diff options
| -rw-r--r-- | Notes | 4 | ||||
| -rw-r--r-- | console.c | 9 | ||||
| -rw-r--r-- | defs.h | 3 | ||||
| -rw-r--r-- | kalloc.c | 3 | ||||
| -rw-r--r-- | main.c | 13 | ||||
| -rw-r--r-- | mp.c | 11 | ||||
| -rw-r--r-- | proc.c | 25 | ||||
| -rw-r--r-- | proc.h | 1 | ||||
| -rw-r--r-- | spinlock.c | 32 | ||||
| -rw-r--r-- | spinlock.h | 2 | ||||
| -rw-r--r-- | x86.h | 14 |
11 files changed, 85 insertions, 32 deletions
@@ -125,6 +125,10 @@ in general, the table locks protect both free-ness and why can't i get a lock in console code? always triple fault + because release turns on interrupts! + a bad idea very early in main() + but mp_init() calls cprintf + lock code shouldn't call cprintf... ide_init doesn't work now? and IOAPIC: read from unsupported address @@ -4,6 +4,7 @@ #include "spinlock.h" struct spinlock console_lock; +int use_printf_lock = 0; /* * copy console output to parallel port, which you can tell @@ -29,7 +30,8 @@ cons_putc(int c) unsigned short *crt = (unsigned short *) 0xB8000; // base of CGA memory int ind; - //acquire(&console_lock); + if(use_printf_lock) + acquire(&console_lock); lpt_putc(c); @@ -62,7 +64,8 @@ cons_putc(int c) outb(crtport, 15); outb(crtport + 1, ind); - //release(&console_lock); + if(use_printf_lock) + release(&console_lock); } void @@ -127,6 +130,8 @@ cprintf(char *fmt, ...) void panic(char *s) { + use_printf_lock = 0; + cprintf("panic: "); cprintf(s, 0); cprintf("\n", 0); while(1) @@ -19,6 +19,8 @@ void wakeup(void *); void scheduler(void); void proc_exit(void); void yield(void); +void cli(void); +void sti(void); // swtch.S struct jmpbuf; @@ -46,6 +48,7 @@ void pic_init(void); // mp.c void mp_init(void); +void mp_startthem(void); int cpu(void); int mp_isbcpu(void); void lapic_init(int); @@ -10,6 +10,9 @@ #include "param.h" #include "types.h" #include "defs.h" +#include "param.h" +#include "mmu.h" +#include "proc.h" #include "spinlock.h" struct spinlock kalloc_lock; @@ -8,6 +8,7 @@ #include "syscall.h" #include "elf.h" #include "param.h" +#include "spinlock.h" extern char edata[], end[]; extern int acpu; @@ -15,23 +16,33 @@ extern char _binary_user1_start[], _binary_user1_size[]; extern char _binary_usertests_start[], _binary_usertests_size[]; extern char _binary_userfs_start[], _binary_userfs_size[]; +extern use_printf_lock; + int main() { struct proc *p; if (acpu) { + cpus[cpu()].clis = 1; cprintf("an application processor\n"); idtinit(); // CPU's idt lapic_init(cpu()); lapic_timerinit(); lapic_enableintr(); + sti(); scheduler(); } acpu = 1; + // clear BSS memset(edata, 0, end - edata); + mp_init(); // just set up apic so cpu() works + use_printf_lock = 1; + + cpus[cpu()].clis = 1; // cpu starts as if we had called cli() + cprintf("\nxV6\n\n"); pic_init(); // initialize PIC @@ -56,7 +67,7 @@ main() p->ppid = 0; setupsegs(p); - mp_init(); // multiprocessor + mp_startthem(); // turn on timer and enable interrupts on the local APIC lapic_timerinit(); @@ -325,8 +325,6 @@ mp_init() struct MPCTB *mpctb; struct MPPE *proc; struct MPBE *bus; - int c; - extern int main(); int i; ncpu = 0; @@ -386,13 +384,20 @@ mp_init() lapic_init(bcpu-cpus); cprintf("ncpu: %d boot %d\n", ncpu, bcpu-cpus); +} +void +mp_startthem() +{ extern uint8_t _binary_bootother_start[], _binary_bootother_size[]; + extern