ref: dac5756766be04f303bceaea49eba4f6ffc4e25e
dir: /sys/src/9/pc/segdesc.c/
#include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "../port/error.h" /* * flags: * P = present * A = accessed (for code/data) * E = expand down (for data) * W = writable (for data) * R = readable (for code) * C = conforming (for code) * G = limit granularity in pages (for code/data) * D = 32 bit operand size (for code) * B = 32 bit stack pointer (for data) * Y = busy (for tss and tss16) * U = available for use by system software */ static struct { char *name; char *flags; } descrtypes[] = { "data", "--------AWE01--P----U.BG--------", "code", "--------ARC11--P----U.DG--------", "tss16", "--------1Y000--P----U..G--------", "ldt", "--------01000--P----U..G--------", "callg16", "--------00100--P----U..G--------", "taskg", "--------10100--P----U..G--------", "intrg16", "--------01100--P----U..G--------", "trapg16", "--------11100--P----U..G--------", "tss", "--------1Y010--P----U..G--------", "callg", "--------00110--P----U..G--------", "intrg", "--------01110--P----U..G--------", "trapg", "--------11110--P----U..G--------", }; /* * format: * idx[4] type[8] flags[8] dpl[1] base[8] limit[5]\n */ enum { RECLEN = 4+1 + 8+1 + 8+1 + 1+1 + 8+1 + 5+1, }; static long descwrite(Proc *proc, int local, void *v, long n, vlong) { int i, j, t; char buf[RECLEN+1]; char c, *p, *s, *e, *f[6]; Segdesc d; int dpl; ulong base; ulong limit; s = (char*)v; e = s + n; if(waserror()){ if(proc == up) flushmmu(); nexterror(); } while(s < e){ for(p = s; p < e && *p != '\n'; p++); ; if((p - s) > RECLEN) error(Ebadarg); memmove(buf, s, p - s); buf[p-s] = 0; s = p+1; if(getfields(buf, f, nelem(f), 1, " ") != nelem(f)) error(Ebadarg); i = strtoul(f[0], nil, 16); for(t=0; t<nelem(descrtypes); t++) if(strcmp(descrtypes[t].name, f[1]) == 0) break; if(t == nelem(descrtypes)) error(Ebadarg); dpl = atoi(f[3]); base = strtoul(f[4], nil, 16); limit = strtoul(f[5], nil, 16); d.d0 = ((base & 0xFFFF)<<16) | (limit & 0xFFFF); d.d1 = (base & 0xFF000000) | (limit & 0xF0000) | ((dpl & 3)<<13) | ((base & 0xFF0000)>>16); for(j=0; c = descrtypes[t].flags[j]; j++){ switch(c){ default: if(strchr(f[2], c) == nil){ case '0': case '.': d.d1 &= ~(1<<j); break; } else { case '1': d.d1 |= (1<<j); break; } case '-': continue; } } /* dont allow system segments */ if((d.d1 & SEGP) && ((dpl != 3) || !(d.d1 & (1<<12)))) error(Eperm); if(local){ Segdesc *new, *old; int c; if(i < 0 || i >= 8192) error(Ebadarg); if(i >= (c = ((old = proc->ldt) ? proc->nldt : 0))){ if((new = malloc(sizeof(Segdesc) * (i+1))) == nil) error(Enomem); if(c > 0) memmove(new, old, sizeof(Segdesc) * c); memset(new + c, 0, sizeof(Segdesc) * ((i+1) - c)); proc->ldt = new; proc->nldt = i+1; free(old); } proc->ldt[i] = d; } else { if(i < PROCSEG0 || i >= PROCSEG0 + NPROCSEG) error(Ebadarg); proc->gdt[i - PROCSEG0] = d; } } poperror(); if(proc == up) flushmmu(); return n; } static long descread(Proc *proc, int local, void *v, long n, vlong o) { int i, j, k, t; char *s; int dpl; ulong base; ulong limit; s = v; for(i = 0;;i++){ Segdesc d; if(local){ if(proc->ldt == nil || i >= proc->nldt) break; d = proc->ldt[i]; } else { if(i < PROCSEG0) i = PROCSEG0; if(i >= PROCSEG0 + NPROCSEG) break; d = proc->gdt[i - PROCSEG0]; } if(o >= RECLEN){ o -= RECLEN; continue; } if(s + RECLEN+1 >= (char*)v + n) break; for(t=0; t<nelem(descrtypes); t++){ for(j=0; descrtypes[t].flags[j]; j++){ if(descrtypes[t].flags[j]=='0' && (d.d1 & (1<<j)) != 0) break; if(descrtypes[t].flags[j]=='1' && (d.d1 & (1<<j)) == 0) break; } if(descrtypes[t].flags[j] == 0) break; } if(t == nelem(descrtypes)) t = 0; s += sprint(s, "%.4lux ", (ulong)i); s += sprint(s, "%-8s ", descrtypes[t].name); k = 0; for(j=0; descrtypes[t].flags[j]; j++){ switch(descrtypes[t].flags[j]){ case '-': case '.': case '0': case '1': continue; } if(d.d1 & (1 << j)) s[k++] = descrtypes[t].flags[j]; } if(k == 0) s[k++] = '-'; while(k < 9) s[k++] = ' '; s += k; dpl = (d.d1 & 0x6000)>>13; base = ((d.d0 & 0xFFFF0000)>>16) | ((d.d1 & 0xFF)<<16) | (d.d1 & 0xFF000000); limit = (d.d1 & 0xF0000) | (d.d0 & 0xFFFF); s += sprint(s, "%.1d ", dpl); s += sprint(s, "%.8lux ", base); s += sprint(s, "%.5lux\n", limit); } return s-(char*)v; } static long gdtread(Chan*, void *v, long n, vlong o) { return descread(up, 0, v, n, o); } static long gdtwrite(Chan*, void *v, long n, vlong o) { return descwrite(up, 0, v, n, o); } static long ldtread(Chan*, void *v, long n, vlong o) { return descread(up, 1, v, n, o); } static long ldtwrite(Chan*, void *v, long n, vlong o) { return descwrite(up, 1, v, n, o); } void segdesclink(void) { addarchfile("gdt", 0666, gdtread, gdtwrite); addarchfile("ldt", 0666, ldtread, ldtwrite); }