d0f7acf9eb
An x86-64 operating system built from xv6, now largely rewritten: SMP, a copy-on-write root filesystem (SchFS), PCI/USB/virtio drivers, a TTF rasteriser, and a Linux-numbered syscall ABI. No history before this point -- the tree was never under version control. This commit exists so the rename that follows has something to undo to.
115 lines
2 KiB
C
115 lines
2 KiB
C
#include "types.h"
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#include "defs.h"
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#include "param.h"
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#include "x86.h"
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#include "memlayout.h"
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#include "mmu.h"
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#include "proc.h"
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#include "spinlock.h"
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void
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initlock(struct spinlock *lk, char *name)
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{
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lk->name = name;
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lk->locked = 0;
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lk->cpu = 0;
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}
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void
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acquire(struct spinlock *lk)
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{
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pushcli();
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if(holding(lk))
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panic("acquire");
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{
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uint64 spins = 0;
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while(xchg(&lk->locked, 1) != 0){
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if(++spins == 200000000ULL){
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cprintf("acquire: stuck on \"%s\" held by cpu=%p pcs0=%p pcs1=%p pcs2=%p, acquirer cpu=%p\n",
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lk->name, lk->cpu, lk->pcs[0], lk->pcs[1], lk->pcs[2], mycpu());
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panic("acquire: deadlock");
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}
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}
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}
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__sync_synchronize();
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lk->cpu = mycpu();
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getcallerpcs(&lk, lk->pcs);
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}
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void
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release(struct spinlock *lk)
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{
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if(!holding(lk))
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panic("release");
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lk->pcs[0] = 0;
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lk->cpu = 0;
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__sync_synchronize();
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asm volatile("movq $0, %0" : "+m" (lk->locked) : );
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popcli();
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}
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void
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getcallerpcs(void *v, addr_t pcs[])
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{
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addr_t *rbp;
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asm volatile("mov %%rbp, %0" : "=r" (rbp));
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getstackpcs(rbp, pcs);
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}
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void
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getstackpcs(addr_t *rbp, addr_t pcs[])
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{
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int i;
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for(i = 0; i < 10; i++){
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if(rbp == 0 || rbp < (addr_t*)KERNBASE || rbp == (addr_t*)0xffffffff)
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break;
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pcs[i] = rbp[1];
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rbp = (addr_t*)rbp[0];
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}
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for(; i < 10; i++)
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pcs[i] = 0;
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}
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int
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holding(struct spinlock *lock)
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{
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return lock->locked && lock->cpu == mycpu();
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}
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void
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pushcli(void)
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{
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int eflags;
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eflags = readeflags();
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cli();
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if(mycpu() == 0){
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extern uint64 kernel_fs_base;
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cprintf("pushcli: cpu==NULL cs=0x%p kernel_fs_base=0x%p actual_fs_base=0x%p\n",
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readcs(), kernel_fs_base, rdmsr(0xC0000100));
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panic("pushcli: cpu is NULL");
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}
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if(mycpu()->ncli == 0)
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mycpu()->intena = eflags & FL_IF;
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mycpu()->ncli += 1;
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}
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void
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popcli(void)
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{
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if(readeflags()&FL_IF)
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panic("popcli - interruptible");
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if(--mycpu()->ncli < 0)
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panic("popcli");
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if(mycpu()->ncli == 0 && mycpu()->intena)
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sti();
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}
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