc() if(np >= &proc[NPROC]) return 0; + // copy from proc[0] if we're bootstrapping + op = curproc[cpu()]; + if(op == 0) + op = &proc[0]; + np->pid = next_pid++; np->ppid = op->pid; np->sz = op->sz; @@ -76,11 +80,12 @@ newproc() np->tf = (struct Trapframe *) (np->kstack + KSTACKSIZE - sizeof(struct Trapframe)); *(np->tf) = *(op->tf); np->tf->tf_regs.reg_eax = 0; // so fork() returns 0 in child - sp = (unsigned *) np->tf; - *(--sp) = (unsigned) &trapret; // for return from swtch() - *(--sp) = 0; // previous bp for leave in swtch() - np->esp = (unsigned) sp; - np->ebp = (unsigned) sp; + cprintf("newproc pid=%d return to %x:%x tf-%p\n", np->pid, np->tf->tf_cs, np->tf->tf_eip, np->tf); + + // set up new jmpbuf to start executing at trapret with esp pointing at tf + memset(&np->jmpbuf, 0, sizeof np->jmpbuf); + np->jmpbuf.jb_eip = (unsigned) trapret; + np->jmpbuf.jb_esp = (unsigned) np->tf - 4; // -4 for the %eip that isn't actually there // copy file descriptors for(fd = 0; fd < NOFILE; fd++){ @@ -96,33 +101,20 @@ newproc() return np; } -/* - * find a runnable process and switch to it. - */ void -swtch() +scheduler(void) { - struct proc *np; - struct proc *op = curproc[cpu()]; - unsigned sp; + struct proc *op, *np; int i; - // force push of callee-saved registers - asm volatile("nop" : : : "%edi", "%esi", "%ebx"); - - // save calling process's stack pointers - op->ebp = read_ebp(); - op->esp = read_esp(); - - // don't execute on calling process's stack - sp = (unsigned) cpus[cpu()].mpstack + MPSTACK - 32; - asm volatile("movl %0, %%esp" : : "g" (sp)); - asm volatile("movl %0, %%ebp" : : "g" (sp)); - - // gcc might store op on the stack - np = curproc[cpu()]; - np = np + 1; + cprintf("start scheduler on cpu %d jmpbuf %p\n", cpu(), &cpus[cpu()].jmpbuf); + cpus[cpu()].lastproc = &proc[0]; + setjmp(&cpus[cpu()].jmpbuf); + + // find a runnable process and switch to it + curproc[cpu()] = 0; + np = cpus[cpu()].lastproc + 1; while(1){ for(i = 0; i < NPROC; i++){ if(np >= &proc[NPROC]) @@ -139,34 +131,47 @@ swtch() acquire_spinlock(&kernel_lock); np = &proc[0]; } - - cprintf("cpu %d swtch %x -> %x\n", cpu(), curproc[cpu()], np); + cpus[cpu()].lastproc = np; curproc[cpu()] = np; + np->state = RUNNING; // h/w sets busy bit in TSS descriptor sometimes, and faults // if it's set in LTR. so clear tss descriptor busy bit. np->gdt[SEG_TSS].sd_type = STS_T32A; + // XXX should probably have an lgdt() function in x86.h + // to confine all the inline assembly. // XXX probably ought to lgdt on trap return too, in case // a system call has moved a program or changed its size. - asm volatile("lgdt %0" : : "g" (np->gdt_pd.pd_lim)); ltr(SEG_TSS << 3); - // this happens to work, but probably isn't safe: - // it's not clear that np->ebp is guaranteed to evaluate - // correctly after changing the stack pointer. - asm volatile("movl %0, %%esp" : : "g" (np->esp)); - asm volatile("movl %0, %%ebp" : : "g" (np->ebp)); + if(0) cprintf("cpu%d: run %d esp=%p callerpc=%p\n", cpu(), np-proc); + longjmp(&np->jmpbuf); +} + +// give up the cpu by switching to the scheduler, +// which runs on the per-cpu stack. +void +swtch(void) +{ + struct proc *p = curproc[cpu()]; + if(p == 0) + panic("swtch"); + if(setjmp(&p->jmpbuf) == 0) + longjmp(&cpus[cpu()].jmpbuf); } void sleep(void *chan) { - curproc[cpu()]->chan = chan; - curproc[cpu()]->state = WAITING; + struct proc *p = curproc[cpu()]; + if(p == 0) + panic("sleep"); + p->chan = chan; + p->state = WAITING; swtch(); } @@ -16,6 +16,23 @@ #define SEG_TSS 5 // this process's task state #define NSEGS 6 +struct jmpbuf { + // saved registers for kernel context switches + // don't need to save all the fs etc. registers because + // they are constant across kernel contexts + // save all the regular registers so we don't care which are caller save + // don't save eax because that's the return register + // layout known to swtch.S + int jb_ebx; + int jb_ecx; + int jb_edx; + int jb_esi; + int jb_edi; + int jb_esp; + int jb_ebp; + int jb_eip; +}; + struct proc{ char *mem; // start of process's physical memory unsigned sz; // total size of mem, including kernel stack @@ -32,17 +49,22 @@ struct proc{ unsigned esp; // kernel stack pointer unsigned ebp; // kernel frame pointer + struct jmpbuf jmpbuf; + struct Trapframe *tf; // points into kstack, used to find user regs }; extern struct proc proc[]; -extern struct proc *curproc[NCPU]; +extern struct proc *curproc[NCPU]; // can be NULL if no proc running. + // XXX move curproc into cpu structure? #define MPSTACK 512 struct cpu { uint8_t apicid; // Local APIC ID + struct jmpbuf jmpbuf; char mpstack[MPSTACK]; // per-cpu start-up stack, only used to get into main() + struct proc *lastproc; // last proc scheduled on this cpu (never NULL) }; extern struct cpu cpus[NCPU]; @@ -4,31 +4,39 @@ #include "mmu.h" #define LOCK_FREE -1 +#define DEBUG 0 uint32_t kernel_lock = LOCK_FREE; +int getcallerpc(void *v) { + return ((int*)v)[-1]; +} + // lock = LOCK_FREE if free, else = cpu_id of owner CPU -void +void acquire_spinlock(uint32_t* lock) { int cpu_id = cpu(); + // on a real machine there would be a memory barrier here + if(DEBUG) cprintf("cpu%d: acquiring at %x\n", cpu_id, getcallerpc(&lock)); + write_eflags(read_eflags() & ~FL_IF); if (*lock == cpu_id) - return; + panic("recursive lock"); - write_eflags(read_eflags() & ~FL_IF); while ( cmpxchg(LOCK_FREE, cpu_id, lock) != cpu_id ) { ; } - // cprintf ("acquired: %d\n", cpu_id); + if(DEBUG) cprintf("cpu%d: acquired at %x\n", cpu_id, getcallerpc(&lock)); } void release_spinlock(uint32_t* lock) { int cpu_id = cpu(); - // cprintf ("release: %d\n", cpu_id); + if(DEBUG) cprintf ("cpu%d: releasing at %x\n", cpu_id, getcallerpc(&lock)); if (*lock != cpu_id) panic("release_spinlock: releasing a lock that i don't own\n"); *lock = LOCK_FREE; + // on a real machine there would be a memory barrier here write_eflags(read_eflags() | FL_IF); } @@ -36,8 +44,9 @@ void release_grant_spinlock(uint32_t* lock, int c) { int cpu_id = cpu(); - // cprintf ("release_grant: %d -> %d\n", cpu_id, c); + if(DEBUG) cprintf ("cpu%d: release_grant to %d at %x\n", cpu_id, c, getcallerpc(&lock)); if (*lock != cpu_id) panic("release_spinlock: releasing a lock that i don't own\n"); *lock = c; } + @@ -0,0 +1,37 @@ +.globl setjmp +setjmp: + movl 4(%esp), %eax + + movl %ebx, 0(%eax) + movl %ecx, 4(%eax) + movl %edx, 8(%eax) + movl %esi, 12(%eax) + movl %edi, 16(%eax) + movl %esp, 20(%eax) + movl %ebp, 24(%eax) + pushl 0(%esp) /* %eip */ + popl 28(%eax) + + movl $0, %eax /* return value */ + ret + +.globl longjmp +longjmp: + movl 4(%esp), %eax + + movl 0(%eax), %ebx + movl 4(%eax), %ecx + movl 8(%eax), %edx + movl 12(%eax), %esi + movl 16(%eax), %edi + movl 20(%eax), %esp + movl 24(%eax), %ebp + + addl $4, %esp /* pop %eip into thin air */ + pushl 28(%eax) /* push new %eip */ + + movl $1, %eax /* return value (appears to come from setjmp!) */ + ret + + + @@ -39,7 +39,7 @@ fetcharg(int argno, int *ip) unsigned esp; esp = (unsigned) curproc[cpu()]->tf->tf_esp; - return fetchint(curproc[cpu()], esp + 8 + 4*argno, ip); + return fetchint(curproc[cpu()], esp + 4 + 4*argno, ip); } int @@ -178,6 +178,7 @@ sys_exit() if(p->ppid == cp->pid) p->pid = 1; + // switch into scheduler swtch(); return 0; @@ -36,13 +36,15 @@ trap(struct Trapframe *tf) int v = tf->tf_trapno; if(tf->tf_cs == 0x8 && kernel_lock == cpu()) - cprintf("cpu %d: trap from %x:%x with lock=%d\n", - cpu(), tf->tf_cs, tf->tf_eip, kernel_lock); + cprintf("cpu %d: trap %d from %x:%x with lock=%d\n", + cpu(), v, tf->tf_cs, tf->tf_eip, kernel_lock); acquire_spinlock(&kernel_lock); // released in trapret in trapasm.S if(v == T_SYSCALL){ struct proc *cp = curproc[cpu()]; + if(cp == 0) + panic("syscall with no proc"); cp->tf = tf; syscall(); if(cp != curproc[cpu()]) @@ -51,7 +53,7 @@ trap(struct Trapframe *tf) panic("trap ret but not RUNNING"); if(tf != cp->tf) panic("trap ret wrong tf"); - if(read_esp() < cp->kstack || read_esp() >= cp->kstack + KSTACKSIZE) + if(read_esp() < (unsigned)cp->kstack || read_esp() >= (unsigned)cp->kstack + KSTACKSIZE) panic("trap ret esp wrong"); return; } @@ -22,9 +22,10 @@ alltraps: * expects ESP to point to a Trapframe */ trapret: - push $kernel_lock + pushl $kernel_lock call release_spinlock - addl $4, %esp + addl $0x4, %esp + popal popl %es popl %ds @@ -1,25 +1,4 @@ int -fork() -{ - asm("mov $1, %eax"); - asm("int $48"); -} - -int -exit() -{ - asm("mov $2, %eax"); - asm("int $48"); -} - -void -cons_putc(int c) -{ - asm("mov $4, %eax"); - asm("int $48"); -} - -int puts(char *s) { int i; @@ -29,38 +8,3 @@ puts(char *s) return i; } -int -pipe(int fds[]) -{ - asm("mov $5, %eax"); - asm("int $48"); -} - -int -read(int fd, char *buf, int n) -{ - asm("mov $7, %eax"); - asm("int $48"); -} - -int -write(int fd, char *buf, int n) -{ - asm("mov $6, %eax"); - asm("int $48"); -} - -int -close(int fd) -{ - asm("mov $8, %eax"); - asm("int $48"); -} - -int -block(void) -{ - asm("mov $9, %eax"); - asm("int $48"); -} - @@ -4,5 +4,6 @@ char buf[1024]; main() { + puts("userfs running\n"); block(); } @@ -0,0 +1,18 @@ +#include "syscall.h" +#include "traps.h" + +#define STUB(name) \ + .globl name; \ + name: \ + movl $SYS_ ## name, %eax; \ + int $T_SYSCALL; \ + ret + +STUB(fork) +STUB(exit) +STUB(cons_putc) +STUB(pipe) +STUB(read) +STUB(write) +STUB(close) +STUB(block) @@ -349,7 +349,6 @@ struct Trapframe { uint16_t tf_padding4; }; - #define MAX_IRQS 16 // Number of IRQs #define IRQ_OFFSET 32 // IRQ 0 corresponds to int IRQ_OFFSET |