diff options
author | Frans Kaashoek <[email protected]> | 2018-10-02 08:36:02 -0400 |
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committer | Frans Kaashoek <[email protected]> | 2018-10-02 08:40:01 -0400 |
commit | d448fd5e6cb6595d70172195afaee56c5097e4ed (patch) | |
tree | 3158dba2a9553ebafd4dd4e5fcc7d470078136f9 | |
parent | a42b7d5dbb8b88aa1fb4dc508600a272c494e3f5 (diff) | |
download | xv6-labs-d448fd5e6cb6595d70172195afaee56c5097e4ed.tar.gz xv6-labs-d448fd5e6cb6595d70172195afaee56c5097e4ed.tar.bz2 xv6-labs-d448fd5e6cb6595d70172195afaee56c5097e4ed.zip |
Simplify by freeing user part of addres pace in one page increments. This
undoes commit ffe444 and 052e18, which skipped page directories, but was
tailored to two-level page table. Undoing doesn't seem to affect boottime for
xv6 visibly.
-rw-r--r-- | mmu.h | 4 | ||||
-rw-r--r-- | vm.c | 4 |
2 files changed, 2 insertions, 6 deletions
@@ -95,7 +95,6 @@ struct segdesc { #define NPDENTRIES 512 // # directory entries per page directory #define PGSIZE 4096 // bytes mapped by a page #define PGSHIFT 12 // offset of PTX in a linear address -#define PDXSHIFT 21 // offset of PDX in a linear address #define PXMASK 0x1FF #define PXSHIFT(n) (PGSHIFT+(9*(n))) @@ -103,9 +102,6 @@ struct segdesc { #define PX(n, va) ((((uint64) (va)) >> PXSHIFT(n)) & PXMASK) #define L_PML4 3 -// construct virtual address from indexes and offset -#define PGADDR(d, t, o) ((uint64)((d) << PDXSHIFT | (t) << PGSHIFT | (o))) - #define PGROUNDUP(sz) (((sz)+PGSIZE-1) & ~(PGSIZE-1)) #define PGROUNDDOWN(a) (((a)) & ~(PGSIZE-1)) @@ -305,7 +305,7 @@ deallocuvm(pde_t *pml4, uint64 oldsz, uint64 newsz) for(; a < oldsz; a += PGSIZE){ pte = walkpgdir(pml4, (char*)a, 0); if(!pte) - a = PGADDR(PDX(a) + 1, 0, 0) - PGSIZE; + continue; else if((*pte & PTE_P) != 0){ pa = PTE_ADDR(*pte); if(pa == 0) @@ -327,7 +327,7 @@ freelevel(pde_t *pgtab, int level) { if (level > 0) { for(i = 0; i < NPDENTRIES; i++) { if(pgtab[i] & PTE_P){ - pd = (pdpe_t*)P2V(PTE_ADDR(pgtab[i])); + pd = (pde_t*)P2V(PTE_ADDR(pgtab[i])); freelevel(pd, level-1); } } |