sanchayanmaity/xv6-cs450
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Because limit gives the address of the last addressable

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byte in the segment, the limit argument to SEG16 and SEG
needs to have 1 subtracted from it.
This commit is contained in:
rsc 2007-08-14 04:55:45 +00:00
parent 64659055bd
commit 2ef3a64bb4
1 changed files with 4 additions and 4 deletions
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8
proc.c
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@ -38,13 +38,13 @@ setupsegs(struct proc *p)
}
c->gdt[0] = SEG_NULL;
c->gdt[SEG_KCODE] = SEG(STA_X|STA_R, 0, 0x100000 + 64*1024, 0);
c->gdt[SEG_KCODE] = SEG(STA_X|STA_R, 0, 0x100000 + 64*1024-1, 0);
c->gdt[SEG_KDATA] = SEG(STA_W, 0, 0xffffffff, 0);
c->gdt[SEG_TSS] = SEG16(STS_T32A, (uint) &c->ts, sizeof(c->ts), 0);
c->gdt[SEG_TSS] = SEG16(STS_T32A, (uint)&c->ts, sizeof(c->ts)-1, 0);
c->gdt[SEG_TSS].s = 0;
if(p){
c->gdt[SEG_UCODE] = SEG(STA_X|STA_R, (uint)p->mem, p->sz, DPL_USER);
c->gdt[SEG_UDATA] = SEG(STA_W, (uint)p->mem, p->sz, DPL_USER);
c->gdt[SEG_UCODE] = SEG(STA_X|STA_R, (uint)p->mem, p->sz-1, DPL_USER);
c->gdt[SEG_UDATA] = SEG(STA_W, (uint)p->mem, p->sz-1, DPL_USER);
} else {
c->gdt[SEG_UCODE] = SEG_NULL;
c->gdt[SEG_UDATA] = SEG_NULL;