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xv6/spinlock.c

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checkpoint. booting second processor. stack is messed up, but thanks to cliff and plan 9 code, at least boots and gets into C code.
2006-06-22 01:28:57 +00:00
#include "types.h"
#include "defs.h"
#include "x86.h"
disable all interrupts when acquiring lock user program that makes a blocking system call
2006-07-06 21:47:22 +00:00
#include "mmu.h"
no more big kernel lock succeeds at usertests.c pipe test
2006-07-12 01:48:35 +00:00
#include "param.h"
#include "proc.h"
#include "spinlock.h"
checkpoint. booting second processor. stack is messed up, but thanks to cliff and plan 9 code, at least boots and gets into C code.
2006-06-22 01:28:57 +00:00
Changes to allow use of native x86 ELF compilers, which on my Linux 2.4 box using gcc 3.4.6 don't seem to follow the same conventions as the i386-jos-elf-gcc compilers. Can run make 'TOOLPREFIX=' or edit the Makefile. curproc[cpu()] can now be NULL, indicating that no proc is running. This seemed safer to me than having curproc[0] and curproc[1] both pointing at proc[0] potentially. The old implementation of swtch depended on the stack frame layout used inside swtch being okay to return from on the other stack (exactly the V6 you are not expected to understand this). It also could be called in two contexts: at boot time, to schedule the very first process, and later, on behalf of a process, to sleep or schedule some other process. I split this into two functions: scheduler and swtch. The scheduler is now a separate never-returning function, invoked by each cpu once set up. The scheduler looks like: scheduler() { setjmp(cpu.context); pick proc to schedule blah blah blah longjmp(proc.context) } The new swtch is intended to be called only when curproc[cpu()] is not NULL, that is, only on behalf of a user proc. It does: swtch() { if(setjmp(proc.context) == 0) longjmp(cpu.context) } to save the current proc context and then jump over to the scheduler, running on the cpu stack. Similarly the system call stubs are now in assembly in usys.S to avoid needing to know the details of stack frame layout used by the compiler. Also various changes in the debugging prints.
2006-07-11 01:07:40 +00:00
#define DEBUG 0
checkpoint. booting second processor. stack is messed up, but thanks to cliff and plan 9 code, at least boots and gets into C code.
2006-06-22 01:28:57 +00:00
no more recursive locks wakeup1() assumes you hold proc_table_lock sleep(chan, lock) provides atomic sleep-and-release to wait for condition ugly code in swtch/scheduler to implement new sleep fix lots of bugs in pipes, wait, and exit fix bugs if timer interrupt goes off in schedule() console locks per line, not per byte
2006-07-15 12:03:57 +00:00
extern int use_console_lock;
i think my cmpxchg use was wrong in acquire nesting cli/sti: release shouldn't always enable interrupts separate setup of lapic from starting of other cpus, so cpu() works earlier flag to disable locking in console output make locks work even when curproc==0 (still crashes in clock interrupt)
2006-07-12 11:15:38 +00:00
Changes to allow use of native x86 ELF compilers, which on my Linux 2.4 box using gcc 3.4.6 don't seem to follow the same conventions as the i386-jos-elf-gcc compilers. Can run make 'TOOLPREFIX=' or edit the Makefile. curproc[cpu()] can now be NULL, indicating that no proc is running. This seemed safer to me than having curproc[0] and curproc[1] both pointing at proc[0] potentially. The old implementation of swtch depended on the stack frame layout used inside swtch being okay to return from on the other stack (exactly the V6 you are not expected to understand this). It also could be called in two contexts: at boot time, to schedule the very first process, and later, on behalf of a process, to sleep or schedule some other process. I split this into two functions: scheduler and swtch. The scheduler is now a separate never-returning function, invoked by each cpu once set up. The scheduler looks like: scheduler() { setjmp(cpu.context); pick proc to schedule blah blah blah longjmp(proc.context) } The new swtch is intended to be called only when curproc[cpu()] is not NULL, that is, only on behalf of a user proc. It does: swtch() { if(setjmp(proc.context) == 0) longjmp(cpu.context) } to save the current proc context and then jump over to the scheduler, running on the cpu stack. Similarly the system call stubs are now in assembly in usys.S to avoid needing to know the details of stack frame layout used by the compiler. Also various changes in the debugging prints.
2006-07-11 01:07:40 +00:00
int getcallerpc(void *v) {
return ((int*)v)[-1];
}
void
no more recursive locks wakeup1() assumes you hold proc_table_lock sleep(chan, lock) provides atomic sleep-and-release to wait for condition ugly code in swtch/scheduler to implement new sleep fix lots of bugs in pipes, wait, and exit fix bugs if timer interrupt goes off in schedule() console locks per line, not per byte
2006-07-15 12:03:57 +00:00
acquire1(struct spinlock * lock, struct proc *cp)
checkpoint. booting second processor. stack is messed up, but thanks to cliff and plan 9 code, at least boots and gets into C code.