int main(); + int c; + memmove((void *) APBOOTCODE,_binary_bootother_start, (uint32_t) _binary_bootother_size); for(c = 0; c < ncpu; c++){ - if (cpus+c == bcpu) continue; + if (c == cpu()) continue; cprintf ("starting processor %d\n", c); *(unsigned *)(APBOOTCODE-4) = (unsigned) (cpus[c].mpstack) + MPSTACK; // tell it what to use for %esp *(unsigned *)(APBOOTCODE-8) = (unsigned)&main; // tell it where to jump to @@ -148,6 +148,7 @@ scheduler(void) if(i < NPROC){ np->state = RUNNING; + release(&proc_table_lock); break; } @@ -157,8 +158,6 @@ scheduler(void) cpus[cpu()].lastproc = np; curproc[cpu()] = np; - - release(&proc_table_lock); // h/w sets busy bit in TSS descriptor sometimes, and faults // if it's set in LTR. so clear tss descriptor busy bit. @@ -252,3 +251,25 @@ proc_exit() // switch into scheduler swtch(ZOMBIE); } + +// disable interrupts +void +cli(void) +{ + cpus[cpu()].clis += 1; + if(cpus[cpu()].clis == 1) + __asm __volatile("cli"); +} + +// enable interrupts +void +sti(void) +{ + if(cpus[cpu()].clis < 1){ + cprintf("cpu %d clis %d\n", cpu(), cpus[cpu()].clis); + panic("sti"); + } + cpus[cpu()].clis -= 1; + if(cpus[cpu()].clis < 1) + __asm __volatile("sti"); +} @@ -69,6 +69,7 @@ struct cpu { 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) + int clis; // cli() nesting depth }; extern struct cpu cpus[NCPU]; @@ -8,6 +8,8 @@ #define DEBUG 0 +extern use_printf_lock; + int getcallerpc(void *v) { return ((int*)v)[-1]; } @@ -15,37 +17,49 @@ int getcallerpc(void *v) { void acquire(struct spinlock * lock) { - struct proc * cp = curproc[cpu()]; + unsigned who; + + if(curproc[cpu()]) + who = (unsigned) curproc[cpu()]; + else + who = cpu() + 1; - // on a real machine there would be a memory barrier here if(DEBUG) cprintf("cpu%d: acquiring at %x\n", cpu(), getcallerpc(&lock)); - if (cp && lock->p == cp && lock->locked){ + + if (lock->who == who && lock->locked){ lock->count += 1; } else { cli(); - while ( cmpxchg(0, 1, &lock->locked) != 1 ) { ; } + // if we get the lock, eax will be zero + // if we don't get the lock, eax will be one + while ( cmpxchg(0, 1, &lock->locked) == 1 ) { ; } lock->locker_pc = getcallerpc(&lock); lock->count = 1; - lock->p = cp; + lock->who = who; } + if(DEBUG) cprintf("cpu%d: acquired at %x\n", cpu(), getcallerpc(&lock)); } void release(struct spinlock * lock) { - struct proc * cp = curproc[cpu()]; + unsigned who; + + if(curproc[cpu()]) + who = (unsigned) curproc[cpu()]; + else + who = cpu() + 1; if(DEBUG) cprintf ("cpu%d: releasing at %x\n", cpu(), getcallerpc(&lock)); - if(lock->p != cp || lock->count < 1 || lock->locked != 1) + if(lock->who != who || lock->count < 1 || lock->locked != 1) panic("release"); lock->count -= 1; if(lock->count < 1){ - lock->p = 0; + lock->who = 0; cmpxchg(1, 0, &lock->locked); sti(); - // on a real machine there would be a memory barrier here } } @@ -1,6 +1,6 @@ struct spinlock { unsigned int locked; - struct proc *p; + unsigned who; int count; unsigned locker_pc; }; @@ -304,20 +304,6 @@ read_tsc(void) return tsc; } -// disable interrupts -static __inline void -cli(void) -{ - __asm __volatile("cli"); -} - -// enable interrupts -static __inline void -sti(void) -{ - __asm __volatile("sti"); -} - struct PushRegs { /* registers as pushed by pusha */ uint32_t reg_edi; |