diff options
author | Mole Shang <[email protected]> | 2024-02-10 13:08:26 +0800 |
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committer | Mole Shang <[email protected]> | 2024-02-10 13:08:26 +0800 |
commit | c9284cd93525436cc823258ab309c1b27eeec714 (patch) | |
tree | 35782f7314100aa821823ee94cc5d28164af8000 /kernel/proc.c | |
parent | 283d5ab4c964ab525e45fcade06d6fd7e977c43e (diff) | |
download | xv6-labs-c9284cd93525436cc823258ab309c1b27eeec714.tar.gz xv6-labs-c9284cd93525436cc823258ab309c1b27eeec714.tar.bz2 xv6-labs-c9284cd93525436cc823258ab309c1b27eeec714.zip |
lab pgtbl: finishpgtbl
Diffstat (limited to 'kernel/proc.c')
-rw-r--r-- | kernel/proc.c | 45 |
1 files changed, 44 insertions, 1 deletions
diff --git a/kernel/proc.c b/kernel/proc.c index 5aa616f..3d215a5 100644 --- a/kernel/proc.c +++ b/kernel/proc.c @@ -132,6 +132,14 @@ found: return 0; } + // Allocate a usyscall page and fill pid. + if((p->usyscall = (struct usyscall *)kalloc()) == 0){ + freeproc(p); + release(&p->lock); + return 0; + } + p->usyscall->pid = p->pid; + // An empty user page table. p->pagetable = proc_pagetable(p); if(p->pagetable == 0){ @@ -158,6 +166,9 @@ freeproc(struct proc *p) if(p->trapframe) kfree((void*)p->trapframe); p->trapframe = 0; + if(p->usyscall) + kfree((void*)p->usyscall); + p->usyscall = 0; if(p->pagetable) proc_freepagetable(p->pagetable, p->sz); p->pagetable = 0; @@ -172,7 +183,7 @@ freeproc(struct proc *p) } // Create a user page table for a given process, with no user memory, -// but with trampoline and trapframe pages. +// but with trampoline, trapframe and usyscall pages. pagetable_t proc_pagetable(struct proc *p) { @@ -202,6 +213,14 @@ proc_pagetable(struct proc *p) return 0; } + // map the usyscall page below the trapframe page, for + // ugetpid(). + if(mappages(pagetable, USYSCALL, PGSIZE, + (uint64)(p->usyscall), PTE_R | PTE_U) < 0){ + uvmunmap(pagetable, USYSCALL, 1, 0); + uvmfree(pagetable, 0); + return 0; + } return pagetable; } @@ -212,6 +231,7 @@ proc_freepagetable(pagetable_t pagetable, uint64 sz) { uvmunmap(pagetable, TRAMPOLINE, 1, 0); uvmunmap(pagetable, TRAPFRAME, 1, 0); + uvmunmap(pagetable, USYSCALL, 1, 0); uvmfree(pagetable, sz); } @@ -706,3 +726,26 @@ get_nproc(void) return n; } + +// lab pagetable: report which pages have been accessed (r/w) +// according to PTE_A and store it in a bit mask (3rd param) +int +pgaccess(uint64 base, int len, uint64 mask_addr) +{ + struct proc *p = myproc(); + pagetable_t pgtbl = p->pagetable; + pte_t *pte; + int mask = 0; + + // iterater thru pages + for(int i = 0; i < len; i++) { + pte = walk(pgtbl, base + i * PGSIZE, 0); + if(*pte & PTE_A) { + *pte &= (~PTE_A); // clear PTE_A to avoid setting it forever + mask |= (1L << i); + } + } + + // now copyout the mask to user memory + return copyout(pgtbl, mask_addr, (char *)&mask, sizeof(mask)); +} |