2006-06-22 01:28:57 +00:00
{
no more big kernel lock succeeds at usertests.c pipe test
2006-07-12 01:48:35 +00:00
if(DEBUG) cprintf("cpu%d: acquiring at %x\n", cpu(), getcallerpc(&lock));
i think my cmpxchg use was wrong in acquire nesting cli/sti: release shouldn't always enable interrupts separate setup of lapic from starting of other cpus, so cpu() works earlier flag to disable locking in console output make locks work even when curproc==0 (still crashes in clock interrupt)
2006-07-12 11:15:38 +00:00
no more recursive locks wakeup1() assumes you hold proc_table_lock sleep(chan, lock) provides atomic sleep-and-release to wait for condition ugly code in swtch/scheduler to implement new sleep fix lots of bugs in pipes, wait, and exit fix bugs if timer interrupt goes off in schedule() console locks per line, not per byte
2006-07-15 12:03:57 +00:00
cli();
while ( cmpxchg(0, 1, &lock->locked) == 1 ) { ; }
lock->locker_pc = getcallerpc(&lock);
i think my cmpxchg use was wrong in acquire nesting cli/sti: release shouldn't always enable interrupts separate setup of lapic from starting of other cpus, so cpu() works earlier flag to disable locking in console output make locks work even when curproc==0 (still crashes in clock interrupt)
2006-07-12 11:15:38 +00:00
passes both usertests exit had acquire where I meant release swtch now checks that you hold no locks
2006-07-12 15:35:33 +00:00
if(cp)
cp->locks += 1;
no more big kernel lock succeeds at usertests.c pipe test
2006-07-12 01:48:35 +00:00
if(DEBUG) cprintf("cpu%d: acquired at %x\n", cpu(), getcallerpc(&lock));
checkpoint. booting second processor. stack is messed up, but thanks to cliff and plan 9 code, at least boots and gets into C code.
2006-06-22 01:28:57 +00:00
}
void
no more recursive locks wakeup1() assumes you hold proc_table_lock sleep(chan, lock) provides atomic sleep-and-release to wait for condition ugly code in swtch/scheduler to implement new sleep fix lots of bugs in pipes, wait, and exit fix bugs if timer interrupt goes off in schedule() console locks per line, not per byte
2006-07-15 12:03:57 +00:00
release1(struct spinlock * lock, struct proc *cp)
checkpoint. booting second processor. stack is messed up, but thanks to cliff and plan 9 code, at least boots and gets into C code.
2006-06-22 01:28:57 +00:00
{
no more big kernel lock succeeds at usertests.c pipe test
2006-07-12 01:48:35 +00:00
if(DEBUG) cprintf ("cpu%d: releasing at %x\n", cpu(), getcallerpc(&lock));
Changes to allow use of native x86 ELF compilers, which on my Linux 2.4 box using gcc 3.4.6 don't seem to follow the same conventions as the i386-jos-elf-gcc compilers. Can run make 'TOOLPREFIX=' or edit the Makefile. curproc[cpu()] can now be NULL, indicating that no proc is running. This seemed safer to me than having curproc[0] and curproc[1] both pointing at proc[0] potentially. The old implementation of swtch depended on the stack frame layout used inside swtch being okay to return from on the other stack (exactly the V6 you are not expected to understand this). It also could be called in two contexts: at boot time, to schedule the very first process, and later, on behalf of a process, to sleep or schedule some other process. I split this into two functions: scheduler and swtch. The scheduler is now a separate never-returning function, invoked by each cpu once set up. The scheduler looks like: scheduler() { setjmp(cpu.context); pick proc to schedule blah blah blah longjmp(proc.context) } The new swtch is intended to be called only when curproc[cpu()] is not NULL, that is, only on behalf of a user proc. It does: swtch() { if(setjmp(proc.context) == 0) longjmp(cpu.context) } to save the current proc context and then jump over to the scheduler, running on the cpu stack. Similarly the system call stubs are now in assembly in usys.S to avoid needing to know the details of stack frame layout used by the compiler. Also various changes in the debugging prints.
2006-07-11 01:07:40 +00:00
no more recursive locks wakeup1() assumes you hold proc_table_lock sleep(chan, lock) provides atomic sleep-and-release to wait for condition ugly code in swtch/scheduler to implement new sleep fix lots of bugs in pipes, wait, and exit fix bugs if timer interrupt goes off in schedule() console locks per line, not per byte
2006-07-15 12:03:57 +00:00
if(lock->locked != 1)
no more big kernel lock succeeds at usertests.c pipe test
2006-07-12 01:48:35 +00:00
panic("release");
passes both usertests exit had acquire where I meant release swtch now checks that you hold no locks
2006-07-12 15:35:33 +00:00
if(cp)
cp->locks -= 1;
no more recursive locks wakeup1() assumes you hold proc_table_lock sleep(chan, lock) provides atomic sleep-and-release to wait for condition ugly code in swtch/scheduler to implement new sleep fix lots of bugs in pipes, wait, and exit fix bugs if timer interrupt goes off in schedule() console locks per line, not per byte
2006-07-15 12:03:57 +00:00
cmpxchg(1, 0, &lock->locked);
sti();
}
void
acquire(struct spinlock *lock)
{
acquire1(lock, curproc[cpu()]);
}
void
release(struct spinlock *lock)
{
release1(lock, curproc[cpu()]);
no more big kernel lock succeeds at usertests.c pipe test
2006-07-12 01:48:35 +00:00
}
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